The Role Of Tropical Legume Condensed Tannins In The Ruminant Environment

There is much we understand of legume condensed tannins (CT) as they relate to ruminant herbivores and their immediate tropical environment. Early evidence suggested that CT can be toxic to grazing ruminants and, in some circumstances, may decrease nutrient availability through protein astringency. We also know that CT can be beneficial, even to grazers, by increasing rumen-protein escape that then translates into greater milk protein secretion or reduced bloat, and that not all CT act in the same way. We have gradually come to understand that CT concentrations in herbaceous legumes can change with modifications in the growing environment. How this results in trophic interaction between foraging ruminants and legumes high or low in CT needs elucidation, especially on metapopulation scales. We know forage nutrient concentrations affect ruminant diet selection as does, possibly, CT polymerization. Ruminants also benefit from dietary CT in their battle against gastrointestinal nematodes (GIN). What happens to CT of leguminous origin in ruminant feces may also be important to the long trophic chain from environment to plant, ruminant and then back to the soil. Where is the environment:CT:ruminant picture in the tropics today? It is complex and rich, but without a doubt, there are still many questions to answer.