Atypical Causes of Stallion Infertility

It pays to think outside the box when considering possible causes of stallion infertility. The stallion’s reproductive conformation, quality of sperm, and history can all impact his performance in the breeding shed.
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Dickson Varner, DVM, MS, Dipl. ACT, professor in the Department of Large Animal Medicine and Surgery at Texas A&M University, presented several cases of stallion infertility at Florida Association of Equine Practitioners (FAEP) Promoting Excellence Symposium, held Sept. 27-29, 2007, at the Atlantis resort on Paradise Island, the Bahamas. These scenarios shed some light on some of the typical and atypical reasons for this expensive problem.

Some of the cases Varner illustrated included issues with the quality and quantity of sperm and problems with the stallion’s reproductive conformation, including congenital abnormalities (present at birth). He also discussed the impact of case history in assessing these horses. Varner looked for feedback on the cases from the assembled practitioners, quizzing the attendees on what steps they would take to diagnose and manage these stallions.

Varner noted that stallions get to remain intact and become sires because of their pedigree, conformation, and performance–not necessarily their reproductive ability. So it might be up to veterinarians to close the gaps to get them performing at their optimal level.

One case involved a stallion that was practically infertile at the beginning of the breeding season, but whose pregnancy rate improved to the high end of normal by the end of the year. The more mares this stallion covered, the better his fertility became

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Written by:

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.

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