Saponins
Cases of toxicosis have been reported in sheep, goats, cattle and horses grazing pastures or fed hay of Panicum coloratum. Clinical signs include icterus, photosensitivity, intermittent colic and fever, weight loss, and hepatic encephalopathy. Sheep are the most vulnerable, and stressed lambs placed on early regrowth following dry conditions are at most risk. Saponins in the grass are assumed to produce crystalloid substances which obstruct the bile duct, resulting in damaged liver function and secondary photosensitization that are lethal to lambs (Lloyd, 2007; Cook et al., 2005, Kahn, 2005). Affected animals should be removed from the Panicum coloratum pasture, fed good quality hay and protected from sunlight. Treatment of the photodermatitis with antimicrobial or softening creams may be needed in severe cases (Kahn, 2005).
Hydrogene cyanide
Lambs born to ewes grazing Panicum coloratum, with sub-clinical levels (51 ppm) of HCN in the grass, can suffer from goitre and other deformities (Cook et al., 2005).