GENETIC RESPONSE OF SOME BODY MALES MEASUREMENTS AND REPRODUCTION FOR GIMMIZAH CHICKENS SELECTED FOR BODY CIRCUMFERENCE

Abstract

: this experiment was conducted on Gimmizah (GM) chickens aiming to investigate the effect of selection for breast circumference at twelve weeks of age through six generations on some physical characters of males and hatchability besides estimating some genetical sire parameters among the selected generations. Two hundred and twenty hens besides twenty two males were randomly chosen from (GM) flock and considered as base population (G 0 ) composing pen's families (10hens and one male / pen). Day-old chicks produced from G 0 were wing-banded and selected for breast circumference (BC) at 12-wk of age within families. Chickens were selected as parents of the next generation and continued throughout five generations. A total number of 6750 hatching eggs representing the six experimental consecutive generations were used for hatching trials. Data were collected for some physical parameters of GM males at 1 day, 8, 12, 25 and 45 weeks of age for six generations. Hatched male body weights (BW 1 ) were significantly higher for selected line among G 0 , G 4 and G 5 generations compared to those for control one. Selection for chicken BC significantly improved fertility percentage with advanced generations. Moreover, fertility percentage was significantly increased for selected chickens compared to those for control line at fifth generation. high body weights at studied ages through the sixgeneration ranked between 0.50 among the most ages and generations with 0.97 for BW 8 and BW 12 at G 4 .Also, BC high estimates of among the ages and generations ranged between 0.32 for BC 12 at G 5 and 0.69 for BC 12 at G 0 .Genetic correlations between fertility and body weights among the studied generations were low differed between 0.10 up to 0.34, with value of 0.28 for BW 1 at G 5 . It is concluded from this study that fertility trait should be taken into consideration during selection of breast circumference, besides other breast measurements such as breast length and width should be included in the coming genetic selection program.