Artificial Insemination

Equine Artificial Insemination at South Coat Equine Veterinary Practice, Meroo Meadow NSW.

Except for the thoroughbred industry, all other breed societies allow artificial insemination to impregnate the mare. Whilst natural breeding is offered by many stallion owners, the use of either chilled semen or frozen semen has become the norm.

Chilled semen – the stallion is collected into an artificial vagina or condom and the ejaculate is filtered, spun down and re extended with a special product which helps the sperm survive while it is chilled and then transported to wherever the mare and her vet are located. Chilled semen can come from anywhere in Australia or New Zealand, either same day or overnight. As is always the case with horses, some stallions “chill” better than others and their semen lasts longer or arrives in better condition, than do others.

At South Coast Equine Vet the process for inseminating your mare with chilled semen goes like this:-
The mare arrives at the practice and is scanned by ultrasound rectally to assess where she is in her cycle. This occurs more frequently as her follicles develop and she comes into season. When she has a follicle of around 35mm diameter and shows sufficient edema in her uterus (ie would be receptive to a stallion), the vet then calls the stallion owner to arrange for a collection in the next day or 2. That semen is then shipped to us, and is put into the mare’s uterus with a pipette. This is done pre-ovulation. An ovulating drug is generally administered to assist with timing. About 6 hours after insemination the mare is re-scanned to check for fluid and ovulation. Usually the mare is flushed with saline. Why? The mare‘s body doesn’t actually like semen, it’s a foreign substance and shouldn’t be there so the mare has a clearance system. Often this clearance system doesn’t work well so the mare gets excess fluid and inflammation which isn’t good for the uterus and will often be the cause of early embryonic death. So by flushing the mare with saline we are helping clearance and aiming to have a healthy uterus. Don’t worry that the sperm are being flushed out – they have swum up rapidly into the oviducts where fertilization takes place and are safely out of harms way. Following ovulation, a pregnancy test is performed 14 days later.

Frozen semen – These days the convenience of using frozen semen and the improved quality of frozen semen has seen it become widely used because it means the genetics of the best horses are available around the world. If you intend to use frozen semen in your mare the first step is to buy it and get it shipped to South Coast Equine Veterinary Practice. We can store it for you in readiness for your mare.
The process of inseminating your mare with frozen semen is more complex and time consuming than is chilled semen, the mare needs to be followed more closely, with frequent ultrasounds as she nears ovulation, so that insemination occurs as close to ovulation as possible. This is enormously important for success as frozen semen once defrosted and put into the mare only lasts about 6 hours. So at SCEVP we assist timing ovulation with the use of “Deslorelin”, then scan the mare 24 hours after its administration, then every 6 hours after that, until the following morning when she is scanned hourly as ovulation nears the 40 hour mark post “Deslorelin”. Rarely is the frozen semen put in pre-ovulation, as there is always a risk the mare doesn’t ovulate or takes much longer than anticipated, and generally mare owners have paid a lot of money for 1 dose of frozen.
Frozen semen comes in straws. A dose may be from 2 straws to 8 straws depending on how and who froze the semen originally. It is sold as either a price per dose, a price per 3 doses to get 1 pregnancy, only occasionally do live foal conditions apply. Check the conditions with the seller so you are aware of all the costs and pitfalls.