Shade type selection by Holstein-Friesian dairy cows

The effect of different shade types on the selection behaviour of Holstein-Friesian cows was investigated under different temperature conditions. The trial was conducted in south-east Queensland, Australia over 88 d in Summer 1992/1993. Forty two cows were placed in a graveled floored yard (zero grazing) provided with different types of shade and their behaviour in terms of shade type preferences were monitored. Shade types provided were galvanised iron roof 3 m high, Sechium edule (choke) vines on a 3 m high trellis, 80 % shade cloth on a 3 m high frame and natural shade trees. An unshaded area was also provided. Each cow was scored for coat color based on its proportion of black and white. The number of cows using a particular shade type and their respiration rates (RR) were recorded daily at 1300 h. 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 degrees C, with no significant differences between the other shade types. At temperatures below 30 degrees C, animals did not seek shade. RR rose as ambient temperature rose, but shade type did not affect RR. Cows with a high percentage of black coat preferred shade, while those with ct high percentage of white coat did not seek shade.