ABSTRACT

 The study was conducted to evaluate strain and sex effects as well as their interactions on growth performance, body conformation, carcass, and cost-benefit parameters of three broiler chickens - Hubbard, Marshall and Ross. A total number of 50 birds each ofHubbard, Marshall and Ross were used for the experiment which lasted for 56 days (8 weeks). The experiment was carried out at the Poultry Unit ofthe Teaching and Research farm ofMichael Okpara University of Agriculture, Umudike, where the birds were raised in separate deep litter pens. The experimental layout was a 3 x 2 factorial in aCompletely Randomized Design (CRD) with strains (Hubbard, Marshall and Ross) and two sex groups (male and female) as factors of interest. Each treatment combination (strain x sex) was replicated four times, consisting of at least 12 birds per replicate. Data collected include body weight and linear body traits (body girth, shank length, thigh length, wing length and body length) at 2 weeks interval beginning from 2nd week, growth performance traits, carcass characteristics and organ characteristics as well as cost-benefit indices. Data were analyzed using Univariate analysis model statistic procedure of SPSS . Analyzed results showed that body parameters were affected by the main effects ofstrain and sex but not their interaction. The Marshall and Ross strains had significantly (P<0.05) higher body parameters than the Hubbard strain. The male sex portrayed higher body parameters than the female sex. Growth performance was equally affected (P<0.05) only by the main effects of strain and sex. The Marshall strain performed better based on its highest final weight (1861.14g) and lower FCR followed by the Ross strain. Based on sex effect, the male sex differed more significantly (P<0.05) in final weight (1795.22 vs.1610.13g) and FCR (2.80 vs. 3.12) compared to the female sex. Significant (P<0.05) effects ofstrain and strain x sex effect exclusively affected the carcass characteristics. There was no significant effect of sex. Sexual dimorphism was not significantly apparent on the carcass characteristics. The Marshall strain was mostsignificant (P<0.05) in live weight (1818.75g), defeathered weight (1643.75g) and dressed weight (1359.38g). This was closely followed by the Ross strain, whereas the Hubbard strain obtained the least (P<0.05) values in these parameters. The Ross strain differed most significantly (P<0.05) in breast weight and shank weight whereas the Hubbard strain differed most significantly in wing weight as well as shank weight. Based on the interaction effect, the male Marshall recorded the most significant live weight and dressed weight values. The female Ross recorded the highest (P<0.05) breast (20.18%). The male Hubbard had the highest relative wing weight. The economics ofproduction was equally affected by the main effects of strain, sex and their interaction. Marshall strain exhibited its genetic superiority based on its least feed cost/weight gain and highest revenue and gross margin, followed by the Ross strain. Based on sex effect, the male sex recorded higher revenue (N1406.55 vs. N1258.57) and gross margin (N627.62 vs. N473.79) and lower feed cost/weight gain (N308.00 vs. N343.20) as well as lower cost of feed consumed (N530.93 vs. N536.78) compared to the female sex. The interaction effect shows that revenue and gross margin, which represents profit, were highest in the male Marshall followed by the male Ross and then the female Ross. In conclusion, among the male groups, the male Marshall followed by the male Ross performed best in terms of its higher body weight, least FCR, highest final weight, highest live weight as well as dressed weight, lowest feed cost/weight gain and highest gross margin. Among the female groups, the female Ross performed most outstandingly especially in terms ofits breast weight. Thus, a cross between male Marshall and female Ross is recommended to generate a superior hybrid.