Authors : M. Mohajer, A.R. Alimon , H.B. Yaakub , A.N. Naslaji and A. Toghdory
Abstract: One hundred eighty four Zel ewes, 3-5 years of age were used to evaluate the effects of strategic supplementary feeding prior to mating and doses of PMSG to ewe synchronization on reproductive performance of Zel ewes mated to Zel or Shal rams. The ewes fed diets containing two levels of metabolizable energy, 2.0 or 2.3 Mcal kg-1 with 115 g kg-1 DM crud protein for 21 days prior to mating period. After 7 days of experiment, the ewes were synchronised with intra vaginal CIDR devices containing 1.9 g progesterone for 14 days. Ewes received 300 or 500 IU of PMSG injection at CIDR removal time and later mated with Zel or Shal ram. All important reproductive parameters such as ewe fertility, prolificacy, lambing rate, lamb mortality and twining measured. The results showed that Shal rams increased ewe fertility (p<0.05) but not affected by PMSG administration and flushing. Ewes bred to Shal rams had higher fertility compared to ewes bred to Zel rams. Prolificacy was not affected by PMSG administration but it was significantly affected by diet and ram (p<0.05). High dietary energy resulted in a higher prolificacy. Lambing rate changed with energy level and ram breed (p<0.05) and high level of energy increased lambing rate by 26%. Administration of 500 IU PMSG resulted in higher lamb mortality in compared to 300IU (p<0.05). High level of PMSG and flushing diet increased twining rate (p<0.05) but ram had no any effect on twining rate.
M. Mohajer, A.R. Alimon , H.B. Yaakub , A.N. Naslaji and A. Toghdory , 2012. Effects of Energy Level and PMSG Dose on Reproductive Performance of Zel Ewes Bred to Shal or Zel Rams. Journal of Animal and Veterinary Advances, 11: 809-813.