Thanksgiving has been a bit of a somber time for me during these past two years of veterinary school. My family has a habit of forgetting that Canadians celebrate their Thanksgiving in October and always sends me an invite to the annual party. Being seven hours away, I have to graciously decline but there is still a twinge of guilt from knowing that I will miss my favorite holiday with my family.
This year was no different. I turned down my sister’s invitation and sulked for a bit. This Thanksgiving would consist of a day of classes and studying for a Monday exam. I was less than thrilled to be missing out on my favorite holiday. Well, things improved quite quickly when I received an invitation from the Food Animal Club to attend a small ruminant theriogenology day.
Early Thanksgiving morning, we loaded up the car and made our way to the university’s sheep research facility. This is a closed herd system, meaning that for biosafety reasons, no new animals are introduced. The ewes are bred to rams on site, or new genetics are introduced through frozen, shipped semen.
The facility only brings in new genetics once every five years. Semen is shipped from another disease-free herd and the ewes are impregnated through artificial insemination. Unlike cattle, it is difficult to introduce the semen transvaginally. Ewes have a very tortuous cervix, which creates complications when semen is introduced via the vagina. Sperm that have undergone freezing for shipment are typically still very viable but often have lower motility. Poor motility paired with a convoluted cervix makes it very difficult for the sperm to reach their final destination. For these reasons, the semen is deposited laparoscopically directly into the uterine horns.
Our job was to prep each sheep for surgery by clipping and cleaning the surgical site. The sheep was then wheeled into surgery where the veterinarian would take over. Two incisions are made into the inguinal area where the laparoscopic instruments are introduced. The veterinarian uses the scope to visualize the uterine horns and then an assistant administers semen directly into the horn with a needled probe. The veterinarian then closes the incisions and sheep is recovered. This method results in an approximately 70% pregnancy rate – which is apparently very good for artificial insemination of sheep!
During our visit, we assisted in inseminating twenty-five sheep in three hours! We were all extremely impressed with the skill and efficiency of the veterinarian. I left no longer feeling somber about the day, but instead invigorated and reminded of why I am so thankful to be a veterinary student.