Effects of Different Feeding Levels During Mating Period on the Reproductive Performance of Norduz Ewes and Growth and Survival Rate of Their Lambs

A total of 78 Norduz ewes and their lambs were used in the study. Group 1 (control) was grazed only on pasture and Group 2, 3 and 4 were supplied with 200, 300, 600 g-1 head day -1 rolled barley, respectively, in addition to pasture. There were increases in live weights in Norduz ewes in response to supplementary feeding during feeding period (P<0.01). Feed supplementation during mating period did not affect reproductive traits. The effect of ewe age on the twinning rate and litter size (P<0.01) and fecundity (P<0.05) was significant. The mean lamb birth weight, weaning weight, daily live weight gain and survivability at weaning were 4.65 kg, 19.29 kg, 192 g and 96.43%, respectively. In conclusion, supplementary feeding in addition to grazing during breeding season affected live weight in Norduz ewes but not other reproductive traits. Further detailed studies should be carried out in order to determine the effects of supplementary feeding on reproductive traits in this breed.