SHORT-TERM SELECTION FOR 4-WEEK BODY-WEIGHT IN JAPANESE-QUAIL

Japanese quail have been utilized as a research animal io establish ge netic relationships that may be present in other poultry species. In t his presentation, short-term selection experiments were reviewed. Sele ction intensity appeared to be the most effective in improving BW when selection experiments were compared on a response per generation basi s; however, when generation interval was reduced, the response per yea r was superior despite lower selection intensities for lines selected the same number of generations. Correlated responses over 30 generatio ns of divergent selection for 4-wk BW indicated that selection had a n egative effect on fitness traits, including egg number and fertility. Traits such as follicle and egg weight and BW at the beginning of and after a 120-d laying period were positively correlated with BW during the growth period. The early response of quail lines selected for incr eased BW at 10, 17, 28, and 40 d of age indicate that the later select ion is applied the greater the selection response at maturity. In fact , lines selected at young ages were competitive with late-selected lin es only to the Feint at which selection occurred.