Effects of Egyptian subtropical summer conditions and the heat-stress alleviation technique of water spray and a diaphoretic on the growth and physiological functions of Friesian calves

The effects of heat stress during summer on the growth of Friesian calves were studied. The growth rate, daily solids gain, feed consumption and feed efficiency, serum concentrations of thyroxine, free thyroxine index, glucose, total protein, urea-N, creatinine, total lipids and total cholesterol, haemoglobin values and packed cell volume decreased significantly in summer as compared with winter conditions. However, total body water percentage, total body water/total body solids, serum transaminase enzymes, rectal temperature and respiration rate increased significantly during the summer. The use of a diaphoretic and sprinkling with tap water significantly ameliorated these responses to heat stress.