An application of the discriminant function for selection in poultry

Summary

Egg production in poultry is controlled by genetic factors at least partly inherited from the sire. Selection of sires is therefore important in ensuring highly productive progenies. A discriminant function score based on different characters of the daughters related to egg production would be the best criterion for this purpose, since the coefficients of the function are so obtained as to maximize the regression of the genetic value of the sire on his phenotype as reflected in the mean performance of the progeny.

Data on the number of eggs laid, egg weight, body weight of the pullet and her period of maturity were examined for 218 Brown Leghorn pullets belonging to progenies of 17 sires. There were significant differences between progenies in egg weight and period of maturity. None of the simple correlations between progenies was significant except that for egg number and body weight which approached significance. The discriminant function obtained showed that egg weight had the highest selective value. Selection with the help of this function was found to register a somewhat higher genetic advance than straight selection. The application of the analysis of variance for testing the significance of discrimination between sires is pointed out.