aOnly in combination with chlortetracycline and penicillin.
bAvailable by prescription only.
Source: Compiled from FDA Approved Animal Drug List (Green Book), 1998a, and Feed Additive Compendium, 1997.
of drugs for hogs. Nine chemical entities are approved in the United States (Shepard et al. 1992), several marketed by more than one company and in forms suitable for use in feed or by injection. They are recommended routinely for breeding animals, when new animals are introduced into a herd, and when weaned animals enter the feedlot. Controlling helminths is the principal objective, but insects also must be controlled. In general, although parasites can severely restrict productivity in hogs, several bacterial and viral infections are more cataclysmic (see Tables 2–6 and 2–7).
Growth and Metabolic Performance
Hog performance (growth rate and feed efficiency [pounds of feed consumed for a gain of 1 pound in carcass or body weight]) is improved with the use of subtherapeutic concentrations of any of 12 antibiotic drugs with claims for