Writer: Steve Hill, (979) 845-2895, newsteam@agnews2.tamu.edu
Contact: Dr. John Reagor, (979) 845-3414, j-reagor@tvmdl.tamu.edu
COLLEGE STATION — With drought-related woes piling up, ranchers and others with livestock need to be sure not to add to them by letting their livestock consume nitrate-laden forage or hay, the Texas Veterinary Medical Diagnostic Laboratory reports.
“The good news is we’ve not seen nitrate levels as high as in the drought of 1996,” said Dr. John Reagor, head of diagnostic toxicology at the laboratory’s College Station facility. “Maybe that’s because it’s still early, or maybe it’s because climatic conditions this year allowed more nitrogen to be used up in plant growth.”
But that doesn’t mean livestock owners can afford to let forage or hay go untested, Reagor said.
Although only one case of nitrate poisoning has been confirmed in the state so far this summer — four cows which died after consuming sudan hybrid sorghum — drought conditions appear to be worsening and the ailment can strike quickly.
“Typically, an animal will die within a few hours, but it can take as little as 30 minutes,” Reagor said. “It will stagger, breathe hard, and die, and the owner doesn’t know until the animal is found dead.”
He is aware of two or three cases in the past two decades where several dozen animals have died on a single farm or ranch, Reagor said.
Probably the most hazardous hay is that made of sudan hybrid sorghum contaminated with pigweed, also known as careless weed, Reagor said. Both are found in most parts of the state, and because sorghum was generally planted later than corn, it may not have been able to take advantage of stored water in the soil.
When conditions began to dry, that meant sorghum was more likely than earlier-planted crops, like corn, to have grown higher and use up nitrogen in the soil, he said.
Reagor said livestock owners should have samples of their hay or forage tested at his laboratory or at the Soil, Water and Forage Testing Laboratory at Texas A&M University’s soil and crop sciences department. The TVMDL’s toxicology lab may be reached at (979) 845-3414, and the soil and crop sciences lab may be reached at (979) 845-4816.
“Generally, if it’s grown under drought conditions, it needs to be checked before being fed to stock,” he said.
The best way to get a test done is to use a hay probe. Most county Extension agents have hay probes, Reagor said.
If forage is to be tested, livestock owners should collect a representative sample of plant stalks from the pasture. Good samples will include plant stalks from both high and low spots and from larger and smaller plants in the pasture.
County agents can also give more information on collecting good samples, Reagor said.
There are ways that forage or hay with high nitrate content can be fed to livestock with proper management, he added. A good rule of thumb is to feed an animal a pound of grain per day for every tenth of a percentage point above 1 percent nitrate content in the hay or forage, he said.
The grain will allow the animal to help build up the proper bacteria content in its rumen to counteract the nitrate, he said.
Producers should be aware, however, that selling hay containing hazardous levels of nitrate is illegal in Texas, said Dr. Konrad Eugster, director of the TVMDL. Questions about this subject should be directed to the state’s Feed and Fertilizer Control Service at (979) 845-1121.
Reagor said the toxicology lab had tested about 120 samples in the two weeks around the beginning of June, but he expects it to be handling about 400 tests a week before long if the drought continues.
“That’s about what we were doing in 1996, and so was the forage testing lab,” he said. “We have to split up the work or we’d never make it.
“But if we prevent just one catastrophic loss, all the effort is worthwhile. That’s what we’re here for.”
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