Effects of two substrate types on the behaviour, cleanliness and thermoregulation of dairy calves

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The use of river stones as a substrate to rear calves on is a management practice that is becoming more common in parts of New Zealand where more traditional substrate types, such as sawdust, can be difficult and/or expensive to obtain. A study was conducted to compare the behaviour, cleanliness, thermoregulation and weight gain of calves reared on river stones or sawdust. At 1wk of age, 40 calves were moved into four pens with floors covered with river stones (RS: n=5 calves/pen) or four pens with floors covered with sawdust (SD: n=5 calves/pen). The river stones were approximately 3cm in length and rounded with a smooth surface. Calf behaviour, body weight, cleanliness and skin surface temperature were recorded at 1 and 5wks of age. Behaviour was video recorded continuously for 24h; the time calves spent lying, standing, walking and running were estimated using 1-min instantaneous scan sampling. In addition, during this period the frequency and duration of lying and play behaviour was recorded continuously for 10h during daytime hours. Skin surface temperature of the calves was recorded continuously using iButtons® and floor surface temperature was recorded continuously using data-loggers during the first and sixth week of the study period. At 1wk of age, calves reared on sawdust played more; they spent more (P<0.001) time running (0.1 and 0.3±0.04% total observations/24h, RS and SD respectively) and performed more (P<0.005, total observations/10h) head shakes, jumps, kicks and leaps compared with calves reared on river stones. At 5wk of age, calves reared on sawdust spent more (P<0.001) time lying (67.6 and 72.1±1.34% total observations/24h, RS and SD respectively) and performed more (P<0.05, total observations/10h) heading shakes and kicks compared with calves reared on river stones. Skin temperature was higher (P<0.001) for calves reared on sawdust at both ages compared to river stones. There were no treatment differences (P>0.05) in body weight, cleanliness and floor surface temperature. In conclusion, reduced lying and play behaviour in combination with lower skin temperature suggest that calves may find river stones more uncomfortable and/or difficult to move on and that river stones have less insulation properties than sawdust under the conditions studied.