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

Abstract

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

Einfluss von Stute, Zuchtmanagement und Tierarzt auf die Ovulationsinduktion und Fruchtbarkeit von mit dem GnRH-Analog Deslorelinazetat (Ovuplant™) behandelten Stuten.

“…The overall response rate of 87.8% and the rate of 82.2% of these mares ovulating within 48 hours confirmed similar values reported previously by Handler and Arbeiter (1996), Jöchle and Trigg (1994) and Meyers et al (1997). The mean interval between treatments and ovulations (ITO) of 44.9 h corresponded well with the range of intervals given with 40.5 and 49.1 h in prior study reports by Handler and Arbeiter (1996), Klug et al (1992), McKinnon et al (1993 and, Meinert et al (1993) and Meyers et al (1997). Of the factors evaluated, only the mares' reproductive status had a significant effect on the product effectiveness, while age, breed and parity had no effect.…”

“…Results obtained with Ovuplant in cyclic mares and their characteristics have been reviewed extensively (McKinnon et al 1993;Meinert et al 1993;Squires et al 1994;Jöchle and Trigg 1994;Mumford et al 1995;Meyers et al 1997). Deslorelin has also been used subsequent to the administration of progesterone by an intravaginal device (CIDR-B) for the treatment of anoestrous mares during the season (Arbeiter et al 1994) and for the induction of follicle growth and ovulation in transition phase mares (Arbeiter et al 1994;Handler et al 1999;Newcombe et al 2002).…”

Induction of ovulation in quarter horse mares through the use of deslorelin acetate and human chorionic gonadotrophin (hCG)

“…In this respect, there is conflicting data. McKinnon and Voss (1993), Meinert et al (1993), Vanderwall et al (2001) and Melo et al (2005) obtained a range of 47.5 and 45.1 h, 46.9 and 43.0 h, 52.8 and 52.8 h and 38.9 and 34.7 h, respectively, between the treatment and ovulation when used hCG and deslorelin. Ley (2006) and Samper et al (2002) compared the use of hCG with deslorelin to check the interval of ovulation in the mares, and obtained 26 to 96 h and 36 to 42 h, respectively.…”

Reprodüktif açıdan sorunlu kısraklarda aşım sezonu başlangıcında uterus yıkamaları ve hormon kullanımının siklus aktivitesi ve fertilite parametreleri üzerindeki etkisi

“…Kısraklarda östrus siklusunun hormonal kontrolün-de PGF 2 α kullanılarak luteal dönem kısaltılabileceği gibi özellikle üreme sezonunun başında hCG, GnRH veya analogları kullanılarak ovulasyonun indüksiyonu ve belirli bir zaman aralığında toplulaştırılması ve kontrolü mümkündür (12,19). GnRH veya analogları anöstrustaki kısraklarda ovulasyonun erken uyarılması amacıyla da kullanılabilir (14).…”

“…Genelde 2.1 mg DA kısraklarda ovulasyonu hızlandırdığı, östrus periyodunu kısalttığı ve çiftleşme sayısını fertiliteyi bozmadan belirgin oranda azalttığı belirtilmiştir. DA uygulaması sırasında follikül büyüklüğünün ≥30 mm olması gerektiği ve uygulama sonrası 36 saat içinde ovulasyonun gerçekleştiği belirlenmiştir (3, 15,18,19,21). Ayrıca aşım sezonunda anöstrusta bulunan kısraklar ile (2) ilkbahar geçiş dönemindeki kısraklarda, follikül bü-yümesi ve ovulasyonun indüklenmesi amacıyla da DA kullanılmaktadır (2,9,22).…”