A social facilitator cow can minimize behavioral and physiological changes of weaning distress in calves?

Abstract

An experienced companion during weaning management of calves may reduce apprehensions associated with novelties. We evaluated the effect of a social facilitator cow (SF), after weaning, on behavior and cortisol concentration of calves. Forty-eight multiparous cows nursing calves (235.6 ± 13.6 kg BW; 224.7 ± 5.7 days old of age) were randomly allocated to one of two treatments (24 animals per treatment; 2 paddocks/treatment): absence (-) or presence (+) of SF. The SF was two non-pregnant multiparous cows and was introduced on the paddock seven days before remote physical separation. Using a direct individual instantaneous sampling of calves, nine mutually exclusive behaviors were recorded from 8:00 AM to 5:00 PM, at a 10-min fixed interval, on days 0, 1, 2, 3 y 7 post-weaning. Also, for 1-min period every 10 min, the occurrence of vocalization, abnormal behavior and/or self-groom was recorded. Cortisol was measured on hair samples on days –19 and 91 respect to weaning day (day 0). For the statistical analysis, MIXED, NPAR1WAY, or GLIMMIX procedure were used depending on the data. Significance was defined as P < 0.05. Vocalizing behavior showed the greatest percentage on days 0 and 1 and grazing on days 3 and 7, and both were not affected by SF. On day 1, walking frequency was greater on -SF than on +SF calves. Calves from +SF showed a lower percentage of eliminating, lying down, playing, and grooming behaviors, and a higher percentage of drinking behavior than -SF group. Hair cortisol concentrations were affected by the sampling time (post > pre-weaning) and by the SF (presence > absence). Although cortisol level is not in the same direction as behavior do, the presence of a social facilitator cow seems to reduce the distress post-weaning, evidenced by the best feeding behaviors and the least motivation behaviors to reunite.