Effect of different dietary energy levels on the reproductive performance of Kivircik sheep under a semi-intensive system in the South-Marmara region of Turkey

Abstract

The objective of the study was to determine the effects of four dietary energy levels (L(1) - 10.3, L(2) - 11.0, L(3) - 11.6 and L(4) - 12.2 MJ ME per kg DM) on oestrus synchronization and fertility in Kivircik ewes. Eighty Kivircik ewes were randomly allocated in equal numbers to the four dietary energy treatments. The groups were treated with intra vaginal sponges containing 40 mg FGA (fluorogestone acetate) for a period of 14 days and 500 IU pregnant mare serum gonadotropin was injected intramuscularly after sponge withdrawal.

The proportion of ewes exhibiting overt oestrus within 96 h after the injection was significantly lower (P<0.05) in the L(1) and L(2) eves (86 and 89 %) than in those on the L(3) (100%) and L(4) (100%) treatments, respectively. Mean litter size and fecundity were higher (P<0.05) in the L(3) (1.95) and L(4) (2.05) compared with the L(1) (1.45 and 1.25) and L(2) (1.63 and 1.55) ewes. It is concluded that short-term (21 days) in the level of dietary energy supplementation pre-mating can have a beneficial effect on reproductive performance in ewes.