Abstract
Endocrine changes in cattle treated with GnRH I. GnRH-stimulated LH and FSH secretion in relation to stage of cycle and in cows with ovarian cysts. The aim of the present investigation was to determine whether there is a difference between LH and FSH secretion in cows with ovarian cyst disease and normal cows stimulated by GnRH. Seven cows were treated with 20 μg GnRH (Buserelin) once in oestrus and on days 3, 13 and 19 of the oestrous cycle. Eighteen cows with ovarian cysts were divided into 2 groups according to a plasma progesterone concentration of greater or lower than 1 ng/ml. These cows, also, were treated with 20 μg Buserelin. The basal LH concentrations in the cyclic cows and in the animals with ovarian cysts were identical. The basal FSH secretion of the cows with ovarian cysts was 25 % lower than in the cyclic animals. The LH secretion released by GnRH of the “cystic” cows was twice that of cows in oestrus and on day 3 of the oestrous cycle. The FSH secretion induced by GnRH in the “cystic” cows with progesterone concentrations below 1 ng/ml were 40 % lower than that of the animals of all other cyclic stages. These differences in the endocrine functions open new aspects for the clinical assessment of ovarian cysts in the cow
Braun, Ueli