Effects of genotype and sex on the growth performance and carcass characteristics of broiler chickens.

Six hundred and eight day-old chicks of Ross 308 and Cobb Avian 48 broiler strains were used in a 49-day experiment to examine the effects of genotype and sex on the growth performance and carcass characteristics. Body weight, body weight gain, feed intake, feed conversion ratio, and mortality rate were recorded. Over all, genotype had a significant effect only on feed conversion ratio, Cobb being a better efficient in converting feed than Ross. Males consumed more feed, utilized the feed more efficiently, gained more body weight, and were heavier at 49 days of age than females but had a higher mortality rate. There were significant genotype × sex interaction effects on 49-day body weight, body weight gain, feed intake, and mortality rate. As regards carcass characteristics, genotype affected only liver weight with a heavier liver in Cobb than Ross. Sex significantly affected carcass, back, wing, leg, liver, gizzard, and abdominal fat weights with higher means for males than females for all the traits except abdominal fat weight where females had higher means than males. Genotype × sex interaction effects significantly influenced carcass, breast, back, wing, leg, and liver weights.