Author/Authors :
Nosrati، M نويسنده Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Nosrati, M , Tahmorespoor، M نويسنده Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Tahmorespoor, M , Vatandoost، M نويسنده Department of Animal Science, Faculty of Agriculture, Payame Noor University of Bojnord, Iran Vatandoost, M , Behgar، M نويسنده Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, Karaj, Iran Behgar, M
Abstract :
This experiment was conducted to determine the reproductive performance of Kurdi ewes which were arti-ficially inseminated (AI). In total 240 Kurdi ewes, weighing 49.5±2.5 kg were used in the trail. The ewes were allocated randomly to one of four groups (n=60/in each group). For synchronizing, controlled internal drug release (CIDR) was placed in the vagina of all individuals for 14 days. After removing the CIDR, pregnant mareʹs serum gonadotropin (PMSG) hormone was intramuscularly injected at the dosages of 300, 400, 500 and 600 IU in four groups of ewes. Cervical artificial insemination was performed after two days following CIDR withdrawal and hormone administration. The conception rates in groups I, II, III and IV were found as 63.7, 66.1, 65.8 and 67.9%, respectively. The mean litter size was significantly higher in groups II, III and IV (1.30, 1.34 and 1.46) than group I (1.11). The fecundity rate was lowest in group I (65.6%). Administration of 600 I.U PMSG resulted in the highest (58.9%) multiple births (P < 0.05). These results suggest that 600 I.U. PMSG was more effective in increasing multiple births in the Kurdi ewes in breeding season.
