As veterinarians, one of the most enjoyable parts of our job is to see clients with their new pets. Whilst some of them are older pets, the majority of cats and dogs are younger, intact animals. Intact refers to any animal that has not been surgically altered to prevent breeding. At these new pet visits, we are often asked questions about spaying or neutering.
Spaying refers to female animals and there are several different surgeries that fall into this category. The two most common variations include removing either the ovaries alone or removing both the ovaries and the uterus. Either of these procedures render a female unable to have babies. They also have the added benefits of the female not being attractive to males, having significantly reduced risks of uterine disease (including pyometra), mammary cancer, sexually transmitted diseases, and birthing difficulties. Of course, the social and management challenges of having an in heat dog or cat are also gone.
Another procedure that is hot news on the internet is an ‘ovary-sparing spay’. This is a surgery which by removing JUST the uterus has ONLY one benefit, and that is no babies. None of that other health or social benefits occur and, in fact, it can actually increase the health risks for the female. These risks come in large part because the new owner and veterinary care team are not made aware that the pet has only had the uterus removed and it can delay diagnosis of serious diseases. Correcting this by removing the ovaries at a later age is a much higher risk procedure than a traditional spay technique. If your new pet is already ‘spayed’ when you get her, it is important to ask whether or not the ovaries were removed.
Castrating, or neutering, is the surgical procedure for males to remove the testicles. This can create a more socially acceptable pet with less aggression, and less roaming and marking behaviour. 70% of dog bites are attributed to intact males. Neutering also has the health benefits of decreasing prostatic and testicular disease, hernias and other health problems.
Males also have a ‘new trend’ surgery for rendering them infertile. Vasectomy is the surgery to remove a part of the tube that transports sperm. This procedure does not have any of the social or health benefits of a castration. It is possible to castrate a dog that has had a vasectomy to acquire the health benefits at a later age.
Both castrations and spays have their cons as well. Some are perceived such as creating a fat and low-energy animal – this risk is only apparent in the first two years after the procedure, but then evens out with intact animals, and weight gain can be managed by reducing the amount of calories when your pet is altered. Cancer is another worry – certain cancers may be increased in some breeds, but are outweighed by the number of cancers that are decreased by surgically altering.
Some cons are real, such as an increase in the chance of urinary incontinence for female dogs over 15kg. Bone and joint problems are very specific to certain breeds and timing of procedures. Pros and cons should always be considered, but generally the pros of getting your pet spayed or neutered outweigh the cons.
Age of spay and neuter is another hot topic these days. Again, thanks to the internet, there is a lot of information and studies that are out there. It is really important to understand how to read a study and to understand that what applies to one breed does not necessarily apply to another breed. Study numbers are also important, as dramatic study findings when only a few animals were included may not be a good indicator of risk to a larger population.
There are pros and cons for early spay/castration (around 8 weeks of age), 6-8 month spay/castration, and late (over 1 year of age) spay/castration. There certainly can be good health reasons to delay these surgeries in some large breed dogs, but all other groups should ideally be done at the 6-8 month age. Behavioural benefits are not as likely to occur in animals over 7 months of age.
Overall, it is important to have these discussions with your veterinarian and definitely bring the information that you have from other sources. We are happy you help you make the best informed, most appropriate decision on the most common surgical procedures in the cat and dog world.
Dr. Katharine North (née Moody) has been a resident and active participant in the Fort St. John community since her family immigrated to Canada from the United Kingdom as a child. Her interest in medicine and animals led her back to the University of Liverpool in the U.K. to complete her Bachelor of Veterinary Science in 2000.