It has been known for years that one of the largest expenses in a beef cattle production system is feed, more specifically, winter feed. Consequently, a great deal of research has focused on ways—shifting the production system to better fit the forage resource base, feeding cheaper alternative feeds and forages, extending the grazing season—to reduce winter feed cost. In the upper Midwest with its short growing season for grasses and significant amount of snowfall received in a typical year, crop residue is the most cost-effective method to extend grazing. Extending the grazing season without adding additional forage acres or substantial cost offers beef cattle production systems a competitive advantage

Tjardes, Kent

Wright, Cody

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South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeExtension Extra SDSU Extension11-1-2004Grazing Corn StalksCody WrightSouth Dakota State UniversityKent TjardesSouth Dakota State UniversityFollow this and additional works at: http://openprairie.sdstate.edu/extension_extraThis Other is brought to you for free and open access by the SDSU Extension at Open PRAIRIE: Open Public Research Access InstitutionalRepository and Information Exchange. It has been accepted for inclusion in Extension Extra by an authorized administrator of Open PRAIRIE: OpenPublic Research Access Institutional Repository and Information Exchange. For more information, please contact michael.biondo@sdstate.edu.Recommended CitationWright, Cody and Tjardes, Kent, "Grazing Corn Stalks" (2004). Extension Extra . Paper 67.http://openprairie.sdstate.edu/extension_extra/671ExEx2044November 2004Animal & Range SciencesCOLLEGE OF AGRICULTURE & BIOLOGICAL SCIENCES / SOUTH DAKOTA STATE UNIVERSITY / USDAGrazing Corn StalksCody Wright and Kent TjardesExtension beef specialistsIt has been known for years that one of the largestexpenses in a beef cattle production system is feed, morespecifically, winter feed. Consequently, a great deal ofresearch has focused on ways—shifting the productionsystem to better fit the forage resource base, feedingcheaper alternative feeds and forages, extending thegrazing season—to reduce winter feed cost. In the upper Midwest with its short growing season forgrasses and significant amount of snowfall received in atypical year, crop residue is the most cost-effectivemethod to extend grazing. Extending the grazing seasonwithout adding additional forage acres or substantial costoffers beef cattle production systems a competitiveadvantage. Producers in the Upper Midwest are blessed with anabundance of crop residues that can be effectively utilizedby beef cattle. Most farm business management andCooperative Extension personnel consider grazed cropresidues to be among the lowest cost feed resources. Thisadvantage is a result of the agronomic cost of productionbeing borne by the crop enterprise. The major expenses associated with grazing corn residueinclude rent (for residue grazing only), fencing, waterdevelopment, freight, and labor. These costs must beincluded in the beef production enterprise, but even withthese added costs it may be possible to significantlyreduce winter feed cost for the cow herd.Forage quality and quantityCorn residue is one of the most commonly harvested andhighest quality residue forages. Iowa State Universityscientists have developed guidelines for estimating residueyield (Table 1). Under most conditions, one acre ofresidue from a combined field can provide 30 to 45 daysof grazing for a 1,200-lb pregnant cow; however, this canbe quite variable.Strip-grazing can extend grazing time and make thequality of the diet more uniform over the grazing period.By limiting access to only a small portion of the field, thecattle are forced to consume residual corn and the high-and low-quality forage components of the residue.Generally, a single strand of electric fence is sufficientto control grazing.When determining the appropriate stocking rate andgrazing time, it is important to consider the amount ofresidue that will be trampled and wasted in the grazingprocess. Research indicates that cattle grazing a wholefield will utilize only 20% of the residue. This percentagecan be substantially higher when fields are strip-grazed.Table 1.  Estimated corn stalk residue yield.Corn yield (bu/acre) Residue yield (tons/acre)> 120 4.0 to 5.090 to 120 3.5 to 4.560 to 90 2.5 to 3.530 to 60 2.0 to 3.0< 30 2.0 to 2.5The nutritional quality of grazed corn residue is quite highearly in the grazing period: approximately 70% TDN and8% crude protein. It then gradually decreases over time toapproximately 40% TDN and 5% crude protein. This is aresult of the cattle selecting the highest quality feeds firstand a weathering, or leaching of nutrients, from theresidue over time. Cattle will first consume any grain thatremains in the field. Then they will shift their preferenceto leaves and husks and finally cobs and stalks.Protein supplementationAs the nutritional quality of the corn residue decreases,producers will need to provide supplemental protein.Without supplemental protein, the digestibility, or the per-centage of the forage that can be digested, will decreaseand the forage will not be able to meet the nutritionalrequirements of the animal. Protein supplementation willhelp the cow’s rumen microbial population digest the for-age and provide nutrients to the animal.A cow’s microbial population requires rumen degradableprotein sources, commonly found in plant proteins, toeffectively digest fiber. Non-protein nitrogen sources, suchas urea and biuret, should be avoided. These nitrogensources require the presence of readily fermentable carbo-hydrates to be utilized effectively. Unfortunately, once thegrain has been consumed, the residue is essentially devoidof readily fermentable carbohydrates.To determine when supplementation is necessary, watchthe manure from the cows. As the corn in the manurebegins to disappear, it is time to begin protein supplemen-tation. Generally, mature, pregnant beef cows should receive 0.5to 1 lb of supplemental protein from a natural source.Common protein sources include alfalfa, oilseed meals,and various alternative feeds. Commercial protein supple-ments are also acceptable.Vitamin and mineral supplementationCorn residue is quite low in most minerals, especiallycalcium, phosphorus, and vitamin A. As a result, a wellbalanced vitamin and mineral mix should be providedfree-choice. Many of the feeds used as protein supplements will pro-vide significant amounts of calcium and(or) phosphorusand may reduce the need for additional supplementation.However, vitamin A and white salt should be provided atall times.Genetically modified cornSome producers have raised questions regarding the graz-ing of genetically modified (GMO) corn—Bt and Round-up Ready hybrids. The majority of the research that hasbeen conducted suggests that there is no difference in thenutritional quality of GMO hybrids compared to theirnon-GMO counterparts. Also, there appears to be no dif-ference in the preference of cattle for GMO versus non-GMO hybrids. However, while there appears to be no difference in theforage quality, there may be a difference in the amount ofcorn that is available. Under good harvest conditions,there will likely be less corn remaining in a field plantedwith a Bt hybrid than in a field of non-Bt corn. This is nota problem for grazing. It simply means that protein sup-plementation may need to begin sooner on the fieldswhere Bt hybrids were planted.Management challengesProducers who elect to graze corn residue may be facedwith two significant challenges, fencing and water. Many crop fields in the upper Midwest do not haveperimeter fencing; however, it is relatively easy and inex-pensive to purchase and erect temporary fencing. As longas there are some grain, leaves, and husks remaining inthe field, a single strand of electric fence attached to tem-porary posts will be sufficient. Once the cattle are forced to consume stalks and cobs,they will likely begin to challenge the fences.For most producers, hauling water is the only option forgetting water to cattle grazing corn residue. However,if grazing residue is to become a normal part of theproduction system, it may be cost effective to developwater  supplies nearer to the corn fields. This is a decisionthat will have to be weighed out on an individual basis.ConcernsGrazing corn residue brings a slight risk for digestivedisturbances in the cattle. Nutritional disorders such asbloat, acidosis, and founder can occur. The risk for theseconditions varies greatly with the amount of grain in thefield. Providing the cattle with increasing amounts of grain for10 to 14 days prior to turning them out on the residue willhelp alleviate this problem. This practice will help therumen microbial population adapt to a higher grain diet.Another potential health concern is nitrate toxicity, apotentially deadly disorder in beef cattle. It is generallyaccepted that the highest nitrate concentrations in a cornplant are in the lowest 18 to 24 inches of the stalk.However, the stalk is near the bottom of the list ofpreferred feeds for cattle grazing corn residue. Thus,unless the fields are grazed extremely heavily, nitratetoxicity under grazing conditions is unlikely. The riskfor nitrate toxicity is greater in drought conditions.2Soil compaction is also a concern when grazing cropresidues. Recent research from Iowa State Universitysuggests that compaction is not an issue once the soil isfrozen. Prior to freezing. there is potential for a smallreduction in subsequent soybean yield in a no-till system,but there was no difference in yield in conventionaltillage systems.SummaryGrazing corn stalks offers beef cattle producers an oppor-tunity to extend the grazing season and reduce winter feedcosts. With a small amount of management and labor, oneacre of corn stalks can provide a mature, gestating beefcow 30 to 45 days of feed and forage. All expenses relatedto corn production are borne by the corn enterprise, so thecost of grazing residue is minimal. Beef cattle producerswho do not raise crops should investigate rental arrange-ments with neighboring crop producers. Considering the many advantages that grazing cornresidue has for beef producers and the removal of cornand residue for crop producers, it appears that grazingcorn residue can be a win-win situation.3Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with theUSDA.  Gerald Warmann, Director of Extension, Associate Dean, College of Agriculture & Biological Sciences, SouthDakota State University, Brookings.  SDSU is an Affirmative Action/Equal Opportunity Employer (Male/Female) andoffers all benefits, services, and educational and employment opportunities without regard for ancestry, age, race,citizenship, color, creed, religion, gender, disability, national origin, sexual preference, or Vietnam Era veteran status. ExEx2044, November 2004. Access at  http://agbiopubs.sdstate.edu/articles/ExEx2044.pdf

Grazing Corn Stalks

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Grazing Corn Stalks

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