Abstract

Body weight and carcass traits are important traits in the poultry industry. Breeding programs are powerful strategies to improve these economic traits. The challenge, however, is to choose an appropriate strategy to increase production. The estimation of genetic parameters in target strains could provide valuable information to determine the potent breeding strategy. Therefore, the aim of the current study was to assess the heritability and the genetic correlations of the Body Weight (BW), Body Dimensions (BD), and Carcass Traits (CT) in four Egyptian strains (Matrouh, Mandarah, Inshas, and Silver Montazah) of dual-purpose chickens. The BW was measured at hatching (BW0), 8 weeks (BW8), and 16 weeks (BW16) of age, and weight gain was calculated from 8 to 16 weeks of age. The BD traits included shank length (SL), keel length (KL), and Body Circumference (BC). Carcass, liver, gizzard, heart, head, and leg percentages were also determined. Data were collected on 2800 dual-purpose chickens with pedigree information. A Multitrait animal model with a restricted maximum likelihood procedure was applied to estimate heritability, genetic and phenotypic correlations for BW, BD, and CT using Wombat software. Heritability estimates for BW traits were between 0.24 and 0.41 for BW0 and BW8, respectively. Heritability estimates of SL, KL, and BC were 0.49, 0.41, and 0.52, respectively. The heritability estimates for CT were low to moderate, ranging from 0.15 to 0.37 for head and gizzard percentage, respectively. The least-square means for BW, BD, and CT varied significantly between strains. The genetic correlation estimates among BW and BD traits indicated a close genetic relationship between these traits. Positive genetic correlations were found between BW and BD with CT (from 0.12 to 0.78). Based on the present results, there were strong positive genetic correlations between all traits, including BW and BD as the most important ones. Therefore, the selection for these traits would improve the carcass traits in the four strains of chickens. Hence, the inclusion of BW and BD as selection criteria in breeding programs would potently affect the improvement in carcass performance, which might positively increase the production profit of such strains.