Effect of season on hormonal profile and some biochemical parameters at different stages of estrous cycles in Baladi goats

Abstract

Understanding the seasonal patterns of estrus cycle in caprine is crucial to develop the efficient breeding plans in the subtropics. Thus, the aim of the current research was to evaluate the effects of breeding season on hormonal profile and blood biochemical indices at different stages of estrus cycle in normal breeding or out-of-season breeding in goats. Forty-four Baladi goats were monitored for a period of eight months (July–February). Baladi goats exhibit a normal seasonal breeding (NS) at midsummer and continue through the autumn season (68%), with a considerable percentage of females having estrus signs during out-of-season (OS) period (32%). At the mid and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum progesterone level than that reported in the OS group (p = 0.013 and 0.039, respectively). At the estrus and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum β-estradiol level than that reported in the OS group (p = 0.022 and 0.001, respectively). Compared to the OS group, the NS breeding group had significantly higher serum cholesterol at the mid and late luteal phases of estrus cycle (p = 0.001 and 0.016, respectively), and higher serum glucose level in the early luteal phase of the cycle (p = 0.009). In conclusion, the NS breeding goats had superior progesterone (mid-luteal and late luteal phases) and estradiol (estrus and late luteal phases) profiles than that reported in the OS group. This may indicate specific approaches to maintain the breeding efficiency of goats during the out-of-season period.