EFFICIENCY OF THE DESLORELIN ACETATE AND EQUINE PITUITARY EXTRACT ON INDUCTION OF OVULATION IN MARES.

Abstract

The induction of ovulation is a fundamental procedure to optimize the protocols of artificial insemination success. Ovulation inducing agents have been largely used in artificial inseminations using either cooled or frozen semen, and also to sincronize ovulation and embryo transfer, being hCG the most commonly used, however its efficacy is reduced when it is given repeatedly due to the development of antibodies. Alternative drugs have been developed to replace the hCG and also to reduce the anti-body production. Deslorelin and equine pituitary extract (EPE) can be used to sincronize the moment of ovulation. The present study compared the efficiency of different concentrations of equine pituitary extract and deslorelin to induce ovulation in mares. One hundred and twenty-six cycles from 25 mares were used. Ovulation was induced with 1mg of deslorelin (IM), 10mg of EPE (IV) or 5mg of EPE (IV). Two mares from 29 did not ovulate with deslorelin (6.9%) and were removed from the experiment. The mean ovulation intervals with deslorelin (1mg), EPE (10 and 5mg) were: 38.89 ± 7.38^a, 34.75 ± 6.72^b and 37.54±3.05^b hours respectively. Based on results it is possible to conclude that both agents were efficient to induce ovulation until 48 hours, being possible to reduce the EPE’s dose reported in the literature.