Selection for egg mass in the domestic fowl. 1. Response to selection. Poultry Sci

ABSTRACT A study was conducted to measure selection response for daily egg mass from 154 to 294 days of age in four lines of White Leghorns and to determine the possibility of selecting males with high packed-sperm volume (PSV) as a corollary to egg mass. After three generations of selection, deviation of the selected lines from the control line in total egg mass per bird for 280 days of production varied from 1307 to 2173 g. Data failed to support the hypothesis that selection for PSV in males is associated with selection for increasing egg mass. Realized heritability for daily egg mass, obtained by dividing the cumulative corrected response by the cumulative selection differentials, ranged from.23 to.66 with a mean across lines of.42. Increases in egg mass equal or superior to those observed during the period of selection (154 to 294 days of age) were also observed during the second half of the test period (294 to 434 days). (Key words: chickens, genetics, egg production, selection, egg mass) 1981 Poultry Science 60:1115-112