Genetic analysis of growth, production and reproduction traits after long-term selection in Rhode Island Red chicken

In present investigation, 325 single-hatchedRIR chicks that has undergone 30 generation of selection based on 40-week part -period egg production were evaluated for growth and layer economic traits using least -squares analysis of variance. Overall least -square means of body weight at 16, 20, 40 and 64 weeks of age were 1362.6 +/- 21.4g, 1791.6 +/- 24.5g, 2184.6 +/- 26.2g and 2433.8 +/- 34.2g, respectively. Males were significantly heavier than females (P 0.001) pound at all ages. Least square means of age at sexual maturity, egg weight at 28, 40 and 64 weeks of age, egg number up to 40 and 64 weeks of age were 134.5 +/- 0.9days, 44.8 +/- 0.3g, 47.73 +/- 0.4g, 51.5 +/- 0.7g, 118.3 +/- 1.2eggs and 214.5 +/- 4.8eggs, respectively. Heritability estimates were high for growth and low to medium for layer economic traits. Genetic and phenotypic correlations among body weights were high and positive. The egg production up to 40 weeks revealed high and positive genetic (0.89 +/- 0.15) as well as phenotypic (0.63) correlations with egg production up to 64 weeks suggesting the its usefulness as selection criterion for genetic improvement of annual egg production.