Overwintered Cattle May Spread Weed Seeds
Producers who have relocated their cattle out of state for winter feeding this year should consider having a weed management protocol in place when the cattle return.
If you have sent your cattle to areas where there are known Palmer amaranth, waterhemp or other noxious or troublesome weed issues, it will be important to allow a ‘cleanout period’ upon return. Crop fields are not the preferred area for this period, since weeds like Palmer amaranth are generally more difficult to control in crops compared to bare ground, pastures or a corral.
The retention time of potential weed seeds in the gastrointestinal tract is heavily dependent on the digestibility of the diet. When we turn cattle out to green, lush cover crop, the passage rate of that feed is high compared to lower digestible forages, such as prairie hay. That does not mean some seeds couldn’t get held up longer in the gastrointestinal tract.
Confining cattle to one area for at least one week upon return is going to be a good practice. The manure, which includes feces, bedding and spilled or uneaten feedstuffs, should be kept in that area and composted. Composting manure has been shown not only to reduce the volume of manure and kill parasites and pathogens, but also is an effective weed seed management strategy.
Piling manure and turning it five to six times every 10 to 14 days should achieve temperatures between 130-160 degrees Fahrenheit. The high temperatures along with proper pile moisture will kill both large and small weed seeds.
To learn more about composting manure, view the NDSU Extension publication, Composting Animal Manures: A Guide to the Process and Management of Animal Manure Compost at https://tinyurl.com/NDSUCompostingAnimalManures.
Livestock owners will want to keep a close eye on the area where the manure is managed to make sure escaped weed seeds that grow in the spring and summer of 2022 are pulled and properly disposed of. Before the plants develop seeds, pull and destroy them by burying them deeply or burning them.
If producers are going to spread the compost from that area, they will want to closely monitor the area where they spread it and practice similar monitoring and disposal techniques as in the feeding area.
It is not recommended to spread fresh manure on fields if it is known to contain noxious or troublesome weeds. However, if producers need to graze before weeds seeds have been passed or if producers need to spread the fresh manure on a field, we recommend spreading weed seed-heavy manure on tame grass pastures or grass hayfields, because more options are available to control on them.
It is never recommended to spread manure on native rangeland. Adding additional nutrients can benefit invasive grass species such as Kentucky bluegrass and smooth brome.
For more information about protocols for bringing your cattle back to North Dakota, or noxious or troublesome weeds, contact the NDSU Extension agent in your county. Visit https://www.ag.ndsu.edu/extension/directory to find your county NDSU Extension office.
Thank you to co-authors Joe Ikley, NDSU Extension Weed Specialist; Zac Carlson, NDSU Extension beef cattle specialist; and Miranda Meehan, NDSU Extension livestock environmental stewardship specialist.
Extension Specialist/Livestock Environmental Management