Providing social contacts and objects for nibbling moderates reactivity and oral behaviors in veal calves.

The aim of this work was to assess the role of social and physical enrichment in the adaptation of veal calves to their environment. We compared calves housed in individual stalls that varied in the extent of contacts they allowed between neighbors (16 calves: open partitions; 16 calves: solid partitions; 32 calves: solid and extended partitions preventing all contact). All but 16 out of the 32 isolated calves were provided with a piece of tire and a chain, objects they could easily nibble. We assessed time budget, behavioral reactions to a water throw, neuroendocrine responses to stress (ACTH challenge and catecholamine synthesis), health, and growth. Calves kept in isolation displayed more startled reactions (16 isolated calves vs 5 non-isolated calves were startled by the throw, P < .05). Calves without objects spent more time nibbling at the feeding grille (5 vs 3% time, P < .01), licking their lips and tongue-rolling (7 vs 4% time, P < .05). Social contacts and the provision of objects had no incidence on neuroendocrine measurements and growth. Contacts with neighbors resulted in a slight but nonsignificant rise in disease. Depriving calves of social contacts increases behavioral reactivity, probably because there are no peer animals through which reactions can be moderated, and the lack of adequate objects to nibble promotes self-directed activities.