Ambient Air Temperature and Weight Gain in Swine

Abstract

Data are reported from 24 experiments involving 94 hogs and 367 hog-periods. A three-dimension correlation surface was developed showing, probable values of average daily gain for specific combinations of constant air temperature (40° to 110° F.) and body weight (100 to 350 lb.). This surface was smoothed through three approximation curves as a joint function of two independent variables. Probable value curves for average daily gain are also plotted against body weight for constant air temperature at 10° intervals and against air temperature for various body weights at 50-lb. intervals. Significant correlation coefficients between average daily gain and body weight for air temperatures at 10° intervals were positive at 50° and 60° F. and negative at 80°, 90°, 100° and 110° F. At 70° F. correlation at weights less than 180 lb. was positive and significant, while at higher weights it was negative and lacked statistical significance. Correlation between average daily gain and body weight was negative at 40° F., but also lacked significance. The constant air temperatures at which daily gain was at a maximum varied from 61° F. for 350-lb. hogs to 73.5° F. for 100-lb. pigs under the conditions of these experiments.