NATURAL HORMONE PATTERNS OF MEAT FROM STEERS AND BULLS DEPENDING ON SLAUGHTER AGE

Natural patterns of steroid hormones (androgens, progestogens and cort icoids), their precursors and metabolites were analysed in 48 beef sam ples with gas chromatography-mass spectrometry (GC-MS). Muscle tissue samples were taken from steers (n = 23) and bulls (n=25) of the breed German Simmental, which were slaughtered at different ages (151-705 da ys of age). Concentrations of testosterone, dehydroepiandrosterone (DH EA), progesterone, cortisol and cortisone in beef from steers were not dependent on age, whereas pregnenolone, androstenedione and epitestos terone increased significantly with increasing slaughter age (r=0.48, P<0.05; r=0.60. P<0.01 and r=0.62, P<0.001, respectively). The concent rations of the me tabolite androsterone tended to increase as well. Th e differences were not significant, however, due to the high level of variability. In beef from bulls cortisone concentrations were inversel y correlated with increasing slaughter age (r=-0.47, P<0.05). The decr ease from day 175 to day 260 was significant. Testosterone was positiv ely correlated with increasing age (r=0.46, P<0.05). The tissue concen trations at the different slaughter ages did not differ significantly, however. The Delta 5-precursors pregnenolone and DHEA tended to show a minimum at the age of 370 days, followed by a significant increase. No age dependence of the progesterone. androstenedione, androsterone, epitestosterone and cortisol concentrations could be detected. Analysi s of steroid hormone concentrations may form part of a reliable method for estimating the age of slaughtered cattle. In this study, the age of samples was estimated to within +/- an average of 10 weeks.