Oxalates
The giant setaria contains high amounts of oxalates (4 to 6.7% DM) after a regrowth period of 3 weeks (FAO, 2009; Jones et al., 1972). Oxalates are deleterious to horses as they cause the "big-head" disease (Osteodystrophia fibrosa).
In dairy cows, oxalic acid conjugates with Ca, thus reducing Ca concentration in the blood and causing milk fever (hypocalcemia). It is also reported to cause hypomagnesemia. Both problems can be treated by combining treatment with calcium borogluconate and magnesium hypophosphite. When Setaria is progressively included in the diet, cattle develops an ad hoc rumen flora that detoxifies oxalates (Cook et al., 2005).