Effects of genotype and stocking density on broiler performance under three feeding regimes

摘要

Ross 308 and Cobb Avian 48 broilers were used in a 49-day study. The effects of genotype, stocking density, and limited-time feeding on growth performance and carcass characteristics were investigated. Overall, Ross consumed more feed, gained more body weight, and was heavier at marketing age than Cobb. Ross also had a higher drumstick percentage, but the percentages of the other carcass parts were similar in the two genotypes. Birds reared at the stocking density of 30 kg BW/m(2) gained more body weight and were heavier at marketing than those raised at 40 kg BW/m(2), but both groups consumed similar quantities of feed and had similar carcass percentages. Neither genotype nor stocking density influenced feed conversion ratio and mortality rate, but genotype x stocking density interaction significantly affected feed consumption and mortality rate. The feed-restricted birds consumed less feed, gained less weight, were lighter at market age, and had lower percentages of breast, neck, and heart than the full-fed birds. Feed restriction also significantly lowered mortality rate but had insignificant effects on feed conversion ratio and percentages of carcass, breast, back, drumstick, neck, wing, gizzard, heart, liver, and abdominal fat. For profitable poultry production in the tropics and subtropics, it is recommended that Ross 308 raised at the stocking density of 30 kg BW/m(2) and subjected to 10-h daily feed removal from 7 to 35 days of age in a 49-day production period be considered.