Myth #1: All plants with high tannin levels are effective treatments for internal parsites.
Mythbuster: Plants contain many compounds that fall into the chemical group called "tannins." In recent years, a number of studies have been conducted to examine the effect of tannins on small ruminant gastrointestinal parasites, like the barber pole worm (Haemonchus contortus). It's quite obvious that these studies show that not all tannins are equal, and some can even be fatal to livestock.
There is a subset of tannins called condensed tannins, and some of the members of this group do seem to have beneficial effects against worms. In the U.S., Sericea lespedeza is one of the forages containing condensed tannins that has potenial for use in parasite control.
Members of the Southern Consortium for Small Ruminant Parasite Control (SCSRPC) are currently investigating how sericea can be used in integrated parasite control programs.
Source: SCSRPC web site. Submitted by Dr. Anne Zajac, DVM, PhD, Virginia-Maryland Regional College of Veterinary Medicine.
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