Shade preferences of lactating Holstein - Friesian cows

Summary. Shade-type preferences by Holstein–Friesian cows were investigated under natural climatic conditions. The trial was conducted in south-east Queensland, Australia, over 88 days in summer. Forty-two cows were placed in a dirt-floored yard (zero grazing) provided with different shade types. Shade types provided were a 3 m high galvanised iron roof, Sechium edule (choko) vines on a 3 m high trellis, 70% shade cloth on a 3 m high frame and natural shade trees. The floor area under the shade structures was concrete. An unshaded area (the remainder of the yard) was also provided. Each cow was scored for coat colour based on the proportion of black and white. Number of cows using a particular shade type and their respiration rates were recorded daily at 1300 hours. Ambient temperature, relative humidity, solar radiation and wind speed were also measured. Cows selected the galvanised iron roof most frequently when temperatures rose above 30°C, with no significant differences between the other shade types. At temperatures below 30°C, animals did not seek shade. As ambient temperature, solar radiation and relative humidity rose, respiration rate rose. Cows with a high percentage of black coat preferred shade, while those with a high percentage of white coat did not seek shade.