In the United States, especially the Southeast, sericea lespedeza (Lespedeza cuneata) is promoted as a tannin-containing forage that can reduce internal parasitism in small ruminants. In Europe, sainfoin (Onobrychis viciifolia Scop.) is reported to have the same effect.
The consumption of sainfoin has been experimentally associated with a decrease in establishment of third stage infective larvae and a reduction in fecal egg count, due either to a reduced female fertility and/or (less frequently ) a reduced worm number.
These "anthelmintic" effects depend on the concentration of condensed tannins in the diet ( a minimal threshold is necessary) and the length of distribution (at least 15 days). The effects have been shown with hay, silage and also dehydrated pellets.
Sainfoin is mainly a legume growing on chalky soils. It is difficult to keep the field for more than three years. There are two main groups of sainfoin varieties: simple sainfoin and double sainfoin. The first one will be in flower only once per year. The second type can have several growths in one year.
Read journal article about benefits of condensed tannins