Thinking Outside the Grazing Box

8/24/2013 7:00 AM
By Philip Gruber Staff Writer

ROCK SPRINGS, Pa. — Farmers prefer to fence pastures in rectangular shapes. That simple layout is practical and economical but not very creative.

Don’t expect retired Chambersburg dairy farmer Titus Martin to stake out a pasture in a curlicue, but as he demonstrated high-density rotational grazing at Ag Progress Days on Aug. 13, he pointed out that he had to make an asymmetrical pasture.

The new pasture he was laying out for a small herd of beef cattle needed access to the water barrel, so he tacked on an extra triangular piece to the rectangular pasture as he spun out the Kencove braided nine-wire cable demarcating the cows’ afternoon grazing area.

“With this type of a system, there is nothing set in stone,” he said.

Martin, who is now a USDA grazing specialist, spoke about his “three-wire rolling system” during the USDA-conducted pasture management and high-density grazing tour.

When he kept cows, Martin would shift his 130 animals several times a day. He would estimate the amount of feed in a certain amount of land and whether that would be enough for the size of his herd. Each pasture change took about 15 minutes.

Rotational grazing is a common practice for giving livestock access to different fields and allowing the fields time to recover from damage caused by the animals’ hooves and teeth.

High-density grazing is a growing subset of rotational grazing that puts cattle in smaller areas for shorter periods of time.

More concentrated grazing can give grasses more time to mature between grazing periods and develop a better balance of fiber and protein. More mature grasses also have more tonnage and can feed more cattle on a smaller area.

Grasses that are tall but not old enough to be woody are ideal, said Kevin Ogles, an NRCS grazing specialist from North Carolina who also spoke at the event. Cattle should be able to get a full mouthful every time they take a bite.

Droughts can tempt farmers to abandon the discipline of high-density grazing, but dry spells are an especially bad time for farmers to throw away their rotational programs and turn the cattle loose on the whole pasture.

“That’s the worst thing you can do,” Ogles said.

Dropping the rotation spreads the animal-inflicted damage out more and leads to a longer recovery time when the rains return.

High-density grazing also helps concentrate animal waste and gives it more time to break down before the cattle have to graze the land again.

Grazers should try to get a few fecal piles or urine spots in every square yard, Ogles said. Cow dung puts into the soil 70 percent of the nutrients the cow consumed, which can cut down on the need to fertilize.

High-density grazing uses hoof action to press older or dead grasses to the ground, where they are available to “the underground herd” of microbes that recycle the nutrients and make room for new forage, he said.

Farmers should avoid making their temporary fencing as rigid as their permanent fences, Martin said. He uses easily movable and somewhat flexible stakes, which are harder for cattle and deer to knock over. Fiberglass posts even work, he said.

High-density pasturing can also be helpful to horse owners.

Horses are hard on grass because they clip leaves to the ground and even pull out the roots, said Kathy Soder, of USDA’s Agricultural Research Service, who spoke at the high-density paddock the USDA maintains at Penn State’s research farm.

Giving grasses more time to grow between grazing periods can help the grasses recover and add enough length to survive the next round of foraging, she said.

Grasses need remaining leaf to regrow after being eaten. The general rule is that only half of the blade should be eaten, and half should be left standing to ensure the health of the plants, Soder said.

“We’re trying to maintain a green cover,” Soder said.

Equestrians should try to leave about 21 days between grazing of a pasture area. That sabbatical allows parasites to go through a complete life cycle. A mistimed rotation could bring the animals back to a pasture just as parasites are poised to hatch and attack the animals.

Pairing horses with other livestock, such as cattle or goats, can lead to more uniform grazing, Soder said.

Other species can digest some weeds that make horses sick, said Melissa Rubano, a USDA animal scientist. Mixed grazing can keep in check weeds that would otherwise go uneaten.

High-sugar forages are also better for cattle than for horses. Cattle get energy from the extra glucose, but horses get laminitis.

Farmers should pick their mixed-grazing animals carefully. “There are some horses that are going to pick up and shake a sheep,” Rubano said.

If pasture managers provide the ideal conditions, the grasses will out-compete the weeds, she said.

The research paddock uses coated high-tensile wires. The coating increases visibility and reduces the danger from breaking and scratching. Deer can also slide through coated wires instead of getting caught and mangling the fencing, she said.

Pastures also benefit when horses have a high-use area in the paddock, said Sharon Scarborough, a USDA soil conservationist.

USDA built its high-use area at the research farm out of a blended stone mix and stone dust; 3- to 4-inch layers were compacted on top of geotextile fabric in a 12-inch excavation in front of the small barn, which houses two horses.

The high-use area should have a slight slope. If it is too flat, puddles will form when the horses urinate right outside the barn during bad weather. If it is too steep, gullies will develop, Scarborough said.

The high-use area and the surrounding sacrifice pasture should have fencing stronger than the high-tensile wires separating it from the high-density pasture.

Horses will spend a lot of time in the area near the barn, and a durable fence will decrease the chance that they will accidentally break into the rotational part of the paddock, Scarborough said.

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