Estimation of heritability and repeatability for pre-weaning body weights of domestic rabbits raised in the humid tropics
Heritability and repeatability estimates are needed for the genetic evaluation of livestock populations and consequently for the purpose of upgrading or improvement. Pooled data on 302 progenies from three consecutive parities of purebred rabbit breeds (Chinchilla, Dutch and New Zealand white) raised in Derived Savanna Zone of Nigeria were used to estimate heritability and repeatability for pre-weaning body weights between 1st and 8th week of age. The experiment was carried out at the Rabbitry Unit of the Teaching and Research Farm of the Ebonyi State University, Abakaliki. Traits studied include: Kit Weight at birth (KWB), 2nd week (K2W), 4th week (K4W), 6th week (K6W) and 8th week (K8W). Nested random effects analysis of (Co) variance as described by Statistical Analysis system (SAS) were employed in the estimations. Respective heritability estimates from the sire component (h2 ) and s repeatability (R) as intra-class correlations of repeated measurements from the three parities for KWB, K2W, K4W and K8W were 0.59±0.24, 0.55±0.24, 0.93±0.31, 0.28±0.17, 0.64±0.26 and 0.12±0.14, 0.05±0.14, 0.58±0.02, 0.60±0.11, 0.20±0.14. Heritability and repeatability (except R for KWB and K2W) estimates are moderate to high. In conclusion, since preweaning body weights in the present study tended to be moderately to highly heritable and repeatable, hence, improvement of rabbits raised in derived savanna zone can be realized through genetic selection criterions.
Keywords: Heritability, Nested design, Parity, Pooled data, Repeatability