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Drought brings feed hazard

Drought increases many feed safety and harvest challenges, says J.W. Schroeder, North Dakota State University Extension dairy specialist.

“The logical questions, given the likelihood of high-cost feed and feed shortages in areas surrounding this region, are: ‘What are the risks of harvesting these feeds?’ or ‘If I receive feed from the drought areas, what should I be testing for?’

Because the state already is dealing with water quality issues, my best recommendation is to stay tuned for updates and be proactive. In other words: Don’t guess. Test.”

Key Points

• Drought conditions increase the need to test feed for safety.

• Watch for the presence of mycotoxins, alfatoxins and nitrates.

• It takes 30 days to reduce the level of nitrates in silage.

Some things to test for include:

  • animals already are working hard to produce milk. Reducing their intake would cut into production and compromise health.”

Recommendations on the use of feed containing mycotoxins are not the same for all animals. Hogs have little or no tolerance for most mycotoxins, and horses cannot tolerate even low levels of fumonisin, a mycotoxin derived from Fusarium, which are fungi that can produce mycotoxins in cereal grains.

  • Aflatoxins. Aflatoxins are not considered common to corn in the northern states, but cases have been found in South Dakota and Minnesota recently. Seven to 10 days of 90- to 100-degree-F heat makes corn suspectible to alfatoxins.
  • Nitrates. In the worst drought-stricken areas, corn and other crops may never mature.

“Stunted corn will have nitrates that it was transporting in the stalks to make an ear of corn,” Schroeder says. “Without adequate moisture, the corn plant shuts down seed formation. That leaves a high concentration of nitrate in the stalks. However, if you know the level of nitrate in your feed, you can dilute it with other feeds. So nitrate in feed generally is manageable.”

There are many ways to utilize marginal crops for feed, from something as basic as placing an electrified wire around a temporary fence to making baleage.

“In 2009, when mold and wet conditions were the challenge, a common practice for cattlemen was to fence and graze standing cornfields not harvested, although I recall concerns about grain overload from livestock munching on the ears,” he says.

“If you have plans of haying the crop, then keep in mind that raising the cutter bar leaves the highest concentration of nitrate [found in the stalk] in the field. The obvious drawback is the loss of precious feed because it’s not harvested.”

An alternative to baling or grazing is to ensile corn. But reducing the nitrate takes time; a minimum wait of 30 days is needed before feeding it as silage to allow time to reduce much of the nitrates in the forage.

More than 50% of the corn silage samples submitted for nitrate testing so far this summer have tested above the “safe” threshold for mature cattle, according to Dairyland Laboratories.

Source: NDSU Extension Communi-cations

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This article published in the August, 2012 edition of DAKOTA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2012.