According to the USDA Federal Grain Inspection Service, grain must contain less than 0.05% ergot by weight. The Merk Veterinary Manual recommends that livestock rations contain less than 0.1% ergot. Here is an example of what this looks like.
Fortunately, ergot is very easy to see in standing or harvested grain and grasses.
Ergot sclerotia rarely survive for more than a year on the soil. While the sclerotia may survive in the soil for up to two years, they will not germinate if buried to a depth of at least 1 inch (source).
High temperatures destroy ergot sclerotia. While surface temperatures vary under field burning, the grass seed industry has had success using burning to reduce, but not eliminate ergot. Research has shown that destruction of 100% of the sclerotia requires 116 seconds at 200F , 48 seconds at 300F, and 15 seconds at 400F.
There is some evidence that low soil micronutrient levels (especially copper) increases the likelihood of ergot infection. Copper deficiency can cause prolonged flowering in small grains, which increased the window for ergot infection.
Weather greatly influences ergot infection. Wet weather and soil favors the germination of ergot on the soil in the spring. Cool, wet weather during flowing favors the initial infection and development of the initial floret and "honey-dew".
- Excitability, staggering, convulsions, backward arching of the back
- Gangrenous tissue on feet and sloughing of tissue on ears and tails
- Low milk production, rough coat, weight loss
- Ergot: A potential Poisoning Problem for Livestock - South Dakota State University Extension
- Ergot Poisoning in Cattle - Iowa State University Extension
- Ergot in Your Feed? - North Dakota State University Extension