Reproductive Performance and Mortality Rate in Local and Dorper × Local Crossbred Sheep Following Controlled Breeding

The reproductive and lamb mortality data (n = 187) of the Local and crosses of Dorper × Local ewes following natural controlled breeding in Ethiopia were analysed. Data were collected during 2009-2011 at Sirinka breeding, evaluation and distribution site, eastern Amhara region of Ethio-pia. Breed, lamb sex, birth season, birth year, birth type and ewes ’ parity were considered as fixed effects. Data analyses were performed using general linear model procedures. Breed was a signifi-cant source of variation: the local sheep attained faster the age at first lambing than the cross-bred ewe lambs (469 ± 8.45 vs. 555 ± 6.25 days, p < 0.0001), whereas the crossbred ewes weighed more than the local sheep ewes at the age of first lambing (32.7 ± 0.63 vs. 22.8 ± 0.43 kg, p < 0.0001). Birth year had also important influence on the age and weight at first lambing of ewes. Ewes showed better performance during the later study years, differences attributed due to the improved management advantages in later years. The crossbred and local ewes were comparable in their litter size, despite the fact that the lambing interval of crossbred ewes was longer than th