wocattle":qnexptdo said:
At what nitrogen % does hay cause nitrate poisoning?
If the forage has extremely high concentrations of nitrate, such as 25,000 ppm, then the risk to livestock health is very great even when all known management techniques are employed.
Factors in Nitrate Accumulation
Practically all plants contain detectable amounts of nitrates. Excessive nitrate accumulation occurs when the uptake of nitrate exceeds its utilization in plants for protein synthesis. The following factors are related to nitrate accumulation in plants:
1. Plant species vary in their ability to accumulate nitrate. Even common barnyard weeds can cause problems.
2. Stalks are highest in nitrate content, followed in order by leaves and grain in decreasing amounts.
3. Immature or young plants have a greater potential for nitrate accumulation than older plants (such as those with seed in the hard dough stage). Management: Be cautious when turning livestock in on a field that is still immature in growth. Hungry livestock are not as likely to selectively graze leaves over stems so allow them to feed before releasing them on a field. Always test fields of concern prior to releasing livestock on them.
4. Any weather condition which reduces plant growth may increase nitrate accumulation. This includes drought and sometimes cool, cloudy weather.
5. Excessive use of nitrogen fertilizer may contribute to the problem.
