Genetic studies of growth and reproduction traits of broiler dam line#

Genetic variation for growth and reproductive traits of broiler dam line was estimated over 13 generations. Cockerels were selected on the basis of their half sisters. The pullets in the first stage were selected on the basis of their sire family means for egg number and finally on index including 20 week body weight, egg number and egg weight. The phenotypic regression of generation means of body weight at 20 and 40 weeks of age, age at first egg, egg number to 40 and 50 weeks of age and egg weight at 40 weeks of age cultch size, pause size, on generation number were -7.76±10.48, -49.52±19.43, -1.15±0.44, 0.87±0.28, 0.98±1.41, 0.03±0.09, 0.003±0.008 and 0.12±0.02 respectively. The heritability estimates for corresponding traits ranged from 0.11±0.08 - 0.60±0.26; 0.10±0.07- 0.64±0.16; 0.16±0.12 - 0.84±0.27; 0.08±0.09 to 0.62±0.26; 0.21±0.13 - 0.77±0.29; 0.11±0.09 - 0.83±0.19; 0.10±0.16 - 0.52±0.14 and 0.22±0.13 - 0.72±0.15 respectively. The genetic regression of heritability estimates on generation number for these traits were 0.009±0.01, 0.003±0.01, -0.006±0.01, 0.009±0.01, 0.007±0.06, -0.01±0.01, -0.02±0.06, -0.10±0.03 respectively.