When the Philadelphia Zoo sought breeding assistance for its Arapawa goats, it reached out to a former contact at the Swiss Village Farm (SVF) Foundation.
Over the past 20 years, Cummings School of Veterinary Medicine collaborated with SVF Foundation and, in 2022, completed the SVF Biodiversity Preservation Project. More than 100,000 samples of semen, embryos, blood, and somatic cells of over 1,100 animals across 36 breeds of cattle, goats, and sheep were collected, cryopreserved, and stored at the Smithsonian Conservation Biology Institute in Virginia.
The SVF Foundation then contacted Tufts Veterinary Field Service (TVFS). One of Cummings School of Veterinary Medicine’s six hospitals and clinics, TVFS cares for nearly 55,000 animals annually and is one of few to offer artificial insemination (AI) of livestock.
“We routinely do laparoscopic AI,” says Dr. Rachael Gately, assistant clinical professor, Department of Ambulatory Medicine and Theriogenology (AMT).
Native to New Zealand, the Arapawa is a rare, domesticated breed of heritage goat and considered as a unique genetic resource, distinct from other breeds due to its hardiness and self-sustaining abilities, according to The Livestock Conservancy.
The AI procedure
“Because you can’t consistently get through a goat’s cervix, we do AI laparoscopically,” Gately explains, noting that sheep are similarly inseminated. This contracts with other species, such as horses and cattle, which can be inseminated trans cervically (without surgery). Dr. Alexandra Uden, assistant clinical professor in AMT, typically works with Gately on the procedures and prepares the semen while Gately prepares the goat for surgery. She places trocars to allow access to the goat’s uterus and fills the goat’s abdomen with carbon dioxide.
Cryopreserved semen is submerged in a temperature-controlled water bath, where it thaws and reanimates. The thawed semen is then loaded into an AI gun. Working together, Gately looks through a tiny camera to find the uterus, and Uden injects half the semen into each side.
“This provides the best chance of success of pregnancy, which is highly important when working with a rare breed of animal and semen,” says Gately, noting that she knows of one other practitioner in the Northeast currently doing this procedure.
Overcoming challenges to create a successful pregnancy
Several factors and circumstances require detailed execution to enable the best chance for a pregnancy. “The female must be at the right time in her cycle, which is probably the most important part,” Gately explains. “The Zoo had a synchronization protocol that we followed for two weeks prior to our arrival [in Philadelphia].” The quality of the semen, the temperature of the room, and the physical condition of the animal are among the other factors. “If any one piece of the chain doesn’t align, it provides a reason why it won’t work,” Uden adds.
To properly harvest, cryopreserve, and store semen requires significant financial considerations, and the process of thawing it at the proper rate can be a challenge, according to Gately, who identified that an automated freezer would be an upgrade from the program’s current method to accomplish this task.
“The Arapawa goats are the most difficult to get pregnant,” Gately shares, as goats can fail to conceive or lose an early pregnancy when they undergo stress around the time of breeding (or in this case, artificial insemination). To minimize the stress associated with transporting the goats, Gately and Uden traveled to Philadelphia to perform the procedure. As of early-May, one of the three Arapawas was pregnant, while tests on the others were pending.
Answering requests for artificial insemination
TVFS performs between 300 and 400 AI procedures annually, ranging from herds of up to 100 down to small groups, such as the trio of Arapawas. Some procedures occur at TVFS, while others take place at the client’s farm, depending on the number of patients and financial considerations. Approximately 50–70 percent of AI procedures using frozen semen result in a successful pregnancy.
Most of the work is completed between August and November, with sessions scattered throughout the rest of the year.
Gately joined Cummings School in 2013 and started doing AI procedures eight years ago. Dr. David Matsas, a recently retired Cummings School assistant professor and a key contributor to the SVF Biodiversity Preservation Project, guided Gately early on. “Much of what I’ve learned was self-taught under his guidance,” Gately shares, as she helped develop the AI program.
Future plans for upgrades and expansion of services
Gately gives presentations about the AI process to groups of practitioners two or three times each year amid a growing demand for these services. “We hope that by training additional veterinarians, clients (and vets) won’t have to travel as far to have laparoscopic artificial insemination done,” she says.
TVFS currently has a diverse set of advanced reproductive service offerings, in addition to the AI program, including embryo collection, transfer, and cryopreservation, breeding soundness examinations, semen collection, evaluation, and cryopreservation. TVFS has also recently obtained a new microscope. Gately states, “The most efficient equipment is expensive, but we hope to make those investments in the future, as well as expansion into ovum pickup and in vitro fertilization.”
Source : tufts.edu