For a large part of the summer we are busy with artificial insemination of mares. Our Veterinarians will be happy to discuss the advantages and disadvantages of using freshly collected semen, fresh chilled semen or frozen semen. Successful AI depends on regular monitoring of the mare’s ovaries and uterus so that she may be inseminated as close to ovulation as possible.

The timing of insemination will be determined by which semen is chosen. For fresh or chilled semen, conception rates are highest when insemination is performed within 24 hours preceding ovulation. Frozen-thawed semen has a relatively short life span and therefore requires that mares be inseminated immediately before (within 6 hours) or after (within 4 hours) ovulation. Therefore management of mares for insemination with frozen-thawed semen is more intensive and mares require multiple ultrasound examinations to assess the correct time for insemination. Many of these examinations need to occur outside of normal working hours, so for this reason we prefer to perform frozen inseminations at our clinic.

Conception rates for mares using frozen-thawed semen are often lower and therefore ideally this should be reserved for mares with the best reproductive histories. Insemination with chilled semen requires good communication with the stallion stud so that semen is delivered on time. After insemination, your mare will be checked for ovulation and for post-breeding inflammation. Provided all is well, your mare will be scanned at 16 days following ovulation and if pregnant, it is advised that scans be performed at 28 and 45 days to make sure the pregnancy is developing normally. Older or problematic mares may require further treatment in this early period.