SOUTH AFRICAN JOURNAL OF ANIMAL SCIENCE, cilt.35, sa.2, ss.83-89, 2005 (SCI-Expanded)
This study was carried out to examine the effect of short-term selection for 5-weeks of age body weight in divergent lines of Japanese quail. Growth curves for both sexes within each selection group resembled the general sigmoid shape of atypical growth curve. Gompertz model curves and the observed growth curves were very similar. In both males and females the parameter estimates of the Gompertz growth curve were obtained with a high determination coefficient (0.9898 >= R-2 >= 0.9840). Sex differences in asymptotic weight were found to be significant across lines. Similarly, in both sexes a significant divergent selection effect was determined for parameter A. The growth rate in all the Japanese quail lines was significantly higher in males than in females. There was also a significant increase in growth rate of the females selected for increased 5-week body weight over the control females, as well as a significant decline in growth rate of males selected for decreased 5-week body weight compared to the unselected control group.