A wet summer and late start to silage harvest likely cut into cover crop production this year.
Patrick Wall, Iowa State University Extension beef specialist based in Knoxville, Iowa, says grazing availability will likely depend on planting dates.
“If we get an Indian summer and the weather warms up, we might be able to get a few more days out of those cover crops,” he says. “But I would suspect fall grazing will be limited.”
Wall says many producers seed immediately after chopping corn silage. In a typical year, he says, cows could graze a month or a bit longer on cover crops.
This year, silage harvest was late and October was wet.
Some were able to do some aerial seeding, but Wall says in those instances, most producers will not plan to turn cows loose on the cover crops.
He says cereal rye remains the cover crop of choice for most producers.
“Cereal rye is able to grow in the coldest soil conditions,” Wall says. “You could see some use triticale or winter wheat even, but they usually try to harvest the wheat as a cash crop.”
On his own farm, Wall says he planted cereal rye behind a short-season soybean variety in 2018. He lightly incorporated the seeds, and was able to get 14 days of fall grazing. In addition, he let it grow in the spring and harvested 170 bales of baleage over 40 acres.
“You wet bale it, so you have to leave it out for 24 to 48 hours,” he says. “As soon as you bale it, you need to wrap it within 12 hours or it starts to rot. Cereal rye is very wet when harvested.”
Kable Thurlow, Extension beef specialist with Michigan State University, says cover crops can be grazed into early winter. He says other than ice, cows should have no trouble accessing the feed.
Thurlow says some producers may treat cover crop as a total mixed ration (TMR).
“You may be able to mix several species together to produce a sort of TMR with cover crops,” he says, adding he recommends farmers work with local experts on what might work best in their specific area.
Thurlow says while it is perfectly safe for cows to graze cover crops after a frost, very hungry cows should probably not be turned directly out into a lush field.
“You could run into bloat issues, so you want them to have a full stomach when you turn them out to graze,” he says.
Producers should also check for potential nitrate toxicity, he says. Prussic acid poisoning could also be a concern after a frost if grasses such as grain sorghum, johnsongrass, sorghum-sudan grass or pure sudangrass make their way into a cover crop mix.
Thurlow says while many types of cover crops are available, it is not a “one size fits all” system.
“If you are interested in something, try it and see if it will work for your farm,” he says. “Start simple, and if you like the results, seed more acres the next year.”