Reproductive performance of seasonal ewes and does fed dry fat during their postpartum period

This study was carried out to evaluate the effect of feeding a dry fat source to seasonal ewes and does on their postpartum reproductive performance. Forty five multiparous Awassi ewes (LW = 60.1 +/- 3.2 kg) and 45 Shami does (LW = 49.6 +/- 2.4 kg) were randomly assigned into 3 dietary treatments (n = 15/spp) for 60 days postpartum in a completely randomized design (CRD) set. Females were housed with their offsprings and fed one of three isonitrogenous total mixed rations (TMR) containing 0, 3, or 5% of dry fat. Blood samples were taken individually every 3 days to determine serum progesterone concentration levels starting one week postparturition via radioimmunoassay kits. Progesterone concentrations increased (P < 0.05) in ewes fed 3% fat addition but not for 5% level. Meanwhile, those of doe were not affected by adding supplemental fat. No differences were observed in days to 1st or 2nd postpartum ovulation in both species. Milk production was higher (P < 0.05) for fat treated ewes with no differences between the 2 fat levels, while it was not different among does groups. Final live weight of females in both species was also not affected by fat supplementation. However, live weight changes were higher (P < 0.05) for ewes with no differences between 3% fat level and control groups, and lower in does with increased fat level and with no differences between the 2 treatment groups. Weaning weight and average daily gain of the newborn in both species were not affected by fat supplementation. Litter weight was not different for ewes, but it was higher (P < 0.05) for treated does with no differences between 3% and 5% supplemented fat groups. Therefore, one can conclude that supplemental fat to ewes at 3% during their postpartum period might recover their cyclicity late in the breeding season, but not at high levels (5%), and can improve their milk production and affect live weight change during that period with no effect on weaning weight or litter weight of lambs. For does, supplemental fat is not capable of affecting their postpartum cyclicity, milk production, and weaning weight of their kids, but reduces their live weight change and litter weight. (c) 2007 Elsevier B.V. All rights reserved.