Some Aspects of combined selection in Poultry

Abstract

The analysis of data collected under the IASRI project on titled “Statistical methodology for developing efficient selection procedure in poultry breeding” from Regional Poultry farm at Bhopal during the laying period 1970 was conducted with a view to study the efficiency of different selection indices with one and more auxiliary traits (modified Osborne’s index) over the Osborne’s index. The data was first adjusted for dams and locations effects for each siro separately the adjusted data was finally used to work out the various genetic parameters such as heritabilities, genotypic and phenotypic correlations. Using these genetic parameters the coefficients of the selection indices along with their efficiency over the Osborne’s index was worked out. The regression coefficient of the egg weight was found constant for all the indices in each set of the data, but it was varying slightly for the other two auxiliary traits i.e. age at first egg and egg production up to 240 days. The regression coefficients for the character under improvement i.e. ratio of lay (Y); half sib-family average for Y, full-sib family average for Y and the individuals dam performance for Y was also found changing with change in the combinations of auxiliary traits I the index. The relative efficiency of modified Osborne’s index for rate lay with various combinations of three auxiliary traits i.e. age at first egg, egg production up to 240 days and the egg weight over the Osborne’s index was found less than one in majority of the cases. But the efficiency of the index with the entire three auxiliary traits end with two auxiliary traits i.e. age at first egg and egg production up to 240 days was found more than one in one of the two sets of data under investigation. The all selection indices with individuals’ dams’ performance was having slightly greater efficiency as compared to the indices without the dam’s performance. Besides, this the graphical analysis of selection index with one auxiliary trait (modified Osborne’s index) and with end without inclusion of individuals dams performance was also conducted end the relative efficiency of the indices over the individuals selection was calculated for various combinations of genotypic (rg) and phenotypic (rp) correlations. The graph for different combination of rg and rp was drawn end the efficiency was found considerably higher than one in all the cases under study.