The Effect of Penicillin and B-Vitamins on the Growth of Pigs Fed Different Levels of Protein2

Publisher Website
Google Scholar
Abstract
Three experiments were conducted to study the effect of penicillin and B-vitamins on the growth of pigs fed different levels of protein. Penicillin at 5 mg. per lb. of total ration and/or B-vitamin supplementation (riboflavin, niacin, pantothenic acid, vitamin B12 and choline) had a highly significant effect in improving rate of gain. This response was shown at all levels of protein fed. The data indicate that the 10 percent protein ration was limiting in one or more of the five B-vitamins fed more than in amount or quality of protein when fed to pigs over 100 lb. in weight. A 12 percent protein ration produced slower gains than higher levels of protein from weaning to 100 lb. and a 9 percent protein ration did not support normal growth from 100 lb. to market weight. Significantly leaner carcasses, as measured by loin-lean area, were produced by pigs receiving the B-vitamin supplementation or the high and medium protein rations as compared to those getting no B-vitamin supplement or the low protein ration respectively. Very little difference in rate of gain or feed efficiency was obtained between the 18-14, 16-12 or 14-10 percent protein levels when fed in corn-soybean meal-tankage rations supplemented with minerals, vitamins and penicillin. However, the results suggest the medium protein combination would be preferred from an over-all economic viewpoint due to the lowering of carcass quality in the low protein group.