Date of this Version



© 1992, The Board of Regents of the University of Nebraska on behalf of the University of Nebraska–Lincoln Extension. All rights reserved.


Effective control programs for equine internal parasites.

All horses have internal parasites. Ninety percent of all the colic cases may be related to blood vessel damage caused by the migrating larvae of Strongylus vulgaris (blood worms). Fifty percent of the deaths in horses may be related to internal parasites.

Internal parasites have adapted themselves to the internal environment of their host animal and have become host-specific. Horse parasites can only exist in horses and cattle parasites only in cattle. If a cow eats the eggs or larvae of a horse parasite (or vice versa), the life cycle of the parasite is broken. This can be a factor in developing parasite control programs.