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Sweet On Swaths

TAGS: Pasture
Jim Gerrish recalls his first try at swath grazing. He was concerned about the quality of his alfalfa swaths left out on the field all winter. What he

Jim Gerrish recalls his first try at swath grazing. He was concerned about the quality of his alfalfa swaths left out on the field all winter. What he got was a pleasant surprise.

“You get clear out to January and pull the swath open, particularly if it's under snow, and the fact that the alfalfa leaves are still on the stems — that's a pleasant surprise.”

As owner of American GrazingLands Services LLC (, the renowned grazing expert works to educate producers about the possibilities of extending the grazing season.

“You need to look at all your grazing resources,” Gerrish explains. “Swaths are one that will maintain quality well, so you can save them for later in the winter if you have other standing forage to put the cows on at the front part of winter.”

Swath grazing consists of grazing cattle on forages cut and left lying in windrows in the field. Also referred to as windrow grazing, the feed is metered out by using electric fencing to optimize its use and minimize waste.

Weather and climate

When he learned the growing season in Minnesota was just 120 days, Ryon Walker, University of Minnesota Extension beef specialist, speculated that windrow grazing might help trim total feeding days.

There are a multitude of factors to consider for swath grazing, but topping the list is an understanding of local weather and climate, the type of cattle you want to graze, type of forage to windrow and managing the swath, he says.

First, evaluate your area's “normal” fall and winter precipitation. “When you have forages lying on the ground, moisture can leach (or deplete) water-soluble carbohydrates, lowering forage quality,” Walker says. Humidity makes it more difficult to cure swaths.

Experts say the Dakotas, Nebraska, Kansas, Montana, Wyoming, Colorado, Idaho, eastern Oregon and Washington, on down through the semi-arid West to New Mexico and Arizona, and even Minnesota and parts of Iowa, can successfully utilize swath grazing.

“Farther east and south of those areas, the amount of typical fall moisture will limit its use,” Gerrish says. He recommends stockpiling forages as an option when swath grazing won't work (see “The skinny on stockpiling, p. 70”).

Producers often question the amount of snow cover cattle can forage through. Canadian research demonstrates cattle can forage through 2 ft. of snow.

“Once they know where those windrows are, they easily get through snow to that hay,” says Jerry Volesky, University of Nebraska Extension range and forage specialist in North Platte.

But snow cover followed by warm weather in an alternating freeze-thaw pattern can leave an icy crust atop the swaths, making it difficult for cattle to get to the hay. When ice is a problem, driving a tractor down the length of the swath will break the crust, providing cattle access to the forage, he says.

But snow cover also has its advantages. Last year, Gerrish had 4-8 in. of snow covering swaths. “That kind of snow cover actually locks in the quality (of the forage) at the state it was when the snow fell on it,” he says.

Classes of cattle

Understanding cattle's nutritional needs is important when evaluating the feasibility of swath grazing. Dry, pregnant cows are usually good candidates.

“During the fall, you're feeding a pregnant dry cow at a stage when her nutrient requirements are the lowest to maintain her body function,” Walker says. Given temperatures at 20° F or above, the cow only needs about 8% crude protein to maintain body function.

“The later you go into winter, the more she'll need from a nutrient standpoint,” adds Greg Lardy, North Dakota State University Extension beef specialist.

Calving date is also important. Gerrish swath grazes cows until they're moved into a bale-feeding situation to prepare for calving. He says cows can calve on swathed forages, but the forage must be tested for the energy and protein levels required for lactation.

Swath grazing also can work well for weaned calves in a preconditioning or backgrounding situation. In work comparing calves on swaths vs. bale feeding, Volesky found similar weight gains (0.55 lbs./day) in one year of a study. In the second year of the study, windrow-grazed calves had better gains (1.17 lbs./day) compared to bale-fed calves (0.86 lbs./day). The difference was attributed to the presence of high-quality regrowth that was available to windrow-grazing calves in November and early December.

What's more, Nebraska work found bale-feeding calves cost 30¢/head/day compared to 16¢/head/day for swath grazing. Plus, the cost of baling was 37% higher than windrow grazing.

Meanwhile, Minnesota research found swath grazing cost 35¢/head/day compared to $1.26/head/day for baleage feeding.

To run your own cost comparison, visit:

Gerrish also recommends forage sampling if producers want to swath graze stockers and replacement heifers. Supplementation may be needed if such animals will be on swaths longer than 45 days.

Windrow management

Windrow grazing works best in an intensive rotational grazing system, Walker says, with temporary electric fence controlling how much forage is available for cattle at one time. “The faster cattle are moved through with a limited amount of forage, the less they'll waste,” he says.

Walker says it may take a day or two for cattle to acclimate to swath grazing because they gravitate to green, leafy material first. He determines his stocking rate based upon cows receiving approximately 2% of their body weight in dry matter.

In areas of heavy snowfall, Gerrish recommends heavy, dense windrows so cattle can find them easier. Typically, swaths should be no more than 3-ft. wide. The larger the windrow, the more cattle are inclined to use it as bedding, especially when the snow flies, he says.

By raking windrows together, manure distribution is more concentrated around the swath and less between swaths. Dragging pastures in the spring to break up manure concentrations and residue is recommended.

For more information on swath grazing, check out these resources:

Water and ground freeze

Depending on how late into the season you graze, stock water can be a problem, says Minnesota's Ryon Walker. Because fields often aren't equipped with heated water sources, he sees swath grazing as a late-fall, early-winter grazing strategy in MN.

North Dakota's Greg Lardy says he's hauled water to inverted tire tanks and used a propane heater to keep the water open.

Producers in Canada often let their cattle consume snow as a water source, but Walker says there must be enough clean snow available. Even then, producers should be ready to supply water, if necessary.

Another consideration is moving fences on frozen ground.

“We're able to get fiberglass poles in the ground where the windrows were because the insulation prevents the ground from freezing,” Walker says.

Other producers sink poles into buckets of sand filled with water. Once frozen, the buckets and poles can be moved around the pasture.

The skinny on stockpiling

For higher rainfall areas, stockpiled grazing — forage left standing at the end of the growing season — is the best option to extend the grazing season.

“It's growing feed in the growing season for use in the dormant season,” explains Jim Gerrish, of American GrazingLands Services LLC. Typically, it takes 60-75 days to stockpile forages.

Forage quality decreases over time, so the longer the stand sits idle, the lower the quality and quantity. Nebraska research shows crude protein levels for windrows and bales at 10.6% through February, while stockpiled forage declined to 5.7%.

Determining yield

Stocking rate is important in swath grazing because you want to minimize waste, and that begins by determining yield.

Ryon Walker, University of Minnesota Extension beef specialist, measures yield by weighing four samples of a 10-ft. section of windrow within a field to arrive at a figure for pounds of forage per square foot per sample. Upon determining an average of the samples, he calculates the tonnage for the acreage.

“It's hard to get an accurate measure of yield in one pasture because of the variation in forage,” Walker says.

Greg Lardy, North Dakota State University Extension beef cattle specialist, suggests producers think about how many bales/acre they would get if the crop was put up for hay. That will give you an estimate of how much forage is available, + or - 10%.