Turnips are often a quick-fix forage for when the rain fails to fall. But increasingly, cattle producers are using the crop as a fall- and winter-grazing option that's nutritious and easy to grow.
Jim Arnaud relies on the fast-growing brassicas year-in and year-out on his farm, near Monett, Mo. He said they raise the fall and early-winter nutritional plane for both his beef and dairy cattle.
It begins in late August after the crop and livestock producer chops corn silage. Arnaud uses his no-till drill to plant 4 pounds of turnips and 65 to 70 pounds of cereal rye per acre. With the extremely fine turnip seed (about 200,000 seeds per pound), it's important not to plant too deep.
"We put them at a quarter-inch," said Arnaud, who plants about 200 acres a year and has grown turnips for a decade.
"If you don't see some seed on top of the ground, you're probably too deep. Planting after chopping silage, the ground is pretty clean and open, so it doesn't take much soil disturbance to get good soil-to-seed contact."
Although he's tried improved forage turnip varieties, Arnaud finds the old standard purple-top turnips to be an economical choice with comparable production. Last year, he paid about $1.55 per pound for the turnip seed.
Turnips respond well to nitrogen, and Arnaud applies 1.5 tons of poultry litter ahead of planting. With commercial fertilizer, he said he wouldn't apply more than 40 pounds of actual nitrogen.
Arnaud makes the most of his turnips by strip-grazing them, beginning about six weeks post-planting. For dairy cows, he allots one day for each move. Beef calves on turnips usually get two to three grazing days. The producer favors the cows and growing calves when it comes to feeding turnips because of their high nutritional content. He has 250 commercial Angus-based beef cows and milks around 100 Holstein and Holstein-Jerseys.
Turnip tops have a protein content of 15% to 22%; the bulb and roots are 8% to 10% protein, according to research from Kansas State University. Total digestible nutrients (TDN) of the tops run around 70%. Turnips can produce 2 to 3 tons of dry matter (DM) per acre. Because of the low DM content, Arnaud cautions calves should be at least 500 to 600 pounds before grazing the forage to minimize scour problems. He also provides dry hay to slow down the rate of passage.
Turnips will grow to nearly 20 inches tall with a 10-inch root and a bulb about the size of a baseball.
"The bulbs can get a lot bigger than that, but if they do, you probably didn't plant thick enough," Arnaud said.
When the temperature reaches roughly 20ºF, the tops will die. Cattle will still pull bulbs from the ground and eat those.
Specifically for his beef cows, Arnaud often plants turnips following corn grain harvest, weather allowing. This can be as late as October.
Using a GPS-guided fertilizer spreader, he puts out a 40-foot pattern of fertilizer, turnips and cereal rye. He then runs a rotary harrow over the field.
"Since it's planted much later, you're not going to get the same forage growth," Arnaud pointed out. "But by the time they are up, the fall calves are a little bigger and can handle it better. It extends our grazing season."
When planting turnips after either silage or mature corn, Arnaud cautioned producers to be aware of potential herbicide carryover and advised them to check product labels.
As a no-tiller and cover-crop user in a corn/soybean/wheat enterprise, the Missouri farmer stressed the positives of the cereal rye he puts in the mix. It provides erosion protection through winter and grows rapidly in early spring, giving Arnaud the option of more forage to graze or silage to harvest.
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