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Comparative study of genetic response in two WLH strains due to selection for egg production up to 64 wks of age

Central Avian Research Institute
Izatnagar - 243 122


A Comparative study of genetic response was conducted in two WLH strains viz. IWH & IWI. The data were recorded on 1022 & 1226 pullets of IWH & IWI strains respectively, which were the progeny of 50 sires mated to 300 dams. Various economic traits measured were body weights and egg weights at various age; average age at sexual maturity & egg production up to 40th & 64th wk of age. The pullets matured at an average age of 148.64 & 152.20 days in IWH & IWI strains respectively. The average egg weight at 40th wk of age was observed to be 54.44 & 54.55 gm in the two strains (IWH & IWI); the estimates for 64th wk egg production were observed to be 191.48 & 171.99 eggs in IWH & IWI strains respectively.

 Average genetic response for main trait of selection i.e. 64-wk egg production was observed as 1.51 & 1.60 eggs per generation in IWH & IWI strains respectively. Corresponding estimates of genetic response in 40th wk egg production were estimated as 1.12 & 0.84 eggs per generation. There was an indication of decline in body weights at 16th, 40th & 64th wk of age in H & I strains, which was significant only for 40th wk body weights in IWI strain. Age at sexual maturity declined significantly to the tune of –0.64 & -0.39 days in ‘H’ & ‘I’ strains respectively. There was general decline in egg weight at 40th & 64th wk of age in the two strains except for non-significant gain at 64-wk of age in IWI strain (0.33 ± 0.48 gm). The regression coefficient for various important economic traits in the control population indicated non-significant changes indicating its stability in eliminating the environmental trend.

Source : IPSACON-2005
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