Following a pilot study, the aim of this study was to test the hypothesis whether occurrence of massaging the anogenital region of a calf by a non-maternal hind is a reliable indicator of adoption. The investigation was conducted between 28 May (1st day of calving) and 2 September (abrupt weaning of all calves) on a red deer farm at Vimperk, Czech Republic. Fifty hinds and their calves were observed but only complete data sets of sucking bouts were considered for evaluation. Massaging occurred mostly during the 1st month of the calf’s life. All filial calves were massaged repeatedly. Other calves received ano-genital massage at least twice (termed adopted), on a single occasion or not at all (termed non-filial). Filial and adopted calves behaved in a similar way but differently from non-filial calves. They sucked in an antiparallel standing position so that the hind could lick their ano-genital region more often than the non-filial calves. This occurred even when two calves were involved in the bout. When two calves were involved in the sucking bout, non-filial calves sucked from behind, between the hind’s hind legs. This position occurred more frequently with non-filial than among the filial and adopted calves. It was therefore concluded, that repeated allonursing accompanied with massaging of the ano-genital region of the sucking calf by the hind can be considered a signal of adoption. Hinds usually adopted calves older than their own progeny. The adopted calves were on average 2·5 days old. This suggests that it is most likely the calf’s activity which leads to bonding. No reciprocity was found in allosucking and/or allonursing. The fact that non-filial calves commonly initiated allosucking from a non-maternal hind during the day when she gave birth appeared crucial for establishing bonding which subsequently led to adoption. Hinds may be bonded with several calves including their own. Therefore, bonding with a non-filial calf did not principally mean failure in looking after their own progeny as shown in other studies.
