Behavioural, biochemical and hormonal responses of heat-stressed crossbred calves to different shade materials

An attempt was made to study the effect of different shade materials on physiological, behavioural, biochemical and hormonal responses in crossbred Vrindavani calves during the summer seasons in the Cattle and Buffalo Farm of Indian veterinary Research Institute, Izatnagar, India. During experiment, 28 crossbred calves were divided into four groups: thatch shading roof (T1), agro-net shading roof - 60% light diffusion (T2), asbestos with canvas shading roof (T3) and well-grown tree (T4). The daily macro- and microclimate data were recorded at 0900 and 1400h. The data for each ongoing behavioural activity were recorded by closed circuit television consecutively for three days for each animal in each group from 1000 to 1700h. Blood was also collected at 0, 15, 30, 45, 60, 75 and 90 days of the experimental period for estimation of different biochemical parameters. The microclimate, that is, maximum and minimum temperatures, relative humidity and temperature humidity index of the roof, was lower in the T2 group. There was significantly more (P<.05) time spent in shade structure by the T2 group as compared to other groups. Among the behaviour, feeding, rumination, resting and sleeping activities were more in the T2 group, whereas standing, moving, drinking, time spent near water tank and abnormal behaviour (cross-sucking, licking) were more in T3 and T4. Among the blood parameters, haemoglobin was significantly higher (P<.05) while, Serum Glutamic Oxaloacetic Transaminase and Alkaline Phosphatase were significantly lower in the T2 group.