Genetic study on important economic traits in two strains of white leghorn chicken

The genetic study was conducted using total 849 and 862 birds of IWN and IWP strains, respectively at the Poultry Complex, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand. The traits measured were body weight at 16 (BW16), 20(BW20), 28 (BW28) and 40 weeks of age (BW40), age at first egg (AFE), egg weight at 24 (EW24), 28 (EW28), 32 (EW32), 36 (EW36) and 40 weeks of age (EW40), total egg number produced up to 40 weeks of age (TEN40)and total egg mass produced up to 40 weeks of age (TEM40).The heritability estimates obtained for BW16, BW28 and BW40 were 0.558±0.13, 0.146±0.07 and 0.306±0.10 in IWN strain and 0.424±0.11, 0.499±0.12 and 0.446±0.12 in IWP strain, respectively. The heritability estimate for AFE was 0.478±0.128 and 0.240±0.091 in IWN and IWP strains, respectively. The heritability estimates for egg weight at 24, 28, 36 and 40 weeks of age were 0.104±0.07, 0.415±0.12, 0.056±0.06 and 0.192±0.08 in IWN strain and 0.093±0.06, 0.200±0.08, 0.054±0.06 and 0.092±0.06 in IWP strain, respectively. The heritability estimate for TEN40 was 0.539±0.13 and 0.227±0.08 in IWN and IWP strains, respectively. The heritability estimate for TEM40 was 0.395±0.11 and 0.162±0.07 in IWN and IWP strains, respectively. Genetic and phenotypic correlations of age at first egg withtotal egg number produced up to 40 weeks of age were found to be negative and high in magnitude. Genetic correlations between age at first egg and egg weights at different ages were in general positive and showed increasing trend from low to high with advancement in age in IWN strain, where as in general positive and high in IWP strain.