Effect of Commercial Crossbreeding and Growth Intensity on Slaughter Indicators, Microstructure and The Quality Characteristics of Biceps Brachii Muscle in Bulls

The commercial crossbreds with various genotypes and different growth rates in terms of the fattening and slaughter value as well as the microstructure and the quality characteristics of musculus biceps brachii were investigated. The experiment involved 38 bulls: 20 crossbreds obtained from Polish Black-and-White Lowland dams (BW) sired by Limousin bulls (LIM) – group I, and 18 crossbreds obtained from BW cows and Simmental bulls (SIM) – group II. The animals of both groups were divided into low growth rate (LG I and LG II; daily weight gain ≤900 g/day) and high growth rate category (HG I and HG II; >900 g/day). The results show that significantly better dressing percentage and carcass conformation (based on the EUROP carcass classification system) were attained by BW × LIM hybrids. The genotype of bulls did not influence the content of valuable cuts in carcass and meat content of cuts, as well as most characteristics of the meat quality. The differences (P<0.05) in anaerobic index were noticed in both genetic groups of bulls in the two growth rate categories. The findings presented in the experiment also show that the number of bulls with giant fibres (GF) and the size of GF was greater in more intensively growing bulls (P<0.05) and it probably determined the higher values of tenderness and acidity of biceps brachii muscle. It should be noticed that the increased growth rate of bulls may result in poorer quality of meat.