Temporary suppression of pulsatile LH release following a single injection of a GnRH agonist (deslorelin) in ovariectomised holstein dairy cows

Abstract

The objective of the experiment was to investigate the potential for using a single injection of the GnRH agonist [D-Trp6, Pro9 - des-Gly10-NH2] GnRH-ethylamide (deslorelin) to suppress LH secretion in ovariectomised Holstein cows. Each dose of 10, 100 and 1000 μg deslorelin was injected intravenously into each of four ovariectomised cows on day 0. Blood samples were collected hourly on day 0 to profile the induced LH release. Frequent serial blood samples were collected at 10 min intervals over 4 h on days -3, - 1, +2, +4 and +6. The injection of deslorelin induced a surge-like release of LH that begun within 1 h in all cows. There was no difference between deslorelin doses in terms of maxi..