Also be aware that not every stallion's semen cools or ships well. Therefore, it is critical for a stallion's sperm viability to be checked after a dose has been extended and cooled for 24 to 36 hours. This is generally the interval between collection and the time the transported semen is placed in the mare. If you are planning to raise a registered foal, be sure to check the association's rules regarding semen transport in advance and follow them. While registry acceptances are growing, not every breed registry permits the use of transported semen.
Timing is critical.
For the greatest chance of pregnancy, a mare must be bred from 12-24 hours before ovulation to up to six hours after ovulation. From a practical standpoint, however, once the mare has ovulated, it may be difficult to determine whether you are still within an acceptable time frame for fertility. Also, remember cooled stallion semen only has a shelf life of 24-48 hours. THE MARE Prior to breeding season, a mare should have a full reproductive examination. A uterine biopsy and culture may be indicated to get a clearer picture of the mare's overall reproductive health.