Swine Internal Parasites: Prevalence and Management Systems

A survey of internal parasites in Oklahoma swine herds indicates that most of the internal parasites common to swine are widespread in the state, although numbers are somewhat lower than those reported in surveys of states with a greater concentration of swine. A total of90 growing-finishing swine were used to study the effect of anthelmintic treatment regimes and management systems on pig performance, liver lesions and intestinal worm burdens. Anthelmintics had no significant effect on rate of gain in pigs fed in confinement, but significantly (P<.05) improved rate of gain in pigs fed in pasture lots. Similar but nonsignificant trends were observed for feed conversion. Anthelmintics were effective in reducing liver lesions in pigs fed on pasture, but not in confinement-fed pigs. The internal parasite control system which would be most economical for each swine producer may be determined by type of management system as well as the types of parasites involved.