Short-Acting Deslorelin Implant (Ovuplant®) Could Not Sufficiently Induce Fertile Cycles of Coloured Mohair Goats in Suckling (Anoestrous) Season

Abstract

It is known that the pituitary FSH and LH stores are dramatically depleted during the anoestrous in seasonal breeders. Hence, the aim of this study was to evaluate the effect of deslorelin implant (a GnRH analogue) to induce oestrus in suckling goats. Suckling goats (n=21) of coloured Mohair breed were randomly assigned into two trial groups: Goats in Group I (n=11, Ovuplant (R)) received subcutaneously the implant (2.1 mg deslorelin), while animals in Group II (n=10, control) received no treatment. Along with the implant administration, serum progesterone (P-4) concentrations were determined (every other day up to 12 d) by RIA method. Within 4 days of implant administration, there were significantly higher (P<0.001) rates (100%) of pro-oestrus signs (attractiveness without mating) in Group I, than those in controls (zero %). The signs sustained for 9 days without oestrus (mating) in the vast majority (10/11) of implant-treated animals. But, an exceptional goat was in receptive oestrus commenced from the third day following the onset of pro-oestrus. Even so, there was no pregnancy post-mating. The P-4 concentrations between the groups remained below 1 ng/ml, regardless of implant treatment. Findings suggest that; i) for the P-4 concentrations, there was no marked difference between implant-treated and control groups, as remaining below 1 ng/ml all, and ii) short-acting deslorelin implant could not induce fertile oestrus cycles in coloured Mohair goats during the suckling (anoestrous) season.