Supplemental shade for dairy calves reared in commercial calf hutches in a southern climate.

Two studies were conducted during consecutive years to determine the effects of providing supplemental shade to dairy calves reared in commercial hutches made of translucent plastic in a southern environment. Calves were assigned at birth to polyethylene calf hutches located in either an open control area or under supplemental shade (n = 9 to 12 per group per year). Shade reduced temperatures both inside the hutches and in the outer exercise areas during both years. However, shade increased humidity in the exercise area during yr 1. Shaded calves had lower rectal temperatures than control calves during yr 1, but differences were not significant during yr 2. Shade did not alter plasma cortisol concentrations. Shaded calves consumed less concentrate feed but had average daily gains that were similar to those of control calves, resulting in a tendency for greater feed efficiency for shaded calves. Counts for both total and fecal coliforms were greater in bedding collected from hutches under supplemental shade, but there was no difference in the incidence of health disorders. Providing supplemental shade to calves reared in plastic hutches in a warm southern environment altered the calf environment in a predictable manner but had little effect on overall growth and health.