Irritation caused by hairs and awns
Proso millet is not extensively used for forage because the hairs on the stems and leaves cause irritation to livestock (Baltensperger et al., 1995). In Mongolia, oral injuries (stomatitis) and head fistulae caused by the awns carried on the spikes were common in equines fed proso millet straw. Mild cases usually recovered after removal of the awns from the mouth, but severe cases left untreated were fatal (Guang YaNong, 1981).
Nitrates
Like other millets, proso millet may accumulate nitrates under conditions of heavy applications of N fertilizer and limited soil moisture. Because nitrate concentrations are in the lower 15 cm, it is recommended to leave a high stubble height when harvesting a drought-stressed crop. Hay curing does not reduce nitrate concentrations but ensiling can decrease them by 40 to 60% (Lang, 2001).
Toxicosis
Some occasional cases of poisoning with proso millet forage occurred in small ruminants, which may have been caused by the presence of steroidal saponins associated with photosentization (Miles et al., 1993; Badiei et al., 2009). In Iran, a severe case of lethal toxicosis was reported in a flock of sheep grazing proso millet. Clinical signs included fever, photosensitization, severe head swelling, decreased appetite and jaundice (Nazifi et al., 2009)