Comparison of growth performance, pasture usage, carcass yield and breast meat characteristics of two different slow-growing broiler genotypes kept in the free-range

Consumers’ interest in animal welfare-friendly systems with outdoor access is growing and therefore the necessity has arisen for genotypes suitable for free-range systems. This study aimed to investigate the suitability of two slow-growing broiler genotypes by comparing growth performance, pasture usage, carcass yield and breast meat traits. Two slow growing genotypes Hubbard ISA Red JA-57 (n= 240) and Sasso XL44 × SA51A (n= 240), were raised in free-range system for 63 days, and their suitability was assessed. Body weight, feed consumption and feed conversion rate were weekly determined. To assess the pasture usage (interior, buffer and outer zones), the observations were performed twice a day. The total of 60 birds (n: 30 broilers/genotype) were randomly sampled for slaughter process at 63rd day of age, and subsequently breast muscle samples were processed for the physical quality and chemical composition parameters of the meat.

At 63 days of age, the final body weight was found to be 2918.0 g and 3253.6 g in Hubbard and Sasso birds respectively (P<0.001). Also, a higher body weight gain was observed for Sasso birds than Hubbard birds as well (3210.2 vs. 2874.8 g, P<0.001). The broilers preferred to pasture at the interior zone rather than buffer and outer zones (P<0.001), and usually in the morning (27.54%) than in the evening (20.93%, P=0.010). The average slaughter weight, carcass weight and carcass yield were higher in Sasso genotype (3296.7, 2540.4 g, 77.1%, respectively] at 63 days of age compared to Hubbard genotype (2878.3, 2192.3g and 76.2%, respectively, P<0.001). The weight and relative weight of breast were also higher in Sasso (746.2 g and 29.4% respectively) than the Hubbard genotype (617.6 g and 28.2% respectively, P>0.001). These findings could help free-range broiler producers to choose a more suitable genotype according to the final body weight, feed efficiency, pasture usage, carcass yield, and breast meat characteristics.