The effect of rearing substrate and space allowance on the behavior and physiology of dairy calves

Abstract

The objective of this study was to investigate the effect of rearing substrate and space allowance on the behavior and physiology of dairy calves. At 1wk of age, 72 calves were moved into 1 of 18 experimental pens (n=4 calves/pen) where they remained until 6wk of age. Half of the pens had floors covered with quarry stones (QS) and the other half were covered with sawdust (SW). For each substrate type, calves were reared at 1 of 3 space allowances: 1.0, 1.5, or 2.0m2/calf. Behavior was video-recorded continuously for 24h in the home pen at 2, 4, and 6wk of age; the time calves spent lying, standing, walking, and running were estimated using 1-min instantaneous scan sampling. Body weight, cleanliness, fecal fluidity, and skin surface temperature were recorded at 1, 4, and 6wk of age. Escherichia coli numbers were assessed on the skin surface of the shoulder and in feces of calves at 4 and 6wk of age. Blood samples were taken at 1, 4, and 6wk of age to measure cortisol, creatine kinase, immunoglobulin G, serum amyloid A, and total protein concentrations. Calves reared on QS spent less time lying and walking and more time standing at 4 and 6wk of age compared with calves reared on SW. Furthermore, calves reared at a space allowance of 2.0m2/calf spent less time lying and more time standing and walking compared with calves reared at a space allowance of 1.0 and 1.5m2/calf. Calves reared on QS had lower skin surface temperatures compared with calves reared on SW. Fecal fluidity scores were lower in calves reared on QS than SW at 2wk of age. Fewer E. coli were recovered from the shoulder of calves reared on QS than those of calves reared on SW, but fecal E. coli counts were similar between rearing substrates and space allowances. Serum amyloid A concentrations were lower in calves reared on QS than SW. We detected no effect of rearing substrate or space allowance on body weight, cleanliness, or concentrations of cortisol, creatine kinase, immunoglobulin G, and total protein. In conclusion, lower skin temperature in combination with reduced lying behavior may reflect reduced comfort of calves reared on QS. Furthermore, a space allowance of 2.0m2/calf may provide calves with more opportunity to perform active behaviors.