Influence of Controlled Temperatures on Growth Rate and Plasma Ascorbic Acid Values in Swine

Abstract

Two factorially designed experiments were conducted in the psychrometric chambers of Herrick Laboratory to study the effect of temperature, as a stressor, on the rate of gain and on plasma ascorbic acid levels of growing pigs. Chamber regimens consisted of 29.4° and 85% relative humidity, 18.3° and 85% relative humidity and rotation of animals between these 2 temperatures every 3 days. Thirty-six Poland China and 36 Hampshire swine, replicated in time, were studied. The pigs were fed a balanced 16% crude protein corn-soybean meal ration and water was available. Statistical analysis of the plasma ascorbic acid values indicated a significant (P < 0.01) quadratic response to the week on test. There was also a significant (P < 0.05) decrease in weekly plasma ascorbic acid due to the higher temperature, but the quadratic response was not altered. When the weekly average daily gains of the pigs were plotted against the weeks on test a cyclic pattern was observed similar to that of the weekly plasma ascorbic acid values. When the plasma ascorbic acid values were highest, weight gains were lowest; when ascorbic acid levels were lowest, weight gains were highest.