Genetic and Phenotypic Parameters of Birth Weight Traits in Fulbe Sheep in Cameroon

Abstract

Data on the birth weight of 610 lambs produced from 21 rams randomly mated with 199 primiparous Fulbe ewes were collected between 1993 and 1996 at the Institute of Agricultural Research for Development, Garoua Research Station. Data were used to identify and quantify factors affecting the birth weight (BWT) and litter birth weight (LBWT), and to estimate direct and maternal heritabilities, genetic and phenotypic correlations between direct and maternal effects. Results indicated that 26.86% variability in BWT and 34.20% in LBWT were caused by sex, season of birth, year of birth, parity, birth type and feed group. Heavier lambs (2.36 kg) were produced during the cold dry season (October to January). Mixed litters had significantly higher weights (3.97 kg) than litters only composed of either males (2.73 kg) or females (2.64 kg). Estimates for direct and maternal heritabilities were 0.61 and 0.32 for BWT, and 0.30 and 0.27 for LBWT. Estimates for genetic and phenotypic correlations between direct and maternal effects were -0.48 and 0.28 for BWT, and -0.65 and 0.57 for LBWT. Due to the high negative estimates for genetic correlations, long-term selection on own performance for either BWT or LBWT will adversely affect maternal performance.