Effect of Acetyl-Salicylic Acid and Oxytetracycline on the Performance of White Leghorn Breeders and Broiler Chicks

CONSIDERABLE evidence has appeared in the literature to indicate a number of adverse effects associated with high environmental temperatures. Decreased rates of production were reported by Wilham (1931), Hutt (1938) and Hinds (1949) during periods of high summer temperature. Reductions in egg weight associated with increased environmental temperatures have been reported by Bruckner (1936), Bennion and Warren (1933), Skogland et al. (1951) and Hutchinson (1953). Additional effects have included decreased shell thickness (Warren and Schnepel, 1940) and lowered feed consumption (Wilson, 1949; Lee et al., 1945). Mueller (1961) reported that a constant temperature of 90°F. resulted in depressed egg production, feed intake, egg weight and shell quality as compared with a constant temperature of 50°F. A number of papers have indicated that the body temperature of laying hens was elevated by 0.5–1.5°F. at environmental temperatures of 90°F. or above (Heywang, 1938; Lee et al., 1945; Wilson, 1948). Yeates et…