Drought-stressed corn can be used for forage as green chop or silage, but since there's potential for nitrate toxicity, use green chop (or grazing) only when emergency feed is needed.

For instance, say University of Minnesota Extension Service agronomists Dale Hicks and Paul Peterson, silage shouldn't be fed for at least three weeks after the silo has been filled. And nitrate testing is recommended, since fresh green-chopped corn will vary in nitrate level due to soil fertility, soil moisture and corn maturity.

Symptoms of nitrite toxicity in animals are increased pulse rate, quickened respiration, heavy breathing, muscle tremble, weakness, staggered gait and blindness. If these symptoms occur, change the feed source.

“Cutting drought-stressed corn for silage is preferred,” Hicks says. “From a third to half of the nitrate accumulated in the plant material can be dissipated when the silage ferments.”

Drought-stressed corn forage containing nitrate produces various forms of nitrogen-oxide gas during the 2-3 weeks of fermentation. The gases are lethal to both humans and livestock, and may occur within 12-60 hours after silo filling begins.

The duo recommends these guidelines:

  • During filling and for 2-3 weeks afterward, don't enter the silo without first running the silo blower for 10-15 minutes.

  • Leave the chute door open at the surface of the silage to prevent accumulation of lethal gases.

  • Call a doctor immediately if anyone is exposed to nitrogen-oxide silage gases.

The advisability or practicality of permanent storage for emergency-use silage is questionable, the experts say. As temporary storage, Hicks and Peterson recommend an above-ground stack, a below-ground unlined trench and silage bags as readily available alternatives. Good compaction will reduce storage losses, they say.

Because of the greater exposed surface, the shallow depth and the difficulty of packing, producers might experience storage losses of 30-40% or more. Select a well-drained site for a stack or trench to exclude surface water, and provide best access when it's wet. A tight cover of plastic held down with old automobile tires helps reduce storage losses.

For more detail, read “Using Drought-Stressed Corn for Forage” at: http://www.extension.umn.edu/cropenews.
University of Minnesota news release

Scientists working for several years to eradicate brucellosis from cattle and bison herds have been stymied by outbreaks in wildlife. USDA Agriculture Research Service (ARS) scientists in Ames, IA, are working on a new solution, which involves shooting bison.

They aren't aiming to kill the bison; they're attempting to vaccinate them without individual restraint. Using a vaccine-filled projectile, the scientists are firing it at close range into the bison's muscle tissue.

It's part of an effort by ARS scientists seeking ways to remotely inject free-ranging bison with RB51, the most effective brucellosis vaccine. The projectile is biodegradable, and the vaccine is encased in a gel pellet to protect the live bacteria in the vaccine.

Brucellosis, a problem for cattle ranchers since the 1840s, is almost eradicated, but it's again spreading via wildlife.
ARS News Service