EFFECTS OF INCREASED AIR VELOCITIES ON HEAT AND MOISTURE LOSS AND GROWTH OF SWINE

摘要

Data are presented from both laboratory and field production tests to show the effect of increased air velocity on animal and room heat and moisture losses, rates of growth and feed conversion, surface and body temperatures and respiration and pulse rates. Pigs in the laboratory are compared when exposed to 35 vs 150 and 35 vs 300 fpm air velocities at temperatures ranging from 50 to 100°F. For five field tests at three California locations, animal production is compared when out-of-door air velocities were increased in amounts ranging from 2 to 6 mph.nTotal heat loss was measured from animals at 50, 70 and 90°F and this increased with increased wind. Radiation loss decreased due to reduced animal surface temperatures, and the convective-plus-evaporative portion increased. The changes in the various heat losses were great enough to affect building and ventilation designs if floor-level air velocities are greater than those used in developing original heat and moisture loss data.