Management strategies for cattle grazing corn fields

There is no supplement that will prevent grain overload in stalk fields with a lot of ear drop. Ear drop is the corn that is left in the field, usually on the ground that was not harvested using the combine. Following are some possible management strategies.

Anytime more than about 8 bushels of grain per acre are left in the field after harvest, cattle grazing the stalks risk getting acidosis and founder. Both diseases are caused by excessive grain intake, which increases rumen acid production. This can cause severe foot and hoof problems, including lameness.

While smut is not a health problem, some grain may contain other molds that can produce mycotoxins. Vomitoxin and fumonisin rarely cause problems for beef cattle at typical contamination levels, and aflatoxin rarely occurs in risky concentrations in Nebraska grain crops. Still, if there are reasons to suspect much mycotoxin may be present, an assay of the grain would provide useful safety information.

Estimate the amount of corn down in a field. An 8-inch ear of corn contains about one-half pound of corn grain, so it takes 112 8-inch ears to equal 1 bushel (1 bushel = 56 pounds). Thus, by counting the number of ears, the amount of corn can be estimated. For corn planted in 30-inch rows, count the number of ears in three different 100-foot furrow strips and divide by two to give an approximate number of bushels per acre. Small ears and broken ears should be counted as half ears, while very large ears could be counted as an ear and a half. Any amount beyond 8 bushels per acre will require a well-planned grazing strategy.

One strategy for using high-grain cornstalk fields is to minimize availability of grain to susceptible animals. A good way to do this is to first graze yearling cattle, calves, or cull cows destined for slaughter, then follow with pregnant cows. This strategy would reduce the amount of ear drop before the pregnant cows have access to the field. Another alternative is to graze only a few hours per day. You could also strip graze the field or fence so that cows have limited access to the entire field. This would limit the grain intake and force cows to consume some husks and leaves along with the ears of corn. A final strategy might be to feed some grain or ear-corn 7 to 10 days before cattle are turned out to help them adapt to a high-grain field, but this strategy may not help with grain overload.

One factor influencing the success of these stalk grazing strategies is the experience level of the cattle grazing the field. Old cows with previous experience in cornstalk fields can pick up amazingly high amounts of corn in a short period of time, as can experienced yearling cattle. If they have not been conditioned to eating a high-grain diet, some of the previously listed strategies may fail. Thus, inexperienced calves may have the least risk of founder or acidosis in high-grain cornstalk fields because they must first learn how to find corn. As a result, their grain intake safely increases gradually.

Bloat is usually not a concern with cows grazing residue with excess corn.

In hailed-damaged cornfields, nitrates could be a concern. The nitrates are usually confined to the stalk and in particular the lower 6 to 8 inches of the stalk. In a stalk field grazing situation, cattle commonly select the stalk last to eat, after the corn, husk, and leaves are eaten.

Some producers have used sodium bicarbonate in the water when cows graze stalk fields with excess down corn. Sodium bicarbonate can be used to buffer the rumen if they overconsume corn. If you can control where cattle get water, this can help avoid acidosis. Remember, in the winter when there is snow available, cattle can get much of their water from snow. If you use bicarb, one suggested ratio is 2.5 pounds of bicarb per 100 gallons of water.

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