EFFECT OF GONADOTROPIN-LIKE HORMONES AND RECOMBINANT GROWTH HORMONE TREATMENTS ON SEMEN CHARACTERISTICS OF FRIESIAN BULLS

Abstract

he present study was carried out at the Department of Animal Production, Faculty of Agriculture, Cairo University in collaboration with Sakha Experimental Dairy Fann (Kafer El-sheikh) belonging to Animal Production Research Institute, Agricultural Research Center, Ministry of Agriculture, during the years of 2000-2001. This study aimed to evaluate the reproductive efficiency of Friesian bulls intended to be_ sires in A. I. Center. Experimental work was carried out to investigate the effect of injection of; rbSf, GnRH, hCG, and PMSG on semen physical characteristics and some biochemical components in seminal plasma and blood plasma. Fifteen Friesian bulls were divided into five similar groups: (1): control, injected (i.m.) saline solution (0.9% Nacl). (2): each bull received 8 injections (S.c.) 500 mg rbSTII4d. (3): each bull rcceh•ed 8 injections (i.m.) 250 pg GnRWI4d. (4): each bull received 8 injections (i.m.) 5000 lU hCGII4d. (5): each bull received 8 injections 1000 I.U. PMSG/J4d. Blood samples were obtained from each bull after 2 hours from injection and afler a week from injection (glucose, total lipids, and testosterone concentration, as well as activities of both AST and ALT enzymes. The obtained results could be summarized as follows: (1). Semen physical characteristics: Hormonal treatments was found to have a highly significant effect on the ejaculate volume. sperm concentration, total sperm output, mass motility score, live (%) and Spcnn abnormalities (%)(P<O.OOJ)..Dulls injected with GnRH or hCG gave a large ejaculate volume (4.10 and 4.08 mi.) rollowed by those injected with rbST or PMSG (4.03 and 3.75 mi.) and the lowest value was that of the control (3.1 J mi.).