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Abstract
This study was carried out in 4 experiments for studying important points associated with reproductive performance in goats.
First experiment aimed to investigate the incidence, timing and factors associated with embryonic/fetal losses (EFL) in 151 goats of different breeds [Zaraiebi, Damascus, and Cross goats]. All goats were examined by B-mode ultrasonography to monitor EFL during different stages of gestation. Results revealed a high EFL% between D20-23 to D47-54 (19.61 %) compared to the period >D47-54 to birth (11.76 %). A high EFL% was observed in Zaraiebi goats compared to others. The goats that were synchronized by P4 sponge, as well as, artificially inseminated showed a higher EFL % compared to goats with spontaneous estrus, and bred by natural mating, respectively.
The 2nd experiment goaled for evaluating testicular blood flow at supratesticular artery (STA) in 8 male Shiba goats by color Doppler ultrasonography after administration of either GnRH or hCG. Results indicated an increase of testicular blood flow in both groups. However, this increase was significantly higher and earlier in hCG group (1 hour) than that in GnRH group (2 hours).
The 3rd experiment aimed to identify whether inhibin hormone has a role in testicular hemodynamic in goats. Therefore, 9 adults Shiba bucks were injected with 10 ml of either inhibin antiserum (INH group; n = 5) or normal castrated goat serum (NGS group; n = 4). Results revealed significant decreases in the resistive index (RI) values of the STA and marginal testicular artery (MTA) in the INH group compared to those in the NGS group, which indicate an increase of testicular blood flow following immunization.
Finally, the 4th experiment aimed to investigate the expression and localization of kisspeptin in the testes of Shiba goats by real time PCR, and immunohistochemistry, respectively. Results revealed testicular expressions of mRNA encoding KISS1 and immunoreactivity of kisspeptin in Leydig cells. These expressions were higher in the postpubertal goats compared with that in the prepubertal goats.