Hot, dry summer weather brings about heat and drought stress
on summer forage crops. Stressed plants such as the forage sorghums can
occasionally accumulate dangerous concentrations of nitrates, says Glenn Selk,
Oklahoma State University Extension animal scientist. These high-nitrate
plants, either standing in the field or fed as hay, can cause abortion in
cattle or death if consumed in great enough quantities.
Nitrates don’t dissipate from sun-cured hay (in contrast to prussic acid), so once the hay is cut, the nitrate levels remain constant. Therefore, producers should test hay fields before cutting for hay, Selk says. Some management techniques to reduce the risk of nitrate toxicity (Note: the risk of this poisoning cannot be totally eliminated), include:
- Test
the crop before harvest. If it has an elevated concentration of nitrates,
you still have the option of waiting for normal plant metabolism to bring
the concentration back to a safe level.
- Raise
the cutter bar when harvesting. Nitrates are in greatest concentration in
the lower stem. Raising the cutter bar may reduce the tonnage, but cutting
more tons of a toxic material has no particular value.
- Know
the extent of nitrate accumulation in the hay. If you still doubt the
hay’s quality, send a sample to a reputable lab for analysis, to get an
estimate of the nitrate concentration. This will give some guidelines as
to the extent of dilution that may be necessary to more safely feed the
hay.
- Allow
cattle to adapt to nitrate in the hay. By feeding small amounts of the
forage sorghum along with other feeds such as grass hay or grains, cattle
begin to adapt to the nitrates in the feed and develop a capability to
"digest" the nitrate with less danger. Avoid the temptation of
feeding the high-nitrate forage for the first time after a snow or ice
storm. Cattle will be stressed, hungry and unadapted to the nitrates.
No comments:
Post a Comment