SHADE PREFERENCES OF LACTATING HOLSTEIN-FRIESIAN COWS

Shade-type preferences by Holstein-Friesian cows were investigated und er natural climatic conditions. The trial was conducted in south-east Queensland, Australia, over 88 days in summer. Forty-two cows were pla ced in a dirt-floored yard (zero grazing) provided with different shad e types. Shade types provided were a 3 m high galvanised iron roof, Se chium 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 p roportion of black and white. Number of cows using a particular shade type and their respiration rates were recorded daily at 1300 hours. Am bient temperature, relative humidity, solar radiation and wind speed w ere also measured. Cows selected the galvanised iron roof most frequen tly when temperatures rose above 30 degrees C, with no significant dif ferences between the other shade types. At temperatures below 30 degre es C, animals did not seek shade. As ambient temperature, solar radiat ion and relative humidity rose, respiration rate rose. Cows with a hig h percentage of black coat preferred shade, while those with a high pe rcentage of white coat did not seek shade.