Acta Vet. Brno 2019, 88: 271-275

The effect of hCG, GnRH and PGF analogue cloprostenol on the oestrus cycle in jennies

Eliška Horáčková, Miroslava Mráčková, Michal Vyvial, Šárka Krisová, Markéta Sedlinská

University of Veterinary and Pharmaceutical Sciences Brno, Faculty of Veterinary Medicine, Equine Clinic Brno, Czech Republic

Received November 28, 2018
Accepted June 13, 2019

The objectives of this study were twofold. Firstly, the present study was designed to examine susceptibility of the corpus luteum (CL) in early diestrus in jennies; and secondly, to investigate the effect of two commonly used hormonal agents in horses on the induction of ovulation in jennies. The oestrus cycles of eleven jennies were monitored by ultrasound every day. When the dominant follicle reached a diameter of 30 mm, the jennies were treated by intramuscular administration of gonadotropin-releasing hormone agonist lecirelin (GnRH, 50 µg pro toto) in the first oestrus cycle, and human chorionic gonadotropin (hCG, 1500 IU pro toto) intramuscularly in the second oestrus cycle. Prostaglandin F analogue cloprostenolum (PGF, 0.125 mg pro toto) was administered intramuscularly 2 days after the first ovulation and the interovulatory interval was monitored. This study showed that intramuscular administration of 50 µg of GnRH agonist lecirelin resulted in ovulation within 48 h in 73% of treated jennies. Intramuscular administration 1500 IU of hCG was found to be poorly effective to induce ovulation, with 36% of animals ovulating within 48 h. Intramuscular administration of PGF analogue cloprostenol 2 days after ovulation was unsuccessful in attempting to shorten the interovulatory interval in donkeys.


The authors are grateful to IGA VFU Brno for the financial support of this research (114/2017/FVL, 109/2018/FVL).


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