Evidence of cooperative calves' care and providers' characteristics in zebu cattle (Bos indicus) raised under extensive conditions.

Communal rearing has been reported in several mammals, including wild ungulates. However, until now, there was no evidence of any alloparental care in the Bos genus. To test the hypothesis that calves' groups are formed under the care of specific cows, a herd of 31 peri-partum zebu cows raised under pasture conditions were used. Groups of ≥ 3 individuals within a 10-m diameter were estimated using aerial pictures taken every other day at 7:00, 10:30, 13:30, 16:00, and 18:00 h, during 6 weeks. Temperament (exit speed, flight distance, intensity of reaction), age, and parity of each cow were registered. A total of 142 groups were observed, and in all of them, at least one calf was present. A total of 75% of the groups were more calves than cows, and in 65.4% of the cases, there were 1 to 3 cows with 2 to 32 calves. While there were no groups integrated only by cows, there were 3.5% integrated only with calves. The most frequent group was formed by 2 calves and 1 cow (14.8%). Parity was positively related with the number of times that a cow was observed in a group (R = 0.19, P = 0.01) and with the number of groups in which her calf was present (R = 0.16; P = 0.03). The results of the temperament tests were unrelated to the total number of groups in which a cow was observed nor the number of groups with or without its calf. It was concluded that zebu calves congregate in newborn groups in companion with one or more adults, preferably high parity cows, regardless of their temperament.