Abstract
A total of 240 late (LB) and early (EB) feathering Saudi Arabia Baladi chicks were used in this study to investigate the effect of feathering genotype on carcass traits. Similar number of Leghorn chicks (EL) were used for comparison. All chicks were subjected to conventional management practices. Five birds of each sex and genotypic group were randomly selected and slaughtered at 4, 8, 12, 16 and 20 weeks of age for carcass studies. Traits were calculated in g/kg of plant weight.
Age had a significant ( P less than or equal to .05) effect on all studied traits and the effects of genotype, sex and interactions were also significant upon most studied traits. LB had higher (P less than or equal to .05) abdominal fat and heart relative weights than their EB peers, whereas EL showed lower liver, heart and higher (P less than or equal to .05) plant weight and gizzard Values compared with Baladi. Males had lower liver, gizzard and higher (P less than or equal to .05) plant weight and heart values compared with females. EB females had lower (P less than or equal to .05) eviscerated carcass relative weight than EB and LB males whereas LB females had similar value. Generally, plant weight, eviscerated carcass and abdominal fat relative weights increased whereas those of liver, heart and gizzard decreased (P less than or equal to .05) with age. EB showed higher feather and lower (P less than or equal to .05) head and leg relative weights than LB but EL had the highest (P less than or equal to .05) feather weight value. Males had also higher blood, head and leg and lower (P less than or equal to .05) intestinal relative weights than females. With regard to the effect of age, blood and feather relative weights significantly increased at early and decreased (P less than or equal to .05) at late age periods, whereas those of head, leg and intestinal started to decrease at early age period. The results revealed that sex-linked feathering genes have no or little effect upon most studied traits. However sex-linked late feathering gene seems to enhance abdominal fat deposition and to reduce feather growth. The results also show that most of the early feathering Baladi carcass traits tended to be more similar to those of Leghorn compared with their late feathering peers.