Imposing constraint in selection for cut up carcass value in broiler chicken

H. Khosravinia 1, H. N. Narasimha Murthy 2 and M. G. Govindaiah 3
1. Dept. of Technology of Animal Products, Agriculture Faculty, LorestanUniversity,
Khoramabad, P.B. 450, IRAN (E-mail: [email protected])
2. AICRP on poultry breeding for meat
3. Dept. of Animal Breeding Genetics & Biometrics Veterinary College, Hebbal, Bangalore -560 024

An experimental flock consisted of five broiler strains used to evaluate the response to selection for breast and thighs weight with imposing restriction against low value portions of carcass over three generations. The linear models fitted for mean Breast yield (BY), Legs yield (LY), Low value portions yield (LVPY), against generation showed an average improvement of 0.5%, 0.05 %, and -0.2 % per generation, respectively. The initial mean values for these traits were 21.6%, 22.8% and 29.1%, respectively. Genetic group showed significant influence on all the traits considered. Carcass weight (CW), breast weight (BW), legs weight (LW) and low value portions weight (LVPW) were significantly influenced by gender. Rate of feathering exhibited a significant impact on CW, BW, BY, and LW. Heritability estimates for CW, BW, LW and LVPW were 0.14, 0.16, 0.17 and 0.17, respectively, based on pooled data. Corresponding estimates for yield traits were 0.11, 0.39, 0.10 and 0.31. Genetic correlations between absolute weight of carcass and cut up parts were generally high (>0.85). However, yield traits showed low correlations ranging from -0.05 to 0.22 with carcass weight. The results showed that imposing constraint in a selection program for low value portions of carcass intended to increase the yield of high value parts could be effective but merely through improvement in breast weight and yield. Negative influence of such a policy on thighs yield might be minimized using higher relative economic values for thighs weight in index construction process. Considering BY and LVPY instead of BW and LVPY in selection programs to create and improve particular lines could be more efficient based on their genetic characteristics and irrespective of constant lower variability in BY and LVPY. However, more investigations are needed for clarification of genetic association between LW and LVPW with LY and LVPY, as well as body weight and carcass quality traits.

Source : IPSACON-2005

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