The analysis of meat and bone traits of Plymouth Rock cockerels and capons (P55) at different age
The aim of the study was the comparison of Plymouth Rock cockerels and capons and the evaluation of the influence of their age on slaughter yield, meat quality, and bone traits. The studies were conducted on cockerels and capons from P55 strain (Plymouth Rock). At 16, 18, and 20 wk of rearing, a dissection of whole carcasses of cockerels and capons was conducted, and breast and leg muscles were evaluated in terms of the physical and chemical traits, as well as the chemical composition. Also, traits of femur and tibia bones were studied. It was indicated that capons were characterized by a higher body weight (BW) before slaughter and higher weight of the eviscerated carcass than cockerels at consecutive dates of slaughter. Based on BW, the slaughter yield and muscle content of carcasses, it was found that the most optimal slaughter time in Plymouth Rock cockerels is at 18 wk and capons at 20 wk. It was observed that caponization had a significant effect on the chemical composition of breast muscles with respect to water and protein content. Along with bird age, collagen content in muscles decreased; however, significant differences were observed only in capons. At consecutive dates of evaluating cockerels, resistance and toughness of their femur and tibia bones increased significantly. Significant changes in the physical characteristics of bones were also found.