Quarterhorse stallion Smart Lena Boon, owned by D4 Quarterhorses USA semen available from EquiBreed Ltd

Natural mating: In Thoroughbreds, 50 - 60% of mares conceive in each oestrous cycle, by the end of the breeding season 89% of mares are pregnant and only 79% of mares go on to produce a live foal.

Fresh / chilled semen: When fresh or good quality chilled semen is used for artificial insemination (AI) we can expect slightly higher (5 – 10%) per cycle pregnancy rates compared with natural mating. It normally takes 1 – 2 cycles for a fertile mare to conceive.

Frozen semen: The fertility of frozen semen after artificial insemination (AI) is quite variable due to the variability of the “freezability” of different stallions. Thus, the fertility of frozen semen ranges from 0 – 70% per cycle conception and the average is around 40% per cycle throughout the world. It normally takes 2 – 3 cycles for a fertile mare to become pregnant.

To maximise the fertility of your breeding programme we recommend the following:

Mare age: Older mares, greater than 14yo have reduced fertility. These mares are more prone to endometritis (infection of the uterus) and uterine cysts. We recommend that these mares be inseminated with fresh / chilled semen. Generally, we recommend that insemination with frozen semen is reserved for mares that are less than 14yo to optimise its fertility.

Mare foaling status: Mares with a foal at foot and young maidens (3 – 10yo) are usually the most fertile group of mares. “A pregnant uterus is a healthy uterus” so we do not recommend resting mares to optimise fertility. Barren or rested mares may benefit from being inseminated with fresh or chilled semen this year and then save your frozen semen for when she has a foal at foot.

Semen quality: There is huge variability between stallions in their fertility after artificial insemination so it is best to use semen from stallions with a record of good fertility. We can obtain semen from almost anywhere if you can provide us with sufficient details of the stud where the stallion stands. It is important that mares are inseminated with high numbers (>300million) motile sperm and that the semen is handled carefully by experienced personnel.

Silverstone VDL x Telereign mare - Owned by Sandy Steven and Rosie Richards

Non pregnant mares: We recommend that you ask your local / regular vet to treat your mare with an injection of prostaglandin or PG (preferably on a Friday) and then organise for your mare to be scanned at EquiBreed 3 days later (ie a Monday).

Foaling mares: Once your mare has foaled then she should be checked 9 days later by your regular vet to make sure her uterus is clean and returning to its normal size. Foal heat…..unless it is late in the season or your mare is young and has a very clean uterus, then normally we do not recommend using artificial insemination in mares during foal heat.

Therefore, allow your mare to have a foal heat and 7 days after the end of foal heat organise for your local vet to treat her with prostaglandin / PG. Three days after her injection she can be brought to EquiBreed Ltd for oestrous management.

Natural mating: We can manage your mare’s oestrous cycle so that you can organise the optimal time to take her to the stallion for natural mating. In these situations it is ideal if we evaluate your mare after mating as well to rule out any problems with uterine infection or ovulation.

Fresh / chilled semen AI: The management of the mare’s oestrous cycle for artificial insemination is similar to that for natural mating. We normally ultrasound scan your mare 4 – 10 times per oestrous cycle to optimise the timing for ordering the semen, inseminating the mare and to rule out post breeding infections.

Frozen semen: The lifespan of frozen semen is usually only 6 – 12h after thawing. Therefore we scan your mare multiple times and often throughout the night to make sure that we inseminate your mare within 6h before she ovulates. For each insemination we evaluate every sample of semen very carefully and can manage your mare’s programme to optimise the semen quality.

Pregnancy diagnosis: It is very important that mares are scanned by ultrasound at 15 days after ovulation to ensure that they are pregnant and to rule out twins. If twins are diagnosed at this stage they can be treated successfully in 90% of cases. Normally, most pregnancy loss occurs between 20 and 30 days so we also recommend that a pregnancy scan be performed every 10 days until she is 45 days pregnant.

Update www.xyinc.com

A collaborative research trial between EquiBreed Ltd, XY Inc and The University of Sydney, produced the first foal by frozen-thawed sex-sorted semen in Australia in October, 2005.

This is the second foal produced by sexed sperm in Australasia...the first was a foal produced by insemination of a polo pony mare with "filly" sperm and then an embryo was transferred when Dr Morris was at The University of Sydney in 2001.

This technology, licensed by XY Inc. USA, combines the use of flow cytometric sorting of sperm into X (filly) and Y (colt) sperm which are then deposited into the mare's uterus using hysteroscopic insemination (developed by Dr Morris and Prof. Twink Allen, UK in 1998).