Purdue News

July 31, 2006

Specialist: Rotational grazing a pick-me-up for tired pastures

WEST LAFAYETTE, Ind. — Some pastures could use a little time off, and a rotational grazing system is the perfect R and R, said a Purdue University Extension beef specialist.

Rotational grazing rejuvenates pasture grasses and legumes worn out from constant livestock feeding and traffic, said Ron Lemenager. The system, which allows livestock producers to extend forage supplies or carry more animals per pasture, is growing in popularity, he said.

"Rotational grazing is dividing your grazing area into smaller pastures or cells, or paddocks as they are commonly called," Lemenager said. "The idea here is that you'd like the animals to graze an area for no more than five to seven days, and then let that area recover for about 28 to 40 days after it has been grazed.

"When you have a rotational grazing system, you can stretch your forage supplies because the plants are healthier and their ability to recover is much, much greater."

In a traditional continuous grazing system, livestock are free to roam pastures, consuming any available forage. Typically, cattle will over-graze younger, more lush forage plants as they regrow but ignore nearby mature forage. The overgrazing weakens younger plants by reducing the leaf area required for photosynthesis and depleting carbohydrate reserves in the roots.

While continuous grazing is still in widespread use, pastures constantly grazed risk poorer regrowth potential and crowding out of desirable grass and legume species by undesirable weeds.

Pastures in a rotational grazing system, on the other hand, are subdivided with fences.

"It's nice to have five to eight cells that you can rotate through," Lemenager said.

Livestock are moved from one paddock to the next. When managed correctly, rotational grazing provides enough forage growth early in the grazing season for producers to harvest feed for later use from one-fourth to one-third of the grazed acreage, Lemenager said.

"After you've made your first cutting off of approximately a third of the land base, you can work that into the grazing cycle in the second or third rotation," he said.

"If you've got a continuous grazing system and want to move to a rotational system, begin by splitting your pasture in half so that you've got two cells. Then you can take those two cells and split them again."

The number of animals a producer should graze within a cell depends on the paddock's size, as well as the number of grazing cells. An important consideration is how close the paddocks are to water, Lemenager said.

"A key factor as you start to think about dividing your pastures is how far do the animals have to move to water?" he said. "In an ideal world, you'd like to have water within 800 feet of the farthest point in the pasture to maximize grazing efficiency. That gets to be tough in some of our pasture areas, particularly as we get into the summer months when streams and springs stop flowing."

The social habits of cattle herds also can affect how much water cows receive. Because bovines are social creatures, they often follow the herd toward — or away from — water sources, Lemenager said. The lead cow and those closest to her usually get as much water as they need. Cows at the end of the line often don't get enough because they leave the water source to follow the lead cow back to pasture or shade.

"Your water resource needs to be an adequate size, so that all animals can drink their fill," Lemenager said. "That probably means that an automatic waterer system for 30 cows and calves is probably not going to be adequate. Consider using a larger tank that holds more volume. When grazing cattle don't drink enough water, forage intake, milk production and weaning weights will be reduced."

Other issues producers should ponder when switching to rotational grazing include forage mix and fencing.

Lemenager recommends a forage mix of 50 percent to 70 percent grass, with legumes making up the remaining 30 percent to 50 percent.

"If you've got some paddocks with a high legume content, you should delay moving animals into those areas until later in the day," he said. "Wait until the dew has dried from the leaves to reduce the risk of bloat."

Paddock fences do not have to be elaborate. "You can get by with a single-strand hotwire connected to a wooden post on each end and fiberglass line posts to make it very economical," Lemenager said.

For more information about fencing, visit the Purdue Fencing Information Web site. For additional information on beef production issues, log onto the Beef @ Purdue Web site.

Writer: Steve Leer, (765) 494-8415, sleer@purdue.edu

Source: Ron Lemenager, (765) 494-4817, rpl@purdue.edu

Ag Communications: (765) 494-2722;
Beth Forbes, forbes@purdue.edu
Agriculture News Page

 

Note to Journalists: Other farm-related story ideas are available at Purdue Agriculture's Farming 2006 Web site

 

Related Web sites:
Purdue University Department of Animal Sciences

The Beef Blog

 

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