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High nitrates detected in forages; cover crops pose risk, too

beef cattle eating forage at feed bunk
AT RISK: Cattle fed forages high in nitrate can die. Pregnant cows may abort their calves.
Extension specialist issued a warning about high nitrate in some forages and cover crops this year.

High levels of nitrates have been detected in some South Dakota forages again this growing season, says Robin Salverson, South Dakota State University Extension cow-calf field specialist.

It’s important to test forages for nitrates before feeding them, she advises.

"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 says.

Forages that commonly accumulate nitrates include: oats, wheat, millet, sudangrass, sorghum, corn, orchardgrass, tall fescue and weeds such as kochia, pigweed, lambsquarters and ragweed.

Cover crops are another forage that should be tested. "Several of the cover crop mixtures include the plants listed above," she says. "In addition, most cover crops include brassicas such as turnips, radishes and rapeseed. These can also accumulate nitrates."

If cows consume forages with nitrate levels above 2,000 parts per million, abortion and or death could occur, she says.

Death may occur within one hour or, in the usual case, three to four hours after the onset of difficult breathing.

Testing costs
Several laboratories in the region perform nitrate testing. Testing costs about $20 per sample. However, costs vary from lab to lab. "Avoiding one abortion will cover the cost of several tests," Salverson says.

When collecting a sample for testing, 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.

Go online for information on the proper method of sampling.

Blending possible
If testing indicates nitrates are present, most forages can be incorporated into a feeding program by blending with feedstuff that are low in nitrates.

However, when nitrates get above 2,000 parts per million nitrate nitrogen, the forage should not be fed to pregnant animals, regardless if you they are blended with other feedstuffs, Salverson says.

Lab list
The following is list some of the forage labs in the region that SDSU Extension Service has compiled: 

Servi-Tech Laboratories
1602 Park West Dr.
P.O. Box 169
Hastings, NE 68902
Services: wet chemistry and NIR feed, nitrates, soil, manure, water 

Ward Laboratories, Inc.
P.O. Box 788
Kearney, NE 68848-0788
308-234-2418 or 1-800-887-7645
Services: wet chemistry and NIR feed, nitrates, soil, water, manure, mycotoxins (Aflofoxin only)

Frontier Mills Inc.
2002 SD Hwy 314
Yankton, SD 57078
1-800-955-2441 or 605-665-2441
Services: NIR feed, nitrates

Valley Ag Supply (Valley Hay Lab)
P.O. Box 221
Gayville, SD 57031
605-267-3100 or 1-866-890-3497
Services: NIR forage testing

Midwest Laboratories
13611 B St.
Omaha, NE 68144
Services: wet chemistry feed, nitrates, soil, manure, water, mycotoxins 

SDK Laboratories
1000 Corey Rd.
Hutchinson, KS 67501
1-877-464-0623 or 620-665-5661
Services: wet chemistry and NIR feed, nitrates, manure, water, mycotoxins, selenium in forages

Stearns DHIA Central Lab
825 12th St. South
P.O. Box 227
Sauk Centre, MN 56378-0227
320-352-2028 or 1-800-369-2697
Services: wet chemistry and NIR feed, nitrates, soil, manure, water, mycrotoxin

Cumberland Valley Zumbrota Forage Lab
38 Jefferson Dr. Ste. A
P.O. Box 9998
Zumbrota, MN 55992
Services: NIR feed

Minnesota Valley Testing Laboratories2
1126 N. Front St.
New Ulm, MN 56073-0249
1-800-782-3557 or 507-354-8517
Services: wet chemistry feed, nitrates, soil, manure, water, mycotoxins

Dairyland Labs, Inc. — St. Cloud
P.O. Box 580
St. Cloud, MN 56302
Services: wet chemistry and NIR feed, nitrates, soil, manure, water, mycotoxins

American Agricultural Laboratory, Inc.
700 West D
McCook, NE 69001
Services: wet chemistry and NIR feed, nitrates, soil, manure, water, mycotoxins

Alltech IFM Laboratory
700 32nd Ave South
Brookings, SD 57006
Services: wet chemistry (no minerals) and invitro fermentation of feeds

Check here for a complete list of labs that SDSU Extension specialists have compiled. 

Source: SDSU

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