Behavioural and physiological responses of male and female beef cattle to weaning at 30, 75 or 180 days of age

Abstract Weaning calves at a young age can generate great stress, but it is widely practiced in the industry despite that. So, to what extend weaning in early ages is more stressful than at later ones, in terms of the amount of stress, is currently unknown. Thus, we studied the behavioural and physiological impacts in beef calves at three ages at weaning (30, 75, and 180 days) and the consequences of the calf's sex. Thirty-six calves were weaned and distributed in hyper-early (W30), early (W75), and conventional (W180) weaning groups, which are weaning ages that occur in practice. Behavioural activities and physiological parameters were measured on days 0, 1, 2, and 7 after weaning. Canonical component analysis (CCA) and analysis of variance (ANOVA) were used to evaluate behavioural and physiological parameters. The variables analysed were influenced by the treatment, day of evaluation and interaction between treatment × day, and without effect for sex. The younger the calf, the greater the intensity of responses to the weaning stress. In this sense, the behavioural results (percentages of observations ± SEM) demonstrate that on D0, W30 calves emitted more extreme vocalization (61 %) compared to W75 (15 %) and W180 (0%) (P