Effects of group housing of dairy calves on behaviour, cognition, performance, and health.

Discipline: calf raising: Key words: social isolation, individual housing, replacement heifers, neonate development 

I have previously interpreted papers on individual experiments which have shown that social rearing, that is where a calf is paired with others, is associated with increased solid feed intake and therefore higher weight gains before and after weaning. Whether this is generally found and which other benefits if at all can be associated with group feeding are not clear. The review of Dr J.H.C. Costa and colleagues, published in the Journal of Dairy Science, Volume 99 of 2016, pages 2453 to 2467, provides some convincing evidence in favour of group housing. Their paper is entitled: Effects of group housing of dairy calves on behaviour, cognition, performance, and health.                                                                                                                                            The authors summarized as follows, I quote:                                                                                                                                                            “Standard practice in the dairy industry is to separate the calf and dam immediately after birth and raise calves in individual pens during the milk-feeding period. In nature and in extensive beef systems, the young calf lives in a complex social environment. Social isolation during infancy has been associated with negative effects, including abnormal behaviour and developmental problems, in a range of species. Here, we review empirical work on the social development of calves and the effects of social isolation in calves and other species; this evidence indicates that calves reared in isolation have deficient social skills, difficulties in coping with novel situations, as well as specific cognitive deficits. We also review the practices associated with group housing of dairy calves, and discuss problems and suggested solutions, especially related to cross-sucking, competition, aggression, and disease. The studies reviewed indicate that social housing improves solid feed intakes and calf weight gains before and after calves are weaned from milk to solid feed. Evidence regarding the effects of social housing on calf health is mixed, with some studies showing increased risk of disease and other studies showing no difference or even improved health outcomes for grouped calves. We conclude that there is strong and consistent evidence of behavioural and developmental harm associated with individual housing in dairy calves, that social housing improves intakes and weight gains, and that health risks associated with grouping can be mitigated with appropriate management”.