Managing mares for chilled and frozen semen

When managing mares for artificial insemination (AI), the aim is to introduce sufficient ‘fertile’ spermatozoa into the uterus close enough to ovulation to offer an optimal chance of fertilisation, without compromising subsequent pregnancy maintenance, e.g. by provoking a persistent breedinginduced endometritis (PBIE). The strategy will take account not only of semen type (fresh, chilled or frozen), but also quality (number of ‘normal’ sperm), availability (e.g. certain days of the week; number of straws) and mare reproductive history. The major practical differences between chilled and frozen semen are the preferred timing of AI with respect to ovulation, and that chilled semen is usually ordered shortly prior to use, whereas frozen semen is usually stored on site ...