Spay/Neuter:
Debating Medical Standards

WA Veterinarian Magazine

by Lisa Parshley, DVM, DACVIM

Mar/Apr 2016

Every now and then the veterinary profession queries or deliberates a medical principle. A very healthy behavior for a medical profession; to periodically question one’s own traditions. For without evaluation custom becomes truth not science and morals do not evolve with cultural growth. Ultimately, debating medical standards prevents stagnation and improves the growth of medicine.

A perfect example of such a debate is the current questions being posed about spaying and neutering. At issue is when and if we should spay or neuter companion animals. The essential questions are whether our recommendations to spay and neuter early impact population control, behavior problems, and are there any health concerns in general surrounding this procedure.

The public opinion arena has been debating these questions for some time. Unfortunately, these discussions have been littered with equal amounts of fact and fiction. Some would say it’s about time that the veterinary profession takes up these deliberations. In reality we have already opened these discussions, as evidenced by both editorials and scientific papers now appearing in our journals.

The data suggests that only 10% of the animals on entering the shelter will be spayed or neutered. Our debate should always go back and ask if a particular health risk outweighs the risks of not controlling our homeless companion animal population.

The issue of spaying or neutering is not a new or novel topic. European veterinarians have wrangled with this subject for years. And most companion animal veterinarians have to answer such questions from clients every day. What is unique about the current version of this debate is that the veterinary profession appears to still be searching for the right answer.

A lack of consensus is likely because this topic poses a very complicated scientific and ethical quandary. On the one hand are all the unwanted animals. On the other hand, are the reported potential health risks associated with the timing of spaying and neutering. And in between are all the potential behavior and surgical risks.

For many veterinarians, the central issue is and always will be population control of companion animals. For example, did you know that according to the ASPCA roughly 7.6 million animals (3.9 million dogs and 3.4 million cats) will enter a shelter each year. Roughly 31% (1.2 million) of the dogs and 41% (1.4 million) of the cats will be euthanatized.

Simply viewing statistics such as these it is easy to see why this aspect of the issue at hand is foremost in many, if not most, veterinarian’s minds. When it is figured that every 20 minutes 108 homeless animals are euthanatized. And when the data suggests that only 10% of the animals on entering the shelter will be spayed or neutered. Our debate should always go back and ask if a particular health risk outweighs the risks of not controlling our homeless companion animal population.

At the same time, is it reasonable to question whether early spay and neutering programs reduce shelter populations? Data is just beginning to be collated and published that may answer this question. Seeking an answer to this query could solve a portion of the debate or provide new avenues to approach in controlling the homeless animal population.

Are there health risks associated with spaying or neutering before puberty? This is an excellent question and one I am sure is asked every day to most companion animal veterinarians. There is no doubt that when we spay or neuter early or immediately after puberty we are changing normal anatomy and physiology. For it is known that puberty signals most anatomic growth to begin slowing and eventually stop. Neutering and spaying before puberty is bound to influence the growth period and anatomic stature of an animal.

Impact of changing this normal programmed process could have far reaching effects on an animal’s life. Some of these changes are likely to be good (such as reductions in reproductive risks, behavior, or mammary carcinoma). Yet some of these alterations may contribute to chronic or late in life health concerns (such as urinary incontinence or orthopedic disease or possibly cancer).

Since we are just starting to address the issue of interrupting puberty or removing lifelong hormonal influences, science has not yet fully weighed in on this issue. What data we have accumulated is very intriguing and may provide far reaching changes in medical recommendations. It is my hope that we will continue to research this aspect as it could really help develop guidelines and provide education for families who adopt companion animals.

Yes, we have started the conversation and debate on what is the best recommendation for spaying and neutering. Without a doubt our growth in this arena will be fraught with sometimes heated debates and ethical quandaries. But if we continue to use our compassion for animals and accumulated science, we will push our profession and its standards into the future. Come participate in this debate Saturday, April 16 at Renton Technical College in Renton, Washington at the Washington State Veterinary Medical Association’s VetMed Matters Conference on Spay and Neutering.