Evaluating beef carcase quality traits in an Australian multibreed population

Multibreed genetic evaluations in beef cattle remain an ongoing area of interest for animal genetics researchers. To implement multibreed genetic evaluations, multibreed reference populations are required using observations recorded across breeds, especially for hard-to-measure traits such as carcase traits. This work aimed to estimate the breed differences for carcase quality traits recorded in a multibreed reference population. A total of 2,034 steers were recorded from the Southern Multibreed Project, with observations for six beef cattle breeds: Angus (N = 629), Brahman (N = 61), Charolais (N = 199), Hereford (N = 445), Shorthorn (N = 283), and Wagyu (N = 274). Matings were predominantly within breeds; however, at one site, a small number of crosses were made between Brahman and Angus (N = 73), and between Brahman and Hereford (N = 69). Carcase traits investigated included hot carcase weight (kg), eye muscle area (cm2), as well as meat tenderness traits; Warner-Bratzler Shear Force (kgf), Compression Testing (kgf) and Hardness (kgf). A mixed linear regression model was evaluated; it included contemporary group (year of birth, herd, harvest date, and, for the tenderness traits, also cooking batch), harvest age, breed proportion (summing to 1 across the six breeds), and heterosis. The final model was determined by backward elimination of non-significant terms (P 2, shear force: 0.94, 0.22, 0.01, 0.09 and -0.65 kgf, compression: 0.36, 0.31, 0.12, 0.11 and -0.53 kgf, and hardness: 0.25, 0.21, 0.06, 0.07 and -0.42 kgf. The results showed that there are differences between breeds within the model for the given carcase quality traits. These breed differences will help inform the development of a multibreed genetic evaluation for carcase and meat quality traits.