Advancing the time of ovulation in the mare with a short-term implant releasing the GnRH analogue deslorelin

摘要: Summary A small, biocompatible and short-term implant releasing 1.5 mg or 2.25 of the GnRH analogue deslorelin was evaluated in 140 Hanoverian (warm blooded) mares during 1990 breeding season (Study I). Mares oestrus with a follicle 40 ± 2 mm diameter were assigned alternately to treatment (70) remained as untreated controls. Implants administered subcutaneously, intervals ovulation determined by rectal examination ultrasound at 12-h intervals. Since results both doses similar, data pooled. Deslorelin implantation resulted ovulations 65 70 within 48 h (93%), while only 5 control ovulated same time period (7%) (P<0.01). Most induced (63%) occurred 36–48 after implantation. In Study II, 4 groups 12 each treated 3,000 5,000 iu hCG, implant, received placebo. All treatments 100% h, versus 25% controls (P<0.01), 63%, 75% 86% these hCG respectively. Hormonal response mares, sampled every consisted elevations FSH LH concentrations >200% >300% baseline values (P<0.001), 67% 79% 24 (P<0.01) 35% 49% (P<0.05), respectively. No local reactions site observed.