REPRODUCTIVE FUNCTION NORMALIZATION OF 15 YEARS OLD MARES
The possibility of overcoming of an anestrus in the spring-summer period with the use of peporelin in mares older than 15 years, during the natural breeding season, which were in an anestrus, was investigated, which was not possible to overcome with traditional methods. It was established that the introduction to mares older than 15 years with signs of age-related ovarian dysfunction of the progesterone-estrone complex followed by induced luteolysis in 31.6 % of cases led to the recovery of reproduction cyclicity and the covered of stallion (50 %) in natural mating. The use for mares, which did not show a result when introducing a progesterone-estrone complex, 0.15 mg of peporelin and subsequent induced luteolysis, showed that 76.92 % of the treated mares came into the oestrus on 7.22 ± 0.795 days after the cloprostenol introduction. For mares with larger sizes of antral follicles for the period of the beginning of the experiment, oestrus was more likely R = -0.67 (p <0.05) and ovulation occurred relatively faster R = -0.72 (p <0.05).