The amount of connective tissue in meat is believed to be one of several factors which affect meat tenderness. Collagen, the major protein component of connective tissue in muscle, exists as an aggregate of three polypeptide chains, stabilized by intra- and inter-molecular cross-links. The degree of cross-linking determines its solubility to heat and affects the amount which is reduced to gelatine on cooking. This factor is now believed to be an equally important determinant of meat tenderness.

The aim of this work was to determine the effect of three different methods of carcass manipulation on muscle composition in young steers with particular reference to their effects on muscle collagen.

Twenty four Friesian steers (12 weeks age, 113± 6 kg) were offered silage ad libitum either alone (12 animals) or supplemented with 150g fishmeal/kg silage dry matter (DM). Half of the animals offered fishmeal-supplemented silage were also ear-implanted with oestradiol-17β. Six animals offered silage alone were also administered the β-agonist cimaterol via subcutaneously implanted osmotic mlnipumps (0.06 mg cimaterol/kg liveweight/d).