The Effect of Gnrh Administration on Plasma Progesterone and Reproductive Performance in Ewes

Authors : Mehmet Akif ÇAM, Mehmet KURAN, Erdoğan SELÇUK

Pages : 1065-1070

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Two experiments were carried out to investigate the effect of GnRH administration at mating and on day 12 post-mating on the reproductive performance of Karayaka and Sakız x Karayaka insert ignore into journalissuearticles values(F2); crossbred sheep. In the first experiment, ewes were allocated into a control group insert ignore into journalissuearticles values(K, n = 27);, and groups administered 4 µg GnRH at mating insert ignore into journalissuearticles values(A, n = 27);, on day 12 post-mating insert ignore into journalissuearticles values(AS, n = 30); and both at mating and on day 12 post-mating insert ignore into journalissuearticles values(AAS, n = 30);. GnRH administration in the A and AS groups increased plasma progesterone concentrations insert ignore into journalissuearticles values(P < 0.01);. The pregnancy rate at first mating in the AS group insert ignore into journalissuearticles values(86.7%); was higher than those in the ASS insert ignore into journalissuearticles values(66.7%);, A insert ignore into journalissuearticles values(51.9%); and K insert ignore into journalissuearticles values(51.9%); groups insert ignore into journalissuearticles values(P < 0.01);. There was no difference between the treatment groups in terms of litter sizes insert ignore into journalissuearticles values(1.31, 1.21, 1.21 and 1.20 for AS, K, A and ASS, respectively);. In the second experiment, ewes were allocated into 2 groups, a control group insert ignore into journalissuearticles values(K, n = 70); and a group administered 4 µg GnRH on day 12 post-mating insert ignore into journalissuearticles values(AS, n = 73);. The pregnancy rate at first mating was 71.4% and 80.8% insert ignore into journalissuearticles values(P > 0.05); and litter size was 1.24 and 1.53 insert ignore into journalissuearticles values(P < 0.01); for K and AS, respectively. In conclusion, GnRH administration on day 12 post-mating can increase the litter size and pregnancy rate in ewes.
Keywords : Ewes, GnRH, pregnancy rate, litter size, plasma progesterone concentration