KEWANEE, Ill. — Selecting a cover crop should be based on what works for a specific operation.
“Cover crops offer graziers a lot of high-quality forage to extend the grazing season,” said Dean Oswald, during a Cover Crop Grazing field tour. “It allows the animals to do the harvesting of their own feed, which saves labor and manure handling.”
Determining which cover crop to plant, Oswald said, depends on if it will be used to feed cattle, goats or sheep and when the crops will be harvested.
“If you’re going to harvest the cover crop in the fall by grazing, you might consider adding oats to the mix,” he said.
Oswald grazes 40 does on his 80-acre farm.
“When we moved here, the only thing that could get through the timber behind our house was coyotes and deer,” said Oswald, who also is a grazing specialist for Zea Mays Foundation and Midwest Grass and Forage. “You couldn’t walk through there because of the weeds and brush, but the goats have done a tremendous job of cleaning it up.”
Eight years ago, Oswald started with Boer-type females and added Kiko bucks for four years.
“Now we have a high percentage Kiko does, a few purebred Kikos and Spanish does,” he said. “We are going back to a Boer buck to get a little more muscle and frame size.”
In addition to grazing, cover crops also can be used to make hay, baleage or silage.
“The neat thing about cover crops is there are so many options,” he said. “It depends on the equipment you have available and your management system.”
There are many cool-season annuals available to farmers, including cereal rye, oats, barley and wheat.
“The difference between spring and winter oats is about two weeks of growing season,” Oswald noted. “All will be killed off by winter temperatures, but the winter oats will kill later in the year.”
These forages can produce as much as 30 percent crude protein.
“Grass tetany is a possibility when there is a magnesium deficiency in ruminate animals,” Oswald noted. “You need to put magnesium in the mineral mix when grazing high-quality grass early in the spring.”
When grasses are extremely high quality, graziers must consider the bloat potential for their animals.
“Animals tend to eat according to quality, so if you have really high-quality forages, they tend to overeat,” Oswald said.
Another potential problem with high-protein forages is blood urea nitrogen levels.
“This can affect fertility if the animals are grazing during the breeding season,” Oswald said. “You might consider adding poorer quality roughages to the diet.”
Cereal rye probably is the most forgiving cover crop, he reported.
“It will grow even if you do things wrong,” Oswald added. “In the spring, you need to terminate it before you plant the cash crop, unless you graze it out.”
Legumes that can be planted as a cover crop include crimson clover, berseem clover or sweet clover.
“Berseem clover is non-bloating,” Oswald said. “If you plant it at the end of July or beginning of August, you can get some very rapid growth, and the quality can equal alfalfa hay.”
However, berseem clover is the least tolerant to cold, Oswald said.
“You have to wait for the chance of frost is over before you plant it, and once you get the first frost, it’s dead,” he explained.
Since most legumes have the potential to cause bloat in animals, it is important for the livestock to be full before they enter a clover or alfalfa field.
“Move animals to a new pasture when the forage is dry, preferably in the afternoon,” Oswald advised. “If you move the animals early in the morning, you might have dew or frost on the plants, and that can affect bloating.”
Bloat risk also can be reduced by planting a mix of legumes and grasses or legumes and brassicas. Strip or rotational grazing also impacts the bloat potential.
“Then you don’t force the animals to eat the whole plant,” Oswald said. “There is less chance of bloat if they just eat the tips of the highest-quality plants.”
Kale, rape, radish and turnip are brassicas that can be planted to provide feed for grazing animals.
“Planting date is probably the most critical thing for brassicas,” Oswald noted.
“There is huge difference what a month will do for the growth of brassicas,” he said. “Normally after Sept. 15, it is better to leave the seed in the bag because you’re not going to get enough growth out of them to make it worth your money.”
Since brassicas provide high-quality feed for livestock, Oswald said, the change from a poor-quality hay or pasture to brassicas should be made over a period of several days.
“Let them graze the brassicas for a couple of hours the first day and maybe three to four hours the second day,” he advised. “That will get the microbes in the rumen adjusted to the high-quality feed.”
Oswald advises planting grasses with brassicas.
“You don’t want the brassica to be over 65 to 75 percent of the diet for your animals or you’ll run into problems,” he added.