The Relative Effect of Two High Levels of an Antibiotic on Laying Chickens During Hot Weather

HEYWANG (1956) reported that the egg production of White Leghorns was increased during hot weather when chlortetracycline was in their diet at the level of either 50 or 100 grams per ton, but the data obtained were not considered extensive enough to show whether the lower level was as effective as the higher. The results indicated that the increase in egg production was greater among the poor than among the good layers. Although it was believed that insufficient data were obtained to warrant definite statements, the trends toward greater egg production during cooler weather appeared similar to those during hot weather. Since that report was prepared an experiment designed to obtain information on whether chlortetracycline is as effective at the 50 as at the 100 gram per ton of diet level in increasing the egg production of White Leghorns during hot weather was conducted at the Southwest Poultry Experiment Station, . . .