Studies on the effect of heat stress on juvenile body weights and carcass qualitytraits in different genetic groups of broilers

摘要

To evaluate the effect of heat stress on juvenile body weights and carcass quality traits, 3 genetic groups of broilers (PB-1, Naked neck and PB-1X Naked neck cross) were used in this study. To maintain the corresponding control population in each ofthe genetic group, chicks were separated and reared in brood grow pens along with treatment genetic groups. In treatment groups temperatures were raised artificially providing high voltage halogen lamps and temperatures were raised to 40° C during 4-6 weeks period. Juvenile body weights were recorded at Oday, 2, 4, 5, 6 and 7th weeks of age. Body weights were significantly (Pd"0.05) different among 6 genetic groups. Lower juvenile body weights were recorded in the heat stressed genetic groups. At 6 weeks of age 10 birds in each of the treatment and control groups were slaughtered and carcass quality traits were recorded. Eviscerated carcass weights were significantly (Pd"0.05) differed among the genetic groups. It was highest in Naked neck control group (62.40%) followed by PB-lx Naked neck control heat stressed genetic group (PNS). Liver weight was also significantly differed (Pd"0.05) among the genetic groups. It was highest in PN control group followed by naked neck control group (NN^. It was evident that in control genetic groups the carcass quality traits were higher as compared to heat stressed genetic groups. It was revealed that naked neck and naked neck cross were performed better for the carcass quality traits in heat stressed environments.