Comparison of Two Live-Animal Ultrasound Systems to Predict Carcase Intramuscular Fat and Marbling in Australian Angus Cattle

Abstract

Genetic and phenotypic parameters were estimated to compare two ultrasound scan systems that predict carcase intramuscular fat (IMF) in Australian Angus cattle. The two ultrasound systems compared were the Pie Medical Esaote Aquila (PIE) and the Central Ultrasound Processing (CUP) technology. The data used in the study was generated from the Angus Sire Benchmarking Program (ASBP), also known as the Angus Beef Information Nucleus (BIN). The heritability of CUP ultrasound scan IMF (CUP_IMF) and PIE ultrasound scan IMF (PIE_IMF) were 0.58±0.07 and 0.35±0.06, respectively. The genetic and phenotypic correlations between the two ultrasound systems were 0.90±0.04 and 0.45±0.02, respectively. The genetic correlations between CUP_IMF and the breeding objective traits of carcase IMF (CIMF), AUS-MEAT marbling scores (AMBL) and MSA marbling scores (MMBL) were 0.70±0.07, 0.67±0.09 and 0.72±0.08, respectively. The genetic correlations between PIE_IMF and CIMF, AMBL and MMBL were 0.74±0.08, 0.69±0.10 and 0.70±0.09, respectively. This study indicates that with the higher heritability of CUP_IMF compared to PIE_IMF, coupled with similar phenotypic and genetic correlations to the objective traits of CIMF, AMBL and MMBL, the CUP ultrasound scan technology is most suitable for genetic evaluation of Angus cattle.