Eye, mouth and skin injury
The seeds of mature plants can induce corneal opacity syndrome in grazing animals (Prasad et al., 1980). Sheep and goats appear more sensitive than cattle and buffaloes to mouth ulceration from hard seeds contained in milled forages, even though grazing animals are able to avoid them by selection (McSweeney et al., 1988). Bristles from spear grass seeds were observed at the upper lateral neck region of lambs, near the larynx. The sharp base of the bristle penetrates the skin against body movement, and the susceptibility in lambs can be explained by the lack of a thick wool coat (Narayanan et al., 2003). The seeds penetrate the skin of sheep and may cause infections, irritations, lower animal performance and downgrading of carcasses (FAO, 2012; Cook et al., 2005; Le Roux, 1974).
Wool quality
The barbed seeds of spear grass may raise concern in sheep as they twist in the wool and hamper its quality (Cook et al., 2005).