Effect of three weaning methods on behavioural, cortisol and weight changes in buffalo calves

Context Calves reared in cow–calf systems separated from their mothers could present various physiological and behavioural changes. Aims The objective of the present study was to examine the effect of different weaning protocols on plasma cortisol concentrations, behavioural responses, and weight gain in water buffalo calves. Methods In total, 40 Murrah buffalo calves (20 males, 20 females) aged 7–8 months and weighing 247.05 ± 33.23 kg were included. The animals were assigned to one of four treatments (10 per group, 5 males, 5 females), as follows: non-weaned calves (NoW); calves weaned abruptly on Day 0 (AW); calves fitted with nose-flaps anti-suckling devices on Day –7 and completely separated from their mothers on Day 0 (NFW); and calves separated from their mothers by a fence line on Day –7 and, then completely separated from their mothers on Day 0 (FENW). Plasma cortisol was measured on Days –7, –6, –4, 0, 1 and 3, while the behavioural variables were measured from Day –7 to Day –4, and from Day 0 to Day 3. The weight of the calves was evaluated on Days –9, –7, 0 and 3. Key results AW calves presented higher cortisol concentrations than did NoW calves (P = 0.0002) and showed a marked increase in walking and decrease in grazing and ruminating on Days 0–3 compared with the other treatments (P < 0.0001). The use of NFW caused behavioural changes after the device placement and after the final separation from the mother (P < 0.0001). In FENW, behavioural changes were observed after the separation by a linear fence but no negative changes were observed after the final separation from the mothers, and positive behaviours such as grazing, rumination and exploration increased. No changes in weight gain were observed (P > 0.05). Conclusions No clear effects were observed in the implementation of alternative weaning, since both NFW and FENW presented changes related to stress at weaning, compared with abrupt weaning. However, in FENW, no behavioural alterations were observed after definitive separation from their mothers. Implications The application of fence-line separation before final separation could be a promising strategy to reduce stress at weaning in water buffalo calves. However, further studies are required to determinate its long-term effect.