Acclimation of young calves to high temperatures: composition of blood and skin secretions.

Total nitrogen and sodium and potassium contents of blood serum and of skin secretions were measured in four 2- to 3-month-old male Bos taurus calves subjected to a 2-week acclimation process in a climatic chamber at 40.5 C, 50% relative humidity, 12 hours each day. Secretions from the skin were absorbed in filter papers that were the used for analysis of sodium, potassium, and total nitrogen. Significant change in serum sodium, potassium, or nitrogen was not observed. A significant (P less than 0.01) rise in the nitrogen content of skin secretions was observed on the 1st day of exposure and continued throughout the entire exposure period. Similarly, there was a significant (P less than 0.01) increase in the content of sodium and potassium in skin secretions. The secretions contained about 2 times more potassium than sodium.