Inheritance of growth traits in young chickens

摘要

The performance records of 1236 progenies of 47 IWG strain sires and 200 IWM strain dams of White Leghorn were utilized in this study. The mean +- SEs of 4 week, 6 week and 8 week body weights were 242.37 +- 1.97, 372.38 +- 3.16 and 503.75 +- 3.37 g, respectively whereas ,growth rates in 0-4, 0-6, 0-8, 4-6, 6-8 and 4-8 weeks of age were obtained as 7.41 +- 0.07, 8.03 +-0.08, 8.37 +-0.06, 9.29 +- 0.15, 9.39 +- 0.15 and 9.33 +- 0.08 g/day, respectively. The heritability estimates of these traits were low to medium. The phenotypic and genetic correlations among body weights at different ages were high , positive and significant. A highly positive and significant phenotypic and genetic correlations were also obtained between body weights at different ages and growth rates during 0-4, 0-6, 0-8 and 4-6 weeks of age. In this study no trend could be obtained in genetic and phenotypic correlations among growth rates at different intervals. The study also revealed that absolute weights are more reliable criteria than body weight gain.