The effect of flooring type and social grouping on the rest and growth of dairy calves

We studied the effect of softness of flooring and the presence of a companion calf on calves' growth and rest by housing 1-week-old calves for 20 weeks in one of the three housing treatments: housed in pairs (n = 12 pairs) in concrete-floor double pens (2.1 m × 1.8 m) (PAIR), individually housed (n = 12) in concrete-floor (CONCRETE) pens (1.05 m × 1.8 m) and individually housed (n = 12) in identical pens, but with soft rubber mats (RUBBER MAT). The calves were filmed continuously for 24-h periods at 2, 4, 6, 7, 11, 14, and 21 weeks of age. Their activity was scored for total daily duration, frequency of bouts and mean duration of bouts of total resting, resting on the side or resting on the sternum. The effect of time of day was examined at 4, 7, 14, and 21 weeks of age. Housing had no effect on the mean daily growth but the mean daily gain was significantly and positively correlated with the total time spent resting over the whole 20-week period. As the calves grew older, the daily time spent resting remained fairly constant, but the proportions of time resting on the side decreased. However, 2-week-old calves were never seen to lie on their sides. The time spent resting around feeding times decreased after solid feeding was introduced. The type of housing had little effect upon resting behaviour. The daily duration and bout frequency of resting on the side were higher for PAIR calves than CONCRETE but no other differences were noted. No differences between CONCRETE and RUBBER MAT calves were seen. Adequate rest appears important for the growth of calves as the longer the calves rested the better they grew. The softness of the floor had little effect on the growth or behaviour of the calves although it is possible that the bedding used alleviated the hardness of concrete floor. Pair housed calves were able to use the larger pen area and rested more often and for longer durations on their side than individually housed calves.