The Effect of Vitamin B12, Aureomycin, Streptomycin, or Dried Whey Factor Supplements on the Growth and Fattening of Weanling Pigs

Abstract

The addition of 0.5 percent Lederle's B12-aureomycin feeding supplement (supplying 12.5 mcg. vitamin B12 and 8.5 mg. of aureomycin per lb. of total ration) markedly stimulated the growth of pigs self-fed a corn-soybean meal-alfalfa meal ration fortified with cod liver oil, calcium pantothenate, riboflavin, niacin, and essential minerals, but exerted only a slight beneficial effect on the feed requirement per unit gain. Supplementation of the basal ration with 0.1 percent Merck's B12 concentrate (supplying 12.5 mcg. vitamin B12 per lb. of total ration) improved pig growth and feed efficiency but not to the same extent as the B12-aureomycin feeding supplement, thus showing an apparent beneficial effect of vitamin B12 and other factors, one of which is aureomycin in the supplement. Two percent dried whey failed to increase the growth rate of the basal-fed pigs. Even the combination of vitamin B12 and 2 percent dried whey (no ribolac) in the basal ration produced no better performance than vitamin B12 supplementation alone. This suggests that the “dried whey factor” is not essential for the optimum feed lot performance of pigs fed a practical plant protein ration. The feeding level of 15 mg. of pure streptomycin base per lb. of total ration stimulated growth more than the 2.5 mg. level. A combination of 12.5 mcg. vitamin B12 (0.1 percent Merck's B12 supplement) and 15 mg. of pure streptomycin per lb. of total ration improved growth rate and feed efficiency more than single additions of either factor. These data suggest that vitamin B12 must be present in sufficient physiological amounts to produce maximum growth stimulation and improved feed efficiency with antibiotics fed in natural rations for pigs. Furthermore, the data emphasize that antibiotics exert their most favorable effect at definite optimum levels which must be established by experimentation. Continuous oral feeding of the antibiotics protected the pigs against bloody dysentery. Pigs fed the antibiotics and/or vitamin B12 grew more uniformly within a lot and consumed more feed, compared with the pigs fed the basal ration.