Phenotypic Variation in Retail Beef Yield in Angus Cattle

This paper reports preliminary estimates of phenotypic variation and relationships for carcase traits using records from 386 Angus steers. Carcase traits recorded included carcase weight (CWT), retail beef yield (RBY), carcase intramuscular fat (CIMF), carcase P8 fat (CP8), carcase rib fat (CRIB) and carcase eye muscle area (CEMA). Carcase trait averages for animals used in this study were higher than for those used for the previous estimation of RBY parameters, and the differences evident between summary statistics for historic and contemporary carcase traits records highlights the value of continually recording carcase traits, as well as the value of re-examining relationships between carcase traits. Phenotypic correlations between carcase traits indicated that animals with higher RBY also had, phenotypically, heavier CWT (rₚ = 0.12), larger CEMA (rₚ = 0.31), lower CRIB and CP8 (rₚ = -0.28 and -0.10 respectively) and lower CIMF (rₚ = -0.16). For every 1-kg increase in RBY EBV, recorded CWT, RBY and CEMA were greater by 2.08kg, 0.24% and 2.77cm², respectively. In contrast, for every 1-kg increase in RBY EBV, recorded CIMF, CRIB and CP8 were lower by 0.39%, 1.31mm and 1.81mm, respectively. These preliminary results highlight the importance of continually recording carcase traits as well as the value of periodically re-examining relationships between carcase traits.