Estimates of genetic trend for carcass traits in a commercial broiler line

Genetic parameters for performance and carcass traits in a paternal 1 lineage of broiler

The objective of this study was to estimate variance components for performance and carcass traits in a paternal broiler line. The (co)variance components were estimated by the restricted maximum likelihood method applied to the animal model, including the fixed effect of group (sex and hatch) and additive genetic and residual as random effects. Estimated heritability for performance traits ranged from 0.09 to 0.42. The genetic correlations between traits ranged from -0.50 to 0.97. The heritability estimates of feed intake, weight gain, and feed conversion from 35 to 41 days of age were of low magnitude. The genetic correlations among them were favorable to genetic selection. These results suggest that moderate genetic gain can be obtained to the feed intake and weight gain when the selection criterion is the body weight and prime cuts traits. The feed conversion that had low heritability estimation and low genetic correlation with the body weight and prime cut traits needs to pay greater attention due to the economic importance in the high-meat production lineage breeding programs.

Correlated responses and genetic parameters for performance and carcass traits in a broiler line

The growth rate of broilers has triplicated in the last decades. The body weight is used as one of the selection criteria whereas the carcass traits are valuable market requirements. Thus, the meat industry like animals with high weights at slaughter and better carcass traits. However, the genetic relation of carcass traits with several body weights is unknown. Therefore, we established genetic associations among performance and carcass traits in a broiler chicken line and estimated genetic gain and trends. We also evaluated what age of selection would lead to a more efficient indirect selection of carcass traits. The data set with information of weights in different ages and carcass traits of 128,459 chickens was used. The pedigree data used contained 132,442 chickens. Genetic analysis were realized using ASREML® software applied a restricted maximum likelihood method. Heritability estimates ranged from moderate to high, which indicates that these traits can have high selection response. Genetic correlations between performance and carcass traits varied from moderate to high, which indicates the presence of a genetic association whereas genetic trends indicated that direct selection is occurring for body weight at different ages. Theselection at 30 and 38 days should be considered instead of the slaughter weight, as it anticipates selection in around 12 days.

Effects of genotype and population density on growth performance, carcass characteristics, and cost-benefits of broiler chickens in north central Nigeria

The influence of genotype and stocking densities on growth performance, carcass qualities, and cost-benefits of broilers were examined in a 28-day trial. Two hundred and seven 4-week-old birds each of Anak Titan and Arbor Acre hybrid broiler types were randomly assigned to three stocking density treatments of 8.3, 11.1, and 14.3 birds/m(2) in a 2 x 3 factorial arrangement. Final body weight, average weekly body weight and average weekly feed intake were affected (P < 0.05) by strain, with higher means recorded for Arbor Acres. However, average weekly body weight gain and feed conversion ratio were similar (P > 0.05) in both genetic groups. The effect of placement density on some growth parameters did not follow a linear trend. Arbor Acres had significantly (P < 0.05) higher relative (%) fasted body, carcass, back, neck, and wing weights compared to Anak Titans. Housing density effect (P < 0.05) was observed for relative (%) fasted body, shank, and wing weights of birds. However, the relative weights of visceral organs of birds were not significantly (P > 0.05) influenced by genotype and housing density. The economic analysis revealed that higher gross margin was recorded for Arbor Acres compared to Anak Titans (euro 2.76 versus euro 2.19; P < 0.05, respectively). Conversely, stocking rate did not exert any influence (P > 0.05) on profit margin. Genotype x stocking density interaction effect was significant for some of the carcass indices investigated. It is concluded that under sub-humid conditions of a tropical environment, the use of Arbor Acre genetic type as well as a placement density of 14.3 birds/m(2) appeared to be more profitable.