Today was my first day as an intern at Multigen Reproductive Solutions in Lexington, Kentucky. When I shadowed Dr. Stan Carnes two years ago, I did not have much knowledge about cattle anatomy or mating processes. However, since 2020, I had opportunities to enrich my knowledge in this field by working with Dr. Brockett on large animal emergency medicine at Spruce Street Animal Clinic in Huntingdon, PA.

Today, I began by feeding the longhorns at the clinic. Then, Stan and I flushed three cows who were 7 days fertilized by artificial insemination to harvest their embryos. We flushed the uterus with sterile fluid and filtered the fluid as it came out. Then, under a microscope, we separated the embryos based on developmental stage and quality using a micropipette. We collected 33 embryos. The particular client had 20 cows who were designated recipients of the embryos. So, we loaded the 20 most developed embryos into syringes with holding media and used liquid nitrogen and freezing media to preserve the other 12. Then, we headed to the clients farm to inseminate the 20 recipient cows.

I began today by feeding the longhorns. Then, I prepared 50 epidurals by filling 5mL syringes with Lidocaine just to restock. Then, we packed up eight frozen embryos and headed out to a clients farm.

The client used synthetic hormone injections to get all of the cows on the same heat cycle. He bred them at the same time so, we used an ultrasound to preg check the herd. Any cows that were open and formed a corpus luteum with a follicle could be artificially inseminated, hence the frozen embryos we brought along. The client had 7/8 successful pregnancies, and we inserted one embryo.

Then, we headed back to the clinic and did a BSE (breeding soundness exam) on a bull. This was something that I had never seen before. Stan put a collecting sleeve on the bull's penis then, inserted an electro-ejaculator into the rectum. Once the sample was obtained, we evaluated the motility and morphology of a representative sample of semen under a microscope. I learned about all the primary and secondary sperm abnormalities a bull can produce and then took a turn at evaluating the sample we collected.

Today began by collecting semen samples from three bulls for BSEs. We used a jumper animal this time instead of the electro-ejaculator to provide a more natural stimulus. Then we evaluated the motility and morphology of each sample before gradually freezing some of the sperm samples for shipment or storage. They must be gradually chilled and then frozen as not to temperature shock the sperm cells which would cause them to die.

Then, Stan and I looked at a cow with a hematoma on her abdomen. He had drained about two gallons of bloody fluid from the hematoma a week ago, but it refilled, as hematomas do. However, when we made a small incision to drain the hematoma, it became apparent that the hematoma had clotted, so not much fluid drained out and in order to remove it, we would have to undergo a much more complicated surgical procedure. This is the only route to proceed in after talking to the cows owner, so no further action was taken today. All we can do now is watch the incision site to make sure it does not get infected and form an abscess, or flies do not bother the hematoma, or lay eggs in the abdomen. (TW! There is a picture of the hematoma below, it SHOWS BLOOD)

Finally, we worked on three cows feet who had overgrown hooves. Two of the three had stepped in gravel which caused abscesses in their hooves. They needed to be cut down, cleaned, and bandaged with topical antibiotics which will help to calm down the infections and encourage healthy hoof growth moving forward!

Today, to begin, we prepped 6 cows- one being a longhorn -to be bred by implanting eazi-breed CIDR into their uterus. This device is used with the purpose of estrous synchronization. The CIDR was coupled with a shot of lutalyse, a drug used to control the estrous cycle in cows with a developed corpeus luteum. CIDR and Lutalyse will promote the secretion of progesterone and be removed in 7 days. Then, the heifers will all come into heat at the same time, making herd breeding more effective. The shape of the CIDR reminds me of an IUD. CIDR and an IUD work similarly in the sense that they both secrete progesterone, however an IUD also causes thickened mucus in the cervix to catch sperm and prevent pregnancy, they are also typically left in for longer than 7 days.

Then, we flushed two cows who had successfully fertilized embryos. There was a hereford cow who only flushed one embryo. Most embryos of the hereford cow were lost to a cervical tear. Then we flushed an angus cow who gave seven embryos. We direct transferred five embryos into recipient cows. This was the first day that I got to prepare the transfer straws myself. Then, we froze the remaining two embryos.

Today we did a lot of IVF work. IVF stands for In-Vitro Fertilization. This means the fertilization of the oocytes takes place outside the body. Before the cow arrives it is given a dose of FSH (follicular stimulating hormone) to induce the production of follicular growth. Once a cow came through the chute, we inserted an ultrasound probe through the vaginal cavity to find follicles in the left and right ovaries. Follicles on the ultrasound look like black dots. Once we located them, a small needle comes out of the probe and is attached to a vacuum which sucks up the contents of the follicular fluid. It is filtered through a sterile fluid which cleans the oocytes out of the follicular fluid and then we can locate the oocytes under a microscope. Using a micropipette, we moved the oocytes into holding medium where they are loaded into straws and sent to another lab to be fertilized.

IVF is typically used because the clients only have to purchase one straw of semen to fertilize all the oocytes we harvest. It is an effective way to utilise high quality semen. Instead of buying a lot of straws of semen for In-Vivo Fertilization, or AI, or buying a high quality bull for natural breeding, the client can get In-Vitro Fertilization so that they only pay for follicular harvesting and one straw of semen.

We did the IVF procedure on 11 beef cows and 1 longhorn cow today and harvested a total of 166 oocytes. The oocytes were all at different developmental stages, some with more preantral cell growth. Shown to the left is 11 oocytes under the microscope!