Effects of Lambing Season, Lamb Breed and Ewe Parity on Production Traits of Fat Tailed Sheep and Their Lambs

摘要

The reproductive performance of 154 local fat tailed sheep, lambed in the Autumn-Winter (AW) or Spring-Summer (SS) and weights and survival to 60 days of their 188 lambs (102 local and 86 Romanov cross) were evaluated. The litter size at birth and 60 days of AW and SS lambed ewes was 1.27 and 1.15; 1.26 and 1.19 lambs, respectively (p>0.05). At birth, ewes with greater (3rd-4th) parity produced more (p<0.05) lambs than ewes in first-second parity. Ewe postpartum weights at lambing were significantly different within parity (p<0.001) and lambing season (p<0.05). Ewes that lambed with greater parity (3rd and 4th) and in SS season had significantly higher body weights. Birth and weaning weights of lambs were affected by the lamb?s genotype. Romanov sired lambs had heavier birth (4.3 vs 3.9 kg) and weaning (19.2 vs 15.7 kg) weights than lambs sired by local breed rams. Lambs born in SS reached higher (p<0.05) weaning weights (18.3 kg) than lambs born in AW (16.7 kg). The lamb?s genetic group played an important but not significant role on survival. It was concluded that the greater parity of ewes results in better productivity and lambing season affected dam body weight and lamb growing performance.