The Influence of Crystalline Aureomycin and Vitamin B12 on the Protein Utilization of Growing-Fattening Swine

Abstract

Data have been secured to determine the effect of crystalline vitamin B₁₂ and crystalline aureomycin on the protein utilization of growing-fattening swine when they were fed rations consisting of corn, soybean oil meal, alfalfa meal, and minerals. These rations were fed at three levels of protein to 12 lots of eight pigs each. The lots within each protein level consisted of the basal ration, basal plus B₁₂, basal plus B₁₂ plus aureomycin, and basal plus aureomycin. The initial crude protein contents of the rations were 21 percent, 17 percent, and 12.6 percent. When each lot averaged 70 pounds, the protein content was lowered to 18 percent, 13.7 percent, and 10.4 percent respectively; and again when each lot averaged 126 pounds, to 15 percent, 11.5 percent, and 9.8 percent respectively. The pigs were removed from the experiment as each lot averaged 213.0 pounds. Vitamin B₁₂ and aureomycin were mixed in the ration at the rate of 20 gammas and 20 milligrams per kilogram of ration respectively. Blood and chromic oxide fecal samples were taken from each pig on the day of the protein change and on the day the lot averaged 213.0 pounds. Hemoglobin, total plasma protein, albumin, and globulin were determined on the blood, and digestibility coefficients for the ration and protein in the ration were determined from the fecal samples. Vitamin B₁₂ was of little or no help in increasing rate of gain, feed efficiency, hemoglobin, total plasma protein, or digestibility. Aureomycin alone was of no help to the high protein pigs after a weight of 70 pounds was reached, however, the performance of the other lots was increased as judged by the above criteria. Aureomycin alone or in combination with B₁₂ increased the protein utilization of pigs to the extent that rations containing 17 percent, 13.7 percent, and 11.5 percent protein were equal to rations containing 21 percent, 18.2 percent, and 15.0 percent under the same conditions. A number of significant correlations of gains with blood data was found. Copyright © . .