The risk of plant poisoning is minimal, however, if adequate hay and other feeds are provided during drought periods. Oat hay can accumulate high levels of nitrate if it is grown on highly fertilized soil and has a short period of rapid growth and recovery from drought due to rainfall shortly before cutting. Oat hay harvested from diverted acres is usually not a high risk feed, since high levels of nitrogen fertilizer are seldom used in this situation. Small oats fields near farmsteads that have been heavily fertilized with manure can lead to an accumulation of potentially toxic levels of nitrates. Oat hay should be thoroughly cured prior to baling.
Cattle are much more resistant to nitrate toxicity if adequate levels of energy are fed.
The first thought by everyone is hay, but let's do some thinking and pencil pushing. Our goal is to supply feed dry matter, but also the cow must receive sufficient energy to maintain weight, nurse the calf and rebreed. This must be done as economically as possible. Table 1 gives a cost breakdown on feedstuffs available to many cow-calf producers. It is likely corn silage will be a lower cost feed energy resource this year.