Effects of breed, parity and post-mating nutrition on reproductive wastage and pregnancy outcomes of Egyptian sheep

Abstract

The aim of this work was to investigate the effects of breed, parity and post-mating nutrition on reproductive wastage and pregnancy outcomes in subtropical sheep. The experimental design was completely randomized and different groups of ewes were arranged factorially (2×2×3) according to the breed (Rahmani or Barki), parity of the ewes (nulliparous or parous) and post-mating nutritional regimen through the first 45 days of pregnancy (70%, 100% and 130% of maintenance requirements). Barki ewes had higher ability to store back fat through the last third of pregnancy compared to Rahmani ewes. The parous ewes had higher body weight gain and higher body condition score through pregnancy, while they lost lower body weight and body condition score through suckling. The under-nourished ewes had lower body weight, body condition score, back fat and back muscle throughout the whole reproductive cycle. Higher reproductive wastage at weaning was observed in the nulliparous ewes (70%) compared to the parous ones (42%). The under- and the over-nourished groups had a double-fold reproductive wastage through different times of reproductive cycle compared to those fed the maintenance requirements. The parous and the moderately-fed sheep had higher proportion of lambs born, kilograms born, lambs weaned, kilograms weaned and ewes weaned to ewes conceived. Therefore, to maximize lamb crop at weaning, it is important to control the feeding allowance of ewes in early pregnancy to be similar to the maintenance requirements.