Being a food animal veterinarian, day 8

Day 8 was not like the other days. My rotation-mate Delilah and I signed up to spend the day assisting with embryo collection at a farm that works with my school to preserve heritage breeds. The farm acquires (usually on loan) individuals from heritage breeds of sheep, cows, and goats. They superovulate and breed the females, then collect the embryos and cryogenically store them. Del and I kept asking what the plans were for the embryos. No plans! We are just storing them in case they are needed some day when these breeds are extinct.

The facility was beyond lovely, a 1920s folly farm that looked like a crazy cross between a medieval castle and a Mexican mansion. Biosecurity was a big concern there, so we had to cross a little bridge with a foot wash on the way in, and multiple signs about the premises said things like “This is private property. Please go away immediately.” The grounds were so immaculately clean that it was hard to believe there were animals there, but there were, beautifully cared for (with lots of pasture!). The farm was restored and updated, so you would for example pass through a stone archway into a modern cryogenic storage facility. Also, it had the cleanest bathroom I had encountered on a farm yet, but then again, that is not saying much. Most farms have bathrooms that rival the worst truckstop bathrooms, so that the vets who drive the trucks will say things like “hang on, we’re passing by a gas station in less than an hour” when you ask about facilities.

Del and I traded off assisting on surgeries and running anesthesia for three ewes. We premedicated, intubated, and maintained each ewe under anesthesia on gas. Then we helped Dr. Thery go in laparoscopically to make sure she had in fact successfully been superovulated. Ideally the ovary would look like a bunch of grapes. We would count the post-ovulatory structures on each ovary. Then we would laparasopically find and grasp the uterus, and pull it out of a small incision. Once it was exteriorized, we flushed it to get all the embryos out of it. The embryos were carried over to the lab, and we watched on video as they were identified, counted, and graded (the more vs less viable ones selected out). We closed up the ewes and recovered them. Each ewe would be kept for two surgeries, then returned to her owner.

It was a lovely day, and of course the surgery experience was a fun bonus. Del and I had some interesting conversations about whether this effort to preserve heritage breeds was worth the investment. Whether or not it is, it was a beautiful facility, and nice to see how a farm can be run when money is essentially not a factor.

Veterinary fact of the day: measuring the scrotal circumference of a bull

Two weeks ago we started a new class, Theriogenology, about the medicine of reproduction. (What do you do if she has trouble getting pregnant? What do you do if she has trouble during her pregnancy? Etc.) So far it has all been about cattle, though we will get into other species soon. Much of the veterinary work for the dairy industry specifically is about timing pregnancies, making sure cows get pregnant promptly, and managing herd health reproductive problems.

We had six hours of lecture on cows, and finished up with two hours on bulls. The Society for Theriogenology has guidelines on how to perform a breeding soundness exam on the bull. Is he physically healthy enough to mount a cow? Is the circumference of his scrotum large enough to suggest that he has plenty of sperm (more important for his ability to service multiple cows sequentially than for his ability to get lots of sperm into a single cow)? Are his sperm well-formed and mobile, and mobile in the right direction (forward, not backward)?

Bull scrotums contain vertically oriented testicles, so it is actually useful to wrap a measuring tape around them. (The circumference should be a minimum of 30 cm in a bull of breeding age.) This sort of measurement is not useful in horses, dogs, pigs, or humans, whose testicles are oriented in a different direction.

Most amusingly, the product used to measure the scrotal circumference, with a feature that lets you see if you’ve wrapped the tape too tight, is called ReliaBull. That made me giggle.