for Tri-State Livestock News
Straw is often used for bedding or as part of the diet for cows. Megan Van Emon, PhD, Extension Beef Cattle Specialist, Montana State University says oat, barley or wheat straw can be fed, if it’s put up right. The important thing is to have enough protein in the diet to help cattle digest enough the straw, and to balance the diet. “You need at least medium-quality hay, like a good grass-alfalfa mix, to go with straw,” she says. Mature straw by itself is only 4 to 5% protein, and high in fiber.
“Straw by itself doesn’t have adequate nutrients. There’s also risk for impaction,” she explains. Mature straw lacks adequate protein to “feed” the rumen microbes that break down straw, so digestion slows. The cow can’t move it through. Since the gut is full already the cow can’t eat enough forage to meet her nutrient needs and loses weight.
“We recommend feeding a forage protein (alfalfa or a high-protein grass-legume mix) rather than using lick tubs. Adequate protein keeps everything moving through, but some straw in the diet can extend expensive high-quality hay,” says Van Emon. In cold weather, mature cattle (with fully-developed rumen) will eat a lot of straw if they have adequate protein, which helps them stay warm (heat of digestion in the rumen, and conversion of roughage to energy by rumen microbes) and not lose weight.
“Recommendation for mature cows is no more than 50% of the diet as straw—up to the third trimester. During the last 90 days of gestation, reduce it to 25%, partly because the growing fetus is taking up more space in the abdomen and limiting rumen capacity,” she says. For heifers, feed no more than 25% of the diet as straw; they are still growing and need more protein than cows.
If a cereal crop like oats or barley is cut for hay (before maturity), it has higher nutrient quality and more protein than if it’s dry, mature straw after grain harvest. “If oat or barley hay does get mature, grain kernels, can add extra energy to the diet, but you’ll lose some of that grain during the baling process,” she says.
For forage or bedding, you want clean straw without mold–put up without a lot of rain on it. It keeps best if you get it put up right, and cover it. “If you can’t cover it, stack it in a way that allows air flow,” says Van Emon.
“A single row works best, with 3 to 4 feet between rows. This allows drying if there’s any moisture. Snow falls off between the rows rather than sitting on top of the bales and soaking in when it melts.”
For bedding, use less palatable, lower-protein straw like mature wheat. “Cows may eat some bedding, regardless of what kind, especially if you spread it in the morning when they’re hungry. Spread it in the afternoon, after they’ve had a chance to graze or fill up on hay, and they won’t eat so much of the bedding.”
Big square bales use twine, but if you’ve harvested grain and bale the straw that’s left, she recommends round bales and net wrap. “You’ve already chopped that straw and net wrap will hold it together better. When putting it up for hay, however, twine will work; those stems are long enough that the bale won’t fall apart,” says Van Emon.
Cereal straws often have higher nitrate levels than other forages, especially if plants were stressed while growing. “Stress could be anything from too much rain to not enough rain, or a hail event,” Van Enom says.
Since nitrates accumulate in the bottom 1/3 of the plant, you can raise the cutter bar and leave some nitrates behind. “I’d still test the forage just to be safe, but leaving 6 inches of stubble rather than 3 or 4 inches might help. Keep in mind that if there’sweeds in your fields, some of them may accumulate nitrates as well,” she explains.
Dr. Tim DelCurto, Department of Animal & Range Science, Montana State University says straw is beneficial when cows need more roughage, and during cold weather.
“When I worked with a grazing co-op in drought conditions, they penned the cows when they ran out of pasture. They bought high-quality alfalfa (the only forage available), and limit-fed about 20 pounds per head per day. This didn’t work; the cows didn’t have enough gut fill and were not happy,” he says.
“On paper, they were meeting nutritional needs, but not providing enough fiber for gut function. The cows were still hungry, so the guys from the co-op called and asked me what they could do. I told them to buy straw for filler, to go with the alfalfa, and that made all the difference,” DelCurto explains.
In cold weather, high-quality low-fiber alfalfa isn’t enough to keep cattle warm. Straw works well as a filler, if you make sure the diet is balanced and meets nutritional needs. “Straw works well when other forages are scarce or expensive. You can limit feed alfalfa-grass hay and provide as much straw as cattle will eat.”
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