Re-Evaluation of Protein Requirements of Growing-Fattening Swine as Influenced by Feeding an Antibiotic

Abstract

GENERAL observations of farm practice have shown that many hog producers have obtained satisfactory growth in swine when feeding rations containing lower levels of protein than those commonly recommended. The research leading to these recommendations was conducted almost a decade ago. In light of recent advances in animal nutrition it seemed advisable to re-evaluate the protein requirements of swine. Keith and Miller (1939, 1941) fed rations varying in protein content from 12 to 27 percent and found that maximum and most economical gains from weaning to 75 pounds were made by those pigs fed the highest percent of protein. Twenty-two percent was recommended from weaning to 70 pounds, 17 to 20 percent from 75 to 125 pounds and 15 percent from 125 to 200 pounds. A series of studies by Carroll and Burroughs (1939) substantiated these conclusions. Mitchell (1939), using the same rations as Carroll and Burroughs, but employing the N-retention technique of measuring efficiency, stated that 40- to 50-pound pigs required more than 26 percent protein, 100-pound pigs in excess of 17 percent, 150-pound pigs 17 percent and 150- to 200- pound pigs 15 percent protein for maximum growth. Copyright © . .