Parasites on swine

Swine performance is influenced by internal parasites, most dramatically in the young, growing pig. Parasites reside in the stomach and intestinal tract of the pig, causing irritation, impaction, indigestion and lack of appetite. Parasites cause loss of nutrients from feed consumed by competing with the host, and by causing poor digestion, gut ulceration and even blood loss. Even small numbers of the large roundworm Ascaris suum can depress feed intake and daily gain and cause a depression in gain:feed ratio. Some worm parasites may be found in the lungs, where they interfere with respiration. This in turn may result in pneumonia. Even though internal parasites are commonly associated with pasture and dry lot husbandry, some parasites such as Isospora (neonatal infection) may be present in total confinement. Ascarid infections frequently are found in finishing barns with concrete floors. The reason for continuing parasitism in these units is that transmission is by infective eggs and oocysts, which are difficult to keep out of any environment. Therefore, appropriate deworming schedules and sanitation are mandatory for parasite prevention programs. There are only a few target parasites of concern, while several dewormers can be used effectively. The dewormers are usually broad spectrum in that most if not all of the worm parasites are removed, and they are safe and easily administered.