Growth performance is usually a fair indicator of subsequent growth rate of chickens. Consequently, the current study was conducted at the Poultry Research Farm, Assiut University on a total of 1272 pedigreed Dandarawi chicks from the 6th generation of selection for high body weight at 8 weeks of age to describe and predict some growth measurements (body weight, shank length and keel length) at different ages of birds by using regression models linear, quadratic, and cubic for males and females in two lines of Dandarawi chicken. Body weight at (day-old, 4, 8, 12, 16, and 20 weeks), shank length at (4, 8, 12, 16, and 20 weeks), and keel length at (8, 12, 16, and weeks) were recorded.
The results revealed that the selection for high body weight at 8 weeks of age in Dandarawi chicken led to remarkable improvement and increasing in growth measurements in the selected line compared to the control line, where the body weight at 8 weeks of age in the selected line was 955.4 gram, while it was 691.70 gram in the control line. As well as males were outperformed females in all growth measurements at all ages in this study. Also, the study indicated that there was highly significant relationship (P<0.001) between body weight and bird age, as well as between shank length or keel length and bird age and the three studied regression models almost very similar and had high coefficient of determination estimates (near to one).
It can be concluded that the selection program is considered a very important tool for achieving further improvement in growth measurements in Dandarawi chicken and the relationship between body weight and bird age was best described with cubic model for males and females in both lines of Dandarawi chicken which had the highest coefficient of determination estimates (0.958 for selected line and 0.951 for control line).