Breed effect and non-genetic factors affecting growth performance of sheep in a semi-arid region of Nigeria

Objective: This study was conducted to investigate the effects of breed and some non-genetic factors on growth performance of Balami and Uda sheep in a semi-arid region of Nigeria.Methodology and results: Data on birth weight (BWT), 90-day weaning weight (90-DWWT), 6-month weight (6-MWT), 9-month weight (9-MWT) and yearling weight (Y-WT) of 595 lambs (306 Balami and 209 Uda) born in the Sheep Meat Project of the Federal Livestock Department (FLD), Katsina, between 1996 and 1998 inclusive were collected and used for this study. Pre and post weaning weight gains were also estimated on each lamb. Data was subjected to analysis of variance using the generalized linear model (GLM) procedure of SAS to determine the effects of breed, parity, sex, type of birth, season of birth and year of birth on the growth of lambs. Breed and sex significantly (P<0.05) affected body weights at all ages. Pre and post-weaning growth rates were significantly (P<0.05) affected by all the factors examined except parity of dam and year of birth. Significantly low to moderate phenotypic correlations were observed between the growth traits studied.Conclusion and application of findings: Most of the non-genetic factors have been shown to be important sources of variation in the growth performance of sheep. Therefore, effects of environmental factors need to be corrected for if mixed model approaches such as the Best Linear Unbiased Prediction (BLUP) values are to be used for breeding value evaluation in Balami and Uda lambs.Key words: Sheep, Balami, Uda, Pre and Post weaning growth, Sex, Parity