PSI-13 Allometric growth patterns in turkeys (Meleagris gallopavo) show no significant increase in total carcass meat yield

Abstract

Abstract The body composition of livestock has been shown to change over time. Generally, bone maturation occurs first, followed by muscle growth. The objective of this study was to evaluate growth patterns of the most economically significant carcass components (pectoralis major, pectoralis minor, thigh, drum, and rack) in a commercial strain of turkeys. Live body weights and carcass component weights were collected on 1688 toms and 1085 hens between 2012 and 2017. Toms and hens were slaughtered between 109–149 days and 91–114 days of age, respectively. Yield values were calculated for each carcass component as a percentage of the live body weight. Regression coefficients (b) were calculated by regressing yield values on the age of the animal at slaughter. P. major and P. minor yield increased with age, though at different rates, for both toms (b=0.120, P < 0.01 and 0.003, P < 0.01, respectively) and hens (b=0.089, P < 0.01 and 0.020, P < 0.01, respectively). Tom drum and rack yield decreased with age (b=-0.012, P < 0.01 and -0.104, P < 0.01, respectively). Hen drum yield also decreased with age (b=-0.018, P < 0.01), while hen rack yield was found to not be significant from zero. Toms and hens showed similar trends of increasing breast yield with age and an equal combined decline in other carcass component yields. Thus resulting in a small significant increase in hen carcass meat yield (b=0.080, P < 0.01) and no significant increase in tom carcass meat yield (b=0.005, P > 0.01) which were both expected to increase with age given expected body composition changes over time. Strong selection for breast meat yield and the observed negative correlations between breast muscle yield and thigh and drum yields are likely the cause of this trend. Further research should investigate the use of carcass meat yield or other carcass component yields in turkey breeding programs.