When a veterinarian is considering a stallion’s suitability as a breeding animal, the horse’s history, current physical condition, and libido are just as important as his semen quality. "It’s not just the semen we’re looking at, it’s the whole package," said Steven Brinsko, DVM, MS, PhD, Dipl. ACT, associate professor at Texas A&M University. Brinsko presented a session on reproductive evaluation of the stallion at the Hagyard Bluegrass Equine Reproduction Symposium 2006, which was held Oct. 18-21 in Lexington, Ky.

"The approach of the breeding soundness examination of a stallion is similar to any other system you’re examining," Brinsko said, and such an exam is often completed prior to the sale of the horse or prior to the breeding season.

"The history can be more important than anything else," said Brinsko. "We’re evaluating the whole package from the age/breed, present usage, prior breeding soundness exams, illnesses or injuries, medications, or vaccinations."

He said that a variety of medications could affect semen quality–cimetidine, for example, has a dramatic effect on spermatogenesis