Abstract Mixing of male cattle prior to slaughter results in increased physical activity, particularly homosexual behaviour, teasing and mounting. The number of mounts exhibited during the initial 4 h after mixing showed statistically significant correlations with serum enzyme levels at slaughter, pHu, glycolytic metabolites, colour and pigment proportions of M. longissumus dorsi at 48 h post-mortem. The amount of teasing showed significant correlations with pHu, glycolytic metabolites, colour and pigment proportions. The aggressive behaviour, pushing and butting, occurred only as retaliative acts and did not seem to affect meat quality. Among the male types used in this study, the vasectomised bulls were found to be more homosexually hyperactive and thus produced the highest number of dark-cutting carcasses, suggesting that the vasectomised bulls are more prone to dark-cutting due to mounting that occurs during pre-slaughter mixing.