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Options for deferred forage management

Robert Fears for Progressive Forage Published on 12 July 2017
Coastal bermudagrass is commonly stockpiled in the southeastern U.S.

Most perennial pasture forage produces dry matter during warm periods when there is ample rainfall. Warm-season plants cease replacement of utilized top-growth after the first killing frost.

If some of the forage supply is not deferred for winter feeding, consumption demands of livestock have to be met with purchased or home-processed feeds, which can drastically increase operating expenses. Fortunately, various options exist for deferring a forage supply for winter use.

Management strategies

“One of the oldest pasture-rangeland management strategies is stockpiling forage,” said Monte Rouquette, Texas A&M AgriLife Research, during his presentation at the 62nd Annual Texas A&M Beef Cattle Short Course. “Grazing of certain pastures is deferred during late summer-early fall for subsequent use after frost occurs. Thus, livestock can graze these non-actively growing forages during late fall and winter.

“Obviously, dormant warm-season perennial grasses do not actively produce dry matter, and quality of stockpiled grass does not improve with time,” Rouquette said. “A dormant forage sample for quality analyses is a good investment to confirm whether feed supplements are required. If supplementation is needed, forage analyses help determine whether the nutrient deficiencies are energy or protein.”

“Grazing dormant winter range is a common practice to reduce costs in South Dakota,” wrote Robin Salverson, South Dakota State University, in an iGrow beef publication. “Grazing winter range when plants are completely dormant minimizes negative impacts on plant function during the growing season. Separate pastures are typically designated for winter use, often selected for availability of shelter, water and access to stored feeds.

“In practice, winter pastures are often deferred from grazing during the growing season to allow for grass to stockpile for winter grazing,” Salverson continued. “Research has shown, however, that carefully planned defoliation or grazing of designated stockpile forage during the growing period may stimulate plant production.

Designing a system that allows for some grazing when plants are growing could possibly increase winter pasture use without sacrificing the amount of stockpiled forage.

“Results of an SDSU study suggest that grazing winter pastures in May, targeting 25 percent relative utilization, allows sufficient regrowth to occur during the remainder of the growing season to provide sufficient stockpiled forages for winter use.”

“Our pasture rotation system is managed in a manner to reserve standing little bluestem grass for winter grazing,” said Gary Price, owner and operator of the 77 Ranch at Blooming Grove, Texas. “Grazing intensity is calculated to leave one-third of the grass for plant re-establishment, a third for trampling into the soil for organic matter maintenance and a third to be eaten by cattle.

“We haven’t fed baled hay to the cow herds in the past six years,” Price said. “Most of the hay we harvest with equipment is sold as an additional income source. We periodically take manure samples for nutrient analysis so we can assure ourselves that cattle nutritional needs are met.”

“For any deferred stockpiled grass, the bottom third of the plant is always lower in nutritive value than the top third of the plant,” Rouquette said. “In many instances of controlled rotational stocking, animals forced to consume the bottom third of the plant may not maintain weight due to lowered nutritive value as well as restricted dry matter intake. Depending on the cows’ lactation or pregnancy stage, rotational grazing may result in better animal performance if maximum utilization efficiency is not the primary stocking objective.”

Grazing management strategies should be developed after determining available dry matter per acre. This is done either by estimation or by clipping and weighing forage from a number of plots in representative areas across the pasture.

Forage utilization and stocking strategies may involve continuous, non-restrictive access to an entire pasture or some rotational grazing system with restrictive access to a designated portion of the deferred area. Due to a limited supply of stockpiled forage, management often controls grazing duration in the “hay replacement” area.

“Stockpiled forage can be valuable under any grazing method, but length of the grazing period can be increased substantially by using improved grazing practices,” wrote John Jennings, University of Arkansas, in an extension publication. “If cattle are allowed to continuously graze the entire pasture with unrestricted access to the stockpiled forage, the potential grazing period will be shortened because of waste and trampling damage. Strip grazing stockpiled forages using temporary electric fence can offer the highest utilization of the pasture.

“In Arkansas field demonstrations, strip grazing management doubled the number of animal unit grazing days per acre compared to continuous grazing of the entire stockpiled pasture. For strip grazing, a single strand of temporary electric fence wire is placed across the field to allow the herd access to a strip of pasture large enough for a two- to three-day grazing allotment,” continued Jennings. “After cattle graze each strip of forage, the electric wire is advanced across the field to provide fresh strips.”

Suitable forage species

“Tall fescue and bermudagrass are the most commonly stockpiled forages, but bahiagrass and dallisgrass have also been stockpiled successfully. Other forages may produce good fall growth but deteriorate quickly after frost,” wrote Jennings. “Some forages, such as crabgrass, are of excellent quality during the growing season but become unpalatable and degrade quickly after a killing frost and are often refused by cattle.

“Stockpiled warm-season grasses such as bermudagrass, bahiagrass and dallisgrass are not as tolerant to freezing temperature as tall fescue and are best used during mid- to late fall. Warm-season grasses become dry after a killing frost and lose leaves and forage quality due to repeated rainfall and freeze events.”

“Ice and snow can ruin stockpiled bermudagrass because cattle often refuse grazing it after ice or snow melts. Because of the steady decline in quality after onset of freezing weather and increasing chances of freezing precipitation in late winter, finish grazing stockpiled bermudagrass by mid- to late December unless adequate supplementation is provided.”

Tall fescue has two distinct periods of growth during the year – spring and fall. The fall growth can account for up to a third of the annual dry matter yield.

“Stockpiled fescue forage is very resistant to freezing temperature due to the heavy waxy cuticle on the leaves,” said Jennings. “It also possesses a chemistry that preserves cell function at cold temperatures. Because of the grass’s cold weather tolerance, stockpiled fescue can provide palatable forage through winter. Stockpiled fescue maintains green color and forage quality late into winter and can be grazed in many areas until March. Fescue managed for fall growth yields better than sod-seeded annual ryegrass or small grains.”

Stockpiling offers an opportunity to extend the grazing season and reduce hay expense. In order to execute the practice successfully, however, forage for stockpiling must be identified in the grazing management plan and managed for maximum benefit.  end mark

PHOTO: Coastal bermudagrass is commonly stockpiled in the southeastern U.S. Photo by Robert Fears.

Robert Fears
  • Robert Fears

  • Freelance Writer
  • Georgetown, Texas
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