August 5, 1999 | By: Aimee D. Heald

Yet another problem of the 1999 drought is nitrate poisoning in drought-stressed corn. Plain and simple, the drought has slowed or stopped growth in most Kentucky corn fields. The damage is not only economic.

In a normal growing year, moisture allows nitrates to turn into proteins. Nitrates will build up in heavily nitrogen-fertilized corn that has grown slowly or stopped growing due to a drought.

"What we want producers to understand is that high nitrate levels can be deadly to cattle," Donna Amaral-Phillips, dairy nutrition specialist for the University of Kentucky College of Agriculture, said. "They should get the forages tested before feeding them to cattle."

Nitrate toxicity commonly causes death and abortion in cattle. Other symptoms include , labored breathing, muscle tremors, staggering, cyanosis (darkening of pink mucous membranes around the eyes and inside the mouth, due to oxygen deprivation), and increased pulse rate etc. In any case, if you notice cattle showing these signs, immediately call a veterinarian. Cattle can recover if the problem is detected and treated in time.

In times of drought, producers are tempted to feed a stressed crop to livestock. When in fact, that is the time to avoid it the most. Amaral- Phillips urges producers not to graze, green chop or bale drought-stressed corn.

"Cutting corn for silage is a good way to reduce nitrates," she said. "This is the only way drought-stressed corn should be fed to cattle." Studies have shown ensiling corn can reduce nitrate levels. However, you still have to wait at least three weeks for fermentation to take place in the silo before the silage is ready to be fed.

It's important to remember nitrate levels will be the highest two to five days after rainfall. The corn always should be tested after rain before it is fed. Producers can take corn samples to their county agent, veterinarian, or local feed company. These individuals will send the samples to a lab for testing.

Corn is the most obvious concern this year for high nitrate levels, however; other plants can be high in nitrates. In times of drought, Johnson grass, pigweed, common lambs quarter, wild sunflower, Canada thistle, black nightshade, jimson weed and barnyard grass also can cause concern if cattle are grazing pastures with these plants.


Writer: Aimee D. Heald 606-257-9764

Source: Donna Amaral-Phillips 606-257-7542