Sweetclover Disease Sweetclover plants contain the chemical coumarin, which reaches its highest levels in the late bud or early flower stage of growth. Most of the material is concentrated in the leaves and flower buds. Excessive moisture in the forage may lead to the formation of a chemical compound called dicoumarol, which reduces the ability of blood to clot. Cattle that eat spoiled sweetclover hay or silage can die from the bleeding disease that results. Unfortunately, spoilage may not always be detectable.
Younger animals are more susceptible to sweetclover disease than older ones.
The disease is less of a threat in sheep and almost negligible in horses. Also, there is little danger of the problem occurring when sweetclover is pastured. To help prevent the disease, dilute sweetclover hay or silage with twice as much non-sweetclover forage. Or feed sweetclover no longer than 10 days at a time, then switch completely to another forage for a while before returning to it. Bloat and Scours Cattle may scour or bloat on sweetclover pasture, although the problem is more likely on alfalfa, red clover or alsike clover.