Soon after I started vet school, a scientific report was released that that said if you drink more than two cups of coffee a day, you would get pancreatic cancer. This meant that I was going to have to spend about 14 hours a day, studying, going to class, taking early exams and doing clinic work on two cups of coffee a day. I did and it was not fun. The year that I graduated, a new scientific report was released that the amount of coffee you drank actually had nothing to do with pancreatic cancer. Ouch. Bad timing.
Let’s be real with scientific reports. They are only as good as the next report that proves the previous one was not correct. This seems to be the case when we look at scientific research regarding whether or not a pet needs to be spayed or neutered or at what age the procedure should be done.
One of the problems with scientific research is that it is done in the lab using black and white data and fails to take into considerations the unlimited variabilities that arise in the real world. This is why science is always contradicting itself.
When I graduated from vet school about one score (40 years ago. Wow, that sounds really old, as in Abraham Lincoln old.), it was standard protocol to spay and neuter dogs and cats at about 6 months of age. This is what we were taught, based on the latest scientific studies. We followed this protocol for many years until new scientific research suggested that we change our protocol.
That research linked mammary cancer to pets that had been spayed after their first heat cycles. It specifically stated that dogs and cats who had a normal spay cycle before being spayed had a 200 times greater incidence for mammary cancer.
We responded by changing our recommendations that all dogs and cats should be spayed before their first heat cycle. Most dogs and cats were then spayed between 4-5 months of age. Some cats, due to their polyesters cycles and seasonal dependence were spayed as early as 3 months. This same protocol stands today.
Recent research suggests that we should not spay or neuter our pets at all as the deprivation of the pet’s normal sex hormones leads to improper development and function resulting in an unhealthy situation for the pet.
Just what is a spay? Spaying a pet means to remove the entire reproductive system; ovaries, uterus and cervix. The purpose of this surgical procedure is to prevent unwanted pregnancy and eliminate those nasty heat cycles that most pet caretakers feel are a pain in the neck. Ever see a cat in heat? Yep, pretty freaky behavior.
The ovaries are responsible for the female sex hormones which not only regulate the heat cycle and reproduction, but also play a role in other body functions. The latest option is to do a surgical procedure that eliminates and prevents pregnancy but maintains ovary function and hormone production. Some are recommending tubal ligation while others recommend removing the uterus while leaving the ovaries.
Remember, all research is done in the lab and on paper and not in the real world. Sometimes, most of the times, it ends up not being that accurate. Scientific research is based on linear thinking and cause and effect. If a = b, and b = c, then a = c. Pretty simple deduction. However, science is pretty on target when there are less than four variables. Once there is more than four variables, the scientist is left scratching their heads. This is why the weather is so hard to predict. Too many variables in weather patterns. Same goes for cause of cancer.
One point that is used as an example is that some dogs that are spayed at early ages develop urinary incontinence, often referred to as “spay incontinence.” The female hormone, estrogen, has been determined to play a role in the integrity of the urinary bladder sphincter. It helps the sphincter stay contracted. When dogs are spayed, and the estrogen is no longer in the system, some dogs develop urinary incontinence (leaking urine). The same goes for human females after menopause. Due to the loss of estrogen, some women will develop urinary incontinence. They are often given synthetic estrogen to resolve this problem.
If we look a little closer at this example, we see that there are flaws in the premise. About 5% of young, female dogs that are spayed, develop urinary incontinence. What about the other 95% of the spayed female dogs that did not develop the problem? Obviously, there is more than one factor in the disorder, otherwise all young, spayed, female dogs would develop the problem. Unfortunately, researchers have not been able to determine what the other factors are.
There are multiple studies here in the US and in other countries, looking at this topic. Research suggest that intact females have less chance for lymphoma, hip dysplasia, hypothyroidism and other diseases. But, when you look closely at the research, it is obvious that there are many other variables that are not taken into consideration. Not all spayed dogs get these diseases. Why? Because it is not the only variable. But, as responsible pet caretakers we must consider that it is an influence. Several research reports strongly suggest that early spaying will affect growth and development, often leading to abnormal muscle and bone formation. Again, not all early-spayed dogs and cats develop these development problems.
What has to be considered when opting not to spay a dog or cat? First, are you willing to put up with heat cycles? Dogs usually have two heat cycles a year and each heat cycle lasts about 3 weeks. This means dealing with bleeding, behavior changes and eliminating the possibility of unwanted pregnancies. I know of one dog that was bred by a roaming Romeo while the owner was taking her on a walk, and she was on a leash. Ouch.
Cats, are seasonal polyestrous, meaning that their heat cycles are determined by the season. They come into heat in February of March in most states, and continue to cycle again and again until about December. So, for about 9 months of the year, you will have a female cat that yowls and meooooows, twitches and rolls around like she is having fits.
In my forty years of clinical practice, almost all female dogs and cats that have mammary cancer have not been spayed. Mammary cancer is considered a horomone-induced cancer. I have seen very pets few develop this type cancer that have been spayed.
Pyometra (infection of the uterus) is a life-threatening disease usually found in senior, non-spayed females. I have personally seen many of these older dogs die from this disease as it can often be difficult to detect until it is too late. I hate it when the vet tells the client that their dog’s death could have been prevented if she had been spayed.
So, what is a person to do? I think you need to make up your mind if you are willing to deal with the pet’s heat cycles first. If so, then look at the other considerations and make your choice. Remember, nothing is set in stone and there are many other variables that lead to diseases. If you are going to have your dog or cat spayed, research the different types of surgeries now available and see which one feels best for you. Lastly, I would not recommend early spays and neuters. If you can deal with the heat cycles until the pet reaches maturity, usually around one year of age, then I would recommend waiting until then. At least, until the next research is released.