Effect of different periods of maternal deprivation on behavioral and cortisol responses at weaning and subsequent growth rate in zebu (Bos indicus) type cattle

Recently, a dual procedure of maternal deprivation at 25 and 45 days postpartum (dpp), has proven to induce cyclic activity in zebu type cattle as early as 50 dpp. However, little is known about the welfare of the animals subjected to these treatments. The objective of the study was to evaluate the effect of two periods of maternal deprivation on some behavioral and cortisol responses of cows and calves at weaning, and subsequent growth rates. Forty Bos indicus cow-calf pairs raised under extensive conditions were randomly assigned to one of four groups (n=10). In the control group (C) calves remained with their dams; in groups G24, G48 and G72, calves were temporally separated from their mothers for 24, 48 and 72 h, respectively, at 25 days and at 45 days postpartum. Calves were weaned at 150 dpp and weighed at 25, 45, 150, 240 and 270 dpp; behavioral and cortisol measures were recorded from both cows and calves at 24, 48 and 72 h post weaning. More calves were observed grazing and fewer vocalizing in the groups subjected to cow deprivation in comparison with the C group. At day 3 after weaning, serum cortisol concentration was higher (P<0.05) in group C than in the treatment groups, while day 1 after weaning, more G24 and G48 calves were observed <10 m from the fence separating them from their dams (P<0.05) compared with G72 and C calves. Most of the behavioral and cortisol weaning responses disappeared on the third day after weaning, with cows displaying fewer signs of distress than their calves, regardless of treatment. No differences (P>0.05) were found in the weight of the calves at 25, 45 and 150 dpp. However, at 270 dpp, calves in G48 and G72 were heavier (P<0.05) than calves in the other groups. We conclude that calves subjected to mother deprivation during the suckling period displayed fewer behavioral distress signs, diminished cortisol response and higher body weights during the first days after weaning. However, the potential negative impact on calf welfare caused by emotional stress due to maternal deprivation needs further investigation.