Animal Protein Factor and Antibiotic Supplementation of Small Grain Rations for Swine

Data are presented on the results of experiments with Yorkshire swine fed basal barley-oat rations supplemented with either all vegetable or mixed animal-vegetable protein.Pigs receiving an APF supplement without antibiotic gained slightly more rapidly and efficiently than the controls but the difference was generally not significant. The amount of response was somewhat greater on an all vegetable protein ration than on an animal-vegetable protein ration.An APF supplement containing residual aureomycin caused marked increases in rate and efficiency of gain when added to basal rations containing protein of either vegetable or mixed animal-vegetable origin. Unthrifty weanling pigs gave a very great response in increased rate and efficiency of gains to this APF supplement.There appeared to be a reduction in carcass quality of bacon-type hogs receiving APF supplementation throughout the growing and fattening period. This was particularly noticeable in those receiving a ration supplemented with APF containing aureomycin.