It’s springtime, and love is in the air. Babies are being born and it’s time for some of the different livestock species to breed. It’s also time to prevent some of these breedings. That’s right, ladies and gentlemen, it’s castration season!

As of this writing I have castrated, let’s see, nine different species. Please don’t think I’m bragging. I’m not. I just find it fascinating that not all testicles are created equal.

In vet school, one of the very first surgeries students learn to perform is the castration. At Purdue, we began with the feline castration, one of the simplest veterinary surgical procedures. There are not even any sutures required! With an experienced surgeon, after the cat is under anesthesia, the procedure can take less than one minute; no blood, minimally invasive, and that’s that.

After we mastered the cat (courtesy of the local animal shelter), it was on to the canine castration, a more complicated procedure requiring clamps and sutures and double-layer skin closures. During my externship, I learned how to do equine castrations (even more challenging due to the size of the animal and the stress of anesthesia); the rest of the species (sheep, goats, llamas, alpacas, pigs, and cattle) came during on-the-job training.

The difference in castrations basically boils down to blood supply.  As I’ve alluded, the reproductive anatomy of each species is different. Some, like the cat, don’t have large testicular arteries, and during any surgical procedure, it’s always the blood vessels that cause the surgeon the most stress. (Rule number one in surgery: don’t allow the patient to bleed to death.) Of course, the size of the animal as a whole dictates the size of the testicular vessels, but not always. The equine species has an extensive and scary testicular blood supply, versus camelids, (including huge 600 pound llamas) who have much less intimidating plumbing.

The methods for large animal castration between species are also not the same. For some species you can simply place an elastic "band" around the scrotum, which kills the blood supply, leaving the testicles to fall off in a matter of weeks. This method, called "banding," is frequently used as a non-surgical form of castration in cattle and small ruminants like sheep and goats. However, don’t ever band a horse. You’ll probably kill it and then go to jail for animal cruelty. Part of this is due to the differences in anatomy and part is due to a horse’s penchant to become infected if you look at it cross-eyed.

Before I conclude, I must leave you with a favorite castration story of mine. A few summers ago, on a hot, humid day in June, I was called to a farm to castrate about five bull calves, all about three to four hundred pounds each. The farmer did not have an adequate squeeze chute to restrain the animals during the procedure (you usually do not place cattle under general anesthesia for castrations), and we were planning to do them surgically (with a scalpel, not a band). When I expressed my dismay at their lack of safety equipment, the three burly men standing around me offered to flip and hold down the steers themselves. After having them acknowledge that both my safety and the safety of the calves were in their burly hands, we went to work, only to have, thirty seconds later, the grandmother of the family holding her hands in the air yelling, "Wait!" As I was kneeling in between the calf’s hind legs, sweat pouring down my face, the scalpel in mid-air, I look up to see this 90-year-old woman rushing toward me with a giant Tupperware container. "Put the oysters in here," she ordered.

It took me a few seconds to understand what she wanted: The "oysters" referred to the bull testicles. She was planning on preparing Rocky Mountain Oysters (cooked bull testicles) for dinner, and she didn’t want me to get them dirty. So, for the first time in my veterinary career, I was tossing surgical refuse into a microwave-safe container for dinner (apparently the secret is to add some hot sauce).

As a side note, bull testicles go by many different names. My personal favorite? Cowboy caviar.

Dr. Anna O’Brien

Image: hansenn / via Shutterstock