SUGARCREEK, Ohio — For decades, artificial insemination has helped beef and dairy farmers improve their genetics, while at the same time making their breeding program more efficient.
Thanks to a grant through the Sustainable Agriculture Research and Education program — known as SARE — a group of northeast Ohio sheep breeders and veterinarians are working to make A.I. profitable with sheep, as well.
Breeding sheep through A.I. is nothing new, but the problem is making it affordable and more efficient, especially for small-scale producers.
During a workshop Nov. 13 at the Noah and Mary Yoder farm, participants talked about their results, following a two-year study of the intravaginal method.
Veterinarian Craig Zimmerly, of Apple Creek, said one of the biggest challenges with breeding sheep is the design of their cervix. Unlike cattle, a sheep cervix has many nooks and crannies — and this makes inserting a straight rod to deposit semen almost impossible.
Different methods
With this in mind, veterinarians have often relied on laparoscopic insemination, meaning they cut a small hole into the lower abdomen, to directly access the ewe’s reproductive organs.
During the process, the ewe is positioned inside a specially designed cradle, with her head toward the ground and her rear legs pointed upward.
This method is costly and requires a trained expert. The tools alone can cost $2,000 or more.
Zimmerly and his partners set out to find a more farmer-friendly way of doing A.I. They researched intravaginal breeding, in which the sperm is deposited directly into the ewe’s vagina, and made to travel through the cervix on their own.
The intravaginal method requires the sperm to travel a longer distance, and the results showed a lower conception rate. But it’s simpler than the other methods and one that farmers could actually do on their own.
“It’s got potential,” Zimmerly said. “We’ve shown that it can be done.”
Easier method
Researchers studied the intravaginal method on 58 ewes, with a 41 percent success rate.
This method also requires careful planning and timing.
First, farmers need to choose good quality, healthy ewes and rams. The ram should have a good body condition, healthy feet, legs and teeth, and a sizable scrotum. A semen sample should be taken first, and studied under microscope.
Fertile rams
The ram should produce sperm that are mobile, in high concentration and of normal shape and function. In general, sheep with larger testicles are more fertile.
Dale Duerr, a veterinarian from Bolivar, said ram semen is collected in two ways, either through an electro-ejaculator, which is inserted into the rectum of the ram, or through manual stimulation with an artificial vagina.
There are between 1-2 billion sperm cells per collection, and they need to be kept at a consistent temperature after collection, to avoid cold shock and death.
The normal heat cycle for a ewe is 15-17 days. Using the intravaginal method, the ewe is first treated with a shallow probe known as a CIDR (controlled internal drug release) that contains the hormone progesterone. This is left inserted for 12 days.
When the CIDR is removed, a PG 600 (combination of hormones) is administered, which stimulates the formation of ovarian follicles and causes ovulation at a set or “synchronized” time.
The ewe is then bred 48-52 hours after the CIDR removal and the PG 600 has been injected.
“It takes a lot of planning and preparation,” Zimmerly said, noting it’s not something a producer just decides to do overnight.
Looking ahead
Cost per ewe is about $15 using the intravaginal method, much less than with the laparoscopic method.
One of the biggest challenges now is finding a way to extend the life of sperm, so that it can be shipped longer distances, such as across state lines.
The group is working with various extenders, such as milk and eggs, which are added to the semen to supply nutrients and create an ideal environment until breeding.
The workshop was sponsored by the Ohio Heartland Sheep Improvement Association. For more information, contact Dale Duerr at 330-339-2363. Zimmerly can be reached at his office number, 330-698-3701.
