Veterinary Advice Online: Male Dog Neutering.

Male dog neutering, otherwise known as sterilisation, "fixing", desexing, castration (castrating) or by its correct veterinary name: orchiectomy (also termed gonadectomy), is the surgical removal of a male dog's testicles for the purposes of canine population control, medical health benefit, genetic-disease control and behavioral modification. Considered to be a basic component of responsible pet ownership, the neutering of male dogs is a common surgical procedure that is performed by most veterinary clinics all over the world. This page contains everything you, the pet owner, need to know about male dog neutering. Neutering topics are covered in the following order:

1. What is neutering?

2. Neutering pros and cons - the reasons for and against neutering.
2a. The benefits of neutering (the pros of neutering) - why we neuter dogs.
2b. The disadvantages of desexing (the cons of desexing) - why people choose not to neuter dogs.

3. Information about neutering age: when to neuter a dog.
3a. Current desexing age recommendations.
3b. Neutering puppies - information about the early spay and neuter of young dogs (puppy desexing).

4. Neutering procedure (desexing surgery) - a step by step pictorial guide to neutering surgery.

5. Neutering after-care - all you need to know about caring for your dog after neutering surgery. Includes information on feeding, bathing, exercising, wound care, pain relief, sutures-out time and stopping dogs from licking surgical wounds.

6. Possible surgical and post-surgical complications of neutering.
6a. Pain after surgery (e.g. dog walking stiffly, not wanting to sit down and so on).
6b. Swollen, bruised, blood-filled scrotum after surgery.
6c. Wound break-down - break down of the skin stitches.
6d. Wound infection.
6e. Suture-site reactions - swollen, red skin around sutures or stitches.
6f. Penis and/or urethra laceration.
6g. Excessive wound hemorrhage (excessive bleeding during or after surgery).
6h. Failure to ligate (tie off) the testicular blood vessels adequately.
6i. Post-operative renal failure (kidney failure).
6j. Anaesthetic death.

7. Late complications of neutering.
7a. Weight gain.
7b. Preputial scalding and infection - a potential complication of early underage desexing.
7c. The neutering didn't deliver the change (improvement) in male behavior that you thought it would (i.e. behavioral problems such as aggression, dominance, marking territory and roaming have persisted despite desexing).

8. Frequently asked questions (FAQs) and myths about neutering:
8a. Myth 1 - All desexed dogs gain weight (get fat).
8b. Myth 2 - Desexed males lose their drive to herd and hunt and guard.
8c. Myth 3 - Without his testicles, a male dog won't feel like himself (i.e. he "won't be a man").
8d. Myth 4 - Male dogs need to have sex before being desexed.
8e. Myth 5 - Male dogs should be allowed to father (sire) a litter before desexing.
8f. Myth 6 - Vets just advise neutering for the money not for my dog's health.
8g. FAQ 1 - Why won't my veterinarian clean my dog's teeth at the same time as desexing him?
8h. FAQ 2 - Why shouldn't my vet vaccinate my dog whilst he is under anaesthetic?
8i. FAQ 3 - Is desexing safe? It's just a routine procedure isn't it?
8j. FAQ 4 - My vet offered to perform a pre-anaesthetic blood screening test - is this necessary?
8k. FAQ 5 - When is desexing surgery not safe to do?

9. The cost (price) of neutering:
9a. The typical cost of neutering a dog at a veterinary clinic.
9b. Where and how to source low cost and discount neutering.
9c. Free neutering.

10. Alternatives to neutering your male dog:
10a. Canine birth control method 1 - separate the dog from the bitch and prevent him from roaming.
10b. Canine birth control method 2 - spay your bitch.
10c. Canine birth control method 3 - "the pill" and female oestrous (heat) suppression.
10d. Canine birth control method 4 - the "male pill" - fertility suppressing implants for male dogs.
10e. Canine birth control method 5 - canine vasectomy.
10f. Canine birth control method 6 - chemical castration - injecting sclerosing agents into testes and/or epididymus.
10g. Anti-testosterone agents (e.g. Tardak, MPA-50, Ovarid, Suprelorin) to reduce testosterone-related medical and behavioural problems.


WARNING - IN THE INTERESTS OF PROVIDING YOU WITH COMPLETE AND DETAILED INFORMATION, THIS SITE DOES CONTAIN MEDICAL AND SURGICAL IMAGES THAT MAY DISTURB SOME READERS.







1. What is neutering?

Neutering is the surgical removal of a male dog's testicles. During the procedure, each of the dog's testes and testicular epididymi are removed along with sections of the dog's testicular blood vessels and spermatic ducts (vas deferens or ductus deferens). The remainder of the male dog's reproductive tract structures, including: the prostate, urethra, penis, bulbis glandis and much of the dog's testicular blood vessels and spermatic ducts are left intact. Basically, the parts of the male reproductive tract that get removed are those which are responsible for sperm production, sperm maturation and the secretion of testosterone (the major male hormone). Removal of these structures plays a big role in canine population control (without sperm, the dog can not father young); genetic disease control (male dogs with genetic disorders can not pass on their disease conditions to any young if they can not breed); prevention and/or treatment of various medical disorders (e.g. castration prevents and/or treats a number of testicular diseases and testosterone-enhanced medical conditions) and male dog behavioural modification (testosterone is responsible for many male-dog behavioural traits that some owners find problematic - e.g. roaming, aggression, inter-male aggression, dominance, leg cocking - and castration, by removing the source of testosterone, may help to resolve these issues).







2. Neutering pros and cons - the reasons for and against neutering.

2a. The benefits of neutering (the pros of neutering) - why we neuter dogs.

There are many reasons why veterinarians and pet advocacy groups recommend the neutering of entire male dogs. Many of these reasons are listed below, however the list is by no means exhaustive.

1. The prevention of unwanted litters:
Pet overpopulation and the dumping of unwanted litters of puppies (and kittens) is an all-too-common side effect of irresponsible pet ownership. Every year, thousands of unwanted puppies and older dogs are dumped on the street (where they ultimately end up dying from neglect or finding their way into pounds and shelters) or handed in to shelters. Many of these animals do not ever get adopted from the pounds and shelters that take them in and need to be euthanased. This sad waste of healthy life can be reduced by not letting pet dogs breed indiscriminately and one way of preventing any accidental, unwanted breeding from occurring is through the routine neutering of all non-stud (non-breeder) male dogs (and female dogs too, but this is another page).

Author's note: The deliberate breeding of family pets should never be considered an easy way to make a quick buck. A lot of cost and effort and expertise goes into producing a quality litter for profitable sale. And that's only if nothing goes wrong! If your bitch needs a caesarean section at one in the morning or develops a severe infection after whelping (e.g. pyometron, mastitis), then all of your much planned profits will rapidly turn into financial losses (the vet fees for these kinds of treatments are high). On top of that, if you fail to do your homework and breed poor quality pups or poorly socialised pups that won't sell, then you've just condemned some of those animals to a miserable life of being dumped in shelters or on the streets.

2. The reduction of stray and feral animal populations:
By having companion dogs neutered, they are unable to go out and mate with feral or stray bitches and get them pregnant. This results in fewer litters of stray and feral dogs being born which, in return, benefits not just those unwanted puppies (who lead a tough neglected life), but also society in general. Feral and stray dog populations pose a significant risk of predation to native wildlife, domestic pets and livestock; they carry diseases that may affect humans and their pets (e.g. rabies); they may attack people and they put a huge financial and emotional burden on pounds, shelters and animal rescue groups.

3. To reduce the spread of inferior genetic traits, genetic diseases and congenital deformities:
Dog breeding is not merely the production of puppies, it is the transferral of genes and genetic traits from one generation to the next in a breed population. Pet owners and breeders should desex male dogs that have conformational, colouring and temperamental traits, which are unfavourable or faulty to the breed as a whole to reduce the spread of these defects further down the generations. Male dogs with heritable genetic diseases and congenital defects/deformities should also be desexed to reduce the spread of these genetic diseases to their offspring.

Some examples of proven-heritable or suspect-heritable diseases that we select against when choosing to neuter male dogs include: hip dysplasia, elbow dysplasia, cryptorchidism, hemeralopia, trapped neutrophil syndrome, collie eye anomaly and congenital cataracts. There are hundreds of others.

4. The prevention or reduction of testicular (and epididymal) diseases:
It is difficult to contract a testicular disease if you have no testicles. Early neutering prevents dogs from contracting a range diseases and disorders including: testicular cancer, epididymal cancer, orchitis (testicular inflammation), epididymitis, testicular torsion, testicular abscessation and testicular trauma.

5. The prevention or reduction of testosterone-induced diseases:
Dogs can suffer from a range of diseases and medical conditions that are directly associated with high blood testosterone levels. These disease conditions include: benign prostate hyperplasia (BPH), prostatitis, prostatic abscess, perianal or perineal adenomas (small cancers that occur around the anus of male dogs), perineal hernias and certain castration-responsive skin disorders (dermatoses). Desexing removes the main source of testosterone in the animal's body (the testes), which not only prevents the onset of these diseases but can even help to control or cure these diseases if they are already present.

6. The prevention or reduction of testosterone-mediated behavioural problems:
The testicles are responsible for producing testosterone: the hormone that makes male animals look and act like male animals. It is the testicles that make male animals exhibit the kinds of "male" testosterone-dependent behaviors normally attributed to an entire animal. Entire dogs are likely to be more aggressive and more dominant and more prone to male-to-male aggression (inter-male aggression) than neutered animals: i.e. they act like bossy entire males. They will tend to exhibit sexualised behaviours including: aroused interest in females of their own species; mounting of females (particularly in-heat, estrus females); mating of females; mounting and humping of inanimate objects (including toys, chair-legs and human legs) and complete erection of the penis when excited. They are more prone to displaying often unwanted masculine territorial behaviours such as the guarding of resources (food, bones, territory, companion people and pets and so on) and the marking of territory with urine and feces (e.g. entire tomcats may exhibit urine spraying in the house; male dogs will cock their legs to urinate on vertical surfaces). Additionally, entire male animals are more likely than neutered animals are to leave their yards and roam the countryside looking for females and trouble. Roaming is a troublesome habit because it puts other animals (wildlife, livestock and other pets) and humans at risk of harm from your animal and it puts the roaming pet at risk from all manner of dangers including: predation by other animals, cruelty by humans, poisoning, envenomation (e.g. snake bite) and motor vehicle strikes. The neutering of entire animals can reduce some of these problematic testosterone-mediated behaviours.


2b. The disadvantages of desexing (the cons of desexing) - why some people choose not to neuter.

There are many reasons why some individuals, breeders and pet groups choose not to advocate the sterilisation of entire male dogs. Many of these reasons have been listed below, however the list is by no means exhaustive.

1. The dog may become overweight or obese:
Studies have shown that neutered animals probably require around 25% fewer calories to maintain a healthy bodyweight than entire male animals do. This is because a neutered animal has a lower metabolic rate than an entire animal does (it therefore needs fewer calories to maintain its bodyweight). Because of this, what tends to happen is that most owners, unaware of this fact, continue to feed their neutered male dogs the same amount of food after the surgery that they did prior to the surgery, with the result that their pets become fat. Consequently, the myth of automatic post-desexing obesity has become perpetuated and, as a result, many owners simply will not consider desexing their dogs because of the fear of them gaining weight and developing weight-related problems (e.g. diabetes).

Author's note: The fact of the matter is that dogs will not become obese simply because they have been desexed. They will only become obese if the post-neutering drop in their metabolic rate is not taken into account and they are fed the same amount of food calories as an entire animal.

Author's note: Those of you who care about your finances might even be able to see the benefits of desexing here. A neutered dog potentially costs less to feed than an entire animal of the same weight and, therefore, neutering your animal may well save you money in the long run.

2. Desexing equates to a loss of breeding potential and valuable genetics:
There is no denying this. If a dog or cat or horse or other animal is the 'last of its line' (i.e. the last pup in a long line of pedigree breeding dogs), a breeder or pet owner's choice to desex that animal and, therefore, not pass on its valuable breed genetics will essentially spell the end for that breeding lineage.

Author's opinion point: of all the reasons given here that argue against the desexing of male dogs, this is probably the only one that has any real merit. Desexing does equate to a loss of breeding potential. In an era where many unscrupulous breeders and pet owners ("backyard breeders" we call them) will breed any low-quality dog regardless of breed traits and temperament to make a quick buck, the good genes for breed soundness, breed traits and good temperament are needed more than ever. Desexing a male dog with good breed characteristics, good temperament and no genetically heritable defects/diseases will count as a loss for that breed's quality in general, particularly if there are a lot of subquality studs saturating the breeding circles.

3. Loss of testosterone as a result of desexing may result in immature development of masculine characteristics and a reduced body musculature:
The testicles are responsible for producing testosterone: the hormone that makes male animals look and act like male animals. It is the testicles that make male animals develop the kinds of masculine, testosterone-dependent body characteristics normally attributed to an entire animal. These include: increased muscle size and development; reduced body fat; mature penis development; mature prepuce development (mature penis sheath development); the ability to extrude the penis from the sheath (prepuce) and the suppression of development of feminine characteristics (mammary gland development, milk production etc.). Desexing, particularly early age desexing, may limit the development of mature masculine features such that they remain immature and juvenile looking and cause the neutered animal to have a reduced muscle mass and strength compared to an entire animal of the same size and breeding.

4. Loss of testosterone as a result of desexing may result in delayed growth plate closure:
Animals that have been desexed early in life (before the age of 12 months) tend to exhibit delayed closure of their growth plates. Growth plates are the cartilage bands located in the ends of the animal's long bones, which are responsible for making the bones grow and elongate during juvenile bone development and formation. As a result of delayed growth plate closure, desexed animals will often be taller and longer in limb than entire male animals. Whether this increase in bone length should be considered a problem or benefit really depends on the individual owner, but some people choose not to desex animals early because of it (i.e. there is a concern that these animals may be more prone to orthopedic injuries).

Author's note - Any concerns about the effects of delayed growth plate closure, whilst not normally a problem, can be overcome by desexing after the growth plates have closed.

5. Neutering reduces the male animal's drive to herd, hunt, guard and work:
Although this phenomenon has yet to be proven, many farmers, hunters and owners of guarding, sporting and working dogs will refuse to desex them because of the fear that their neutered animals will no longer have any drive to perform the work required of them. This topic is discussed in more detail in section 8b.

Author's note: one could well argue that such a dog might work better if it does not have testosterone-fuelled hormonal urges distracting it from the task at hand.

6. As an elective procedure, desexing costs too much:
The high cost of veterinary services, including desexing, is another reason why some pet owners choose not to get their pets desexed. See section 9 for more about the costs of neutering.







3. Information about neutering age: when to neuter a dog.

The following subsections discuss current desexing age recommendations and how they have been established as well as the pros and cons of early age (8-16 weeks) neutering.

3a. Current desexing age recommendations.

In Australia and throughout much of the world it is currently recommended that male dogs are neutered at around 5-7 months of age and older (as far as the "older" goes, the closer to the 5-7 months of age mark the better - there is less chance of your dog developing a testicular or testosterone-dependant medical condition if he is desexed at a younger age).

The reasoning behind this 5-7 month age specification is one of anaesthetic safety for elective procedures.

When asked by owners why it is that a dog needs to wait until 5-7 months of age to be desexed, most veterinarians will simply say that it is much safer for them to wait until this age before undergoing a general anaesthetic procedure. The theory is that the liver and kidneys of very young animals are much less mature than those of older animals and therefore less capable of tolerating the effects of anaesthetic drugs and less effective at metabolising them and breaking them down and excreting them from the body. Younger animals are therefore expected to have prolonged recovery times and an increased risk of suffering from severe side effects, in particular liver and kidney damage, as a result of general anaesthesia. Consequently, most vets will choose not to anesthetize a young dog until at least 5 months of age for an elective procedure such as neutering.

Whether the 5-7 month age specification for general anaesthesia is valid nowadays (2008 onwards), however, is much less clear and is currently the subject of debate. The reason for the current desexing-age debate is that the 5-7 month age specification was determined ages ago, way back in the days when animal anaesthesia was nowhere near as safe as it is now and relied heavily upon drugs that were more cardiovascularly depressant than modern drugs (e.g. put more strain on the kidneys and liver) and required a fully-functioning, almost-adult liver and kidney to metabolize and excrete them from the body. Because modern animal anaesthetic drugs are so much safer on young animals than the old drugs used to be, there is increasing push to drop the age of desexing in veterinary practices. This puts us onto the topic of early age neutering (see next section - 3b).

Are there any disadvantages to desexing at the normal time of 5-7 months of age?
Just as there are disadvantages of desexing an animal at a very young age (see section 3b), there are also some disadvantages associated with desexing at the normal age of 5-7 months:

• Some people find it inconvenient to wait until 5-7 months of age to desex.
  
• There is a chance that an early-maturing dog may be able to mate and sire unwanted pups before this age.
  
• For people who choose to have their pets microchipped during anaesthesia, there is an inconvenient wait of 5-7 months before this can be done. If it gets lost prior to this age, the unchipped dog may fail to find its way home.
  
• Many of the behavioural issues commonly associated with entire male animals may become manifest before the time of the desexing age recommendations (e.g. cocking the leg to urinate). These behavioural problems may persist even after the animal is sterilized.

3b. Neutering puppies - information about the early spay and neuter of young dogs (puppy desexing).

As modern pet anaesthetics have become a lot safer, with fewer side effects, the debate about the recommended age of canine neutering has been reopened in the veterinary world with some vets now allowing their clients to opt for an early-age spay or neuter, provided they appreciate that there are greater, albeit minimal, anaesthetic risks to the very young pet when compared to the more mature pet. In these situations, cat and dog owners can opt to have their male and female pets desexed as young as 8-9 weeks of age (the vet chooses anaesthetic drugs that are not as cardiovascularly depressant and which do not rely as heavily upon extensive liver and kidney metabolism and excretion).

NOTE - in 1993, the AVMA (American Veterinary Medical Association) advised that it supported the early spay and neuter of young dogs and cats, recommending that puppies and kittens be spayed or neutered as early as 8-16 weeks of age.

The advantages of the early spay and neuter of young dogs:
Certainly, there are some obvious advantages to choosing to desex an animal earlier rather than later. These include the following:

• People do not have to wait 5-7 months to desex their pets. The procedure can be over and done with earlier.
  
• Dogs neutered very early will not attain sexual maturity and will therefore be unable to sire any pups of their own. This role in canine population control is why most shelters choose to neuter early.
  
• It makes it possible for young pups (6-16 weeks old) to be sold by breeders and pet-shops already desexed. This again helps to reduce the incidence of irresponsible breeding - dogs sold already desexed cannot reproduce.
  
• For owners who choose to get their pets microchipped during anaesthesia, there is no inconvenient wait of 5-7 months before this can be done.
  
• Some of the behavioural problems and concerns commonly associated with entire male animals may be prevented altogether if the pup is desexed well before achieving sexual maturity (e.g. cocking the leg to urinate).
  
• From a veterinary anaesthesia and surgery perspective, the duration of surgery and anaesthesia is much shorter for a smaller, younger animal than it is for a fully grown, mature animal. I take about 3-7 minutes to neuter a male pup of about 9 weeks of age compared to about 10-15 minutes for an older animal.
  
• The post-anaesthetic recovery time is quicker and there is less bleeding associated with an early spay or neuter procedure.


• From a veterinary business perspective, the shorter duration of surgery and anaesthesia time is good for business. More early age neuters can be performed in a day than mature dog neuters and less anaesthetic gas is used on each individual, thereby saving the practice money per procedure.
  
• Routine, across-the-board, early spay and neuter by shelters avoids the need for a sterilisation contract to be signed between the shelter and the prospective pet owner. A sterilisation contract is a legal document signed by people who adopt young, non-desexed puppies and kittens, which declares that they will return to the shelter to have that dog or cat desexed when it has reached the recommended sterilisation age of 5-7 months. The problem with these sterilisation contracts is that, very often, people do not obey them (particularly if the animal seems to be "purebred"); they are rarely enforced by law and, consequently, the adopted animal is left undesexed and able to breed and the cycle of pet reproduction and dumped litters continues.

The disadvantages associated with the early spay and neuter of young dogs:
There are also several disadvantages to choosing to desex an animal earlier rather than later. Many of these disadvantages were outlined in the previous section (3a) when the reasons for establishing the 5-7 month desexing age were discussed and include:

• Early age anaesthesia and desexing is never going to be as safe as performing the procedure on an older and more mature dog. Regardless of how safe modern anaesthetics have become, the liver and kidneys of younger animals are considered to be less mature than those of older animals and therefore less capable of tolerating the effects of anaesthetic drugs and less effective at metabolising them and breaking them down and excreting them from the body. Even though it is very uncommon, there will always be the occasional early age animal that suffers from potentially life-threatening side effects, in particular liver and kidney damage, as a result of young age anaesthesia.
  
• There is an increased risk of severe hypothermia (cold body temperatures) and hypoglycemia (low blood sugar) occurring when young animals are anesthetized. This hypothermia predisposition is caused by the young animal's increased body surface area (higher area for heat to be lost), reduced ability to shiver and reduced body fat covering (fat insulates against heat loss). The predisposition towards hypoglycemia is the result of a reduced ability to produce glucose from stores of glycogen and body fat as well as the fact that these stores of fat and glycogen are smaller in the young animal.


• Loss of testosterone production at a very early age, as a result of desexing, may result in extremely immature development of masculine characteristics and a significantly reduced body musculature.
  
• Early neutering may result in retained juvenile behaviours inappropriate to the animal's age later on.


• Desexing equates to a loss of breeding potential and valuable genetics. Many breeders choose to only desex their dogs after they have had some time to grow (after all, it is not possible to look at a tiny puppy and determine whether or not it will have the right color, conformation and temperament traits to be a breeding and showing dog). This allows the breeder time to determine whether or not the animal in question will be a valuable stud animal or not. Early age neutering prevents breeders from being able to accurately determine which pups will be valuable stud animals (it is too early to tell when they are only puppies).
  
• Pups neutered very early will be completely unable to extrude their penises from their preputial sheaths throughout life. This can potentially result in urinary hygiene problems and an increased risk of preputial urine scalding and prepuce infections throughout life.
  
• Early spaying and neutering will not 100% reduce pet overpopulation and dumping problems when a large proportion of dumped animals are not merely unwanted litters, but purpose-bought, older pets that owners have grown tired of, can't manage, can't train and so on. Those people, having divested themselves of a problem pet, then go and buy a new animal, thereby keeping the breeders of dogs and cats in good business and promoting the ongoing over-breeding of animals.

Author's note: at the time of this writing, I was working as a veterinarian in a high output animal shelter (RSPCA) in Australia. Because shelter policy was not to add to the numbers of litters being born irresponsibly by selling entire animals, all dogs, including puppies, were required to be desexed prior to sale. Consequently, it was not unusual for us to desex male and female puppies and kittens at early ages (anywhere from 9 weeks of age upwards). Hundreds of puppies and kittens passed under the surgeon's knife every year on their way to good homes and I must say that the incidence of post-operative complications that were a direct result of underage neutering was exceedingly low.

Please remember, however, that if you do decide to have your pet neutered at an early age, you do make this choice at your own risk. Current veterinary recommendations do still state that pet cats and dogs should be neutered at 5-7 months of age and that there is a greater risk (albeit minor) of young animals suffering from operative or post-operative complications as a result of general anaesthesia.

4. Neutering procedure (desexing surgery) - a step by step pictorial guide to canine neutering.

As stated in the opening section, neutering is the surgical removal of a male dog's testicles. During the procedure, each of the dog's testes and testicular epididymi are removed along with sections of the dog's testicular blood vessels and spermatic ducts (vas deferens or ductus deferens). And to be quite honest, from a general, non-veterinary pet owner's perspective, this is probably all of the information that you really need to know about the surgical process of desexing a dog.



Desexing basically converts this ...


Image: This is a preoperative picture of a dog scrotum containing two testicles.



... into this ...


Image: This is a photo of the same dog's scrotal sac after the testicles have been removed at surgery.



... by removing both of these.


Image: This is a picture of two canine testicles that have been removed by sterilisation surgery. You can clearly see the testis and epididymus of each testicle: these are the main sites of testosterone production and sperm production and sperm maturation in the male animal.

For those of you readers just dying to know how it is all done, the following section is a step by step guide to the surgical process of desexing a dog. There are numerous surgical desexing techniques available for use by veterinarians, however, I have chosen to demonstrate the very commonly-used "open procedure" of dog castration. Both diagrammatical and photographic images are provided to illustrate the process.

STEP 1: Preparation of the animal prior to entering the vet clinic.
Preparation of an animal for any surgical procedure begins in the home.

Your animal should be fasted (not fed any food) the night before a surgery so that he has no food in his stomach on the day of surgery. This is important because animals that receive a general anaesthetic may vomit if they have a full stomach of food and this could lead to potentially fatal complications. The pet could choke on the vomited food particles or inhale them into its lungs resulting in severe bronchoconstriction (a reaction of the airways towards irritant food particles, which results in them spasming and narrowing down in size such that the animal can not breathe) and even bacterial or chemical pneumonia (severe fluid and infection build-up within the air spaces of the lungs).

The dog (or cat) should be fed a small meal the night before surgery (e.g. 6-8pm at night) and then not fed after this. Water should not be withheld - it is fine for your animal to drink water before admission into the vet clinic.

Any food that the animal fails to consume by bedtime should be taken away to prevent it from snacking throughout the night.

Please note that certain animal species should not be fasted prior to surgery or, if they are fasted, not fasted for very long. For example, rabbits and guinea pigs are not generally fasted prior to surgery because they run the risk of potentially fatal intestinal paralysis (gut immotility) from the combined effects of not eating and receiving anaesthetic drugs. Ferrets have a rapid intestinal transit time (the time taken for food to go from the stomach to the colon) and are generally fasted for only 4 hours prior to surgery.

Young puppies and kittens (8-16 weeks) should not be fasted for more than 8 hours prior to surgery.

If you are going to want to bath your pet, do this before the surgery because you will not be able to bath him for 2 weeks immediately after the surgery (we don't want the stitches to get wet). Your vet will also thank you for giving him a nice clean animal to operate on.


STEP 2: The animal is admitted into the veterinary clinic.
When an animal is admitted into a veterinary clinic for desexing surgery, a number of things will happen:

• 1) You should arrive at the vet clinic with your fasted pet in the morning. Vet clinics usually tell owners what time they should bring their pet in for surgical admission and it is important that you abide by these admission times and not be late. If you are going to be late, do at least ring your vet to let him know. Vet clinics need to plan their day around which pets arrive and do not arrive for surgery in the morning. A pet turning up late throws all of the day's planning out the window. Do remember that your vet has the right to refuse to admit your pet for surgery if you arrive late.
• 2) The animal will be examined by a veterinarian to ensure that he is healthy for surgery. His gum colour will be assessed, his heart and chest listened to and his temperature taken to ensure that he is fine to operate on. Some clinics will even take your pet's blood pressure. This pre-surgical examination is especially important if your pet is old (greater than 7-8 years).
  
• 3) You will be given the option of having a pre-anaesthetic blood panel done. This is a simple blood test that is often performed in-house by your vet to assess your pet's basic liver and kidney function. It may help your vet to detect underlying liver or kidney disease that might make it unsafe for your pet to have an anaesthetic procedure. Better to know that there is a problem before the pet has an anaesthetic than during one! Old dogs in particular should have a pre-anaesthetic blood panel performed (many clinics insist upon it), but cautious owners can elect to have young pets tested too.
  
• 4) The dangers and risks of having a general anaesthetic procedure will be explained to you. Please remember that even though neutering is a "routine" surgery for most vet clinics, animals can still die from surgical and/or anaesthetic complications. Animals can have sudden, fatal allergic reactions to the drugs used by the vet; they can have an underlying disease that no-one is aware of, which makes them unsafe to operate on; they can vomit whilst under anaesthesia and choke and so on. Things happen (very rarely, but they do) and you need to be aware of this before signing an anaesthetic consent form.
  
• 5) You will be given a quote for the surgery.
  
• 6) You will be asked to sign an anaesthetic consent form. As with human medicine, it is becoming more and more common these days for pet owners to sue vets for alleged malpractice. Vets today require clients to sign a consent form before any anaesthetic procedure is performed so that owners can not come back to them and say that they were not informed of the risks of anaesthesia, should there be an adverse event.
  
• 7) Make sure that you provide accurate contact details and leave your mobile phone on so that your vet can get in contact with you during the day! Vets may need to call owners if a complication occurs, if an extra procedure needs to be performed on the pet or if the pet has to stay in overnight.
  
• 8) Your pet will be admitted into surgery and you will be given a time to return and pick it up. It is often best if you ring the veterinary clinic before picking your pet up just in case it can not go home at the time expected (e.g. if surgery ran late).

STEP 3: The animal will receive a sedative premedication drug (premed) and, once sedated, it will be given a general anaesthetic and clipped and scrubbed for surgery.
The animal is normally given a premedication drug before surgery, which is designed to fulfill many purposes. The sedative calms the animal making it slip into anaesthesia more peacefully; the sedative often contains a pain relief drug (analgesic), which reduces pain during and after surgery and the sedative action results in lower amounts of anaesthetic drug being needed to keep the animal asleep. Depending upon the drug cocktail given, other specific effects may also be achieved including: reduction of saliva production and airway secretions (this reduces drooling and the risk that saliva and respiratory secretions may be inhaled into the lungs during surgery); improved blood pressure; airway dilation (making it easier to breathe) and so on.

General anaesthesia is normally achieved by giving the pet an intravenous injection of an anaesthetic drug, which is then followed up with and maintained using an anaesthetic inhalational gas. The animal has a tube inserted down its throat during the surgery to facilitate the administration of the anaesthetic gas.

The skin over the animal's groin, penis sheath (prepuce) and scrotum is shaved and scrubbed with antiseptic solution prior to surgery.


The surgery:
In order for you to properly understand the process of dog neutering surgery, I have to take a second to explain the anatomy of the male dog's reproductive structures (testicles, penis and so on).



Image: This image is a diagram of the reproductive anatomy of an entire male dog. The animal is drawn laying on its back as it would be positioned during a sterilization surgery. On the diagram, I have indicated the following structures: testicles (pink) contained within the animal's scrotal sac; bladder and urethral outflow tract (yellow); kidneys (brown); ureters (mauve); abdominal wall muscles (marked in dark red); vas deferens or ductus deferens (white); testicular blood vessels (red) and other male reproductive structures, such as the prostate and bulbourethral gland (a gland in the dog's penis that swells during copulation), both marked in orange. Notice how the ureter of the kidney loops around the vas deferens (spermatic duct) of the testicle - this occurs during early life when the testicle descends from the abdominal cavity and into the scrotal sac.




Image: This diagram is a close-up view of the image contained above and is designed to highlight certain anatomical structures that are important considerations in this neutering surgery.

The first thing to notice is that each testicle is contained within a pouch of skin located just behind (caudal to) and slightly lateral to (alongside) the animal's penis. This pouch of skin is called the scrotum or scrotal sac. This is where the testicles will be taken from.

The second thing to notice is that the spermatic ducts (vas deferens) and blood vessels supplying each of the testicles arise from within the animal's abdominal cavity. These vessels exit the animal's abdominal cavity in the region of the animal's groin, via a natural hole in each side (right and left) of the abdominal wall called the inguinal canal or inguinal ring (marked in purple). After exiting the abdominal cavity via the inguinal canal, these ducts and vessels run deep within the fat situated alongside the animal's penis and into the scrotum, where they unite with the sperm ducts and blood vessels within the animal's testicles.

The third thing to remember is that some of the thick connective tissue lining the animal's abdominal cavity (the peritoneal lining - marked in green) actually comes out through the inguinal canal when the testicle descends during infancy and encases the testicle within the scrotal sac. The section of peritoneal lining containing the testicle within the scrotal sac and inguinal canal is termed the tunica vaginalis or vaginal tunic. On top of this, some of the abdominal fluid (lubricating fluid that exists in small amounts within the abdomen to let the organs slide over each other and not adhere to each other) and abdominal 'space' that exists within the abdominal cavity also goes with the peritoneal outpouching (tunica vaginalis) and into the scrotal sac and inguinal canal surrounding the testicular structures. This abdominal fluid and 'space' is marked in pale blue. It allows the testicular vessels and testicles to slide a bit within the scrotal sac and tunica vaginalis casing.

The fourth thing you'll notice is that the urethra (outflow tract for urine) and penis of the dog runs underneath the skin in the region of the scrotum. This is important to remember during surgery.


STEP 4: The skin just in front of the scrotal sac is incised.


Images: An incision is made into the skin just ahead of the animal's scrotal sac, on the midline of the animal. Both testicles will be removed through the one incision.

Caution needs to be taken to ensure that the urethra is not accidentally cut into during this incision.


STEP 5: The testicle and tunica vaginalis is elevated through the hole in the skin.


Image: The first testicle is pushed forwards towards the hole in the animal's skin. The fat surrounding the testis and tunica vaginalis is trimmed away and the testis (enclosed within the thick, capsule-like tunica vaginalis) is lifted through the hole in the animal's skin.


STEP 6: The tunica vaginalis is incised and the testicle exposed.


Image: The tunica vaginalis (green) is incised and the testicle itself (testis and epididymus) is exposed. Because the space between the tunica vaginalis and testicle contains small volumes of lubricating fluid (blue) from inside of the abdominal cavity, the testicle does not stick to the tunica vaginalis but instead slips easily out of it.


STEP 7: The testicular blood vessels and sperm ducts are ligated (tied closed).


Image: Sutures are placed around the testicular blood vessels and spermatic cords. They are tied tightly to ensure that the blood vessels supplying the testes are fully occluded (closed off). This will prevent the animal's testicular blood vessels from bleeding once the testicle is cut off. These sutures are absorbable and so do not need removing later on.


STEP 8: The testicle is removed.


The surgeon cuts off the testicle (testis and epididymus) above the level of the sutures and discards it. The first testicle has been removed.

Author's note: Some surgeons like to also tie off the tunica vaginalis itself, instead of leaving it open. There are two main reasons for this. The first is that the tunica vaginalis has some blood supply of its own and oozes blood when you cut it. Although this seldom ever presents a significant, life-threatening bleeding issue, in large dogs this oozing of blood from the cut tunic can be enough to cause the scrotal sac to become swollen up with blood and therefore very painful and bruised after surgery. The second reason for tying off the tunic is that the open tunic does represent a theoretical open channel between the animal's skin/scrotum and abdominal cavity. Leaving the tunic open may potentially increase the risk of suture-line infections extending through into the abdominal cavity. There is also the potential (though it is rare) for abdominal contents to travel down the inguinal canal within the tunica vaginalis and end up under the skin, resulting in an inguinal hernia, which can be life threatening.


STEP 9: Steps 5-8 are repeated for the opposite testicle.


STEP 10: The subcutaneous fat layers and skin are sutured closed (stitched shut).


Image: The skin wound is closed using sutures (stitches). The veterinarian will choose to use either superficial skin sutures (these are visible on the surface of the skin and need to be removed in 10-14 days) or intradermal sutures (these are located deep within the skin layer and do not need removal).


A note on cryptorchidism (undescended testicles):
If your dog has cryptorchidism or retained testicles, a different surgical procedure may be indicated. Please see our excellent cryptorchidism page for more details.

5. Neutering aftercare - what you need to know about caring for your dog after neutering surgery.

When your dog goes home after neutering surgery, there are some basic exercise, feeding, bathing, pain relief and wound care considerations that should be followed to improve your pet's healing, health and comfort levels.

1) Feeding your dog immediately after neutering:
After a dog has been desexed, it is not normally necessary for you to implement any special dietary changes. You can generally go on feeding your pet what it has always eaten. Some owners like to feed their pet on bland diets (e.g. boiled skinless chicken and rice diet or a commercial prescription intestinal diet such as Royal Canin Digestive or Hills i/d) for a few days after surgery in case the surgery and anaesthesia has upset their tummies. This is not normally required, but is perfectly fine to do.

Unless your veterinarian says otherwise, it is normally fine to feed your pet the night after surgery. Offer your pet a smaller meal than normal in case your pet has an upset tummy from surgery and do not be worried if your pet won't eat the night after surgery. It is not uncommon for pets to be sore and sorry after surgery and to refuse to eat that night.

If your pet is a bit sooky and won't eat because of surgery-site pain, feel free to tempt your pet with tasty, strong-smelling foods to get him to eat. Skin-free roast chicken often works well and is not too heavy on the stomach. Avoid fatty foods such as mince, lamb and processed meats (salami, sausages, bacon) because these will cause digestive upsets.

Be aware of your pet's medications and whether they need to be given with food. Many dogs go home on non-steroidal anti-inflammatory drugs (NSAIDs) such as Carprofen (tradenames include: Prolet, Rimadyl, Carprofen tablets); Firocoxib (tradenames include Previcox) and Meloxicam (tradenames include Metacam). These drugs need to be given with food. Do not give these drugs if your pet is refusing to eat.

Most dogs that are neutered are not normally off their food for more than a day. You should contact your vet if your pet does not eat for more than 24 hours after surgery.


2) Exercising your dog after neutering:
It takes 10-14 days for superficial skin sutures to heal after surgery. It is therefore recommended that running-around exercise be avoided or minimised during this period to allow the skin the best chance of staying still and healing. Quiet, on-lead walking is normally fine.


3) Wound care after neutering surgery:
Normally you do not have to do anything special with your pet's surgical desexing wounds (e.g washing and bathing them) after surgery. The most important thing that you do need to do is monitor the wound to ensure that it remains looking healthy and clean.

Check the suture line daily. Look out for any signs of redness, swelling and wound pain (surgical wounds should not normally appear painful or red beyond the first 3-5 days after surgery). Look out for obvious signs of infection (e.g. a yellow or green pussy discharge) or signs that the wound is breaking down (the wound will split and contain cheese-like white or yellow necrotic tissue inside it if it is breaking down). If you see any of these signs, take the pet to your vet for a check up.

If the wound site gets dirty (e.g. covered in mud or faeces), you can clean it with warm salty water, saline or a very dilute betadine solution (betadine solution in water made up to a weak-tea colour concentration) to remove the contamination. The wound and sutures should then be dried thoroughly to stop bacteria from wicking deep into the surgical site. The wound should then be closely monitored over the next few days because wounds soiled in dirt or faeces are at high risk of becoming infected, even if they are bathed.

Do not let your pet lick its wounds! This is a major cause of wound breakdown - the pet licks the wounds making them wet and infected or the pet actually pulls out the sutures, resulting in the wound breaking apart.

At the very first sign of wound licking, go to your vet immediately and get an Elizabethan collar (E collar) for it. The collar will stop the pet tampering with the stitches and hopefully prevent wound break down. If the dog starts licking in the middle of the night and you can not get an E collar, you can cut the circular bottom out of an appropriately-sized, clean plastic flower pot (leave the drainage holes intact); place this over your pet's head and neck like an Elizabethan collar and thread the pet's collar or a stocking through the pot-plant drainage holes to secure it to your pet's neck. Be careful to place it so that your pet can not choke and go and get a proper E collar from your vet in the morning.

Wound licking can also be reduced by putting bitter apple spray, methyl phthalate solution or another commercial bitterant solution onto the pet's suture line. Woundgard is one commercial product that serves this role (there are many other products that serve a similar function).


4) Bathing or washing your dog after neutering:
Because it takes 10-14 days for sutured (stitched) skin wounds to heal and seal closed, it is advised that the animal not be bathed or allowed to go swimming for the first 14 days after surgery. Wetting the sutures before this time may allow bacteria to enter the surgery site and set up an infection which could result in wound breakdown (bacteria are carried deep into the skin by the wicking capillary action of water traveling along the sutures).


5) Suture removal after neutering surgery:
If your dog had superficial, non-absorbable skin sutures placed in its skin to close its desexing wound, these will need to be removed once the incision line has healed. Sutures are normally removed 10-14 days after surgery. They can be removed at home, but ideally they should be removed by a veterinarian (the vet can determine if the wounds have healed up before removing them). Vet clinics do not normally charge a fee for suture removal.


6) Pain relief after neutering:
In my experience, most dogs do not seem to show all that much pain after neutering surgery. Many try to go for walks and "play ball" the very next day! If your pet is in pain, however, there are ways that you can help.

Go to your vet for some analgesic pills. Most vets send their neutering patients home with a few days of pain relief as a matter of course, however, some vet clinics do not. If you haven't been sent home with any pain relief for your pet and your pet shows signs of pain after surgery, you can return to your vet clinic and request pain relief pills. If your pet is very old or it has compromised kidney or liver function, certain pain medications may not be recommended and other pain relief solutions may need to be found.

DO NOT self-medicate your pet with human pain-killers. Some human pain relief drugs are toxic to pets.

Keep your pet confined and quiet. Pets that are allowed to run around after surgery are more likely to traumatize and move their sutures, leading to swelling and pain of the surgical site. Reducing activity means less pain.

Consider placing hot and cold compresses on your pet's surgical site to reduce pain and swelling. Placing a dried-off ice pack wrapped in a tea towel (never put ice directly against the skin) on the pet's surgery site for 10 minutes and then placing a hot water bottle (also wrapped in a tea towel) on the site for another 10 minutes and then replacing the cold pack and so on (i.e. alternating hot and cold packs) can go a ways towards reducing surgery site pain and swelling.
CAUTION - Only do this if you have a very nice tempered dog - remember that pets in pain can bite and you may well upset the animal more by handling his wound, even though you are only trying to help him. Do not push the issue if he gets grumpy.


7) Monitor your pet's general demeanour and well-being after neutering:
Your pet should be back to normal within 1-3 days after surgery. He should be eating, drinking, urinating, defecating and wanting to play and interact just as much as he did prior to the surgery. If your pet is depressed; not eating; not drinking; drinking excessively; not defecating; defecating black, tarry stools; not urinating and/or shows any signs of vomiting a few days after surgery, this is not normal. You need to take your pet to a vet clinic.

6. Possible surgical and post-surgical complications of neutering.

There are some surgical and post surgical complications of desexing a dog that should be considered before you take the step of having your pet neutered. These are outlined below. The most important thing to remember about the complications listed below is that the vast majority of these complications are very rare and the small risk of them occurring should not outweigh the benefits of having your pet neutered. Of those complications that are more common (the common ones are indicated), the vast majority of these are not life-threatening and most can be prevented by good attention to after-care and wound care.

6a. Pain after surgery (common).
It is not uncommon for dogs to show some signs of mild to moderate discomfort and pain immediately after having a desexing surgery. It stands to reason: the vet has just performed a surgical procedure on a very delicate area of the male body.

Dogs that are in discomfort after desexing will normally show signs suggestive of pain in the groin region. The animal may pant a lot; pace the room (not want to settle); adopt a stiff hind leg gait (these animals are reluctant to move their hind legs much when walking) and refuse to sit down in a normal sitting posture. Some dogs will be irritated by the sutures and/or by the fact that the delicate scrotal skin was shaved (and thus abraded a little) and keep licking the region obsessively (this licking needs to be discouraged by placing an Elizabethan Collar on the dog or a bitterant on the wound - see section 5 on aftercare). Some dogs will even go off their food for a few days after desexing because of the discomfort.

If your pet is in pain, you can return to your veterinary clinic for some analgesic (pain killer) pills. Most vets send their neutering patients home with a few days of pain relief as a matter of course, however, some vet clinics do not. If you haven't been sent home with any pain relief for your pet and your pet shows signs of pain after surgery, you can return to your vet clinic and request pain relief pills - these will normally be enough to keep your pet comfortable. If your pet is very old or it has compromised kidney or liver function, certain pain medications may not be recommended and other pain relief solutions may need to be found.

Keep your pet confined and quiet if it is in pain. Pets that are allowed to run around after surgery are more likely to traumatise and move their sutures, leading to swelling and pain of the surgical site. Reducing activity means less pain.

Consider placing hot and cold compresses (nothing that will wet the site however) on your pet's surgical site to reduce pain and swelling. Placing an ice pack wrapped in a tea towel (never put ice directly against the skin) on the pet's surgery site for 10 minutes and then placing a hot water bottle (also wrapped in a tea towel) on the site for another 10 minutes and then replacing the cold pack and so on (i.e. alternating hot and cold packs) can go a ways towards reducing surgery site pain. Do this for around 30-45 minutes.
WARNING - Only do this if you have a very nice tempered dog - remember that pets in pain can bite and you may well upset the animal more by handling his wound, even though you are only trying to help him.

If the scrotal skin appears very abraded and red to you (either from clipper rash during pre-surgical shaving of fur or due to your pet's licking), you should speak to your vet about it. He may prescribe some cream containing a steroidal anti-inflammatory drug, an antibiotic compound and a local anaesthetic (e.g. tradenames include Ilium Neocort Cream, Neotopic Cream) to apply to the abraded regions to soothe them. Do not apply the cream directly to the surgical wound.

If your pet's discomfort lasts more than about 1-3 days after surgery, you should seek advice from your vet. Most pets don't show signs of surgical discomfort beyond about 3 days and pain persisting beyond this point may be a sign of wound infection, suture-line reaction or some other issue.


6b. Swollen, bruised, blood-filled scrotum after desexing surgery (common).
It is not uncommon for dogs to go home from sterilisation surgery with a very swollen, bruised-looking, blood-filled scrotum.

The condition is more commonly seen in large breed dogs that have been desexed and in males that have been neutered as adults later in life (basically, these animals have larger blood vessels in their scrotal pouches and vaginal tunics, which are more prone to heavy bleeding when incised). From a clinical viewpoint, I have most commonly encountered the condition when the same large breed or adult dogs are neutered and their tunica vaginalis (see section 4, STEP 8, on dog desexing techniques) is not ligated (tied off).
Author's note - I do tie off the incised tunica vaginalis once the testicle has been removed and have to say that I have not personally had a lot of dogs coming back with giant, blood-filled scrotal sacs.

From a post-operative perspective, bleeding into and swelling of the scrotal sac may also occur if a pet is allowed to run around too much (excessive exercise and rough-and-tumble) or lick its surgery site excessively in the hours to days after surgery.

Rarely, a blood filled scrotal sac may be an indication that the animal in question has a bleeding disorder, which needs to be worked up. It is not uncommon for vets to diagnose a medical blood clotting condition such as vwD (von Willebrand's Disease) in a Dobermann Pinscher because its surgical site will not stop bleeding. Similarly, other severe bleeding disorders like rodenticide poisoning (rat bait poisoning), platelet deficiency, hemophilia and so on may occasionally be found by accident during surgery because the animal won't stop bleeding during surgery or the scrotal sac fills with blood afterwards.

When hemorrhage into the scrotal sac occurs, the signs are normally pretty evident. The animal will develop a swollen, enlarged scrotal sac, which may appear very red and bruised-looking in appearance. Some owners even ring their vet accusing him or her of not desexing their dog because the large, blood-swollen scrotum sac looks the same size as it did when it contained testes. Animals with swollen testicle sacs will often exhibit signs of pain: they may pant a lot; pace the room (not want to settle); walk stiffly with their hind legs and refuse to sit down in a normal sitting posture. Some will lick the swollen region obsessively, which only increases the scrotal trauma and swelling.

Generally, blood-filled, swollen scrotal sacs will resolve and shrink on their own as the blood is reabsorbed back into the body. They do not normally require any specific treatment. You can manage the animal's discomfort by giving it canine pain killers, restricting exercise, preventing licking and pacing hot and cold compresses on the scrotum. In severe cases, your vet may insert a needle into the swollen sac to remove some of the blood and relieve some of the pressure and pain, however, this is seldom necessary and does run the risk of introducing bacteria into a sterile site and setting up an abscess.


6c. Wound break-down - break down of the sutures or stitches (moderately common).
It is possible for the neutering incision site to break down days to weeks after desexing, leaving an open, rotten-looking, fleshy hole in the base of the penis sheath. Wound break-down most commonly occurs because of poor home care. It tends to occur because the pet was permitted to lick the sutureline and/or pull the sutures out or because the animal was permitted to run around a lot (exercised). In some cases, the wound breaks down because of bacterial infection (wounds can not heal if they infected) and, again, this is often the result of poor home care, not poor surgical technique. Infection tends to occur if the sutures are allowed to get wet (the animal is bathed, allowed to go swimming or allowed to lick the wound excessively) or if the sutures are allowed to become soiled by faeces, urine or dirt.

Very occasionally, wound break-down can be a result of poor surgical technique (the sutures were not placed correctly or the wrong sutures were used); performing surgery on infected or diseased skin (animals should not be operated on if they have allergic, rashy or highly-infected skin) or removing the sutures too early (before the skin has had time to heal). Some cases of wound break-down may even be the end result of suture-site inflammatory reactions (see section 6e).

Very rarely, wound breakdown may also be a sign that the animal in question has some form of healing disorder. Such disorders are uncommon, but do exist. For example, animals with Cushing's Disease (Hyperadrenocorticism) may be prone to slower-healing wounds and their sutures may need to be left in longer than usual (taking them out too early may result in wound break down). Animals with collagen disorders (e.g. Erhlos Danlos Syndrome in cats), inflammation-response disorders and other disorders affecting tissue healing function may also heal very poorly and be prone to wound break-down.

Wound breakdown is cause to see your vet. If the wound break down is only mild, the animal may only require antibiotic coverage; an Elizabethan collar and better home care to treat the problem. If the wound has completely fallen apart, the vet may need to operate on your pet again to retrim and repair the surgical wound. Healing will then take another full 10-14 days to occur.


6d. Wound infection (moderately common).
The causes of wound infection bear many similarities to those mentioned in section 6c and infection of surgical incision-sites can often lead to secondary wound break-down.

Wound infection occurs when bacterial organisms gain access to the surgical incision site and multiply there in large numbers. The bacterial invasion causes damage to the body tissues in the site of infection (this limits healing of tissues) and triggers a secondary immune system attack on the region, resulting in inflammation and a build up of pus (invading white blood cells produce yellow or green discharges) in the area.

Owners often first notice infection when the neutering incision line becomes sore, swollen, red and hot-to-touch. Sometimes, the pet will tell the owner that it is in pain by licking the infected regions obsessively: infection should certainly be suspected if a pet goes from not being bothered by its wounds to licking and biting at them excessively. Within hours to days of this redness and inflammation being noticed, the owner may witness a yellow to green purulent discharge coming from the suture holes or the incision line itself. If allowed the progress, the wound may split apart completely, resulting in wound breakdown.

Wound infection is very uncommon in most routine desexing surgeries and most commonly occurs because of poor home care. It tends to occur because the pet was allowed to lick the sutureline and, consequently, introduce mouth bacteria into its surgical incision. Infection also tends to occur if the sutures are allowed to get wet (the animal was bathed, allowed to go swimming, allowed to lay in mud) or if the sutures are allowed to become soiled by faeces, urine or dirt. Wound infection may also occur if the vet performs the surgery on an animal with diseased allergic or infected scrotal/groin skin. Bacterial numbers are very high in diseased skin and will easily enter the wound site during surgery, regardless of the amount of prepping done.

Very occasionally, wound infection may be a result of poor surgical technique (e.g. vets not wearing gloves to do surgery); poor skin preparation technique before surgery; a freak bug entering the surgical site (sometimes nasty bacteria like Golden Staph and flesh-eating Streptococcus and Mycobacteria species will find their way into a vet clinic and cause havoc) or the animal having a poor or compromised immune system. Animals with Cushing's disease, Diabetes Mellitus and other immune suppressive disorders may be more prone to wound infections.

Wound infection is definitely cause to see your vet. If the wound infection is only mild, the animal may only require antibiotic coverage; an Elizabethan collar and better home care to treat the problem. If the wound has completely abscessated and is at risk of falling apart, the vet may need to operate on your pet again to retrim and repair and clean the surgical wound. Healing will then take another full 10-14 days to occur.


6e. Suture-site reactions - swollen, red skin around the suture holes (not too common).
Suture site reactions refer to allergic-type skin reactions that some dogs and other animals develop because of the type of suture being used in the surgical incision repair. Basically, suture site reactions are immune-mediated inflammatory reactions that occur when the dog's body decides to reject the foreign bodies (the sutures or stitches) that the vet has just implanted into the skin. True suture site reactions are not that common (modern day sutures are normally very inert and non-reactive) and most so-called suture site reactions are actually wound infections or break-downs caused by all of the factors mentioned in sections 6c and 6d.

When suture site reactions do occur, what tends to happen is that the animal develops signs of inflammation (redness, swelling, heat, maybe even a serous (watery) or pussy discharge) around the suture holes themselves, but not along the surgical incision line in general.
i.e. The reaction is centred around the sutures, but the rest of the surgery site appears fine.

Author's note - early bacterial infections can mimic suture-line reactions if the bacteria have gained access to the body tissues by traveling up the sutures. In these cases, the inflammatory reaction will also be centred around the sutures because this is where the bugs are lurking. Untreated, however, bacterial infections will be expected to spread and become more generalized (i.e. all of the incision line), whereas true suture-line reactions should remain localized and focussed upon the stitches.

Usually what happens with suture site reactions is that the wound incision itself heals up fine because the reaction is centred around the sutures only. Once the sutures are removed (usually after the surgical site has healed), the problem usually resolves on its own. If the condition is severe and the wound healing itself is becoming secondarily compromised by the suture reaction, the vet may elect to remove the skin sutures early to let everything settle down again and heal. This does, however, pose a risk of the main wound breaking down prematurely. In most cases, especially mild cases, the vet will elect to leave in the sutures until the main wound has healed and then remove the sutures to let the suture reaction resolve.

To prevent the problem in the future, a different type of suture material should be selected.


6f. Penis and/or urethra laceration (very rare).
In the diagram image opposite, you can see that the penis (pale pink) and urethra (urine outflow tract - indicated in pale yellow) run deep under the skin, just beneath the site where the first neutering skin incision is made. It is, therefore, theoretically possible (very rare) for a careless or inexperienced surgeon to slice into the animal's penis and/or urethra if he or she cuts too deeply.

If this occurred, a very severe, costly and potentially life-threatening situation would result.

If the penis was cut, the animal would suffer from extreme penile bruising and hemorrhage (the penis is extremely vascular with massive blood chambers and vessels inside of its fleshy wall). Bleeding could be so severe that the animal might require a blood transfusion and intravenous fluid support to save it. It is also possible that the animal could potentially lose the end of its penis as a result of loss of blood supply to the end of the penis and tissue death. Reconstructive surgery would then be required to remove the necrotic (dead) penis and refashion it so that the animal was able to pass urine.

Rupture of the urethra would result in all of the severe bleeding and other potential complications described above for penis laceration because the penis would have to be cut in order for the urethra to be lacerated (the urethra runs inside of the penis and can not be cut without the penis also being cut). The animal would suffer bleeding into the urethral tract (it would urinate blood-filled urine). If repair was not carried out promptly and correctly, urine would start to leak from the torn urethra into the fat and skin of the surgical site. This urine is very acidic and irritant and leakage of urine under the skin would result in severe tissue swelling, pain and inflammation. It is very likely that much of the fat and tissues exposed to the urine would break down and rot along with the skin suture site itself, resulting in a nasty, open surgical neutering wound through which urine and inflammatory fluids would ooze. Such an animal would be expected to be very unwell (would need 24 hour care) and very painful. Laceration of the urethra would require urgent surgical repair and there is a high risk that the animal might develop urethral strictures (scarring and narrowing of the urine outflow passage) down the track.


6g. Excessive wound hemorrhage - excessive bleeding during or after surgery (rare).
It is very uncommon to have a pet bleed excessively from its incision site following a desexing surgery. They sometimes ooze a bit (an occasional drop here and there) a hour or so after surgery, but they do not normally pour blood.

Excessive bleeding may be a sign that the veterinarian has not performed the surgery properly (e.g. has lacerated the penis or a major blood vessel or not tied off the testicular stump properly), however, in these cases, the vet is usually aware of a mistake having been made at the time of surgery and will have taken steps to repair it prior to waking the dog up. More commonly, excessive bleeding from the surgical site is an indication that the pet has some kind of significant blood clotting disorder including: hemophilia, von Willebrand disease (vWD), rodent poison ingestion or a low platelet number problem (e.g. platelet deficiency, thrombocytopenia, ITP).

If excessive wound bleeding is observed, the animal needs to go back to the vet or (if it is afterhours) to the nearest emergency center for treatment and work-up. This is particularly so if the animal looks at all pale or white in the gums (pale or white gum colour is often a sign of severe blood loss and shock setting in). Animals with severe bleeding may require a blood transfusion and supportive care (perhaps even an exploratory surgery to find a ruptured blood vessel) to save their lives.


6h. Failure to ligate (tie off) testicular vessels adequately (uncommon).
This is the diagram picture presented earlier which shows the reproductive and vascular anatomy of the entire male dog.



What you will notice is that the spermatic ducts (vas deferens) and blood vessels supplying each of the dog's testicles arises deep within the animal's abdominal cavity. These vessels exit the animal's abdominal cavity in the region of the animal's groin, via a natural hole in each side (right and left) of the dog's abdominal wall called the inguinal canal or inguinal ring (marked in purple). After exiting the abdominal cavity via the inguinal canal, these ducts and vessels run deep within the fat situated alongside the animal's penis and into the scrotum, where they unite with the sperm ducts and blood vessels within the animal's testicles.

It is important to understand this anatomy because it has a bearing on what can happen to the animal if the testicular vessels tear off or the vet accidentally fails to ligate the testicular blood vessels properly before cutting them (STEP 8 in section 4 of this page). If this occurs, the cut and bleeding ends of the testicular blood vessels will not remain under the skin and easily accessible. They will, instead, retract and spring back into the abdominal cavity and begin to hemorrhage out there, resulting in the animal developing a belly full of blood. The vet will need to cut quickly into the animal's abdominal cavity to find the bleeding vessel, tie it off and thus save the animal. If the vet fails to do this, the animal could die from excessive testicular artery hemorrhage and blood loss. Even if the vet does find the bleeder in time, animals with severe testicular artery bleeding may require a blood transfusion and further supportive care to save their lives.


6i. Renal failure (uncommon in young, healthy animals).
Although anaesthetic drugs are much less cardiovascularly depressant (depressant on blood pressure) and rough on the kidneys and liver these days, there is still the possibility that an individual animal may develop acute renal failure immediately after or days after any anaesthetic procedure, even such a quick, routine procedure as neutering.

Animals can develop renal failure because their blood pressure dropped below certain critical levels during anaesthesia (e.g. the animal received a drug that suppressed its cardiac contractility and heart-rate, resulting in reduced blood pressures). Kidneys require a certain pressure of blood to go through them in order for them to receive enough nutrients and oxygen to stay alive and functional (they are sensitive to low blood pressures and become damaged easily). Animals can also develop renal failure if they experienced a severe surgical complication that caused their blood pressures to fall critically during aneasthesia (e.g the animal experienced severe bleeding during the anaesthetic - see 6f-6g).

Kidneys require a minimum systolic blood pressure of 90mmHg and a mean arterial blood pressure over 60mmHg to survive. Blood pressures below these levels are very dangerous.

Animals may develop renal failure because they received an anaesthetic or pain-killer drug (or both) during the surgical procedure that had toxic side effects on the kidneys. For example, NSAIDs (non-steroidal anti-inflammatory drugs) used for pain relief act by inhibiting the formation of prostaglandin, a common chemical initiator of pain and inflammation (inhibiting prostaglandin is how these drugs reduce pain). Body prostaglandins, however, also have an additional role in protecting the kidneys from the damaging effects of low blood pressure (in times of low blood pressure the vessels leading into the kidneys release prostaglandins, which causes these vessels to dilate and the kidneys to, therefore, receive more blood and oxygen). NSAIDs inhibit the protective action of prostaglandin in the kidneys, resulting in a kidney that is more prone to becoming damaged if blood pressures fall (as they often do during surgery).

Additionally, because the kidneys are designed to filter waste and toxins from the body, a lot of commonly-used anaesthetic and pain relief drugs require these organs in order to be cleared from the body. Kidneys, particularly kidneys already compromised by age, low surgical blood pressures or pre-existing disease, may not be able to tolerate these drugs moving through them and may, as a result, become injured and fail to function.

Renal failure after surgery is more common when aged animals (>8 years) are operated on. These animals are more likely to already have some degree of renal compromise and the compounding effects of low blood pressures during anaesthesia as well as renal-toxic drugs (esp. non-steroidals), can be enough to push their kidneys over the edge. It is for this reason: to detect mild, sub-clinical renal disease that might be exacerbated by surgery, that most vets insist upon pre-anaesthetic blood panels being performed prior to performing surgery on older animals.

Young animals, however, are not immune from suffering the effects of acute renal failure after surgery. Certain breeds: e.g. Staffordshire Bull terriers (Staffies), English Bull Terriers, Shar Peis, Beagles, Basenjis, Cairn Terriers, Tibetan Spaniels, Dobermanns, Elkhounds, Samoyeds and many others are prone to various congenital renal defects. Affected animals are more likely to already have some degree of renal compromise by the time of neutering and the compounding effects of low blood pressures during anaesthesia as well as renal toxic drugs (esp. non-steroidals), can be enough to push their kidneys over the edge, even though they are only young animals (and thus, presumably healthy). It is for this reason: to detect mild, sub-clinical, congenital renal disease that might be exacerbated by surgery, that many vets offer pre-anaesthetic blood panels prior to performing surgery on young animals. It is often a box that can be ticked on the anaesthetic permission form.

Animals that develop acute renal failure after surgery will often become very sick over about 24-72 hours. They will drink excessively or not at all, they will go off their food, they will often vomit (the vomit may contain blood), they will become very depressed and listless to the point of being non-responsive, they will be dehydrated, they will stop urinating and they may start to pass black, tar-colored faeces or diarrhea.

Animals presenting with these signs must see a vet. They will require aggressive and intensive (and expensive) therapies to save their lives. Many animals with severe, acute renal failure will not recover.

The risk of post-operative renal failure can be reduced by letting the vet perform a pre-anaesthetic blood profile on your pet, young or old, prior to surgery. This way, early renal disease may be picked up. Vets can reduce the risks of pets developing renal failure by performing swift surgeries; monitoring blood pressures during surgery and by not giving the animal non-steroidal drugs prior to surgery, only afterwards as the pet is recovering.


6j. Anaesthetic death (rare but does occur).
Very rarely, but often enough that most vets will have encountered a few during their careers, a young "healthy" animal booked in for a routine desexing procedure will inexplicably die. This is, needless to say, very distressing for the owner and for the veterinarian (having had one inexplicable death myself, I do vouch for this) and people will demand answers. The fact of the matter is that, while in some cases we can determine the cause of anaesthetic death (e.g. the animal bled to death because it had eaten rat poison and no-one knew about it; the animal developed an acute, fatal anaphylactic reaction to an anaesthetic drug; the animal was not monitored properly during or after anaesthesia and died; the animal vomited on recovery, inhaled its vomit and died and so on), in a good many more cases the reason for death can not be determined. The animal simply died and we have no idea why. We presume that these animals may have had a pre-existing disease; suffered a sudden, fatal heart arrhythmia (a heart problem never picked up before); suffered a "stroke" or thrown a blood clot into the lungs or heart, but we never actually find the cause of death.

7. Late onset complications of neutering.

7a. Weight gain.
Not really a complication per se, but an often complained about sequelae of desexing surgery.

Studies have shown that neutered animals probably require around 25% fewer calories to maintain a healthy bodyweight than entire male animals of the same weight do. This is because a neutered animal has a lower metabolic rate than an entire animal. Because of this, what tends to happen is that most owners, unaware of this fact, continue to feed their neutered male dogs the same amount of food after the surgery that they did prior to the surgery, with the result that their dogs become fat. Consequently, the myth of automatic obesity has become perpetuated through dog-owning circles and, as a result, many owners simply will not consider desexing their dogs because of the fear of them gaining weight.

Author's note: The fact of the matter is that most dogs will not become obese simply because they have been desexed. They will only become obese if the post-neutering drop in their metabolic rate is not taken into account and they are fed the same amount of food calories as an entire animal. Any weight gain that is experienced can be reversed through not feeding the pet as many calories and treats.


7b. Preputial scalding and infection - a potential complication of early age desexing.
Normal testosterone levels are required in order for young male dogs to be able to break down the adhesions between their penises and prepuces (penis sheaths) and therefore extrude their penises. Animals that are desexed very young (i.e. early age desexing) may not be capable of extending their penises from their penis-sheaths at all. These animals are therefore prone to having urine pool within their prepuces during urination, resulting in urine scalding of the prepuce and secondary preputial infections and discharges. Vigilant hygiene and cleaning of the prepuce is needed in these animals.


7c. Neutering didn't deliver the change (improvement) in problematic male behavior that you thought it would (e.g. behavioural problems such as aggression, dominance, marking territory and roaming have persisted despite desexing surgery).
Again, this is not really a complication per se, more a problem of unfulfilled expectations. A lot of owners only get their animals desexed as a means of trying to correct already established male behaviours that are annoying or unsafe to the owner or pet (e.g. roaming, humping legs and toys, aggression, dominance, marking territory and so on). Such owners often become very disappointed when the desexing surgery fails to correct these behavioural "defects" in their animal.

The trouble with having such expectations is that, while desexing a dog early may often go a good way towards preventing these adverse male behaviours from developing (one of the reasons we advocate early neutering), once these behaviours have become well established in the dog's behavioural repertoire (i.e. become part of its character), they are often difficult to reverse by desexing alone. The reason for this is that, over time, these adverse behaviours go from being purely hormonally-driven behaviours (i.e. treatable by removing the hormone responsible: testosterone) to learned behaviours (which are hard to unlearn). For example: a dog might initially start roaming the countryside because of a hormonally-driven imperative to find females, however, over time, such a dog will soon learn that roaming the countryside is fun and will therefore continue to do so, regardless of whether it has testicles or not. Dominance behaviours are also learned: a young male cat or dog might start pushing the leadership boundaries in your household because of testosterone, however, it will also learn what it get away with by the way you, the owner, react to its pushes for leadership.

Another major reason why desexing surgery often fails to deliver improvements in a pet's behaviour is that the behaviour being 'corrected' by surgery is not a testosterone-induced behaviour! Many "bad" behaviours have nothing to do with testosterone and are a result of poor socialization and bad training and lack of "owner leadership" - thus, removing the testicles won't cure these problems. Aggression is a good example of this. Many owners with aggressive dogs try to cure the aggressive behaviour by desexing their animals. The trouble with this is that the aggressive behaviour may or may not be being caused or contributed to by testosterone and, thus, desexing may not help matters. For example: fear-induced aggression (fear-biting) is caused by past experiences; owner reinforcement (e.g. owners that pet and soothe snappy, fearful dogs in the veterinary clinic are often making the aggression problem worse because the dog is getting rewarded for the nasty behaviour by being petted) and the emotional nature of the dog (this has a bit to do with the dog's genetics, breeding and the temperament of the dog's mother and father), not by testosterone. Desexing will not fix fear-biting. Inter-male aggression (dog-to-dog aggression), however, is contributed to by high testosterone levels and desexing dog-aggressive entire males may go some way towards helping the issue, provided it hasn't been going on too long and the animal hasn't now 'learned' to dislike other dogs.

Author's note: certain testosterone-mediated behaviours like inter-male aggression and hypersexualised behaviours like mounting chair-legs and toys may not resolve with desexing alone because of presumed alternate-sources of testosterone production in the body. Although the testicles are the major source of testosterone in the body, other glands (e.g. the adrenal glands) and even parts of the brain may produce it too, resulting in some testosterone-mediated behaviours persisting despite desexing. The mounting of chair legs and toys is an excellent example of this - it is a hypersexualised behaviour and although many cases are 'cured' by desexing, the problem often persists despite desexing surgery.

Animals whose testosterone-mediated behavioural problems have not resolved after desexing surgery may be able to be treated with the administration of "anti-testosterone" drugs such as MPA (medroxyprogesterone acetate), megestrol acetate (tradenames include Ovarid) and delmadinone (tradenames include Tardak). These progesterone-based drugs oppose the effects of testosterone in the body and effectively neutralise the effects of testosterone coming from alternate sites in the body. They can produce excellent results in the management of hypersexualised behaviours such as chair-leg mounting and toy humping.

8. Frequently asked questions (FAQs) and myths about neutering:

This section outlines some of the commonly held myths and misconceptions about neutering surgery and answers some of your commonly asked questions.

8a. Myth 1 - All desexed dogs gain weight (get fat).
I have previously discussed this topic in other sections of this page: it is a commonly held belief that is, quite simply, not true.

Studies have shown that neutered animals probably require around 25% less calories to maintain a healthy bodyweight than entire male animals of the same bodyweight do. This is because a neutered animal has a lower metabolic rate than an entire animal does. Because of this, what tends to happen is that most owners, unaware of this fact, continue to feed their neutered male dogs the same amount of food calories after the surgery that they did prior to the surgery, with the result that their pets become fat. Consequently, the myth of automatic obesity has become perpetuated through the dog-owning circles and, as a result, many owners simply will not consider desexing their dogs because of the fear of them gaining weight and getting diabetes and so on.

Author's note: The fact of the matter is that dogs will not become obese simply because they have been desexed. They will only become obese if the post-neutering drop in their metabolic rate is not taken into account and they are fed the same amount of food calories as an entire animal. Any weight gain that is experienced can be reversed through not feeding the pet as many calories and treats.


8b. Myth 2 - Desexed males lose their drive to herd, hunt and work.
Although this has yet to be proven, a lot of farmers, hunters and owners of guarding, sporting and working dogs will refuse to desex them out of the fear that their animals will no longer have any drive to do the work required of them. They believe that, without testosterone, the animal won't chase sheep; chase pigs; chase burglars; run races and so on.

As discussed in section 7c, however, many kinds of behaviours, including these herding, driving, guarding and predatory-type behaviours, are not mediated by testosterone at all. They are instead instinctive drives that have been built into the various breeds by genetic selection over centuries and which can be enhanced through the correct training of the animal. Removing the animal's testicles and therefore its testosterone should not really have any bearing on the animal's drive to do these instinctive, non-testosterone-fueled activities.

One way to consider it is to look at the female of the species. Female dogs hunt and herd and drive and guard as well as male dogs do and yet they have no testicles and nowhere near as much testosterone as a male. They have less muscling, strength and stamina than a male animal does, however, and therefore they may not be as physically adept at certain tasks (e.g. bringing down wild pigs) as a male animal. Their drive to fulfill these tasks, however, is just the same, even if their physicality is not.

Author's note: one could well argue that such a dog might work better if it does not have male hormonal urges distracting it from the task at hand.

Author's note: the only time that a male dog's herding, hunting etc. performance might be adversely affected by desexing is if the dog is allowed to get fat after desexing (point 8a). Fat, neutered dogs have less muscle-bulk, strength and stamina than an entire male animal and they may, therefore, not be as physically adept at performing certain tasks (e.g. bringing down wild pigs) as an intact male, however, their drive to fulfill these tasks will be just the same.

8c. Myth 3 - Without his testicles, a male dog won't feel like himself (i.e. he "won't be a man").
It is common these days for humans to attribute human feelings and emotions (e.g. love, sadness, grief and so on) onto their animals and, in doing so, make them out to be more human than they actually are. Pets have an understanding of concepts like being part of the pack and needing to behave to fit in with the pack and receive food. To then extrapolate their needy, cuddly behaviour, as many pet owners do, and claim that these animals act well-behaved and cuddle up to us as a sign of their "love" for us is probably a little far-fetched. Similarly, this testicle myth is another common example of human emotions being incorrectly attributed to our pets. What often happens is that, because the owner (often a large, burly guy with a large testicled dog) believes that he himself would feel incomplete and therefore "not a man" without his own testicles, then so will his dog feel the same way if his testicles are taken.

The fact of the matter is that dogs probably don't even notice that their testicles are missing. They certainly don't seem to be in any way depressed about it (as a human in the same situation would) and tend to go about their doggy business just the same as always once the procedure is performed. If dogs were truly depressed or worried about being neutered and not having their testes, there would be some sort of long term depression, shyness or behavioural change seen in them and this just does not seem to occur.

Despite me telling you all this, if you are still concerned that your animal will not be "a man" after the neutering surgery is done, then consider getting your pet some testicular implants to replace the real testicles removed at surgery. Owners of show animals commonly have them put into their dogs' scrotums so that they seem more complete and pet owners can request these too. They cost a few hundred dollars on top of the normal costs of desexing. The prosthetic testicles are implanted at the time of castration and so, as far as the dog's appearance goes, nothing will have seemed to have changed after the surgery is done. Peace of mind.


8d. Myth 4 - Male dogs need to have sex before being desexed.
No, no and no! Dogs do not need a sexual experience to be in any way complete either emotionally or behaviorally. Similar to the myth above (myth 3), this is a situation where human emotions and desires have been superimposed on top of what is best for the dog. Allowing the pet to have a sexual experience prior to desexing may well lead to some established behavioural problems developing that persist even after neutering has occurred (e.g. roaming, mounting and humping toys and other pets). The "experience" could also result in an unwanted litter of pups being born.

You could argue that, from a human emotional viewpoint, it is cruel to let the dog experience the "pleasures of sex" only to then take it all away from him by desexing. Better for him to never know what it feels like because then he won't know what he's missing.


8e. Myth 5 - Male dogs should be allowed to father (sire) a litter before desexing.
Allowing a litter to be born simply because you feel that the 'dog should be allowed to be a father' is very irresponsible and just results in more and more unwanted, dumped puppies finding their way into pounds and shelters and waste-disposal units.


8f. Myth 6 - Vets just advise neutering for the money and not for my dog's health.
Whilst it is true that desexing, along with vaccinations, worming and flea prevention, is one of the main bread-and-butter activities of the veterinary profession, we do not advocate the procedure just for the money. Face it, if money and not the animal was all that we considered when making these decisions to operate or not, then vets in Australia (can't vouch for the rest of the world) would still be tail-docking and ear-docking pets and we would now be starting to see many veterinary surgeons dabbling in pointless cosmetic surgery to suit an owner's particular aesthetic tastes (as does occur overseas). If money was our only concern, veterinarians would not be now promoting 3-yearly vaccine regimens instead of the previously popular and more lucrative yearly vaccinations.

Surgical procedures are not without risk to the animal (see section 6 on surgical complications) and, therefore, vets do not advocate surgical procedures, including desexing, if there is no benefit for that animal or society as a whole. The benefits must outweigh the risks. Vets advocate the desexing of male and female dogs for all of the population control, genetic disease control and medical and behavioural benefits previously discussed (section 2).

Another thing to consider is that, by advocating the mass desexing of animals, veterinarians are essentially desexing themselves out of business. Fewer puppies around means fewer vaccinations and fewer clients. Veterinarians could also be making a lot more money out of all of the caesarean sections and dystocias (inability to give birth) and mammary cancers and testicular cancers that would be the result if we weren't pushing desexing so aggressively.


8g. FAQ 1 - Why won't my veterinarian clean my dog's teeth at the same time as desexing him?
Veterinarians the world over have a policy of not performing a "dirty" surgery at the same time as a "clean" surgery.

A dirty surgery is a surgery or procedure whereby the tissues involved have a high level of bacterial contamination, such that many bacteria are likely to be released into the animal's bloodstream and surrounding tissues as a direct result of the surgical or medical procedure. Dentistry is a good example of this - when an animal gets its teeth cleaned, millions of bacteria from the teeth and gums are released into the animal's blood stream.

A clean surgery is a surgery or procedure with minimal bacterial contamination risk. Desexing and orthopedic surgeries are common examples of clean surgeries.

The reason why veterinarians will not perform a dirty surgery (such as a dental scale and polish) at the same time as they will a clean surgery (e.g. desexing) is because of the risk that the bacteria from the dirty surgery will travel throughout the animal's bloodstream and lodge in the site of the clean surgery. This could result in infection setting up in the site of the clean surgery, which could be disastrous in situations like orthopedic operations and desexing surgeries, which are supposed to remain as sterile and bacteria-free as possible.


8h. FAQ 2 - Why shouldn't my vet vaccinate my dog while he is under anaesthetic?
In order for vaccines to work effectively, the animal needs to have a fully functional immune system that is capable of responding to the vaccination contents. See our great How vaccines work page for more details on the immune response to vaccination.

The reason why most vets will not vaccinate an animal that is undergoing an anaesthetic procedure is because the animal's temperature will often fall to below normal levels when it is under an anesthetic. Since many of the body's immune cells do not work as well when body temperatures are very low, there is the risk that the vaccination might fail to induce the full immunological protective response if it is given to a cold animal. Hence the reason why vets don't vaccinate anesthetized pets.


8i. FAQ 3 - Is desexing safe? It's just a routine procedure isn't it?
There is no such thing as a routine or "safe" anaesthetic procedure, regardless of whether the procedure is elective or not. There is always the risk, albeit small, that a normal, healthy individual animal or human may not wake up from an anaesthetic process or that it will develop a potentially fatal complication from having had surgery or anaesthesia performed (e.g. renal failure).

In the case of desexing, yes it is a "routine" procedure insofar as we vets perform hundreds of them every year. For the most part, the complications of the procedure are exceptionally low: very very few animals die or suffer severe, life-threatening complications as a result of neutering. To say that the procedure is perfectly safe, however, would imply that nothing bad can ever happen and this is simply not true. Section 6 of this page lists a whole string of operative and post-operative complications that can occur, some of which can be fatal.


8j. FAQ 4 - My veterinarian offered to do a pre-anaesthetic blood screening test - is this necessary?
As mentioned in an earlier section (section 6i), anaesthesia does drop the animal's blood pressure and place the animal's kidneys and liver under strain, both from the lower blood pressures and from the need to metabolise and excrete the drugs from the body. The pressure on and risk of damage to the kidneys and liver from an anaesthetic procedure is much greater if those organs (liver and kidneys) are already compromised by disease or scarring (old-age changes).

The role of a pre-anaesthetic blood panel is to detect significant kidney and liver pathology before the animal has an anaesthetic so that the vet can decide upon safer, alternative drugs or anaesthetic strategies or decide to not do the procedure at all (e.g. if it elective), thereby reducing the risks of a pet succumbing to post-operative renal or liver failure. The reason that a blood test is crucial in detecting if any pathology (disease) exists is because the veterinarian often can not tell what is going on in your pet's liver or kidneys from a clinical exam alone. The pet may look totally fine on the examination table and yet have only a small bit of renal function remaining. All the owner may notice at home is that the animal is drinking more water than normal and even this might not be all that obvious.

Most vets these days offer a pre-anaesthetic blood panel to all animals so that all owners have the option of checking their pet's kidneys and liver before any anaesthesia is done. Although this test is much more valuable in older animals (> 8 years old) because they are the age group most likely to have some degree of kidney or liver compromise, young animals may also benefit from pre-anaesthetic testing. Young animals are not immune from suffering the effects of acute renal failure after surgery. Certain breeds: e.g. Staffordshire Bull terriers (Staffies), English Bull Terriers, Shar Peis, Beagles, Basenjis, Cairn Terriers, Tibetan Spaniels, Dobermanns, Elkhounds, Samoyeds and many others are prone to various congenital renal defects. These animals are very likely to have some degree of renal compromise at a young age and this may first be picked up on a pre-anesthetic blood screen.

So, as to the question, "Is pre-anaesthetic blood screening necessary?" - I would say yes. In animals over the age of 8 years, I would say that it is very necessary because these older animals commonly get organ dysfunction, which might only be detectable on a blood screening test. Diagnosing the problem before anaesthesia and taking it into account during anaesthesia may well prevent the animal from developing acute renal or liver failure after surgery. In animals under 8 years, I would say that blood screening is necessary, but more optional. Playing the odds, it is less common for an animal under 8 years of age to have severe liver or renal disease. However, if you are the kind of owner who wants to cover all of the safety bases for your pet, I would advise pre-anaesthetic blood screening in all animals that have an anaesthetic. This way, if your pet does happen to be one of the animals that has developed young-age kidney or liver issues, the problem will be detected prior to surgery commencing (it will also allow earlier diagnosis and treatment for the condition to start, which is beneficial for the prognosis).


8k. FAQ 5 - When is desexing not safe to do?
Desexing is not safe to perform on any animal which has a medical condition that precludes it from having a safe anaesthetic. Any disease or condition that results in compromise to the animal's heart beat, heart contractility, heart rhythm, respiratory function or ability to metabolise (break down) and excrete drugs may be exacerbated, perhaps terminally, by general anaesthesia. Examples of such diseases include: heart failure, heart arrhythmias, pneumonia, shock, sepsis (systemic infection, causing shock), renal failure, liver failure and many more.

Any animal with a severe blood clotting disorder should not be operated on because it will not be able to clot its blood during the surgery and could well hemorrhage to death. Examples include: platelet disorders, platelet deficiencies, hemophilias A, B and C, vwD (von Willebrands disease) and rodenticide poisoning.

Any animal with severely infected or diseased skin in the region of the surgical site should not be operated on. These animals are likely to have a high level of superficial bacteria and this could well result in wound infection and wound break down.

9. The cost (price) of neutering a dog:

Much as I would love to be able to do so, to attempt to place a flat $ figure on the costs of desexing a dog would be grossly irresponsible of me and quite impossible to do. The cost of desexing male dogs is greatly variable and varies from place to place and region to region. It depends on many factors including: the size of the vet clinic, the competition the vet clinic has, the nature of the clinic (e.g. is it a shelter clinic), the suburb the clinic is located in, the size (weight) of the dog, whether the animal is a cryptorchid or not and so on.

In this section, I will give you an idea of the costs and the range of prices that may exist in one town/city when you are considering getting your dog neutered in Australia. (The principles discussed here will most likely to apply to any city in the world). I will outline the ways that vets arrive at these prices and discuss ways that you can source lower cost and discount neutering.

9a. The typical cost of neutering a male dog at a veterinary clinic.
For this section, I rang 9 of the veterinary practices in Canberra, Australia, asking about the costs of routine desexing for a 7kg dog, a 20kg dog and a 40kg dog. The clinics were chosen at random, aside from the fact that five of them were large, multiple-vet practices and the other four were small 1-2 vet practices. The prices (in Australian dollars) are listed below (for legal reasons, I can not identify the clinics I contacted).


Clinic 1:
7kg dog - $260; 20kg dog - $270; 40kg dog - $300.

Clinic 2:
Dog <12kg - $215-260; 12-30kg dog - $260-319; >30kg dog - $319+ (a 40kg dog was about $340).

Clinic 3:
0-10kg dog - $240-250; 20kg dog - $250-260; >40kg dog - $300-310.

Clinic 4:
<20kg dog - $319; 20-40kg dog - $355; >40kg dog - $406.

Clinic 5:
7kg dog - $200; 20kg dog - $215; 40kg dog - $230.

Clinic 6:
7kg dog - $265; 20kg dog - $290; 40kg dog - $380.

Clinic 7:
7kg dog - $280; 20kg dog - $300; 40kg dog - $330.

Clinic 8:
7kg dog - $210; 20kg dog - $230; 40kg dog - $250.
Clinic also featured a 10% discount for multiple dogs.

Clinic 9:
7kg dog - $145; 20kg dog - $145; 40kg dog - $145.
Clinic also featured a 10% discount for multiple dogs despite the low prices.


Summary:
Highest prices: 7kg dog - $319; 20kg dog - $355; 40kg dog - $406.

Lowest prices: 7kg dog - $145; 20kg dog - $145; 40kg dog - $145.

You can see from this small survey that there is some variation in price range and that, therefore, it pays to shop around. In this case, the difference in price would have been significant had you shopped around (in the case of a 40kg dog, you would have saved yourself $261). Veterinary clinics are competitive entities and many will attempt to undercut others on price to secure you as a client.


How do vet clinics arrive at their charges?
Overall, veterinary clinics charge a lot for surgery and medication for two main reasons: the high costs of running the practice (veterinary clinics are expensive to own and maintain) and the high costs of veterinary drugs (drug companies charge vets a lot of money for the drugs we purchase). Staff costs are high, land rates are high, equipment costs are high and many drugs only have a certain limited shelf-life (used-by date), after which they can not be used and are therefore wasted.

As a general rule, the larger, multiple-vet veterinary clinics tend to charge more for their surgical procedures than the smaller one to two man vet clinics do. This is often because the larger clinics have massive staffing and operational overheads that need to be met through higher charges, however, higher costs can also sometimes be a sign of the quality of monitoring and patient care that your pet is receiving. The other reason large vet clinics tend to charge a lot more for their services is because they can. They have enough clients and reputation built up to not need to compete for your business: if you can't afford their fees, they don't mind if you look elsewhere as it doesn't affect their bottom line. On the flip side, sometimes large clinics will actually charge less for their routine procedures, such as neutering, because they benefit from economics of scale (big places often save a lot on drugs and medications because they make such large orders with drug companies that the drug companies give them significant discounts). Clinic 3 in my survey was actually one of the largest clinics surveyed and its prices were surprisingly reasonable and in the low-middle range.

Smaller clinics, on the other hand, do tend to charge less for their services, depending on where they are based and how much competition they have. Smaller clinics struggle to get a foothold in the market and will often have very competitive prices to get routine surgeries, such as castration surgeries, through the door. The two clinics with the lowest prices in the survey were both small, 1-3 man vet clinics. Be very choosy when opting to have your pet's surgery done through a small clinic, however: whilst most small vet clinics are run by highly competent people who provide a very good standard of care, some small clinics remain small because people know not to go to them (their service might be bad, their premises unclean or their patient care and monitoring not up to scratch). As a general rule, however, most vets in big and small clinics have done thousands of neutering surgeries (they're not hard to do) and it is unlikely that you will experience a problem even if you do go to a tiny little clinic in the middle of nowhere for your services. For example, the clinic that offered the lowest-priced services in my survey ($145 for a neutering surgery of any weight group) is a small clinic, however, it is run by an excellent surgeon who performs really good work. i.e. low procedural costs and small practice size does not always equate to poor service.

Suburb also makes a huge difference to the price of services. Clinics in affluent suburbs, be they big or small (they are often large clinics), often charge much more for their services than clinics in lower socioeconomic suburbs. Their clients can afford to pay more. In my survey, suburb wealth was actually one of the most significant factors dictating the costs of neutering services. The most expensive clinic surveyed (Clinic 4) was a large, multi-vet practice located within a very rich area of Canberra. One of the next-most-expensive clinics (Clinic 7) was only a small, one-man practice, but it could charge high fees because it was also located within a wealthy area (in a similar location to clinic 4).

Competition also makes a huge difference to the price of neutering services. Clinics in suburbs or towns that have many vet clinics often charge less for their services than vet clinics in towns where there is little to no competition.

Finally, the size of the animal does make a big difference to the costs of desexing. Big dogs use more drugs, take more staff to lift them and have longer surgical times than small dogs do and they are therefore priced accordingly. Compare the prices for the 7kg versus the 40kg dog.

Costs will also be increased if your dog experiences complications during the procedure (e.g. needs a blood transfusion during surgery) or if it has a neutering surgery that is more complex to perform than normal (e.g. the animal is cryptorchid and the vet needs to enter the animal's abdomen to find the retained testicle). Added costs will also apply if the pet needs pre-anaesthetic bloods done or needs additional procedures performed (e.g removal of a retained baby tooth, dewclaw removal, microchipping and so on).

9b. Where and how to source lower cost and discount neutering.
Once again, for legal reasons, I can not name the names of veterinary clinics that offer discounted and low cost neutering services. I can, however, provide tips on how and where you might find them.

1. Ring around:
For the cost of a couple of phone calls to different clinics in my area, I was able to discover that the price of neutering varied by as much as $261. By shopping around, you can often find lower cost veterinary clinics in and around your area.

2. Don't forget to look at clinics in lower socioeconomic areas:
Just because you live in an affluent area does not mean that you have to pay affluent area prices for your vet services. There is no rule to say that just because you live in a wealthy suburb, you need to go to a vet clinic in that suburb. Try looking outside of your area. A lot of veterinary clinics in lower socioeconomic areas provide perfectly good services (certainly, most can desex a dog with no trouble), but do not charge the kinds of prices that rich suburb clinics do. This was certainly borne out in my survey - the highest cost clinics were the wealthy suburb clinics.

3. Consider having your pet desexed by a shelter or pet charity such as the RSPCA:
Shelters these days often have large vet clinics attached to them, with veterinarians that perform thousands of desexing surgeries every year (shelter vets probably perform far more routine animal desexings than most other GP vets would do). These charity organisations tend to charge a good deal less for their services than commercialized private vet clinics do. Pensioners in particular can often receive good discounts for services at these places.

4. If you are buying a dog, consider buying your pet from a shelter, pound or pet charity such as the RSPCA:
These animals are normally sold to you already vaccinated, neutered and microchipped.

5. Find out what the threshold weight ranges are for desexing costs:
Most veterinary clinics have a series of pet weight ranges that they use when billing you for desexing. For example:
A dog of 0-10kg may cost $120 to neuter.
A dog of 10-25kg may cost $150 to neuter.
A dog of 25-50kg may cost $180 to neuter.
A dog of 50kg+ may cost $200 to neuter.

These are not accurate costs, I am just using them as example.

If your pet is an overweight terrier that weighs in at 11kg, then you will be charged $150 to have it desexed (the same price as a 20kg Border Collie). If you can diet your pet a bit and get his weight down to just under 10kg, however, not only will he be happier and healthier for the weight loss, but he will now only cost $120 to neuter (a saving of $30).

NOTE: please do not diet your pet unsafely just to get a reduced desexing fee. You will never be able to turn a 50kg dog into a 23kg dog safely! If your pet is overweight, however, or only a few hundred grams above a price threshold, some dieting may help you to move your pet into a marginally cheaper price range.


Alternatively, you can ring around the various clinics and find out what their weight thresholds for price actually are. They're different in most clinics.

For example, Clinic A might charge according to these weight threshold levels:
A dog of 0-10kg may cost $120 to neuter.
A dog of 10-25kg may cost $150 to neuter.

But, Clinic B might charge using different weight thresholds:
A dog of 0-12kg may cost $120 to neuter.
A dog of 12-30kg may cost $150 to neuter.

In the case of the person with the overweight 11kg terrier, that person would have to diet the pet and reduce its weight to below 10kg in order to reach the $120 neutering weight of clinic A. The same person would not, however, have to do anything to reach the $120 neutering weight of clinic B because the weight cut-off for that same price is 12kg.

9c. Free neutering.
It is very uncommon for any veterinary clinics to ever offer their clients free neutering. Neutering an animal for free is essentially a business loss to that clinic.

If you live in a place where there are active, charity-run or government-operated pet control programs going on (e.g. in India and Cambodia where street dogs and pet dogs are desexed for free to reduce population numbers and the spread of diseases such as rabies or in Australia where aboriginal camp dogs are often government neutered to reduce their numbers and prevent the spread of mange and hookworm to the people), it may be possible for you to get a pet desexed for free.

10. Alternatives to neutering your male dog:

Owners who do not elect to get their dogs desexed often request other ways of preventing or managing the breeding, behavioural or medical problems faced by their entire pets. Which preventative measures and treatment options can be offered really depends on what the owner is trying to achieve. Owners just looking to prevent their dog or dogs from breeding can make use of a range of birth/pregnancy control measures available (sections 10a-10f). Owners looking to control or manage testosterone-mediated behavioural or medical problems (e.g. prostate hyperplasia, perianal adenomas) can look at option 10g. The reality is, however, that no one of these alternative measures alone will manage all of the problems of overpopulation, behaviour and testosterone-mediated health issues like desexing will. Additionally, many of these alternative solutions do come with significant side effects and health risks of their own. Desexing is always the best choice.


IMPORTANT: Check your local state and regional laws before opting for any of these alternatives. Animal population control laws are changing and increasing all the time. It may be illegal for you to keep a non-breeding-purposes (i.e. an entire male "stud" dog not owned by a registered breeder) entire male dog on your property.


10a. Canine birth control method 1 - physically separate the dog from the bitch and prevent roaming.

If your main concern is preventing your entire male dog from impregnating one or more of your entire females or other people's dogs in the neighbourhood, you can devise ways of preventing the dog from physically accessing your females and leaving your property.

This is a scenario that commercial dog breeders have to deal with all the time: they can't get their stud male desexed, but do not want him to breed ad libitum with everyone. In these situations what breeders tend to do, and what you can do too, is house their dogs (males and females) individually in specially-constructed, escape-proof dog runs so that male dog escape and mismating can not occur.

Simply constructing a separate fenced-off yard is not enough! It needs to be escape proof and that includes putting a roof on it. Many dogs will scale massive heights and climb high fences to reach a female in heat.

Simply keeping the dog away from the bitch while she is in heat (in season) is also no guarantee of her not falling pregnant. Most owners can not determine accurately when a dog's heat starts and ends (it can be a month long in all!). Moreover, this technique will not stop your dog from escaping its yard and wandering off to find other neighbourhood females to mate with.

Not desexing the male animal in this situation, however, will do nothing for his behaviour or health. He will still be inclined towards showing unfavourable entire-male behaviours (roaming, aggression, dominance, territory marking etc.) and he will still be prone to a range of testosterone-mediated health problems.

The best option is to get the male and female animals in your household desexed if they are not breeding animals. There are important behavioural, medical and population-control benefits to be gained by having each of the sexes desexed.


10b. Canine birth control method 2 - spey (spay) your bitch.

It never ceases to amuse and amaze me how many owners (particularly male owners) are horrified by the thought of having their male animals desexed and yet will happily get their female animals desexed, even though female dog desexing is a far more invasive and risky procedure to perform than male dog neutering is. It possibly harks back some underlying cultural belief that pregnancy is the woman's problem.

It is however, an option. If you do not want your male animal to impregnate the female animals in your household, you can elect to have the females desexed so that the male has nothing to mate with. Certainly, there are important health benefits to the female animal if she is desexed and desexing her will prevent dogs outside your household from coming over and getting her pregnant.

Not desexing the male animal in this situation, however, will do nothing for his behaviour or health. He will still be inclined towards showing unfavourable entire-male behaviours (roaming, aggression, dominance, territory marking etc.) and he will still be prone to a range of testosterone-mediated health problems.

The best option is to get the male and female animals in your household desexed if they are not breeding animals. There are important behavioural, medical and population-control benefits to be gained by having each of the sexes desexed.


10c. Canine birth control method 3 - "the pill" and female oestrous (heat) suppression.

There are a number of ways to suppress oestrus (heat, season) in female dogs and therefore prevent them from becoming pregnant by an entire male animal. Most of these solutions involve manipulating the female animal's reproductive cycle (estrous) cycle using a range of reproductive hormone and reproductive-hormone-like chemicals. Some of these include: progesterones (progestagens) and progesterone-like chemicals and testosterone and testosterone-like anabolic drugs.

The problem with many of these hormonal estrous suppression solutions is that they can have potentially devastating, life-threatening and/or aesthetically displeasing side effects.

Progesterones:
The progesterone and progesterone-derived drugs commonly used to temporarily or, with repeated use, permanently suppress estrous in the bitch include: medroxyprogesterone acetate (MPA), megestrol acetate and proligestone. Having less or fewer side effects than the testosterone-based products, progesterones are the most common drugs used for estrous suppression in the bitch. They are not, however, without certain important potential side effects.

Common side effects of progesterone use in the bitch include: lethargy (sleepiness); increased appetite; weight gain and, occasionally, loss of hair or change in hair colour and shrinkage of the subcutaneous tissues at the site of injection. Insulin resistance and diabetes mellitus may also be induced by long-term progesterone usage as can growth hormone problems like acromegaly. Progesterones can sometimes mimic the effect of corticosteroids in the dog, resulting in a Hyperadrenocorticism effect (Cushing's disease) and a liver condition called steroid hepatopathy (a liver full of fat).

Some bitches treated with progesterone products have been found to develop severe mammary enlargement, mammary nodules and even nasty mammary tumors (breast cancer).

In breeding animals, the use of certain oestrous-suppressing progesterone drugs has been found to result in reduced fertility for many individuals, thereby reducing the affected animals' value as breeding animals. Permanent infertility can be induced if the animal receives long term, prolonged progesterone treatments or is given progesterone prior to its first cycle (never give progesterones before the first season).

The incidence of false pregnancy (also called pseudopregnancy or phantom pregnancy) may also be increased by the use of progesterones.

Animals treated with progesterone whilst already pregnant may have delayed parturition, resulting from a failure of normal hormonal birth-induction processes (i.e. the bitch does not receive the 'signal' telling her body when to give birth). This delayed parturition results in the death and mummification of the fetuses inside the womb. These animals will often need a caesarean section to give birth. The milk production of such animals (ones given progesterone while pregnant) will also be adversely affected by the progesterone usage (the animal's milk production is inhibited by progesterone) and the live pups born by C-section may require milk supplementation and hand-rearing.

More catastrophically, the use of certain heat suppressant progesterone drugs (e.g. medroxyprogesterone acetate, repeated doses of megestrol acetate) has been shown to increase the risk of the bitch developing pyometron - a severe, life-threatening, infection and abscessation of the animal's uterus. Many bitches that develop pyometron need to be desexed to save their lives and those that are treated medically may not be able to go on to produce viable litters due to permanent uterine damage and scarring. The risk of pyometron does not seem to be as high with proligestone as it does with some of the other progestagens.

Author's note: of all of the progesterone products marketed for this purpose, proligestone (proligesterone) is considered to be one of the safer ones, with the lowest incidence of side effects. It is traded as Covinan. Megestrol acetate has more side effects, but these are not too common provided the drug is used according to instructions and not for prolonged periods of time. The use of medroxyprogesterone acetate (MPA) is not recommended at all for this purpose because it stays in the body for many months and has a high incidence of severe reproductive and mammary side effects.

Testosterones:
The use of testosterone and testosterone-like products to reduce cycling in the bitch is rarely done these days, the side effects often being deemed more unacceptable than those of the progesterone-type products.

Testosterones can make the female animal look and act more masculine (e.g. it may show increased muscle development and clitoral enlargement) and cause it to develop many of the same behavioural issues as the entire male animal (e.g. mounting and aggression). Testosterone-treated females are also more prone to developing many of the same testosterone-induced medical conditions - e.g. perianal adenomas - more commonly encountered in male dogs.

Testosterone-treated animals are more prone to developing liver problems (some develop jaundice) and renal disease. They are more prone to developing oily, stinky-smelling skin and various skin conditions. They sometimes develop vaginitis and vaginal discharges. Treated animals are also more likely to develop fertility problems (subfertility issues) later on.

Author's note - because testosterone-based products used in pets are similar to those used illegally in human body-building competitions and competitive sports, they are becoming more and more restricted for veterinary use because of the risk of them falling into the wrong hands. This is another reason why progesterone has overtaken testosterone for pet estrous suppression.


Because of the risk of severe, life-threatening side effects, hormonally-induced heat suppression should only be used as a very last resort and, even then, only in animals that are intended to be used as breeding animals later on (breeders need to be aware that significant loss of fertility can occur with their use as well as uterine diseases like pyometron and mammary diseases like breast cancer). It is far safer to isolate your breeding bitch from the males when it is in heat (season) than it is to try to artificially manipulate the female animal's reproductive cycle and keep heat suppressed. If breeding is not an aim for you, it is far better and safer to desex the female dog than it is to try to manipulate its reproductive cycle using hormones.

Remember again that not desexing the male animal in this situation will do nothing for his behaviour or health. He will still be inclined towards showing unfavourable entire-male behaviours (roaming, aggression, dominance, territory marking etc.) and he will still be prone to a range of testosterone-mediated health problems.

The best option is to get the male and female animals in your household desexed if they are not breeding animals. There are important behavioural, medical and population-control benefits to be gained by having each of the sexes desexed.


10d. Canine birth control method 4 - the "male pill" - fertility suppressing implants (contraceptives) for male dogs.

The GnRH analogues are a group of drugs that produce a negative effect on testosterone production by exerting a negative feedback effect on the brain-derived hormone (called luteinising hormone or LH) that is responsible for stimulating the testicles to produce and release testosterone. By preventing the production of LH, the GnRH analogues essentially prevent the LH-mediated production of testosterone by the testicles.

The GnRH analogue most commonly used in Australia is deslorelin (tradenames include Suprelorin-12). It is currently being marketed as a male form of "the pill". It is a slow-release, 12-monthly, contraceptive implant that suppresses male testosterone production to such a low level that canine fertility, sperm production, ejaculation and libido are all but non-existent. The male animal essentially becomes infertile whilst it has the implant and is unable to father any pups.

Because of this product's inhibitory effects on canine testosterone production, it is also possible that such an implant may, in the future, play an important role in the control and management of testosterone-mediated medical and behavioural problems as well.


Image: This is Suprelorin-12, a 12-monthly slow-release implant used to reduce fertility and unwanted breeding by male dogs.

10e. Canine birth control method 5 - canine vasectomy.

If all you desire is that your male dog not be able to breed with any females inside of or outside of your home, then canine vasectomy is an option for you. Vasectomy is the surgical removal of a section of the male animal's vas deferens or spermatic duct (the tube that takes the sperm from the testicle where it is made, to the lower reproductive tract regions of the prostate and urethra). Without this section of piping, the sperm can not reach the animal's urethra and penis and the animal, therefore, can not get anything impregnated.

Vasectomy is certainly effective at stopping breeding and the passing on of defective genes to any offspring. It will not, however, do anything for that male animal's behaviour or health. Because the testicles are left intact during vasectomy, the animal will still have plenty of testosterone in its body. He will still be inclined towards showing unfavourable male-animal behaviours (roaming, aggression, dominance, territory marking, mounting and copulating with females etc.) and he will still be prone to developing a range of testosterone-mediated health problems.

Author's note: vasectomy is not instantaneous. A vasectomised dog will still be fertile and capable of impregnating bitches for 3 weeks following the procedure. The vasectomised dog should be evaluated by a vet prior to the reintroduction of the dog to any females to ensure that his semen contains no sperm (i.e. that the procedure has been effective).


10f. Canine birth control method 6 - chemical castration - injecting sclerosing agents into the dog's testes and epididymides.

If all you desire is that your male dog not be able to breed with any females inside of or outside of your home, then chemical castration is an option for you.

During chemical castration, a sclerosing or scarring agent (e.g. chlorhexidine) is injected into the animal's testis and/or epididymus. This chemical induces a strong inflammatory reaction within the testicle and/or epididymus, resulting in severe scarring of the testis and epididymal sperm ducts such that they do not permit the passage of sperm from the testicle to the lower reproductive tract regions of the prostate and urethra. The sperm can not reach the animal's urethra and penis and the male animal, therefore, can not get anything impregnated. Additionally, the chemically-induced inflammation of the testicle and epididymal tracts exposes the sperm (considered "foreign" cells to the male's immune system) to the animal's immune system. The immune system reacts aggressively against these sperm and all subsequently-made sperm cells, thereby rendering the animal effectively infertile (the immune system "kills off" all the sperm that get made in the future).

The main side effect of chemical castration is that the process of testicular and epididymal inflammation and scarring is very painful for the animal in the short term. The animal will be expected to have hot, swollen, painful testicles and epididymi for quite a few days after the procedure has been performed. Some animals may suffer severe tissue reactions as a result of this process.

Chemical castration, like vasectomy, is certainly effective at stopping breeding and the passing on of defective genes to any offspring. It will not, however, do anything for that male animal's behaviour or health. Because the testicles are left intact during chemical castration, the animal will still have plenty of testosterone in its body. He will still be inclined towards showing unfavourable male-animal behaviours (roaming, aggression, dominance, territory marking, mounting and copulating with females etc.) and he will still be prone to developing a range of testosterone-mediated health problems.

Author's note: chemical castration is not instantaneous. A chemically castrated dog will still be fertile and capable of impregnating bitches for around 35 days following the procedure. The chemically castrated dog should be evaluated by a vet prior to the reintroduction of the dog to any females to ensure that his semen contains no sperm (i.e. that the procedure has been effective).


10g. Anti-testosterone agents (e.g. Tardak, MPA-50, Ovarid) used to reduce testosterone-mediated medical and behavioural problems.

All of the alternatives to surgical desexing mentioned thus far (i.e. sections 10a-10f) have pertained to canine birth control and the prevention of unwanted pregnancy. None of them (except perhaps for 10d - also mentioned in this section) have provided any solution to the castration-responsive behavioural and medical problems that are caused or contributed to by the presence of too much testosterone in the animal's bloodstream. As mentioned previously, the problematic testosterone-mediated behavioural issues include: dominance, inter-male aggression, territorial marking, territorial guarding, hypersexual behaviour (chair-leg mounting and toy humping), excessive libido, excessive sexual interest in females and so on. Testosterone-mediated medical problems include: benign prostate hyperplasia, prostatitis, prostatic abscess, perianal adenoma and perianal carcinoma.

Undesexed animals with significant testosterone-mediated behavioural and/or medical problems should, ideally, be neutered. Desexing is the best way to drop that animal's blood testosterone levels rapidly and permanently and thereby provide some relief and treatment for the medical and/or behavioural issues at hand.

Owners who are unwilling to desex their animals, however, even in the face of significant testosterone-mediated behavioural and/or medical problems, can make use of various alternative "anti-testosterone" medications as a way of treating or managing these conditions. These anti-testosterone medications are mainly reproductive hormone and reproductive-hormone-like chemicals; with progesterone and progesterone-derived compounds the most frequently used, closely followed by various other drug compounds (e.g. estrogens, GnRH analogues, 5-alpha-reductase inhibitors, testosterone-receptor antagonists).

These anti-testosterone drugs work by either:
a) inhibiting the action of testicularly-made testosterone on cells of the body (e.g. 5-alpha-reductase inhibitor drugs, testosterone-receptor antagonist drugs, progesterone drugs) or by
b) reducing the production of testosterone altogether (e.g. progesterones, oestrogens, GnRH analogues).
By reducing the production or effect of testosterone on the body, these drugs essentially mimic the effects of neutering as a means of treating or controlling these testosterone-caused medical and/or behavioural conditions.

Similar to what was discussed in section 10c (hormonally induced estrous suppression in the bitch), the problem with many of these hormonal testosterone-inhibiting solutions is that they can have potentially devastating, life-threatening and/or aesthetically displeasing side effects on the dog.

Progesterones and progesterone-derivatives:
The progesterone and progesterone-derived drugs commonly used to temporarily or, with repeated use, permanently suppress testosterone production, testosterone action and testosterone-mediated medical and behavioural problems in the male dog include: medroxyprogesterone acetate (MPA), megestrol acetate and delmadinone. Common tradenames include: MPA-50, Ovarid and Tardak.

These progesterone drugs are thought to have several effects on the male reproductive system including the following:

• They exert a negative feedback effect (suppressive effect) on testosterone production by the testicles.
  
• They inhibit the enzyme (5-alpha-reductase) responsible for converting the testosterone made by the testicles into its more active, potent form: 5-alpha-dihydrotestosterone (5-DHT).
  
• They reduce or down-regulate testosterone-receptor numbers in certain tissues normally targeted by testosterone (e.g. the cells of the prostate), thereby providing the secreted testosterone molecules with fewer places to bind on to and exert their effect. Put simply, in order for testosterone to have any effect on a cell of the body (e.g. a prostate cell), it must be able to bind onto the surface of that cell first by attaching to a testosterone-receptor. If there are fewer testosterone-receptors available for testosterone molecules to attach on to, the testosterone can not exert its effect on those tissue cell/s.

At normal doses, these drugs have not been found to reduce male fertility or decrease sperm number and nor do they appear to have any significant effect on male libido. Because of this, even though these drugs will reduce certain testosterone-mediated behavioural problems and help to improve or treat medical issues like benign prostate hyperplasia and perianal adenoma, these drugs will not prevent a treated male animal from getting a female animal pregnant. At extremely high doses (higher than recommended), however, progesterones may adversely affect sperm production and motility, resulting in reduced fertility.

Common side effects of progesterone use in the male dog are similar to those seen in the bitch and include: lethargy (sleepiness); increased appetite; weight gain and, occasionally, loss of hair or change in hair colour and shrinkage of the skin and subcutaneous tissues at the site of injection. Insulin resistance and diabetes mellitus may also be induced by long-term progesterone usage as can growth hormone problems like acromegaly. Progesterones can sometimes mimic the effect of corticosteroids in the dog, resulting in a Hyperadrenocorticism effect (Cushing's disease) and a liver condition called steroid hepatopathy (a liver full of fat).

Some males treated with progesterone products have been found to develop mammary enlargement, mammary nodules and even nasty mammary tumours (breast cancer).

Author's note: of all of the progesterone products marketed for this purpose, delmadinone (tradenames include Tardak) and megestrol acetate (tradenames include Ovarid) are the more commonly used. They do have side effects (described above), but these are not too common provided the drug is used according to instructions and not for prolonged periods of time. The use of medroxyprogesterone acetate (MPA), although much safer in the male dog than in the female, is probably better left as a last resort (e.g. if Tardak or Ovarid fails to control prostate hyperplasia, perianal adenomas, hypersexualised behaviours and so on). MPA stays in the body for many months and, because of this, poses a greater risk of producing severe side effects (e.g. diabetes) that are difficult to reverse (the drug, once-injected, can not be taken away). MPA does have an advantage in that a single injection of the compound will have an effect on the testosterone-mediated disorder for many months (i.e. the owner does not have to keep dosing the animal).

Author's note: An anti-testosterone agent such as progesterone is never going to be as effective at reducing or controlling testosterone-mediated behavioural and medical conditions as neutering will. As long as the testicles remain in place, the drug will only be able to temporarily hold-off these medical conditions and problem behaviours. These testosterone-induced problems will recur whenever the drug wears off, necessitating that the animal remain on repeated doses of medication for life. This is not only inconvenient and costly for the owner, but it also increases the risk that the animal will develop severe side effects as a result of the ongoing medication.


Estrogens (oestrogens) and estrogen-derivatives:
The estrogen and estrogen-like drugs most commonly used to temporarily or, with repeated use, permanently suppress testosterone production and testosterone-mediated medical and behavioural problems in the male dog include: diethylstilbestrol (diethylstilboestrol) and estradiol (oestradiol). Common tradenames include: Stilbestrol tablets.

The estrogen drugs exert their negative effect on testicular testosterone production by exerting a negative feedback effect on the pituitary-derived hormone (called luteinising hormone or LH), which is responsible for stimulating the testicles to produce and release testosterone. By reducing or preventing the production of LH, oestrogen essentially prevents the LH-mediated production of testosterone by the testicles.

Currently, estrogen is not recommended for use in the prevention or control of testosterone-mediated medical and behavioural problems in the male dog. Although the hormone is effective at treating such medical issues as benign prostate hyperplasia, the potential side effects of excessive and prolonged estrogen usage in the dog are severe and potentially life-threatening. Side effects of estrogen use include: oestrogen feminising syndrome (male dogs become feminized and feminine in appearance); squamous metaplasia of the prostate (a hormone-induced change in the prostate's structure that makes it less functional and more prone to infection and abscessation) and bone marrow suppression (a complete failure of production of all of the dog's blood cells, which can often be fatal). For further information on oestrogen toxicity, see our great cryptorchidism page.

Author's note: An anti-testosterone agent such as estrogen is never going to be as effective at reducing or controlling testosterone-mediated behavioural and medical conditions as neutering will. As long as the testicles remain in place, the estrogen drug will only be able to temporarily hold-off these medical conditions and problem behaviours. These testosterone-induced problems will recur whenever the drug wears off, necessitating that the animal remain on repeated doses of medication for life. This is not only inconvenient and costly for the owner, but it also increases the risk that the animal will develop severe side effects as a result of the ongoing medication. In the case of oestrogen, these side effects can be very dangerous for the dog.


5-alpha-reductase inhibitors:
The 5-alpha-reductase inhibitors are a group of drugs that inhibit the action of the enzyme (called 5-alpha-reductase) responsible for converting the testosterone made by the testicles into its more active, potent form: 5-alpha-dihydrotestosterone (5-DHT). There are several drugs in this class, the most common being finasteride and chlormadinone, and they are currently being used in the control and management of such testosterone-mediated medical problems as benign prostate hyperplasia. In the future, they may also have a role in the control and management of testosterone-mediated behavioural problems.

Of the two drugs, finasteride is the more commonly used. At normal doses, it does not seem to reduce male fertility or decrease sperm number. Because of this, even though finasteride will improve or treat testosterone-mediated medical issues like benign prostatic hyperplasia, it will not prevent a treated male animal from getting a female animal pregnant. Chlormadinone, on the other hand, has been known to reduce fertility in male dogs and it is therefore less popular.

Author's note: An anti-testosterone agent such as finasteride is never going to be as effective at reducing or controlling testosterone-mediated behavioural and medical conditions as neutering will. As long as the testicles remain in place, the drug will only be able to temporarily hold-off these medical conditions and problem behaviours. These testosterone-induced problems will recur whenever the drug wears off, necessitating that the animal remain on repeated doses of medication for life. This is not only inconvenient and costly for the owner, but it also increases the risk that the animal will develop severe side effects as a result of the ongoing medication.


The testosterone-receptor antagonists:
The testosterone-receptor antagonists are a group of drugs that work by binding-to and blocking-up testosterone-receptors in certain tissues normally targeted by testosterone (e.g. the cells of the prostate), thereby providing the secreted testosterone molecules with fewer places to bind on to and exert their effect. Put simply, in order for testosterone to have an effect on a cell of the body (e.g. a prostate cell), it must be able to bind onto the surface of that cell first. It does this by attaching to a testosterone-receptor on the surface of the cell. If there are fewer testosterone-receptors available for the testosterone molecules to attach on to (because the drug molecules have blocked them up before the testosterone gets to them), then the testosterone will not be able to exert its effect on the target cell/s.

There are several drugs in this class, the most common being flutamide and hydroxyflutamide, and they are currently being used in the control and management of such testosterone-mediated medical problems as benign prostate hyperplasia. In the future, they may also have a role in the control and management of testosterone-mediated behavioural problems as well.

At normal doses, these drugs (flutamide and hydroxyflutamide) do not seem to reduce male fertility or decrease sperm number, nor do they seem have any significant effect on male libido. Because of this, even though these drugs will improve or treat testosterone-mediated medical diseases like benign prostatic hyperplasia, they will not prevent a treated male animal from getting a female animal pregnant.
Author's note: An anti-testosterone agent such as flutamide is never going to be as effective at reducing or controlling testosterone-mediated behavioural and medical conditions as neutering will. As long as the testicles remain in place, the drug will only be able to temporarily hold-off these medical conditions and problem behaviours. These testosterone-induced problems will recur whenever the drug wears off, necessitating that the animal remain on repeated doses of medication for life. This is not only inconvenient and costly for the owner, but it also increases the risk that the animal will develop severe side effects as a result of the ongoing medication.


The GnRH analogues - deslorelin:
The GnRH analogues are a group of drugs that produce a negative effect on testosterone production by exerting a negative feedback effect on the pituitary-derived hormone (called luteinising hormone or LH), which is responsible for stimulating the testicles to produce and release testosterone. By preventing the production of LH, GnRH analogues essentially prevent the LH-mediated production of testosterone by the testicles.

The GnRH analogue most commonly used in Australia is deslorelin (tradename Suprelorin-12). It is currently being marketed as a male form of the "pill". It is a slow-release, 12-monthly, contraceptive implant that suppresses testosterone production to such a low level that canine fertility, sperm production, ejaculation and libido are all but non-existent. The male animal essentially becomes infertile while it has the implant and is unable to father any pups.

Because of the inhibitory effects of this product on canine testosterone production, it is also possible that such an implant may, in the future, play an important role in the control and management of testosterone-mediated medical and behavioural problems as well.


Image: This is Suprelorin-12, a drug used to reduce fertility and unwanted breeding by male dogs.

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References and Suggested Readings:

1) Induced Abortion, Pregnancy Prevention and Termination, and Mismating. In Feldman EC and Nelson RW: Canine and Feline Endocrinology and Reproduction, 2nd ed. Sydney, 1996, WB Saunders Company.

2) Surgery of the Reproductive and Genital Systems. In Fossum TW, et al, editors: Small Animal Surgery. Sydney, 1997, Mosby.

3) Canine Reproduction. In Daris W, editor: Compendium of Animal Reproduction, 5th ed. 1998, Intervet.

4) Kustritz MVR, Olson PN, Early Spey and Neuter. In Ettinger SJ, Feldman EC, editors: Textbook of Veterinary Internal Medicine, Sydney, 2000, WB Saunders Company.

5) Verstegen J, Contraception and Pregnancy Termination. In Ettinger SJ, Feldman EC, editors: Textbook of Veterinary Internal Medicine, Sydney, 2000, WB Saunders Company.

6) Kustritz MVR, Klausner JS, Prostatic Diseases. In Ettinger SJ, Feldman EC, editors: Textbook of Veterinary Internal Medicine, Sydney, 2000, WB Saunders Company.

7) Davidson AP, Birth Control Alternatives. In Ettinger SJ, Feldman EC, editors: Textbook of Veterinary Internal Medicine, Sydney, 2000, WB Saunders Company.

8) Johnson CA Disorders of the Estrous Cycle. In Nelson RW, Couto CG, editors: Small Animal Internal Medicine, Sydney, 1998, Mosby.

9) Johnson CA Disorders of the Prostate Gland. In Nelson RW, Couto CG, editors: Small Animal Internal Medicine, Sydney, 1998, Mosby.

10) The Pelvis and Reproductive Organs of the Carnivores. In Dyce KM, Sack WO, Wensing CJG editors: Textbook of Veterinary Anatomy, 2nd ed. Sydney, 1996, WB Saunders Company.

Pet Informed is not in any way affiliated with any of the companies or clinics whose products appear in images or information contained within this article. The images, taken by Pet Informed, are only used in order to illustrate certain points being made in the article.

Copyright October 31, 2008, www.pet-informed-veterinary-advice-online.com.
All rights reserved, protected under Australian copyright. No images or graphics on this Pet Informed website may be used without written permission of their owner, Dr. O'Meara.

MPA-50 and Neocort are registered trademarks of Ilium Veterinary Products.
Neotopic H Lotion is a registered trademark of Delvet Pty Ltd.
Covinan is a registered trademark of Intervet Australia.
Rimadyl is a registered trademark of Pfizer Animal Health.
Ovarid, Prolet and Tardak are registered trademarks of Jurox Pty Ltd.
Previcox is a registered trademark of Merial Australia Pty Ltd.
Metacam is a registered trademark of Boehringer Ingelheim Pty Ltd.
Prescription Diet Canine i/d is a registered trademark of Hill's Pet Nutrition Pty Ltd.
Suprelorin 12 is a registered trademark of Peptech Animal Health.
Carprofen tablets and Stilbestrol tablets are registered trademarks of Apex.
Wound-Gard is a registered trademark of Allerderm.
Royal Canin Digestive Low Fat is a registered trademark of Royal Canin.


Please note: the desexing information provided on this page contains general recommendations and medical advice only. The information provided is based on published information; relevant veterinary literature and publications and my own experience as a practicing veterinarian. The advice given is appropriate to the vast majority of pet owners, however, owners with pets should take it upon themselves to ask their own veterinarian for further advice on neutering. Owners with specific circumstances (breeding dogs, showing dogs, stud dogs, breeding businesses, those seeking prosthetic implants, those whose dogs have testosterone or hormone-mediated medical or behavioural issues, those seeking to control estrous artificially in breeding/showing bitches etc.) should ask their vet what the safest and most effective protocol is for their situation.

Any dose rates mentioned on these pages should be confirmed by a vet. Dosing rates for common drugs are being changed and updated all the time (e.g. as new research comes in and as drug formulations change) and information here may not remain current for long. What's more, although we try very hard to maintain the accuracy of our information, typos and oversights do occur. Please check with your vet before dosing any pet any medication or drug.

Common misspellings: criptorchidism, criptorchid, cryptorkidism, cryptorkid, criptorkidism, criptorkid, cryptorkydism,cryptorkyd, criptorkydism, criptorkyd, cryptorchydism, cryptorchyd, criptorchydism, criptorchyd, testical, testecal, testacal, testucal, testecle, testacle, testucle, nuter, nutered, nutering.

Alternative, slang synonyms for testicles: ball, balls, nut, nuts, goolies.

Alternative, including slang, synonyms for desexing: nut, nutting, nutted, the snip, the chop, castrate, castrating, castrationing, castration, gonadectomy, sterilisation, sterilising, sterilised, sterilization, sterilizing, sterilized, neutered, neutering, neuter, fix, fixed, fixing, desex, desexing.