Impacts of shade on physiological and behavioural pattern of Dehong buffalo calves under high temperature

Abstract Shade shelter is widely used to reduce heat load for farm animals, but little research focus on the cooling effects for Dehong buffalo calves. The aim of this experiment was to evaluate the impacts of shade cooling on the physiological and behavioural parameters for Dehong buffalo calves. Shade with 99% blockage of solar radiation was covered on steel frame with a 2.5 m height above the loafing area floor (shaded). The loafing area of the control group was the same as the shaded group, apart from no shade shelter above the loafing area (non-shaded). Twenty-four Dehong buffalo calves were randomly and averagely allocated to the non-shaded and shaded groups. Six Dehong buffalo calves were loose housed in a barn, and they had access to loafing area. The results showed that the average daily air temperature of the loafing area under shade was lower 1.5 °C than that of the loafing area without shade shelter. No difference in rectal temperature was found between the non-shaded and shaded calves ( P  > 0.05), but respiration rate of the non-shaded group in noon (12:00 h, 31.6 breaths) and evening (18:00 h, 28.5 breaths) was greater than for calves in shaded group (26.1 and 25.3 breaths, respectively) ( P P P