Some North Dakota State University Extension Service specialists are urging livestock producers in drought stricken states to be aware of nitrate poisoning.
Nitrate poisoning may occur if livestock eat drought-stressed crops and forages, which can accumulate nitrates.
“If producers are considering utilizing low-yielding crops as livestock forage, they should be tested for nitrates prior to feeding.” Plant stresses, such as drought, can increase the levels of nitrate in plants.
“Not all drought conditions cause high nitrate levels in plants,” says Livestock Environmental Stewardship Specialist Miranda Meehan.
“Some moisture must be present in the soil for the plant to absorb and accumulate nitrate.
In plants that survive drought conditions, nitrates are often high for several days following the first rain.” Grazing Drought-stressed Plants Carl Dahlen, Beef Cattle Specialist, has this advice for producers who are scouting or sampling for nitrates in cereal crop fields they are planning to have their livestock graze: “Severe drought-stressed areas such as hilltops with very sandy soils might have plants that look bad, but these plants may be so stressed that they are not accumulating much nitrate at all unless there is a recent rain event.
“Plants have to be in active growth stages to take up nitrogen from the soil,” he says.
Acute poisoning usually occurs from a half-hour to four hours after livestock consume toxic levels of nitrate.
Those symptoms include: Bluish/chocolate brown mucous membranes Rapid, difficult or noisy breathing Rapid pulse (150-plus beats per minute) Salivation, bloating, tremors, staggering Dark chocolate-colored blood Weakness, coma, death Pregnant females that survive nitrate poisoning may abort because of a lack of oxygen to the fetus.
“Overstocking increases the amount of high-nitrate plant parts (stems and stalks) that are consumed by livestock.” The nitrate content of small-grain forages also can be reduced by up to 50 percent by chopping and ensiling, Dahlen says.