Annual Change of Reproductive Hormones in Female Angora Goats

In this research, annual changes of melatonin, gonadotropin-releasing hormone, follicle stimulating hormone, luteinizing hormone, estrogen, testosterone and progesterone were studied on 6 heads of 1.5 years old female Angora goat. To determine hormones concentrations, blood samples were taken from jugular vein of each goat in every month for a year. The blood samples were centrifuged at 4000xg for 5 min. and serum was stored at -20°C until analyses time. Hormones analyses in the serum were performed by enzyme immunoassay (EIA) method. Monthly climatic values and photoperiod were obtained from the Turkish State Meteorological Service and temperature-humidity index was calculated with climatic values. In the study, in order to determine any possible differences in the observed hormones concentrations with respect to months, repeated measures ANOVA analysis was performed. As a result of statistical analysis, there were no significant differences among the months for gonadotropin-releasing hormone, follicle stimulating hormone and testosterone concentration, while significant differences were found among the months for melatonin, luteinizing hormone and progesterone, and estrogen concentration in female Angora goats. According the results of this study, could be concluded that the releases of reproductive hormones examined in female Angora goats was seasonally dependent.