Ovulation induction in Caribbean jennies in the tropics

Abstract

The population of some endangered donkey breeds in tropical regions has declined recently. Therefore, there is an increasing interest to improve the reproductive management of these animals. Ovulation induction agents are often used in equine practice to optimize reproduction techniques. However, limited information exists to support its use in donkeys. Therefore, we compared 2 ovulation-inducing agents (commonly used in equine practice) to hasten ovulation in Caribbean jennies in the tropics. Five cycles of 8 Caribbean jennies were used. Jennies were monitored via transrectal ultrasonography and in 4 estrous cycles they had ovulation induced with either 2,500 IU of hCG or 1.8 mg of deslorelin acetate when a follicle measuring between 27 - 30 mm or > 30 mm in diameter was diagnosed. In the Control-assigned cycle, jennies were not treated with hormones and had spontaneous ovulation. Follicle diameters affected (p < 0.05) the interval to ovulation. When given with a follicle > 30 mm, either treatment reduced (p < 0.05) the interval to ovulation. A higher percentage of jennies ovulated within 48 hours after hCG or deslorelin acetate with > 30 mm follicle (p < 0.05), and with deslorelin acetate with 27 - 30 mm follicle (p < 0.05) than in the Control-assigned cycle. In conclusion, Caribbean jennies in tropics with > 30 mm follicle responded to ovulation induction with hCG or deslorelin acetate, with ovulation occurring within 48 hours.