Article Review: Epidemiology of Surgical Castration in the United States

I recently had a professor tell me that if I didn’t let them know if I made it into vet school, they would forever curse me with fat, in heat, Labrador spays for the rest of my career. I can think of few fates worse for a future veterinarian (though I did mention that the owners also had to have  no way to pay, and will forget to mention this until after the procedure). Today’s article is really cool and discusses the prevalence of ovariohysterectomy and orchiectomy (spaying and neutering, fixing, castration, gonad removal,de-nutting, whatever you prefer to call it) in the USA. It breaks the percentages down into region, animal species, animal breed, animal age, and enrollment in wellness plan from Banfield (animal health insurance).

Banfield Pet Hospital is an amazing organization for animal research because all of their records are computerized and kept in a central database (I should mention that the man who made Banfield what it is today is an OSU alum, go beavs). Because of this treasure trove of data, this study was able to get a sample size of over 300,000 cats and over one million dogs. While this represents less than 1% of the US pet population, its still a valuable amount of data, and we can reasonably assume that Banfield has a decent representation of the rest of the pet population that regularly visits private clinics. The article mentions that one of the only large differences is the mean age at clinics (Banfield’s is slightly lower). The numbers found in this study also line up well with previous examinations using distributed surveys to collect data.

I’m very proud to say that the Northwest region (making up Washington, Oregon, Idaho, and Montana) has the highest percentage of castrated cats and dogs compared to any other region (tied with the North Central region for percentage of dogs) according to the study. The region with the lowest percentage was the Southeast region (making up Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina, and Tennessee). That’s an area of the country I haven’t ever visited, so I can’t comment on cultural factors that may influence the decision to castrate pets, but clearly more outreach could be focused on that area.

The breed distribution is interesting, but doesn’t offer too much information for most breeds. In my own head I see the Labs’ and Retrievers’ high numbers understandable, as you can in some ways consider them “white-collar” or suburban dogs. This would be associated with a higher income and thus one less roadblock to castration. Pit Bulls can maybe be considered a “blue-collar” dog, but that can’t be the only reason their numbers are so low. I’m actually at a loss as to why the castration rate of Pit Bulls is so much drastically lower than all the others. It’s an obvious outlier. I myself love Pits and believe that in the right hands they make great dogs. But considering their stigma, low rate of adoption (and consequently high euthanasia rate), insurance liability, and higher risk, I do believe we should make castrating Pits a priority. I’ll definitely be looking for more literature that attempts to explain the demographics and other factors that create this problem. The second lowest group, Chihuahuas, is also interesting. Again, I’m not sure why the numbers for this breed are so low, but one factor may be that many Chihuahua’s are kept as indoor-only dogs, and that may reduce the motivation to perform the procedure, as the largest benefit is wasted on them (as seen by those owners).

I’m not surprised to see that mixed animals were more likely to be castrated, and I really have no problem with that. There aren’t too many unwanted animals that come from intentional breeding, and purebred animals generally don’t have trouble finding homes (pending behavioral issues). Responsible breeding doesn’t contribute to the pet overpopulation problem significantly, and leaving that option open to purebred owners is acceptable. With cats on the other hand, I’m happy to see the extremely high rate of castration. Cats are allowed to roam unsupervised much more than dogs, and we have enough trouble controlling the feral population without accidental pregnancies also occurring in animals that could have been easily castrated.

One rather frightening statistic was the percentage of dogs and cats from shelters that do not return for castration. This concerns me as in many cases the cost is free or subsidized to less than $50. In a private clinic you can pay upwards of $200, but this seems to be little incentive as 40-60% of animals are returned for the procedure when it is already paid for. To me, this is indicative that some of those owners will provide a low level of veterinary care for the lifetime of that animal, when they already haven’t taken advantage of a free procedure. This is pure conjecture however, and there could be a host of reasons that owners do not return. However, because the rate is so low, I would bet that there is some significant factor that is relatively consistent among owners who adopt from shelters, whether that be income (shelter’s are a very inexpensive option to get a purebred-looking dog) or attitude.

All in all, a good look at where castration is common, and where education and improvement needs to be made.  I do think that many PSA’s, advertizements, and advocacy campaigns are too often directed at groups that are already in agreement. Even looking the statistics from a PSA I made back in high school show that the primary people concerned with animal welfare are women over 35, and it’s clear that similar announcements are marketed at that group. New campaigns should focus on a new approach to educate people why castration is important, and maybe spend less time showing us pictures of sad puppies. Tell me why I personally should do it, because until it’s too late to change anything, there’s no reason I should think I’m part of the problem.

ResearchBlogging.orgTrevejo R, Yang M, & Lund EM (2011). Epidemiology of surgical castration of dogs and cats in the United States. Journal of the American Veterinary Medical Association, 238 (7), 898-904 PMID: 21453178