High levels of nitrates have been detected in South Dakota forages this growing season. South Dakota State University (SDSU) Extension Cow-Calf Field Specialist Robin Salverson encourages livestock producers to get their forages tested for nitrates before feeding.
“Asking your neighbor if he or she has high nitrates is no indication of what your forage will be. Likewise, there is variation within fields that sit side-by-side,” Salverson said.
Forages which commonly accumulate nitrates include oats, wheat, millet, Sudangrass, sorghum, corn, orchardgrass, tall fescue and weeds like kochia, pigweed, lambsquarters and ragweed.
Cover crops are another forage that Salverson said livestock producers should have tested. “Several of the cover crop mixtures include the plants listed above,” she said. “In addition, most cover crops include brassicas, such as turnips, radishes, rapeseed—these can also accumulate nitrates.”
If nitrate levels in forages are too high, abortion and or death could occur. Death may occur within one hour or in the usual case, three to four hours after the onset of difficult breathing.
Where to test?
Several laboratories perform nitrate testing. Depending on the lab, testing costs up to $20 per sample. For a complete listing of laboratories in South Dakota, visit iGrow.org and search Feed & Water Testing Laboratories.
“Avoiding one abortion will cover the cost of several tests,” Salverson said.
When collecting a sample for testing, Salverson said it is important to select a representative sample of standing forage or bales.
When sampling from a standing crop, collect plants from all parts of the field, the good and bad areas. Do not sample from just one end of the field or the most convenient.
If the hay is in a bale, a hay probe needs to be used to collect cores.
For the proper method of sampling, visit iGrow.org and search for the document, “Proper Sampling of Hay and Forages.” If you have questions, contact Salverson at Robin.Salverson@sdstate.edu or an extension cow-calf specialist in your area.
What happens if nitrates are found?
If a test indicates nitrates are present, Salverson said most forages can be incorporated into a feeding program by blending with feedstuff that are low in nitrates.
However, she said when nitrates get above 2000 parts per million nitrate nitrogen, it should not be fed to pregnant animals, regardless if you were going to blend. — SDSU iGrow Extension
