Individual housing of dairy calves prevails in Europe and North America despite its negative effects on calf development. One of the main reasons is that farmers find individual housing of calves more practical than group-housing. A 'compromise' between practice and welfare could be housing calves in pairs. Therefore, we aimed to compare health, feed intake, growth, and behavior in a novel arena of 22 individually (INDI) and 44 pair-housed (PAIR) calves that were randomly assigned to the treatment. Diarrhea and respiratory problems were recorded every day for the period of 49 days. Intake of calf starter and milk were measured every day for the period 48 and 49 days, respectively. Calf body weight gains were calculated as average daily gain. Calves were individually tested in a novel arena at 11–18 days and and their behavior was recorded according to an ethogram including 8 behavioral categories. Behavioral categories were first diminished by Principal Component Analysis (PCA). We found that 2 PCs explained 66 % of the total variation in calf behavior. Movement-related behaviors (activity, play, and crossing the stair) loaded positively on PC1 while PC2 had positive loading on self-grooming and negative on exploration. There were no significant effects of housing on calf health, feed intake or average daily gain. INDI calves had higher PC1 scores than PAIR calves, indicating a rebound effect of movement. Our results are consistent with other studies that found no negative effect of pair housing of calves on their health, feed intake or growth compared to individually housed calves. The rebound effect of movement-related behaviors of INDI calves in a novel arena implies that individual housing of calves causes activity deprivation by the 2nd week of age.
- calf health; calf performance; calf behavior; individual versus pair housing