Breeding the Mare with Cooled Semen
Using cooled semen to breed a mare requires some special management and planning. Working closely with your veterinarian will be very helpful and cost effective.
Inseminating cooled semen:
- Insemination should occur 0 - 24 hours before ovulation. The semen should be ordered so that it is shipped to arrive within this time frame. Be sure to communicate in advance with the stallion owner to ensure that semen will be available.
- A cooled semen insemination dose should be 1 billion sperm in no more than 50 ml of extender. Larger volumes can be used but in general this type of semen should be concentrated before addition of the extender. The semen supplier should provide you with the initial semen quality values. Prior to cooling, the extended semen should have greater than 50% motility and 65% sperm with normal morphology (shape). Morphology evaluation may not always be done.
- Check the semen microscopically before breeding. Evaluation will be for motility of the sperm and to detect any contamination in the sample.
- Insemination (12-24 hr before ovulation), determining
the time of ovulation:
- Daily teasing and past estrus records to anticipate when ovulation is likely to occur (1 day before going out of estrus)
- Veterinarian checks: either rectal palpation or ultrasound to detect follicular size and estimated time of ovulation (>42 mm).
- Veterinarian checks: either rectal palpation or ultrasound to detect the presence of a >35 mm follicle, administer 2500 IU HCG, inseminate 24 hr after HCG injection.
- Breeding can be done up to 6-12 hr after ovulation however more than 6 hr post ovulation will have decreased fertility.
Some problems which can negatively effect the use of cooled semen are:
Stallion:
- Unable of collect semen or improper processing
- Problems shipping semen (arrival, ability of stallion's sperm to survive)
- Lack of fertility data
Mare:
- Not enough attention paid to estrus detection or previous records
- Microscope not available to evaluate semen before insemination
- Insemination technique
