Evaluation of two doses of Buserelin as an ovulation inducer in mares

Abstract

The rational and controlled management of equine reproduction in commercial programs has led todevelopment of drugs that contribute to regulate certain physiological processes in mares, such as luteolysis or ovulation. Among them, human chorionic gonadotrophin (hCG) and GnRH synthetic analogs (histrelin, deslorelin, gonadorelin, buserelin, among others), as ovulation inducers, allowing greater reproductive efficiency. Buserelin has been on the global veterinary market for many years, however there is no formulation adapted specifically to equines. This communication describe our preliminary results from experiments carried out during the 2019-2020 reproductive season, in which two different doses of a new formulation of buserelin were used as ovulation induction drug in mares, with the aim of evaluating and comparing their clinical efficacy, in the framework of a Master in Equine Production (UNRC). The analysis included 51 healthy mares (25 Quarter Horses and 26 mixed breed), in a total of 96 cycles. They were randomly divided into group 1 (N = 61) and group 2 (N = 35) that in the presence of estrous clinical signs, a ≥35mm follicle and uterine edema received 0,2mg (G1) and 0,4mg (G2) of buserelin intravenous rute.The results showed a greater efficacy of the drug, which produced 89% ovulation rate within 48 hours after application in group 1 and 77% of ovulations in group 2. No statistical significance difference was found between treatments using chi square test (p>0.05). Also there wasn´t found statistical significance difference between age groups (p>0.05).