ABSTRACT
The study was undertaken to compare and evaluate growth performance, conformation and morphological traits of three commercial strains of broiler chicken. A total of 315 day old chicks of three broiler strains (105 from each strain) consisting of NAPRI-X, Marshall and Ross strains, respectively were used in this experiment. Computed indices comprising of Daily feed intake (DFI), weekly weight gain, percentage mortality (MTLY) and feed conversion ratio (FCR) as growth traits; whereas the conformation traits which include Neck length (NEL), back length (BKL), thigh length (THL), shank length (SHL), breast width (BRW), body length (BDL) and wing length (WNL) were obtained. Traits consisting of ocular length (OCL), ocular width (OCW), comb length (CBL), comb width (CBW), beak length (BEL), ear lobe length (ELL), ear lobe width (ELW), wattle length (WTL) and wattle width (WTW) were the morphological traits. Descriptive statistics, correlation, regression and principal component analyses (PCA) were carried out. Results for comparative growth performance, conformation and morphological traits among the three strains at 4 and 8 weeks of age showed that Marshall strain had significantly (P<0.05) higher mean values, except for WTL and WTH in which NAPRI-X breed had the highest values at 8 weeks. However, no significant (P>0.05) differences were observed among the three strains for MTLTY, FCR, BDL, WNL, ELL and ELW, respectively, at 8 week and also MTLTY at 4 week. Correlations among growth traits revealed positive and perfect correlations between FBW, DWG, TWG, DFI and TFI in all the three strains at 4 weeks of age. At 8 week of age, positive and highly significant (P<0.01) correlations were observed between IBW and FBW in Ross strain and also between FBW, DWG and TWG in all the three strains. In addition, positive and perfect correlations existed between DWG and TWG in the three strains as well as between DFI and TFI in NAPRI-X and Marshall strains. The prediction equations for conformation traits revealed that NEL and BKL were the most significant predictors of body viii weight among the three strains. For morphological traits WTL was observed to be the most significant predictor of body weight among the three broiler strains. The PCA for conformation and morphological traits depicts highest eigen values in PC1 for both conformation and morphological traits. The percentage total variance of 84.40%, 73.54% and 88.50% for NAPRI-X, Marshall and Ross strains were adequate for conformation traits. Similarly, adequate percentage total variance of 45.57%, 90.53% and 57.56% were also obtained in morphological traits. In conclusion, it has been observed that Marshall strain was superior for growth, conformation and morphological traits at 4th and 8th weeks of age followed by NAPRI-X and Ross strains. Further study should be carried out to map the genes that make Marshall the best strain in growth, conformation and morphological traits
