In horse breeding, it is very important to keep mares foaling annually and having foals early in the breeding season (January-June). Because the foal born at the end of a breeding season (June) has to race with those born early in the year (January). This represents a serious competitive disadvantage for race foals born at later stages of the breeding season. Therefore it is important to correct mare's cycling irregularities in the transition periods and achieve early first ovulation of the season.

Additionally, achieving pregnancy of the mares with possible minimum number of insemination is also very important for horse breeding. Thus, the stallions are benefitted optimally and extra cost of additional insemination is prevented. Risk of uterus inflammation due to multiple breeding will also be reduced. Mare's pregnancy can be obtained with minimum number of insemination by screening the follicular development and by applications involving stimulation of ovulation before insemination.

Loss of performance and unwanted signs during estrus period in race and show mares is another concern of horse breeders. These problems can be overcome by procedures for suppression of estrus signs or cyclic activities.

This review, provides information about solving these problems by focusing on subtitles involving “stimulation and regulation of reproductive activities” and “suppression of reproductive activities”.