Nitrate and nitrite poisoning
German grass may cause nitrate and nitrite poisoning in cattle. In some cases, the nitrate + nitrite content of this forage can reach up to 20-25% of total nitrogen. Several outbreaks resulting in cattle mortality have been reported in Paraiba and Rio Grande do Norte in Brazil (Silva et al., 2006; Riet-Correa et al., 2005; Medeiros et al., 2003). Clinical signs of nitrate poisoning include anorexia, respiratory distress, teeth grinding, depression or hyperexcitability, tremors, abdominal contractions, salivation, nasal discharge, uncoordinated gait, cyanosis and recumbency. Nitrate accumulation in the plant is thought to occur after prolonged drought followed by rain, which is what happened for instance in 2001 in Paraiba, where nitrate poisoning caused the deaths of 5 out 11 animals after they were fed German grass regrowth (Medeiros et al., 2003).