The amount of genital microflora (bacteria) residing on a stallion's penis and surrounding areas can fluctuate during a breeding season. However, using proper and sterile management techniques can help ensure microflora increases do not affect semen quality or put the mare at risk for reduced fertility or disease, European researchers learned.

When owners manage breeding stock used in artificial insemination (AI) programs according to the European guidelines, only harmless bacteria should survive and flourish during the breeding season, said Christine Aurich, DVM, PhD, head of the Graf Lehndorff Institute for Equine Science in Neustadt, Germany.

The European guidelines for a sterile environment in AI breeding programs recommend:

• Using a sterile artificial vagina for collection;

• Handlers wash their hands between handling different stallions;

• Housing stallions away from other horses and isolating them from other horses in collection settings; and

• Preventing the stallions’ genitalia from coming in contact with a mare’s genitalia.

Furthermore, European guidelines do not call for washing the stallion’s external genitalia, unlike the guidelines many American breeding centers follow, Aurich said