Feeding high levels of antibiotic during the first weeks cattle are put on feed often has increased performance as much as 15 to 25 percent for this period. Responses from antibiotics in the ration have been higher and more consistent with calves than with yearling cattle. In some recent trials, feeding 350 to 400 milligrams of aureomycin per head daily in salt-mineral mixtures to steers and heifers on summer pasture has increased average daily gain by 0.1 to 0.3 pounds per head. A summary of 27 trials showed that this product increased rate of gain 23 percent and feed efficiency 19 percent for the first 28 days of the feeding period. Cattle with acute liver abscesses have gained 3 to 5 percent more slowly and 7 percent less efficiently than non-affected cattle.
Liver abscesses are a problem with cattle fed high concentrate rations.
Liver abscesses are related to ulcerative lesions of the rumen wall or acute rumenitis. Bacteria penetrate the rumen wall at these ulcer sites and are carried to the liver, where they localize and produce abscesses. Antibiotics recommended for control of liver abscesses include bacitracin, tylosin, chlortetracycline and oxytetracycline. None of the antibiotics are cleared by FDA for feeding with Bovatec to cattle. Rumensin is cleared at 10 to 30 grams per ton for improvement for feed efficiency with Tylan at 10 grams per ton, for reduction in the incidence of liver abscesses.