Cattle Grazing: Turnips and Other Root Crops for Livestock
By Loretta Sorensen | Dec 8, 2015
Historically, man and beast alike were great beneficiaries of the turnip plant. Heck, before the 20th century, beef producers relied heavily on a steady stream of crops to sustain their herds through winter, even in a specific order of turnips, rutabagas, and fodder beets (mangels) and carrots, based on crop storage qualities.
But if you think turnips are simply something European farmers commonly grazed and fed hundreds of years ago, think again.
In an era of high feed prices and widespread, persistent drought, new turnip varieties – such as Pasja – are giving beef producers an opportunity to extend grazing options and seasons. Just as important, turnips can help improve pasture quality.
Way out west
Chris Benedict, regional specialist at Washington State University Extension, directed a two-year study of root-crop production in 2011 and 2012 to help farmers in western Washington make decisions about using root crops such as turnips in livestock operations.
“Pasja turnip produces massive amounts of biomass per acre,” Benedict says. “The plant has very little root system in comparison to other varieties, such as Purple Top. For a grower, that means the plant puts a lot of energy into the forage. Pasja also has potential for multiple harvests since it can be grazed or cut within 30 to 40 days after planting, and then allowed to regrow.”
Beginning in the 1600s, turnips were grown extensively in England for winter feeding of sheep and cattle, as a pasture crop for pigs, and winter fodder for sows.
Some of the first North American settlers in the 1600s brought turnips here. Over time, as less labor-intensive corn silage became widely available, turnips began losing popularity with livestock owners. The Brassica is gaining notoriety once again as research like Benedict’s demonstrates that forage crops such as turnips can be grown in soils and climates unsuitable for corn or alfalfa.
“Turnips are a short season crop and can be grown either as a spring or a fall crop,” Benedict says. “They’re not real frost tolerant, are moderately shade tolerant and can be successfully intercropped with corn. Because they’re tolerant of colder climates, they’re well suited for production in the northern United States and southern Canada.”
The first hybrid turnips – documented as far back as 1844 – were developed to combine the cold tolerance and greater amount of dry matter in rutabagas with the faster growth and maturity of turnips. Current forage turnip varieties include Pasja, Seven Top, Appin, All Top and Tornado (Forage Star).
Pasja turnips have been bred for rapid growth and high performance, featuring a high leaf-to-bulb ratio. It has excellent regrowth ability and provides leafy summer livestock feed.
Five common turnip shapes include long, tankard, round, globe and flat. Most turnip forage varieties currently used are globe-shaped.
In the past, when grazing root crops was more common, tankard type varieties were valued for uniformity. Round types are also uniform in shape, tending to sit at or above soil surface. Globe-shaped turnip varieties are nearly spherical in form. Their root remains below ground much more so than tankard or long turnip varieties.
“Globe type turnips tend to be more frost hardy,” Benedict says. “Flat types have similar characteristics as globe varieties, but develop greater width than length, leaving a large amount of the root exposed above the soil surface.”
Today’s fodder turnip varieties have optimal root development and high leaf-to-root ratio for grazing purposes. There are white-fleshed and yellow-fleshed varieties with skin color varying from white to purple.
“The majority of modern-day turnip varieties are cultivated as a vegetable crop,” Benedict says. “Vegetable breeding programs generally focus on small, tender roots and vigorous leaf production. Vegetable variety turnips can be used for livestock fodder, but they won’t produce the maximum yield seen with older fodder varieties.”
The cabbage flea beetle and striped flea beetle feed exclusively on Brassicas such as turnips, attacking the cotyledons and first true leaves, causing extensive loss to turnip crops. Turnip louse and aphids can also be problems. All Top and Tornado are resistant to turnip mosaic virus and tolerant of aphids.
“Crop rotation helps control turnip diseases,” Benedict says. “To avoid pests, don’t grow turnips in soil where root crops or Brassicas were grown in the previous four to five years. Clover, beans, peas and grain crops are all good in rotation with turnips.”
Turnips are more tolerant of a greater variety of soil types than other root crops, thriving on moist, well-drained, slightly acid sandy loam soils and loam soil with a pH range of 5.5 to 6.8.
“Fertilizer should be applied near the time seeds are sown to give the crop a competitive advantage over weeds,” Benedict says. “Spring turnip crops typically require heavier fertilizing than fall crops.”
In general, depending on soil conditions and organic matter, 50 to 70 pounds of nitrogen (N) per acre, 20 to 150 pounds of phosphorus (P205) per acre, and 120 pounds of potassium (K20) per acre should be applied at planting. But soil testing is the best tool for developing effective fertilizer applications.
Turnips can be successfully sown into pasture ground with minimum tillage if pasture crops are suppressed to allow young seedlings to compete. For pasture production, seed can be broadcast using 4 to 6 pounds of seed per acre and lightly harrowed. If drilling turnip seed, 3 to 4 pounds per acre is generally recommended.
Adequate moisture is key to turnip root enlargement. Depending on the time of year and growing region, 8 to 12 inches of water is required during the growing season. Water requirements vary between soil types. Lighter soils may require additional moisture.
“Turnips don’t germinate well under cold soil temperatures,” Benedict says. “In spring, sow seed when soil temperatures have reached at least 50 degrees. Turnips are cold hardy but don’t withstand frost as well as root crops such as rutabagas.”
For midsummer grazing, turnip seed should be sown in late May or early June. For fall forage, planting should be completed between July 20 and August 1, or about 70 days prior to the first hard frost.
“The first and second cultivation of turnips for weed control may be relatively deep, but succeeding cultivations should be shallow to avoid damaging roots,” Benedict says. “Once turnips are established, they compete well with most weeds.
Application to stock
Turnip roots, stems and leaves are all palatable to livestock. However, livestock can become sick if allowed to eat too much turnip too quickly. If livestock are subsisting on forage with low nutritional quality, producers should gradually add high-quality feed such as turnips to their diet to build up healthy rumen microbial populations that can break down protein. When grazing turnip leaves, livestock should have access to hay or other pasture. Additionally, lower-quality hay should simultaneously be made available to provide animals with adequate amounts of fiber.
“You don’t want to totally switch to grazing crops like turnips,” Benedict says. “What is economically feasible is mixing turnips with corn silage to increase crude protein content of corn silage and reduce the acid detergent fiber (ADF) content in the silage.”
The ADF value of feed correlates with cell wall digestibility. As ADF increases, digestibility decreases.
“Turnips in particular, when mixed with corn silage, cause ADF in silage to be relatively low,” Benedict says. “In turn, neutral detergent fiber (NDF) increases when turnips are mixed with corn silage, which means livestock can consume less dry matter without sacrificing nutrition because nutritional value of silage mixed with forage such as turnips is higher.”
Turnip greens grown for forage yield an average of 3 to 4 tons of dry matter per acre. A good average harvest of turnip roots is 15 tons per acre.
Roots may be harvested 45 to 80 days after seeding. Turnips are frequently pulled by hand, but beet lifters can be used for lifting and topping turnip roots.
“If turnips are grown for forage or green chopping, they should be harvested when leaves are 12 inches tall, which is generally 70 to 90 days after planting,” Benedict says.
Topped roots can be stored in piles or pits in well-drained soil. To prevent heating, pile dimension should be no greater than 8 feet wide and 6 feet deep. Wooden chutes or perforated PVC pipe can be inserted into the pile to promote sufficient aeration. Smaller quantities can be stored for four to six months in a root cellar in damp sand to prevent drying.
To revive aging pastures, turnips can be used to help create root channels for moisture and reduced compaction. Grazed turnips will also leave decomposing materials behind that enrich the soil.
“Turnips decompose quickly after grazing,” Benedict says. “They scavenge available nitrogen below the root zone and leave micronutrients such as zinc and sulphur that grasses can take up. They also add to soil organic matter, which helps revive pastures that have been grazed for many years.”
Loretta and her husband farm an acreage in southwest South Dakota where they raise Belgian draft horses.
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