In the wake of a Grant County Palmer amaranth infestation, North Dakota State University weed specialist Joe Ikley, and colleagues from various disciplines, issued a press release warning producers to be wary of purchasing livestock feed containing weed seeds.

RELATED: Sunflower screenings receive increased scrutiny after additional Palmer amaranth outbreaks

“Sunflower screenings merit particular attention, as contaminated sunflower screenings have been linked to infestations in six counties in North Dakota over the last 12 months. If purchasing sunflower screenings, be sure to ask the origin of the sunflowers,” the warning said.

Ikley noted that the U.S. Department of Agriculture has emergency funds for bringing in (presumably, weed-free) feed to counter the drought.

“That cheap load of feed might turn out to be the most expensive feed-related problem you have encountered,” Karl Hoppe, an NDSU livestock specialist at Carrington, said.

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And Mary Keena, an NDSU livestock environmental management specialist at Carrington, said that when feeding screenings to livestock in pens, manure should be “contained and composted." If livestock are fed on pasture or hay land, producers should use land with non-native grass areas where “weeds can be easily spotted and treated.”

The following are additional tips Extension officials suggest for handling feed that could be contaminated:

  • Buy cleaned grain, but realize purchased feed isn’t routinely tested for weed seeds.

  • Have screenings tested to determine the presence of weed seeds prior to feeding the screenings to livestock. Feeding whole seeds may perpetuate the problem. Some seeds, especially tiny, hard-shelled seeds from Palmer amaranth, can escape digestion by cattle.

  • Grind the screenings so fine that the seeds are destroyed. For a small-seeded plant such as Palmer amaranth, aggressive grain processing is needed, and hammer milling usually is the best. The small black seeds are about 1 millimeter in diameter.

  • Compost manure to reduce seed viability.

  • Keep records of where feed resources are unloaded and fed.

For more information about noxious and troublesome weeds or manure management, contact the NDSU Extension agent in your county. Visit to find the Extension office in your county.