Oxalates
Cenchrus ciliaris is reported to contain 1 to 4% DM of total oxalate (Mannetje et al., 1992; Silcock et al., 1983; Walthall et al., 1976; Jones et al., 1972), which may cause "big head" disease (Osteodystrophia fibrosa) in horses and hypocalcemia in grazing animals (Cheeke, 1995). Symptoms of big head diseases are ill thrift, lameness, and swelling of the skull (Walthall et al., 1976). This disease is most prevalent during the wet season when buffel grass is young and lush (FAO, 2010). Ruminants are less susceptible to oxalate poisoning but may suffer from hypocalcemia (milk fever in dairy cows) and develop renal problems. They have to be gradually introduced to oxalic acid in order to change the rumen flora into one able to mitigate oxalate toxicity (Duncan et al., 2000). Calcium supplementation by feeding limestone or dolomite may help controlling hypocalcemia (FAO, 2010).