Induction of double ovulation in mares using deslorelin acetate

• Published in: Animal reproduction science Vol. 136; no. 1-2; pp. 69 - 73
• Main Authors: Nagao, J.F, Neto, J.R. Neves, Papa, F.O, Alvarenga, M.A, Freitas-Dell’Aqua, C.P, Dell’Aqua, J.A. Junior
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2012
• Subjects: acetates; Animals; artificial insemination; Deslorelin acetate; Double ovulation; Embryo transfer; Embryo Transfer - veterinary; Enzyme Inhibitors - pharmacology; estrous cycle; Female; Horses - physiology; human chorionic gonadotropin; Mare; mares; Ovarian Follicle - drug effects; Ovarian Follicle - physiology; ovulation; Ovulation - drug effects; Ovulation Induction - methods; Ovulation Induction - veterinary; Triptorelin Pamoate - analogs & derivatives; Triptorelin Pamoate - pharmacology; Embryo transfer; Double ovulation; Mare; Deslorelin acetate
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/j.anireprosci.2012.10.015

This study aimed to determine whether deslorelin acetate could induce double ovulation in mares. In Experiment 1, eight mares were treated with prostaglandin on Day 8 (D8) after ovulation, then treated with saline or with 100μg of a controlled-release formulation of deslorelin acetate vehicle intramuscularly (IM) every 12h from D8 after ovulation until at least two follicles reached 33mm. At this time, ovulation was induced with 2500 IU of hCG. Artificial insemination was performed 24h after induction, and embryos were collected on the eighth day after ovulation was first detected. In Experiment 2, 112 estrous cycles in 56 mares were studied. In this experiment, the deslorelin acetate protocol was initiated only in mares that achieved a follicle with a diameter of at least 25mm and at least one second follicle with a diameter≥20mm was detected, at which time 100μg deslorelin acetate or saline was administered IM every 12h. The other procedures were similar to those described in Experiment 1. The variables studied were analyzed using Student's t-test and Fisher's exact test. In Experiment 1, only two mares in deslorelin group having second follicles of 20–25mm on responded with double ovulation. In the second experiment, 82% of treated mares responded with double ovulation, and the embryo recovery per estrous cycle was 1.12 and 0.57 in the group treated with deslorelin acetate and the control group, respectively (P<0.05). Deslorelin acetate is effective in inducing double ovulation in mares using the protocol proposed. On average, it allows for the recovery of one embryo by uterine flushing.