The effect of hormonal treatment with kisspeptin, GnRH and hCG on semen characteristics in buck Cyprus goats during non-breeding season as compared with breeding season

Abstract

The current study aimed to determine the effect of hormonal treatment with kisspeptin, GnRH and hCG on plasma testosterone concentration and semen characteristics in buck Cyprus goats during non-breeding season as compared with breeding season. This study was executed at the Ruminant Researches Station pertaining to the Directorate of Agricultural Researches, Ministry of Agriculture, Abu-Ghraib, Baghdad (latitude 33˚20' N) for the period from November 15th, 2012 to December 〖31〗^st 2013. A total of 20 buck Cyprus goats 2 years old and averages 55 kg body weight. During non-breeding season bucks were randomly divided into five equal groups (4 bucks / group). The first group (A1) was regarded as a control group, i.m injected with normal saline, whereas, the second (A2) and third (A3) groups were i.v injected with 4 and 8 µg / kg body weight of Kisspeptin-10 respectively. The fourth (A4) and fifth (A5) groups were i.m injected with hCG (250 IU / buck) and GnRH (20 µg / buck) respectively. Plasma testosterone concentrations were significantly (P≤ 0.01 and P≤ 0.05) increased at 20, 30, 40 and 50 min post-treatment in A5, A2 and A3 groups as compared with control A1. Mass motility and individual motility were significantly (P≤ 0.01) in A5, A4, A2 and A3 as compared with control during non-breeding season. In conclusion, our results show that Kisspeptin-10, GnRH and hCG can stimulate the quiescent hypothalamic–pituitary–gonadal axis of bucks during non-breeding season by increasing plasma testosterone concentration post treatment that leads improving some semen characteristics during non-breeding season.