Breed and environmental effects on lamb production in Nigeria

Abstract

SUMMARYTwo indigenous breeds of sheep in Nigeria, the Yankasa and Uda and crosses of these with exotic breeds, were evaluated for lamb weights at birth, 3 months and 6 months of age and for adult ewe weight. The cross-bred lambs were significantly (P < 0·05) heavier than the indigenous breeds at all ages. Differences among the indigenous breeds were not significant. Mature ewe weight was 40·8 kg in the cross-bred and 36·0 and 31·1 kg in the Uda and Yankasa respectively, differences between all breeds being significant (P <0·05). Lamb productivity (lamb weight per kg of ewe metabolic body weight) estimates demonstrated that the differences between breeds were small.Least-squares estimates of effects of environmental factors on lamb performance showed that type of birth and age of dam were important for lamb weights at the three ages. Season and sex also had significant effects on birth and 6-month weights respectively. Correction factors for lamb weights were derived from least-squares estimates.The correlation coefficient between birth and 3-month weight was significant in all breeds and ranged from 0·39 to 0·55. Three-month and 6-month weights were highly correlated with estimates of correlation coefficients ranging from 0·71 to 0·74. Repeatability estimates of birth, 3·month, 6·month and ewe weights, all as traits of the ewe in the Yankasa, were 0·25, 0·21, 0·09 and 0·48, respectively.