HERITABILITY AND REPEATABILITY ESTIMATES FOR BIRTH AND WEANING CHARACTERISTICS IN DOMESTIC RABBIT

Abstract

Records of 422 kits born in 96 litters were used to estimate heritability and repeatability of litter size at birth (LSB) in domestic rabbit (Oryctolagus cuniculus). Estimates of heritability and repeatability were also calculated for Litter Birth Weight (LBW), Gestation Length (GL), Litter Size at Weaning (LSW), Survival to Weaning (SW), Litter Weaning Weight (LWW), Average Kit Weaning Weight (AKWW) and Weaning Sex Ratio (WSR). Heritability estimates for LBW, GL, LSW, SW, LWW and AKWW were obtained from the buck variance component, while the heritability estimate for WSR was obtained from the doe variance component. Repeatability estimates for traits considered in the study were computed from the variance components of the buck or doe. Mean litter size at birth, litter birth weight, gestation length, litter size at weaning and litter weaning weight were 4.50±1.50, 198.00±68.00, 31.79±0.34, 3.57±1.64 and 1154.57±57.00, respectively. Heritability estimates ranged between 0.27±0.74 and 0.96±0.42. Repeatability estimates varied between 0.09±0.21 and 0.55±0.17. The results indicated a potentially high genetic gain accruable from selection for LSB, LBW, LSW and LWW. The estimates of heritability suggest strong contribution of additive genes in the expression of all the litter traits investigated (except SRW). The lower estimates of heritability for litter size and weight at weaning compared with estimates obtained for the same traits at birth suggest greater environmental influence on weaning traits. The low estimates of repeatability obtained for many of the traits suggest the need for more than two measurements in evaluating the studied rabbit population for future breeding programme.