Effects of Penicillin and Streptomycin on the Growth Rate and Bacterial Count in the Feces of Pigs

Abstract

Various antibiotics have been shown to stimulate growth rate in weaning pigs. Luecke (1950) reported that strepthomycin had a growth promoting effect in the pig. Dyer et al (1950) likewise reported an increase in growth rate of weanling pigs fed a corn-cottonseed meal ration when streptomycin was added. Luecke et al. (1950) reported a significant increase in growth rate of pigs fed a corn-soybean oil meal raion with penicillin at levels of 1 an d 5 mg. per pouncd of feed. However, streptomycin did not result in a significant increase in growth rate. Nesheim (1950), working with baby pigs fed a “synthetic” milk diet, reported a highly significant increase in average daily gain and efficiency of feed utilization of pigs when 500 mg. streptomycin/kg. dry matter was fed. Pigs were pair-fed with equal feed intake for 49 days. Bird et al., Groschke (1950), McGinnis (1950) and Stokstad (1950) reported increased growth rate in chicken and turkey poults when streptomycin was included in the ration. Copyright © . .