Spay and neuter - why and when?
Updated: Apr 18, 2022
Do you consider yourself a pet owner or pet parent? Over 75% consider pets as family members. This makes it hard to believe that around 13.5 million dogs and cats were euthanized in the US in the early 1970s, nearly 20% of the entire population! Even with all those deceased animals, millions of cats and dogs were still roaming in our neighborhoods. Shelters could have an intake of over 100 dogs per day. For us pet lovers, this was a dismal time. What turned things around? Spaying and neutering played the biggest role. About 10 years after we started sterilizing, dog and cat euthanasia due to overpopulation dropped by an estimated 3.5 to 5.9 million and fewer animals were entering shelters despite the growth of communities. By the early 2000s, free-roaming dogs were no longer an issue.
Currently, 6-8 million cats and dogs still enter shelters each year. Sadly, over 2.4 million healthy animals, mostly cats, are still euthanized annually due to lack of available homes. Where do all these cats come from? The vast majority of kittens born each year, around 80%, are produced by community cats - those stray, feral, and even indoor-outdoor cats that are free roaming in our neighborhoods. Because this is the main source of cats coming in to shelters and rescues, progressive animal welfare organizations are implementing life-saving strategies and putting more resources to spay/neuter rather than housing and, eventually euthanizing, these cats. Rather than take obviously feral cats into the shelter, a “return-to-field” or “shelter-neuter-return” program is in place to get the cats back to their outdoor homes. Not only is this advocated for feral cats, but also for friendly stray cats that are doing well in their outdoor homes. This prevents the cats from getting sick or being euthanized in the shelter and they have a much higher chance of getting back home or being adopted.
Even with shelters and rescues working diligently to decrease the cat population, only about 2% of community cats in the U.S. are currently spayed/neutered. These data make it clear that spay/neuter awareness, especially for community cats is still crucial. It is also clear that those of us in shelters and rescues, need help. Help from private practice veterinarians, caregivers of community cats, pet parents, cities, boroughs, townships, and anyone who wants to volunteer. As I mentioned in my previous article about community cats, the scientifically valid and widely accepted method to help reduce the unnecessary euthanasia of healthy cats is through Targeted Trap-Neuter-Return (TNR). Every birth that we prevent saves a shelter cat’s life.
We know that spay/neuter is critical to save lives from an overpopulation standpoint, how about from an individual animal standpoint? I cannot state strongly enough that, especially for female cats, dogs, and rabbits, surgical sterilization is extremely important for their health. I have seen too many animals die of pyometra (a life-threatening uterine infection), mammary carcinoma (a form of breast cancer), and from complications due to pregnancy and birth. Intact female dogs have a 50% chance of getting breast cancer, three times that of women. Rabbits not only get breast cancer, but over 65% get uterine cancer. What makes this worse, is that these types of tumors do not respond well to chemotherapy and can recur or spread throughout the body. The good news is that there is less than 0.5% chance of a dog getting mammary tumors if she is spayed before her first heat cycle! The data for cats states a 91% reduction in risk of breast cancer if they are spayed prior to 6 months of age. Of course, spaying pets completely prevents them from having life-threatening uterine infections or pregnancy related issues since the uterus has been removed.
So how about male cats, rabbits, and dogs? While I have seen testicular tumors and torsions as well as prostate issues, I think the most compelling reason to neuter our pets is due to the impacts on their behavior. Indoor urine marking, mounting, and roaming are all much more likely to occur in unneutered males. Anyone that has smelled tomcat urine knows this is not something we want in our homes! As for the roaming, not only do these animals have a chance to get lost, but there is a good chance of an injury occurring. Many of these animals are at risk for being hit by a car and fighting with other intact males. We see dozens of scars on tomcats, as well as many broken teeth from the vicious fights that occur. Neutering dogs decreased indoor urine marking, intermale aggression, and mounting of other dogs by 50 to 70% and roaming by 90%. Based on our experience with cats, the vast majority will stop spraying after neutering and typically do not spray at all if neutered before sexual maturity.
I would be amiss not to mention some recent studies being discussed regarding spay/neuter. You may have heard of concerns of increased incidence of joint problems (ACL rupture, hip dysplasia), various cancers (lymphoma, hemangiosarcoma, osteosarcoma, mast cell tumors), and immune disorders in some sterilized dogs. While there may be an association with spay/neuter and these conditions, there is no current evidence of causation. The type of studies performed do not allow for a cause-and-effect relationship to be established, due to the retrospective design, the low sample size, lack of controls, and bias inherent in the population of dogs (i.e. is there a genetic predisposition in this lineage of dogs?). Even if it is found that sterilization causes these conditions, the results cannot be extrapolated from one breed of dog to another (these studies were with German Shepherds and Retrievers).
Two studies on life expectancy in pets, with huge sample sizes, have been recently conducted as well. Analyzed medical records from over 80,000 dogs showed a strong association with spay/neuter and an increased life expectancy of 1.5 years. Another analysis of data from 2.2 million dogs and nearly a half million cats also concluded that spayed/neutered cats and dogs live longer. While dogs had more moderate increases in their lifespan (a 23% increase for spayed dogs and 18% increase for neutered dogs), the lifespan of spayed/neutered cats doubled! Ultimately, we may find in future studies that sterilized animals do have a proclivity towards some medical conditions, but the data clearly demonstrate that spayed and neutered pets live longer.
The last question we must consider is when is it best to spay/neuter cats and dogs? Based on his review of the current data and experience in pediatric spay/neuter of over 50,000 cats and dogs, veterinary surgical specialist Dr. Philip Bushby recommends spaying all female cats and dogs and neutering all male cats and small breed dogs prior to 5 months of age. For large breed male dogs, if potential orthopedic issues outweigh the concerns for undesirable behaviors mentioned earlier (including risk of injury from fighting or roaming) neutering should occur after growth stops at 15 to 18 months of age.
I personally would much rather spay a puppy than a large, female dog. It is much faster and is an easier to perform surgery. There is also a lower risk of complications due to smaller incision size and minimal blood loss due to the small vessel size and minimal fat surrounding the uterus and ovaries. I have been doing pediatric spays/neuters in dogs, cats, and rabbits for 16 years and a good percentage of our 8,000+ procedures each year are in animals under 5 months of age. Our rule of thumb is over 1.5 pounds for a healthy kitten and over 6 weeks of age for a healthy puppy. The young animals recover much faster and are typically back to normal just hours after they wake up. They bounce back quickly! Much faster than in adults.
So, based on experience and science - spay and neuter is the way to go. It saves lives and allows our furry family members to stay with us longer.