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Online Journal of Veterinary Research©
Volume 22 (4):315-321, 2018.
Effect of gonadotrophin-releasing hormone given at insemination and 10 days later on reproductive performance and progesterone levels in ewes.
Maythem Abdulealah Ismaeel1, Ziyad Tariq Omer AL-Doori2
Departments of 1Medicine, Surgery and Obstetrics and 2Public Health, School of Veterinary Science, Tikrit University, Iraq .
Ismaeel MA, Omer AL-Doori ZT., Effect of gonadotrophin-releasing hormone given at insemination and 10 days later on reproductive performance and progesterone levels in ewes, Onl J Vet Res., 22 (4):315-321, 2018. Authors report effect of gonadotrophin-releasing hormone (GnRH) on reproductive performance and serum progesterone in Nuaemie ewes. Estrus was synchronized with intra vaginal sponges for 14 days and IM injection of 400iu equine chorionic gonadotropin upon removal of sponges. Fifteen ewes were injected IM 0.004mg GnRH at insemination and another 15 ewes at insemination, and 10 days later. Controls (22) were not treated. All ewes were inseminated naturally. Compared with controls, lambing increased 126%, fecundity 172%, and multiple birth rate 63% (P ≤ 0.05), in ewes given GnRh twice. There were significant increases (P ≤ 0.05) in serum progesterone at 10th day of pregnancy in ewes treated twice with GnRH (9.71+1.19 ng/ml and 7.61+0.76 ng/ml progesterone, respectively) compared with controls (3.91+0.44 ng/ml). In ewes given GnRH twice, progesterone increased (P< 0.05) also by the 18th day of pregnancy compared with those treated once or controls (4.85+1.46 ng/ml and 3.39+1.36 ng/ml respectively). We find that GnRH given at mating and 10 days after was most effective.
Key words: GNRH analogue, rate of lambing, fecundity, progesterone concentration.