TDK conference 2019

With the aim of optimal breeding management, and mare’s monitoring, several methods spread which we can detect the breeding activities and also can influence them.

Advanced breeding season and induced ovulation become practice nowadays. With artificial light programmes we can imitate natural long day photoperiod which advance the onset of ovarian activity in horses. In the thoroughbred industry this allows the breeders to meet the required breeding needs, and economic aims, because the foals born earlier can perform better in races, than the younger ones of the year. However, several studies proved that photostimulation has negative effects on gestation length and performance in mares and foals.

The purpose of this study is to examine IGF-1 and IgG, and hair fibre that may reflect the mare's life processes and responses to a supplemental lighting.

Fifty-nine late pregnant mares were divided into two groups, according to whether they received light supplementation or not. The treated group received additional light for 35-45 days, while the control group was exposed to natural light conditions during the experiment (January-March). From all of the mares were blood, and colostrum, as well as hair samples collected within 12 hours after foaling.

Our preliminary results prove that the age of the mare, the gestation length, the mare’s weight, the foal’s birth weight, the foaling day and the extended photoperiod do not influence significantly the IGF-1 level and the IgG concentration. At the same time, for fibre properties, the effect of light supplementation was statistically proven (P = 0.031): treated mares have shorter, finer and weaker hair by the calving.

As a result of the effect of supplemental lighting, we conclude that it may lead to earlier shedding, furthermore early onset of the reproductive cycle.