While most farmed mammals stay with their dams throughout the milk feeding period and usually have extensive interaction with other newborns of a similar age, in dairy cattle production the standard practice has been to separate calves from the dam soon after birth and often raise them through weaning in individual pens, free from social contact. What negative effects does this social isolation have? And is group housing necessarily the solution?
In "Effects of group housing of dairy calves on behavior, cognition, performance, and health," J.H. Costa et al. (2016) explore these questions by reviewing the available scientific information on the effects of social isolation on calves' development, as compared with the developmental effects of social housing.
What they found supports the argument of those who promote social housing for pre-weaned dairy calves. Costa et al. note that calves reared in social isolation have deficient social skills. One example of this is that those raised in isolation tend to be more fearful than pair-housed calves. Calves housed individually also had greater difficulty coping with new situations including new feed sources, and they tend to develop specific cognitive deficits and poor learning abilities.
On the other hand, they found that calves that were housed, either in pairs or in larger groups, have greater solid feed intakes pre-weaning and higher body weight gain both pre- and post-weaning. While they do note that social housing "can have profound (positive) influences on total feed intake, diet, and persistence of solid feed intake," social housing is not without its difficulties. The possibility of increased aggression, competition, cross-sucking and disease risk all need to be directly addressed with appropriate on-farm management methods when calves are housed socially.
Also read our Technical Note to learn more about this research and its implications when upping the plane of nutrition in dairy calves.
You can also take a look at the original research: Costa, J.H., von Keyserlingk M.A., and Weary D.M. "Invited Review: Effects of group housing of dairy calves on behavior, cognition, performance and health. J. Dairy Sci. 2016 99: 2453-2467