Study of Gn-RH dose-LH response in dioestrous ewes: A dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Agricultural Science with Honours in the University of Canterbury

Abstract

Five dioestrous ewes were each treated with four doses of synthetic Gn-RH in a random order over a four day period. The doses of Gn-RH used were 0.125 pg, 0.25 μg, 0.5 μg and 1.0 μg. The increase in plasma LH was calculated as a fractional increase in basal LR and this appeared to be directly related to the dose of Gn-RH used. Each ewe was also treated each day with a second identical injection of Gn-RH to investigate priming of the pituitary. No priming was evident with the doses being used, but a biphasic release of LH was noted with the larger doses of Gn-RH. The importance of accurately establishing baseline LH levels is discussed.