The changes in serum FSH and LH levels during the estrus cycle in Xinjiang goats
To investigate the changes of serum FSH and LH concentrations in different fertility ewes during the estrous cycle,17 high fertility ewes and 14 low fertility ewes from Xinjiang goats were selected for the experiment,and the concentrations of FSH and LH in the blood serum were determined by enzyme-linked immunosorbent assay(ELISA).The results showed that both FSH and LH concentrations in the blood of high and low fertility ewes showed pulsatile secretion during the estrous cycle.Serum FSH concentration of high fertility ewes showed four peaks on days 1,5,13 and 21 of the estrous cycle,and LH concentration showed four peaks on days 2,5,11 and 21 of the estrous cycle.Serum FSH concentration of low fertility ewe showed 3 peaks on days 1,5 and 21 of the estrus cycle,and LH concentration showed 3 peaks on days 5,13 and 21 of the estrus cycle.The serum concentrations of FSH and LH in estrus and preestrus were higher than those in late estrus and interestrus.The concentrations of FSH and LH in the serum of high and low reproductive ewes begin to increase during the preestrus period(>17-21 days)and reach their peak on the day of estrus(0-48 hours).The concentrations of FSH and LH in the serum of high reproductive ewes during the four stages of the estrus cycle are higher than those of low reproductive ewes.The basal concentrations of FSH and LH in serum of high and low fertility ewes were the highest in estrus and the lowest in interestrus.These results indicated that the changes of FSH and LH secretion were consistent in estrus cycle of Xinjiang goats with different fecundity;in the whole estrus cycle,the concentration of FSH and LH in high fertility ewes was higher than that in low fertility ewes,and the number of crest was higher than that in low-fecundity ewes.