Nitrate poisoning
The oat plant is prone to accumulate N and may cause nitrate poisoning in livestock, especially when it is harvested at the flowering stage, or if the plant has been stressed by frost or drought, particularly when followed by rain (SARE, 2008; Suttie et al., 2004). Ensiling, which reduces N levels by 40 to 60% during fermentation, may help to reduce this risk (Suttie et al., 2004).
Winter tetany
Oat forage grown during drought or on acidic soils can have a high K content, which hinders Mg absorption, resulting in winter tetany in cattle, particularly in high producing cows in early lactation or in late pregnancy. The symptoms are nervousness and irritability, and eventually extreme excitement and violent convulsions. It is possible to prevent winter tetany using mineral supplements rich in calcium (15%) and/or magnesium (6-8%) (Andrae, 2007; Fraser et al., 2004).
Digestive and bowel occlusion in horses
Oat straw has been reported to cause digestive and bowel occlusions (phytobezoars) in horses (Kohnke et al., 1999).