Haying, Grazing Freeze-Damaged Wheat May be Option for Some

Manhattan, Kansas (April 24, 2007)--Producers with wheat damaged by the recent frost have some difficult decisions to make, which may be limited to some extent by crop insurance requirements, a Kansas State University agronomist said.

“Many fields have a combination of standing, freeze-damaged wheat and patches of downed wheat,” said Jim Shroyer, K-State Research and Extension crop production specialist.

If the freeze damage is severe, one option is to use the wheat as a forage crop – either by cutting it for hay or grazing it out. Before haying or grazing, producers should first have the wheat tested for nitrate levels, said David Mengel, K-State Research and Extension soil fertility specialist. This applies to any freeze damaged crop.

“A very limited number of freeze-damaged wheat samples taken recently have shown high nitrate levels -- 6,000 to 15,000 parts per million (ppm) -- in the forage. The highest values came from fields fertilized shortly before the freeze,” Mengel said. “Therefore, producers wanting to graze or hay this wheat should test it for nitrates before turning cattle in or cutting for hay. The potential for problems is great.”

Nitrate levels higher than 6,000 ppm can potentially be toxic, depending on the situation.

Canola and other brassicas are known accumulators of nitrates, Mengel added. “It is likely that freeze-damaged canola will contain high nitrates. Producers planning to graze freeze-damaged canola should test for nitrates first,” he said.

The potential also exists for freeze-damaged alfalfa to have high nitrate levels, although this is much less likely. High nitrates in alfalfa would be especially likely in fields where manure was applied last fall. Therefore, testing might be advisable if there was a nitrate source present. More information is available in the “Nitrate and Prussic Acid Toxicity in Forage,” K-State Research and Extension publication.

If the decision is made to hay or graze growing wheat, producers have until the late-boot stage to harvest the forage before the nutritional quality begins to decline sharply, said John Fritz, K-State Research and Extension forage management agronomist.

If the crop was already in early heading when damaged and awns are present, this can cause cattle considerable soreness and irritation to the eyes, mouth, lips, gums, and lower surface of the tongue, said Ron Hale, K-State southwest area Extension livestock specialist. “In general, a crop with rough awns should be ensiled rather than hayed or grazed. If the crop can be picked up, it can be made into wheatlage as long as it still contains about 30 to 35 percent dry matter and 65 to 70 percent moisture,” Hale said.

To cut the crop for hay (or silage), a sicklebar mower can be used to slide under the down wheat to cut it, said Jana Beckman, K-State Research and Extension sustainable agriculture coordinator, and Carol Blocksome, Extension assistant, grassland water quality. Rake and bale as usual. Grazing can begin at any time the ground is dry enough, pending crop insurance considerations. Care must be taken when grazing to minimize soil compaction.

“Dead wheat should be grazed as soon as possible, as nutritional quality will decline immediately. To maximize grazing potential, the wheat should be strip-grazed, using a heavy stocking rate and moving the electric fence daily. Animals will need an adequate water supply,” Fritz said.

Cattle on wheat pasture are often “washy” due to the high moisture content and digestibility of the wheat, he added. Offering dry, lower-protein hay or allowing access to native range can minimize this condition.

Avoid Problems if Grazing Wheat Pasture

Two potential problems when grazing wheat pasture are bloat and grass tetany, said K-State Research and Extension forage management agronomist John Fritz.

The following excerpt from the K-State Research and Extension publication “Wheat Pasture in Kansas” (C-173 revised) covers potential animal health problems with wheat grazing. See: www.oznet.ksu.edu.

“High crude protein and low fiber contents in wheat pasture are associated with bloat. Cool, moist conditions also favor bloating. To aid in preventing bloat, do not put hungry cattle on lush pasture. When grazing begins, carefully monitor to identify animals more susceptible to bloat, so they can be removed before chance of loss. Observing the cattle often to detect bloat can prevent loss. Bloat potential is greatest during the 3- to 4-week periods of lush growth in the fall and early spring. Feeding Bloat-Guard (poloxalene) as a dry or liquid energy supplement, molasses block, or mineral supplement is the most effective procedure to prevent bloat. Feeding high-quality grass hay, silage or grain with Rumensin or Bovatec will minimize bloat potential.

“Tetany is characterized by a low blood magnesium level in livestock. It occurs more often in older cows nursing young calves, but may affect stockers as well. Tetany frequently occurs during rapid spring growth following cool temperatures (45 to 60 degrees F), but may occur in fall. The easiest prevention is to provide 6 to 8 percent magnesium in a palatable, free-choice mineral supplement.”

Contact:
Jim Shroyer
785-532-5776