Breeding Truths & Folklore

Breeding season is upon us. With that, many questions are often raised that we don\’t typically think about at other times in the year. Plus, the subject of breeding can conjure up many different opinions and conversations regarding what\’s \”best\” to obtain equine reproductive success. Here are two of the most commonly debated breeding myths and breeding specialist, Dr. Chris Berezowski of Moore Equine\’s Veterinary Reproduction Centre helps us sort through the mire.

1. Two doses, two inseminations.

MYTH

When two doses of semen are shipped, there are varying opinions regarding whether or not both should be used at the same time, or if one should be held until the following day. This is a widely debated subject in the world of equine reproduction. Says Dr. Chris Berezowski of Moore and Co. vet clinic located in Balzac, Alberta, “When two doses are sent, it’s a bit of a myth to do a breeding immediately and save one dose to breed with again the next day.”

Dr. Berezowski says it’s actually better to put both doses in at same time. “The reason is because as soon as sperm is collected from a stud, it’s dying,” he says. “Extender helps it survive transport but regardless, that sperm is dying. By putting one dose in and then waiting 24 hours for the second dose – you have more sperm dying. It’s better for the sperm to be in the mare’s uterus rather than sitting in a box. Sperm still die in the mare’s uterus but not to the same degree they do sitting in a syringe.”

2. A larger breeding dose is always better.

MYTH

“A larger breeding dose does not mean a larger sperm concentration,” Dr. Berezowski states. “There are some studs that do better with very a small volume where the sperm are centrifuged to concentrate them. So more volume doesn’t necessarily mean better odds for breeding.”

Of course, it all depends on the horse but a larger volume can actually mean a smaller concentration: doses with a lot of extender in it can amount to some “pretty watered down stuff.”

In terms of the mare, usually her uterus can handle about 100 mls of volume. “So if you were putting in two syringes of 60mls each, the last little bit might not fit in there,” explains Dr. Berezowski.

Additionally, more volume can also occasionally lead to irritation of the mare’s uterus. “If anything, this happens with an extender and in particular it’s a frozen semen issue. But it can occur with normal cooled semen as well. The ingredient added for cryo-protection can sometimes irritate the mare’s uterus,” said Dr. Berezowski.

Chris Berezowski is an equine reproductive specialist at Moore & Co. veterinary clinic in Balzac, Alberta. He received specialty training at Texas A &  M University and prior to that, went to the Western College of Veterinary Medicine in Saskatoon, Saskatchewan.

Stayed tuned for tomorrow’s blog on My Stable Life where we reveal three additional breeding debates. Are they fact or fiction? You decide.