Abstract
This study investigated play behavior of dairy calves kept with the cow either full time or half time in groups of 4 dam-calf pairs in 68-m(2) straw-bedded pens. Twenty-four of 48 calves entering the experiment (2 calves in each of 12 pens) were observed during 24 h at 3 and 7 wk of age. The total duration of locomotor play did not differ between the 2 treatments, but full-time calves performed less frontal pushing (social play). Irrespective of treatment, calves performed less parallel locomotor play and more frontal pushing at 7 wk than 3 wk of age. Analyzing the intensity of play behavior during milking times (morning and afternoon, respectively), during the night and between morning and afternoon milking, showed that calves performed locomotor play more intensively after the cows had left the pen for milking than during other periods. The results illustrate the importance of space and external stimulation for the performance of play behavior.