Pasture, Rangeland andATTRA Grazing Management    A Publication of ATTRA - National Sustainable Agriculture Information Se...
grass pastures, such as those that occupy         the presence of high-yielding plant species                          lar...
greater germination of seeds                                                                      and encouraging regenera...
defoliation can seriously reduce the grass’s                 ability to persist over time. Warm-season             Clip an...
bromegrass when measuring stand density          Table 1. Animal intake by specieswith a ruler or rising plate meter.     ...
plant community; and seasonal variations               behave in very different ways because of                          i...
we can significantly reduce weed problems.         can even favor grass over legume growth, soFor more information see ATTR...
Figure 1. Plant preferences for grazing livestock                              successfully used to control kudzu, English...
occupy all available space both above               and amendments with rock powders. Plantand below ground, and therefore...
as timothy, orchardgrass and most warm-           timing and the intensity. This means con-                            sea...
determining the number of paddocks and                  Table 2. Rest periods for selected plantspaddock size. By doing th...
Overgrazing                                       January in the Deep South, and early spring                             ...
to minimize environmental impacts such as                                                Table 3. Forage species for stock...
Developing a grazing                            following grazing. It will also allow you to                              ...
Cattle especially tend to graze severely, so     Dealing with the dry years is a real challengedon’t get too caught up in ...
Plant toxicity                                          • feeding one-third of the daily dry                         Grazi...
quickly after consumption. Prussic acid          most commonly affected plants are annualdoes not persist like nitrates do...
Pasture, Rangeland, and Grazing Management
Pasture, Rangeland, and Grazing Management
Pasture, Rangeland, and Grazing Management
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Pasture, Rangeland, and Grazing Management

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  1. 1. Pasture, Rangeland andATTRA Grazing Management A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.orgBy Lee Rinehart In a time of high-cost inputs, pasture-based livestock production systems can naturally maintain soilNCAT Program and plant integrity while growing healthy ruminants. This publication profiles the general types ofSpecialist pastures and rangelands and offers information about management and expected yields. Weed man-© 2006 NCAT agement strategies are also discussed and tips are offered to rehabilitate depleted land. Issues in graz-Updated Nov. 2008 ing management, such as paddock development, plant selection, drought and plant toxicosis, are also discussed. Resources and references are also presented.ContentsIntroduction ........................ 1Temperate pasture ........... 2Rangeland............................ 2Managing soil andforage resources ................ 3Intake, sward densityand grazing period........... 5Legumes and soilfertility ................................... 5Stocking rate ....................... 5Ecological weedmanagementin pastures ........................... 6Multispecies grazing ....... 7Pasture renovationand establishment............ 8Rotational grazingand paddock size ............ 10 Photo by Lee Rinehart, NCATOvergrazing ...................... 12Plant species and Sheep on native range in southwestern Montana.systems for extendingthe grazing season ......... 12Prescribed grazing Introduction with the use of high-grain rations. Grain- fed ruminants typically require treatmenton rangeland .................... 13 Pasture is the basis of any livestock opera- for maladies such as acidosis, mastitis andDeveloping a grazing tion that purports to be truly sustainable. It respiratory disease due to the fact that theirmanagement plan on is especially important as the livestock sec-rangeland........................... 14 immune systems have been seriously com-Managing for drought .. 15 tor continues to experience extraordinarily promised. A singular focus on productivityPlant toxicity ..................... 16 high fuel and other input costs. Pasture- often causes more problems than a systems based production systems offer farmers andSummary ............................ 18 approach. A well-planned and managed ranchers the ability to let the ruminant’sReferences ......................... 18 pasture-based operation can maintain rea- environment and immune system workFurther Resources .......... 19 sonable production, reduce input costs and together, thereby gaining an acceptable achieve a positive economic return, given aATTRA—National Sustainable level of production while naturally main-Agriculture Information Service well-conceived marketing plan.is managed by the National Cen- taining the integrity of the ecological con-ter for Appropriate Technology nections between ruminants, the soil and Much of the grazing land in the United(NCAT) and is funded under agrant from the United States the pasture plants. Ruminants on pasture States can be used more efficiently for live-Department of Agriculture’s Rural experience fewer health problems due par- stock grazing. For instance, U.S. Depart-Business-Cooperative Service.Visit the NCAT Web site (www. tially to reduced stress, whereas ruminants ment of Agriculture Agricultural Researchncat.org/sarc_current. that are subjected to confinement have their Service scientists have utilized wheat pas-php) for more informa-tion on our sustainable digestive physiology running at top speed ture and old world bluestem perennialagriculture projects.
  2. 2. grass pastures, such as those that occupy the presence of high-yielding plant species large sections in the Southern Great Plains, such as bromegrass and alfalfa. Temperate and stocked them with double the number pastures will on average yield anywhere of cattle they normally would when using from 2,000 pounds of dry matter per acre intensively managed grazing techniques. per year to more than 12,000 pounds per Even on the arid rangelands of the west- acre depending on the species, soil type, ern United States, increased stock density growing season, grazing management and coupled with decreased time on a pasture other environmental factors. has been successful in increasing livestock enterprise productivity while improving the Rangeland condition of the rangeland. According to the Society for Range Man- The ecological processes that occur on tem- agement, rangelands are a type of land on perate pastures and on arid rangelands are which the natural vegetation is dominated basically the same, but occur much slower by grasses, forbs and shrubs and the land on rangelands due mainly to temperature is managed as a natural ecosystem (SRM). and moisture differences. The following In North America, rangelands include the section is an attempt to clarify the nature of grasslands of the Great Plains stretching both types of pasture ecology. from Texas to Canada, from the prairie states of the Dakotas and Nebraska to the annual Temperate pasture grasslands of California and forestlands and wetlands throughout North America. Temperate pastures are typically very Included in this definition are arid shrub- productive. They are characterized by lands throughout the western United States, well-developed soils, medium to high pre- the arctic tundra, and mountain mead- cipitation and moderate to rapid nutri- ows and deserts throughout the Southwest. ent cycling. They can be dominated by Rangeland can also encompass pastures of warm- or cool-season plants and occupy introduced grasses, such as crested wheat- niches from Maine to Florida, from Texas grass, that are managed as rangelands. to Minnesota and from Southern Califor- Arid rangelands, which typify much of Ari- nia to the Pacific Northwest coastal regions zona, New Mexico, Colorado, Utah, Nevada, of Washington and Oregon. Many irrigated Idaho, Montana, Oregon, California and riverine pastures in the desert and Inter- Washington, can yield anywhere from 200Temperate pasture can mountain West also resemble temperate to 1,500 pounds or more of dry matter perbe highly productive pastures due to deep soils, adequate mois- acre per year.with proper grazing ture from irrigation or high water tables andmanagement. Rangelands are typically characterized by low precipitation, shallow soils and slow nutrient cycling. They are usually domi- nated by grasses, forbs and shrubs effi- cient at water and nutrient utilization, so practices that are appropriate to temper- ate pastures, such as fertilization and plow- ing, are often inappropriate on rangelands. Regardless, rangelands can be very produc- tive, providing sustainable income for ranch communities while protecting valuable nat- ural resources through appropriate grazing strategies. Specific strategies for sustainable rangeland management are covered below in the sections Prescribed grazing on rangeland and Developing a grazing Photo courtesy of USDA NRCS. management plan on rangeland.Page 2 ATTRA Pasture, Rangeland, and Grazing Management
  3. 3. greater germination of seeds and encouraging regeneration of pasture swards. Rotational grazing is a proven method of increasing the effi- ciency of pasture systems. Intensively managed rota- tional grazing systems have the potential of maintaining pastures in a vegetative state for most of the growing season in many regions of the coun- try. Coupled with the use of Photo courtesy of USDA NRCS. stockpiled pasture and stored forage, the possibility of year-Native rangelands are more fragile than temperate pastures, and often Related ATTRArequire different approaches to management for sustainable production. round forage finishing of live- Publications stock becomes more feasible in more parts of the country. Assessing the PastureManaging soil and In addition, intensively managed grazing Soil Resourceforage resources systems make it possible to feed livestock Dairy Resource List:Fertile soil is the foundation of sustain- without concentrating wastes in manure pits Organic and Pasture-able production. Soil macro-organisms and and lagoons, thereby maintaining nutrients Basedmicroorganisms are the external diges- within the pasture ecosystem and preventing Managed Grazing intive system that processes organic matter, them from becoming pollutants. Riparian Areasdelivering a smorgasbord of minerals, vita- An intensively managed pasture system is Multispecies Grazingmins and other nutrients to the crop at a appropriate for maximizing gain per acremetered pace. This contrasts the conven- and maintaining soil and pasture stand Nutrient Cycling in Pasturestional approach of flooding crops with a health. But to take advantage of the ben-limited number of soluble fertilizer nutri- eficial qualities of an intensively managed Pastures: Sustainableents, leading to luxury consumption, imbal- pasture system, a grazier should pay careful Managementanced plant nutrition and a susceptibility to attention to grass stubble height after graz- Pastures: Goingdisease and attack by insect pests. ing. A grazier should be aware of the direct OrganicPasture systems are maintained through correlation between after-grazing stubble Paddock Design,grazing and animal impact on the land, heights and pasture health. Fencing, and Waterwhich accomplish the following: Systems for Livestock should be turned onto cool-sea- Controlled Grazing • nutrient cycling through feces and son grass pastures such as orchardgrass, wheatgrasses, timothy, fescues and more Rotational Grazing urine; when the grass is from 8 to 12 inches tall, • timely defoliation and removal and removed when the stubble height is of plant material that encourages from 3 to 4 inches tall. Cool-season grasses regrowth; have the ability to regrow relatively quickly • root death through leaf removal, after grazing, given enough time and soil resulting in underground organic moisture. Cool-season grasses can regrow matter accumulation and nutrient through tillering (new shoot growth from cycling; the crown) or through sprouting new plants • increased water-holding capacity by way of underground rhizomes, depend- through accumulation of soil organic ing on the species. matter; and Native warm-season grasses such as big • hoof action that breaks soil surface bluestem, switchgrass and Indiangrass and compacts soil, thereby allowing should not be grazed too short, as heavywww.attra.ncat.org ATTRA Page 3
  4. 4. defoliation can seriously reduce the grass’s ability to persist over time. Warm-season Clip and weigh method grasses will not take the kind of defoliation Construct a 2-square-foot quadrant frame that cool-season grasses can without caus- from PVC or copper pipe. Each straight edge ing harm to the pasture. It is also advis- should measure 17 inches. Randomly throw the frame on the ground and clip all the plants able to leave from 6 to 8 inches of stubble inside the hoop at ground level. Place the after grazing during the growing season for clipped forage into a paper sack and repeat native warm-season grasses. The extra leaf the procedure at least nine more times, plac- area is needed for the plant to photosynthe- ing samples in separate paper bags. size plant sugars and prepare for later win- 1. To determine percent dry matter, weigh ter dormancy. A grazing system that leaves one sample in grams (453.6 grams per a 12-inch stubble at frost is appropriate for pound, 28.47 grams per ounce), and place these grasses (Conservation Commission of in a microwave for two minutes on a high the State of Missouri, 1984). setting. Weigh the sample in grams and repeat until no change in weight occurs. Graze warm-season annual grasses such as Place a small dish of water in the microwave sorghum-sudan just before heading when to prevent damage. the plants are 2 feet tall. Livestock should 2. Calculate the dry matter percentage of the be removed when these grasses have from 4 sample by dividing the dry weight by the to 6 inches of stubble. Take care when graz- fresh weight and multiplying by 100. ing sorghum-sudan and related grasses, as 3. Multiply the percent dry matter by the fresh prussic acid poisoning can be a problem if weights of the remaining samples. grazed too early. See Plant toxicity below for more detailed information. 4. Average the weights of all samples and mul- tiply the dry matter weight in grams by 50 Grazing can begin when grass is shorter to get pounds per acre. on warm-season bermudagrass, bahaigrass 5. Remember to adjust this figure for allow- and buffalograss pastures because these able use. If you wish to use only half the grasses have a more prostrate growth pat- forage in the pasture, multiply the result by tern and can generally handle heavier defo- 0.50 to get pounds per acre for grazing. liation. From 2 to 3 inches of stubble on these grasses is not too short. For this measure in Iowa and Missouri, each Cool-season grass yields range from 4 to 6.5 inch of forage height equals 263 pounds per tons per acre, and warm-season pastures acre of dry matter and has been verified by can typically yield from 2.5 to 4 tons per numerous clip and weigh field studies. This acre. In addition, pastures with grasses and measure should be calibrated for local con- legumes grown together typically yield from ditions by clip and weigh method to obtain 10 to 15 percent more forage than monocul- accuracy. ture pastures. Producers should determine A good rough estimate is 300 pounds of dry the annual pasture productivity, as this will matter per acre per inch on a ruler. This provide a baseline of information to make measure is likely to have from 50 to 80 per- management decisions. cent accuracy depending on if you have cal- ibrated your measurement procedure. Jim Determining forage yield Gerrish’s values range from 150 pounds per Forage yield can be determined with a pas- acre per inch in a fair stand to 600 pounds ture ruler or a rising plate meter. A pasture per acre per inch in an excellent stand ruler is just that: a ruler calibrated in inches as determined by clipping and weighing placed on end at ground level, with forage numerous quadrants and comparing them to height measured in inches. A rising plate sward heights (Gerrish, 2004). The vast dif- meter measures density as well as height. ferences in the above estimates reflect dif- A 20-inch by 20-inch plate weighing 2.6 ferences in pasture types. For example, ber- pounds is dropped on a rule at waist height. mudagrass will most likely be different fromPage 4 ATTRA Pasture, Rangeland, and Grazing Management
  5. 5. bromegrass when measuring stand density Table 1. Animal intake by specieswith a ruler or rising plate meter. Intake (% Intake inConsideration must be given to forage qual- of body Species pounds per weight) perity and the species of livestock grazing day daythe pasture. The higher the forage qual- Mature cattle 2 to 3 20 to 30ity (vegetative, growing grass and clover),the greater the intake. Please refer to the Sheep 2.5 to 3.5 5 to 10accompanying box for information on ani- Goats 4 to 5 3 to 5mal intake by species. Understanding howmuch an animal will eat each day can assist Legumes and soil fertilityproducers in estimating forage demand. Legumes like clover, alfalfa, birdsfoot tre- foil, sainfoin and vetch have the ability toIntake, sward density and convert atmospheric nitrogen to the plant-grazing period available form of nitrogen through the sym- biotic work of rhizobium bacteria, whichForage intake is directly related to the den- occur naturally in a healthy soil. In a natural Asity of the pasture sward. Ruminants can ecosystem, legumes can fix nitrogen at rates n animal’stake only a limited number of bites per ranging from 25 to 75 pounds of nitrogen intakeminute while grazing, and cattle in partic- per acre per year. In cropping systems, theular will only graze for about eight hours decreases amount is several hundred pounds (Linde-per day. It is important to ensure that each the longer it remains mann and Glover, 2003). For well-managedbite taken by the grazing animal is the larg- diverse pastures, supplemental nitrogen fer- in a given paddock.est bite possible. Cattle graze by wrapping tilization can be eliminated altogether. Fortheir tongue around and ripping up forage. pastures under high-density grazing sys-Large bites of forage are therefore ensured tems, from 70 to 85 percent of the nitro-by maintaining dense pastures. gen taken in by the animals is returned andDense pastures are pastures with actively cycled back to the soil in the form of fecesgrowing and tillering forage plants. Tiller- and urine. A diverse pasture with a signif-ing occurs in grasses that are grazed or icant legume component that is managedmowed while vegetative, resulting in the intensively with heavy stocking and frequentactivation of basal growing points and the moves has the potential to become a stable,initiation and growth of new stems and closed system.leaves. Tillering results in a plant coveringmore basal area, therefore helping make a Stocking ratepasture denser. Determining the initial stocking rate for a given pasture is relatively simple, but notThe length of the grazing period, or time in necessarily easy. It is simple because thea paddock, also has a direct effect on pas- calculations are relatively straightforward.ture intake. An animal’s intake decreases It is not easy because you must familiar-the longer it remains in a given paddock. ize yourself with basic forage growth princi-This happens due to plant disappearance ples and apply those principles to what youas plants are grazed and cattle search for observe on your own pasture.their next bite. The decrease in crude pro-tein content begins roughly two days after There are several key issues to considerthe animals have been turned into the pad- when thinking about how many animals adock. Jim Gerrish has shown that as an pasture will support. Consideration mustanimal remains in a paddock, intake and be given to forage production potential; uti-liveweight gains decrease (2004). It is for lization patterns by livestock; the nutrientthis reason that most dairy graziers move content of the forage and forage growth pat-high-producing cattle to new paddocks after terns; the plant species that comprise theeach milking. pasture; species diversity of the pasturewww.attra.ncat.org ATTRA Page 5
  6. 6. plant community; and seasonal variations behave in very different ways because of in temperature and moisture. differences in soil type and depth; indige- nous or local plant cover; cropping systems; Stocking rate can be determined using the and temperature and water availability, not following formula: to mention field cropping history. By devel- pasture size X pasture yield per acre oping a cropping system or perennial pas- Number of animals = ture that utilizes nature’s own defenses and daily intake X average animal weight X days of grazing achieves ecological balance, a sustainable, pest-limited crop can be grown. The formula is completed with the following: 1. pasture size in acres Do you really have a 2. pasture yield in pounds per acres of dry weed problem? matter Many plants that are considered pasture weeds are highly palatable and nutri- 3. daily intake as a percent of body weight tious during the vegetative stage. Take, for (2 to 3 percent for cattle, see Table 1 for instance, dandelion and plantain. Both are other species) plentiful in many pastures, and producers 4. average animal weight in pounds for the can spend thousands of dollars spraying grazing herd them with herbicides. They are, however, valuable plants that occupy different root 5. length of the grazing season in days zones and deliver nutrients from different Example: Determine the number of soil depths. They are also very nutritious 1,000-pound cows a 50-acre pasture and palatable when young. These and many will support for 100 days, given a pas- other so-called weeds can be a valuable ture yield of 3,000 pounds of dry matter contribution to sustainable pastures. Even per acre. our so-called noxious weeds like knapweed and kochia can be grazed by sheep, goats 50 acres X 3,000 pounds per acre and cattle with skilled management. Number of animals = 0.02 X 1,000 pounds X 100 days Weeds are often a result of soil disturbance and human interference in nature. Weeds Number of animals = 75 are plants that occupy space that humans do not want them to occupy, and farmers For very high-quality pasture, the intake rate have many very good reasons for not want- used in the calculation could be increased ing weeds to occupy certain spaces. Some to 3 percent for cows. The intake rate may are non-native, invasive plants that have also be increased to account for forage that the capacity to crowd out or compromise is trampled or otherwise wasted. If the cal- the health of other plants and animals. culations are for sheep or goats, the daily Those types of weeds may need concerted intake and the average animal weight would control strategies. In agriculture we have be different. See Table 1 for values. become very accustomed to taking reac- More information on stocking rate is covered tive measures such as pesticide application below in the section entitled Rotational or mechanical approaches such as cultiva- grazing and paddock size. tion in order to eliminate unwanted plants and establish a favorable environment for the kinds of plants we choose to be there. Ecological weed But if we can look at crop production and management in pastures pasture as systems and begin to understand Agricultural systems are very complex bio- how plants, animals and humans interact on logical systems that operate in a particular a given landscape, weeds will become much ecological balance. Each region of the coun- less of a problem. By managing croplands try, indeed each watershed and field, might and pastures according to natural principles,Page 6 ATTRA Pasture, Rangeland, and Grazing Management
  7. 7. we can significantly reduce weed problems. can even favor grass over legume growth, soFor more information see ATTRA’s Prin- pay careful attention to the legume compo-ciples of Sustainable Weed Management nent of intensively grazed paddocks. Reseedfor Croplands. annual legumes by frost-seeding, feeding seed to cattle, broadcasting in the fall orTechniques for dealing with allowing legumes to go to seed to maintainproblem weeds in pastures legumes in these systems. See the section Pasture renovation and establishmentKeeping weeds out of a pasture is much for more information.easier than trying to get rid of a bad infesta-tion. Some management practices for keep- Most of all, know your pastures. Make iting pastures weed-free include: a point to understand soil types and how they change with the aspect and slope of • terminate low-producing, weedy fields; the land. Obtain some reference guides that will assist you in identifying the plants • rotate perennial pastures with on your farm or ranch. Your Cooperative annuals; Extension Service is a great place to find M • integrate a high-density rotational these. The more you know about what your any plants grazing system; pastures will produce, the better position you will be in to make appropriate manage- considered • know your pastures; and ment decisions. pasture • consider multispecies grazing. weeds are highly Remember the principal concerns in man-The aforementioned methods, used singly or palatable and nutri-in combination, can easily be incorporated aging unwanted pasture plants are: tious during theinto a pasture management system, setting • encouraging forage growth overup a situation in which weeds find it hard vegetative stage. weed growth through selection ofto get ground. When pasture stands such appropriate livestock species andas alfalfa get too old, they often begin to proper timing of grazing;decline and allow other plants to take over. • ensuring adequate soil fertility throughMany times the grass component of the field nutrient cycling, species diversity andwill increase as alfalfa decreases, but in inclusion of legumes; andinstances of low fertility or drought, weedscan take advantage of the open niche and • rotating non-erodible fields, espe-become established. In these cases, termi- cially monoculture perennial fields,nating and reseeding the fields is sometimes to break weed cycles.recommended. Some producers refer to this Perennial pastures on non-erodible landas farming the pasture. For some pastures can be rotated with cereals, summer annu-that are terminated, you might consider als or even vegetables to interrupt weeds,planting to winter wheat or oats and winter diseases and problem insects.peas for a season. These are valuable for-age crops and they help to break pest cycleswhile building soil. Multispecies grazing Multispecies grazing refers to the practiceHigh-density grazing systems also diminish of utilizing different livestock species to:weed invasion by reducing grazing selec-tivity. As an animal is forced to consume • diversify farm income;all the plants in a given area, no one plant • utilize pastures of different ecologi-is favored. This gives grass an advantage. cal types on the farm;Grass, because of the lowered position of itsgrowing point when vegetative, tolerates leaf • manipulate the plant communityremoval better than broadleaf plants, which to meet the production goals of theoften elevate their growing points much ear- farm; andlier in the season. Very intensive systems • interrupt parasite life cycles.www.attra.ncat.org ATTRA Page 7
  8. 8. Figure 1. Plant preferences for grazing livestock successfully used to control kudzu, English ivy, scotchbroom, Chinese tallowtree, juni- 80 per and mesquite in many parts of the coun- 70 try. Small ruminants can also add value to a 60 farm by providing meat and milk productspercent intake 50 cattle to growing ethnic groups that seek these 40 sheep traditional foods. Refer to the ATTRA pub- 30 goats lication Multispecies Grazing for more 20 information. 10 Using small ruminants on cattle operations 0 will necessitate a change in farm and ranch grass forbs shrubs infrastructure. Fencing, lambing sheds and secure paddocks in areas with predators Cattle, sheep and goats evolved eating dif- such as wolves, coyotes or bears are often ferent plant types. Cattle typically consume, necessary, but costs can add up and drain in order of preference, grasses, forbs and profitability. shrubs. Sheep will consume, also in order of preference, forbs, grasses and shrubs and Other methods of maintaining small rumi- goats will seek shrubs, forbs and grasses. nants on ranches include employing a com- petent herder who will ensure the sheep or Sheep have been effectively utilized on goats graze the necessary places and plac- Western native ranges to control invasive ing guardian animals such as guard dogs, species such as spotted knapweed, leafy donkeys or llamas with the livestock for spurge and yellow starthistle. Cattle that predator control. are grazing in conventional rotations often remain on Western ranges for weeks at a For more information see ATTRA’s Preda- time during the summer and are moved tor Control for Sustainable and Organic when a set stubble height of key grass spe- Livestock Production. Small ruminants cies like bluebunch wheatgrass or rough are excellent additions to diversified farms fescue is attained. and ranches because they have the ability to remove weed problems by shifting plant When cattle, being primarily grass eaters, succession towards a more complex, bal- remain in a pasture for long periods of time, anced stage. they tend to exhibit grazing selectivity and choose vegetative grasses and young forbs over knapweed and other noxious weeds. Pasture renovation and Ranchers who have allowed a band of 800 establishment or more sheep to graze for several days When is it appropriate to renovate pas- before or immediately after the cattle have tures? Renovation often isn’t necessary. seen significant knapweed usage by the Many farmers and ranchers have noticed sheep, with moderate grass utilization. See increased productivity and decreased weed Figure 1 for a comparison of plant prefer- problems merely by working out a high-den- ences for grazing livestock. sity rotational grazing system. Pastures are very resilient and, when maintained in the Applying pressure with diversified live- vegetative stage for most of the grazing sea- stock to knapweed, other forbs and grasses son, ecologically appropriate grasses and in equal amounts will increase range bio- forbs often begin to dominate where weeds diversity significantly over time. Sheep can and other unpalatable plants once prolifer- be used as an alternative enterprise by tak- ated. This happens due to the ecological ing value from wool, lambs or by contract principle called succession. grazing on other parcels to control nox- ious weeds. Goats have a similar utility in Nature tends toward the stability that comes areas with shrub infestation and have been with species complexity. Complex systemsPage 8 ATTRA Pasture, Rangeland, and Grazing Management
  9. 9. occupy all available space both above and amendments with rock powders. Plantand below ground, and therefore utilize materials should be adapted to the nativenutrients and water more efficiently. Com- soil pH and water-holding characteristics;plex systems are more resilient from year annual precipitation; temperature; seasonal-to year, as some species will thrive during ity; and grazing system. This is a good timewet times and others will proliferate during to incorporate rock phosphate and adjustdryer times. Simple systems, on the other the soil pH by adding lime according to soilhand, are less resilient and are prone to dis- test recommendations.ease and insect attack due to the absenceof diversity. In simple systems, one or twospecies prevail and there are fewer nichesfor beneficial organisms to occupy. Sim-ple systems also exploit only a single soillayer, and therefore many soil nutrients willremain isolated from the system. Ecological succession and grazing management In nature, ecosystems evolve from simplicity to complexity. Consider a field that is plowed and abandoned. Usually the first plants to show up are annual grasses and forbs, followed by perennial forbs and grasses. As the years prog- ress, the grasses begin to occupy more of the Photo courtesy of USDA NRCS. space and some shrubs will establish. If left alone and provided adequate precipitation, No-till grass seeders ensure proper seed placement and result in better germination. the shrubs will dominate. Trees will show up next, and woodland will appear at the height Proper seedbed preparation is very impor- of succession. Managed grazing can hold tant for establishing a productive pasture. succession to perennial forbs and grasses by There are essentially three ways to plant maintaining the pasture in the vegetative, or pasture grasses and legumes: planting into growing, stage. a prepared seedbed, no-till planting into the stubble of a prior crop or interseedingFor those fields that have been cropped into an existing stand.with annuals for the past several decades, Seed-to-soil contact is of extreme impor-renovation and reseeding might be appro- tance when planting by any method. Thepriate, especially if high-yielding dairy cattle S seed must remain in contact with moist soilor growing lambs graze them. What follows eed-to-soil for the first month after germination or theis a short discussion on pasture renovation. contact is seedling will whither. There are variousFor more information on field renovation methods for achieving seed-to-soil contact of extremeand reseeding, including budgets for pas- while planting. Drilling with a grass drill importance whenture establishment on a per-acre basis, see is the most effective, as it allows for bet-ATTRA’s Converting Cropland to Peren- planting by any ter control of seed placement. Many timesnial Grassland. method. packer wheels follow the drill to firm the seedbed and ensure seed-to-soil contact.Pasture establishment Broadcasting seed can be effective for someEstablishing a new pasture is a time-consum- species, especially if the soil is packed aftering and expensive process. Careful atten- planting. Pulling a roller or dragging a har-tion should be paid to proper plant material row behind a tractor or four-wheeler is anselection; soil tilth and seedbed prepara- effective tool to increase the germination oftion; soil fertility and the addition of com- broadcast plantings, especially for ryegrasspost or manures; green manure plow-down; and clover seeds. Other grass seeds suchwww.attra.ncat.org ATTRA Page 9
  10. 10. as timothy, orchardgrass and most warm- timing and the intensity. This means con- season native grasses do not establish well trolling the number of animals and how by broadcasting and should be drilled. Be long they are in a pasture. careful not to plant too deep or the seeds Rotational grazing systems take full advan- might not germinate. Follow local Coopera- tage of the benefits of nutrient cycling as tive Extension Service recommendations for well as the ecological balance that comes seeding rate and depth. from the relationships between pastures and Another method of planting new pastures is grazing animals. High-density stocking for frost seeding. Frost seeding works well in short periods helps build soil organic mat- areas that experience a freeze-thaw pattern ter and develops highly productive, dense, in the spring before green-up. Broadcast resilient pastures. For more information see seeds after snowmelt and allow the natural ATTRA’s Rotational Grazing and Pad- freeze-thaw action that occurs each day to dock Design, Fencing and Water Sys- work the seed into the ground. If the tim- tems for Controlled Grazing. ing is right, this can be an effective way to A rotational grazing management plan need achieve seed-to-soil contact and incorpo- not be complex. It merely has to direct the rate legumes into a grass pasture. For the grazing animal to eat when and where you humid areas of the South or drier areas of want them to in order to keep the plants in the West, fall-seeding of legumes is more their growing, or vegetative, stage. Rota- appropriate so that seeds can establish dur- tional grazing allows for more effective for- ing the winter rainy season. age utilization by increasing herd size on smaller paddocks for a shorter time, thereby Rotational grazing and decreasing grazing selectivity and giving the farmer more control of what and when the paddock size livestock eat. The basic principles of rota- If given a choice, livestock will only eat the tional grazing management include: highest-quality, most palatable plants in a pasture. In order to ensure that plant bio- • proper timing of grazing correspond-Paddocks divided by diversity is maintained in the pasture, it is ing to plant physiological stage;a single electric wire necessary to set up a grazing management • proper intensity of grazing, or dura-increase options for system to better control livestock grazing. tion on the pasture;managing pasturethroughout the grazing The elements of grazing to control are the • residue or plant height after grazing;season. and • duration of rest. Allow the pasture plants to get to sufficient height prior to turning the cattle onto the pasture. By waiting until the grass is from 8 to 12 inches high, depending on species, the roots have become well developed and the plants can handle defoliation. Grazing intensity, or duration, can be taken care of by designing a suitable rotational graz- ing system. Rotational grazing, as the name implies, involves moving the cattle peri- odically from pasture to pasture or pad- dock to paddock. For instance, a good rule of thumb is to split a pasture into 10 or more paddocks with electric wire or elec- tric tape and stock each paddock heavily Photo by Linda Coffey, NCAT, taken at Nichols Dairy, Westphalia, KS. for a short amount of time. See Table 2 forPage 10 ATTRA Pasture, Rangeland, and Grazing Management
  11. 11. determining the number of paddocks and Table 2. Rest periods for selected plantspaddock size. By doing this you are forcing Cool weather Hot weatherthe animals to eat all that’s there, including Species (Days)weedy plants they might otherwise not eat. Cool-season grasses 14 35-50However, before the animals eat the plants Warm-season grasses 35-40 21to the ground, move them to the next pas-ture. This takes into account the third prin- Legumes 21-28 21-28ciple. It’s important to leave several inches Blanchet et al. ,2003of grass to allow adequate leaf area for sub- to move according to forage height rathersequent regrowth. than by the number of days on pasture.Depending on the species, you will need to Grasses need from 15 to 50 days of restleave from 2 to 6 inches of plant stubble at between grazing events to allow adequatemoving time. An 11-paddock rotational graz- regrowth, depending on season, moistureing system that allows animals to graze each and plant type. The accompanying chartpasture for three days will give each pad- shows typical rest times for various pasturedock 30 days of rest. These figures are for plants, realizing that water and moistureplanning purposes, and it is recommended will have a large effect on plant regrowth. Calculating paddock size and number Two questions that will immediately come up for someone contemplating a rotational grazing system are: • How many paddocks should I have? • How big should the paddocks be? The University of Minnesota Extension gives details for calculating paddock numbers in their Grazing Systems Planning Guide (Blanchet et al., 2003). See the Further resources section for more information. Essentially, answers to these two questions can be easily acquired by utilizing the following formulas: To calculate the number of paddocks needed, use the following formula: Paddock number = Rest period (days) Grazing period (days) + number of animal groups Example: Paddock number = 30 days 2 days + 1 animal group = 16 paddocks Then, to calculate the size of each paddock in acres, use this formula: Paddock size = Daily herd forage requirement (pounds) X grazing period (days) available forage per acre (pounds) Example: Considering that growing steers will generally consume around 2.5 percent of their body weight, we will estimate the intake of 100 700-pound steers to be 17.5 pounds per animal per day, times 100 animals equals 1,750 pounds daily herd forage requirement. If the animals will be in each paddock for two days, and the available forage in the paddock is 2,000 pounds per acre, then, Paddock size = 1,750 pounds X 2 days/ 2,000 pounds per acre = 1.75 acres Therefore, for a herd of 100 700-pound steers and grass availability of 2,000 pounds per acre, you would need 16 paddocks of 1.75 acres each, allowing for two days of grazing in each paddock before moving the herd to the next paddock. It is very impor- tant to realize, however, that 2,000 pounds per acre is not the total productivity of the paddock, but reflects only the amount of forage the animals will be allowed to consume. A dense orchardgrass-timothy pasture in good condition can produce approxi- mately 400 pounds of forage for each inch of plant height. So if you plan to begin grazing when the grass is 10 inches tall, and move the cattle when the grass is 5 inches tall, you should only calculate the 5-inch difference in height in your paddock size calculations. In our example, 400 pounds per inch times 5 inches equals 2,000 pounds per acre of available forage. The figures and interpretations in this example are highly variable, and your situation will likely be different from this or any other grazing plan. This example is intended to familiarize producers with the basics of developing a rotational grazing system.www.attra.ncat.org ATTRA Page 11
  12. 12. Overgrazing January in the Deep South, and early spring for parts farther north. Ryegrass establishes Overgrazing occurs when the grazing pres- well when broadcasted into perennial sod, sure exceeds the carrying capacity of the but small grains typically establish better pasture. This condition is not really a func- when drilled into sod. tion of how many animals are on a pasture, but how long they remain there. In graz- Brassicas can be spring or summer planted ing management, time is the most impor- into corn or other annual crops to provide tant factor to consider in establishing a late summer or fall forage for livestock. grazing system for sustained forage produc- These crops produce as much as 12,000 tion. Continuous grazing allows livestock to pounds per acre and are well suited to strip- selectively graze the most palatable plants grazing. over and over. The problem with this isn’t Warm-season annuals like pearl millet, necessarily in the selective grazing activity, corn and sorghum-sudan are highly nutri- but in the fact that the grazed plant does tious and provide quality forage during the not get the time to regrow before it is grazed summer when cool-season pastures such as again. New growth is more palatable and orchardgrass, fescue and bromegrass slowD contains more nutrients than older growth, down. Summer annuals fit nicely in rota- ivide so animals will come back for a second and tional grazing systems. Careful attention to pastures third bite as long as they are in the pas- into enough drought-stressed plants is warranted as these ture, resulting in the most palatable forages are susceptible to excessive nitrate accumu-paddocks to ensure being killed out. lation, prussic acid accumulation or a com-that all plants Divide pastures into enough paddocks to bination of the two and subsequent livestockhave ample time to ensure that all plants have ample time to re- poisoning. Contact your local Cooperativeregrow after grazing. grow after grazing. In addition, for pastures Extension Service office for information on with adequate water during the growing testing for these compounds. season, a very high stock density encour- Other species that can be used success- ages animals to graze the pasture more fully to extend the grazing season are Aus- uniformly than if the pasture was lightly trian winter pea and forage soybeans. Win- stocked. In this situation the so-called ter pea, a cool-season legume, is often used weedy species are being grazed at the same as a cover crop in cereal rotations. Spring intensity as the so-called good species. grazing of winter pea allows ranchers to rest more sensitive pastures and graze them Plant species and when the soil is drier and the vegetation systems for extending the better established. Forage soybeans like- wise have a place in summer cropping sys- grazing season tems where farmers are rotating crops such Species used to extend the grazing season as corn or grain sorghum with legumes to include cool-season annual grasses such as build soil organic matter. Grazing these ryegrass and cereal grains; forage brassi- crops for several months before plowing cas such as kale, rape and turnips; warm- down the green plants is an added bonus to season annual grasses such as sorghum- building soil organic matter and tilth. sudan hybrids, pearl millet and corn; and Annual forage crops can be an excel- legumes such as Austrian winter pea (cool- lent addition to a farm since they extend season) and forage soybeans (warm-season). the grazing season several weeks or even These annual crops can be incorporated in months. However, annual cropping systems a perennial pasture by several methods. often come with environmental costs such as Annual ryegrass and cereal grains such as erosion, loss of organic matter and destruc- oats, wheat and rye can be overseeded into tion of soil structure, most notably when warm-season pastures in the fall. These pas- soils are heavily tilled. Consider rotating tures will be ready to graze in December to annual crops to different fields each yearPage 12 ATTRA Pasture, Rangeland, and Grazing Management
  13. 13. to minimize environmental impacts such as Table 3. Forage species for stockpilingwater or wind erosion. In the North and West In the South and EastStockpiling forages Altai Wildrye BermudagrassStockpiling is defined as letting forage grow Orchardgrass Tall Fescueduring summer and deferring grazing to the Reed Canarygrass Reed Canarygrassfall or winter. This is an effective way of Timothyproviding winter forage in some areas andcan reduce the need for harvested forage. If Alfalfait reduces hay use at all, significant savingscan be realized. This system works well for regions where weathering is less likely toearly winter when spring-calving cows are reduce the nutritional quality and palatabil-in mid pregnancy. Stockpiled grazing can ity of the hay.be followed with meadow feeding of high- For more information on grazing seasonquality alfalfa hay prior to calving. extension call ATTRA at 1-800-346-9140.Stockpiling has been shown to work wellgiven appropriate pasture management Prescribed grazingand efficient allocation of dormant pastureduring the winter. Many grass species will on rangelandmaintain a relatively high nutrient content Prescribed grazing can be thought of as aand palatability for several months after process of developing a grazing system thatdormancy begins. Two extra months of seeks to integrate the economic and ecologi-grazing can significantly reduce the costs cal realities that ranchers are faced with onassociated with producing and feeding hay. the Western range. The USDA defines pre-In some cases, producers have been able to scribed grazing as “the controlled harvestutilize stockpiled forage and eliminate the of vegetation with grazing or browsing ani-need for hay feeding completely. This usu- mals, managed with the intent to achieve aally works better in climates where the dor- specified objective” (USDA, 1997).mant grass can be preserved longer under Management objectives addressed by pre-adequate snow cover or because of reduced scribed grazing include:microbial decomposition caused by low tem-peratures and limited moisture. • Improve or maintain the health and vigor of selected plants and main-Stockpiled forages can be fed by either tain a stable and desired plantlimit-feeding (allowing only so many hours community;of grazing per day) or by strip-grazing witha movable electric wire or tape. Another • Provide or maintain food, cover andoption for feeding stockpiled forages is to shelter for animals of concern;swath them with a hay mower and then • Improve or maintain animal healthrake them into windrows. Cattle can graze and productivity;directly off the windrow during the winter • Maintain or improve water qualityby using an electric wire or electric tape to and quantity; andration hay on a daily basis. This is similarto strip-grazing in that the wire is moved • Reduce accelerated soil erosion andeach day to expose a predetermined amount maintain or improve soil conditionof forage for grazing. This method, while for susceptibility of the resourcestill relying on a tractor to cut and windrow (USDA, 1997).the hay, reduces the amount of fuel, materi- A very crucial aspect of a prescribed graz-als and hay equipment needed for bale-and ing regime is the development of a workablefeed-hay by eliminating the baling process and ecologically appropriate grazing man-altogether. This method works best in dryer agement plan.www.attra.ncat.org ATTRA Page 13
  14. 14. Developing a grazing following grazing. It will also allow you to rotate grazing on a seasonal basis. Deter- management plan on mine how much forage is available in each rangeland grazing unit and map it out. Note key spe- Designing an effective grazing plan isn’t cies, percent cover, water availability, facil- as daunting as it seems. Mostly it is apply- ities and other aspects important to you. ing observation to management, observing Remember that livestock should always be some more and then adjusting as needed. within a two-hour walk from water. This will There are five steps in developing a grazing help you to determine grazing unit size for plan. They are: large parcels. 1) Create an inventory Develop a grazing schedule 2) Define goals This will be a graphic illustration of your 3) Determine grazing units plans for grazing each unit during the graz- ing season. Develop the schedule based on 4) Develop a grazing schedule your total animal units and available ani-R 5) Develop a monitoring and evaluation mal unit months in each unit. If you have emember plan (Montana DNRC, 1999) a 100-acre pasture with two animal unit that live- months per acre, you have 200 animal unit stock should Create an inventory months of forage available. At 50-percentalways be within a allowable use, cut it in half to 100 animal This is for gathering baseline information unit months. This means you have enoughtwo-hour walk to allow you to make appropriate decisions forage available to feed 100 animals forfrom water. about land and pasture use. Obtain soil one month. Or, said another way, 50 ani- maps from your Natural Resources Con- mal units for two months, 33 for three servation Service office and mark appropri- months and so on. For more detailed infor- ate land forms, soil types and fences and mation on calculating animal unit months, paddocks. Find out what plants are in each see the Montana Grazingland Animal Unit pasture and evaluate the pastures based on Month Estimator located at www.mt.nrcs. a condition score. Utilize features such as usda.gov/technical/ecs/range/technotes/ key species, percent canopy cover, amount rangetechnoteMT32.html of bare ground, presence of noxious weeds, annual forage production in pounds per Important concepts here are duration of acre and amount of residue to determine grazing and time for regrowth. Some range pasture condition and productivity. ecologists and managers believe that graz- ing intensity is also important, and it is. A Define goals plant needs to have green leaves left after grazing for photosynthesis and subsequent Make a list of what you want to accomplish. regrowth. However, others feel that graz- This will be a list of your expectations and ing severity isn’t as important as regrowth will guide you in making plans and deci- time. Whichever you choose, it is impor- sions. Do you want to improve the economic tant to remember to allow plenty of time for value of the ranch? Maintain wildlife habi- adequate regrowth before the animal gets tat? Improve water quality and quantity? to bite a plant a second time. Take a look at Reduce noxious weeds? Also consider avail- the native plants on an upland range site if able acreage and the amount of time you you have the opportunity. Some, like blue- have to put into this project. bunch wheatgrass and little bluestem, are large-statured and can handle several bites Determine grazing units from an animal in one grazing event. Some, Divide the pastures into units that you can like Sandburg bluegrass, Idaho fescue and rotate animals through. This will allow you black grama, are smaller and one bite is all to rest pastures and allow for regrowth it takes to reduce the plant to stubble.Page 14 ATTRA Pasture, Rangeland, and Grazing Management
  15. 15. Cattle especially tend to graze severely, so Dealing with the dry years is a real challengedon’t get too caught up in how much they to livestock operations that rely on water totake off. Strive for 50-percent use and allow grow the plants and recharge the aquifersfor regrowth. For some sites on dry ranges, and streams that feed the animals. Having athis will mean one grazing event per year. drought plan is a very important componentFor areas with more moisture, you might of a well-thought-out farm or ranch manage-be able to return every 15 to 30 days for ment plan.another grazing event. A drought-management option that deserves serious consideration is for a producer toDevelop a monitoring maintain livestock numbers at 75 percent ofand evaluation plan carrying capacity for normal years and uti-This is the most neglected part of range lize the extra forage in wet years for high-management, and the most important. A value animals such as stockers (Ruechel,good monitoring system will allow you to 2006). In dry years the pastures will becheck how your management decisions are better able to accommodate current live-working on the ground. It will allow you to stock numbers. Another option is to slowdetermine, for instance, if a particular graz- down rotations during dry years, therebying plan is having the desired effect over allowing more paddock or pasture rest time.time. A monitoring plan will often involve This option can be effective especially whena few important evaluation criteria, such as the herd is split between different pasturesplant species composition, percent cover to minimize the impact on drought-stressedand frequency of species. By comparing plants.these measurements over time, you can If you must de-stock during drought, con-start to see trends and can alter and adjust sider which animals should be the first toyour grazing system in order to arrive at go. Do you have low-producing females? Doyour goals. you have older calves that can be sold as A rangeland monitor-Recordkeeping is a very important part of stockers? Whichever you do, be sure not to ing photo of a transect inpasture monitoring. In addition to recording de-stock too late. Pasture that is overstocked southwestern Montana.the aforementioned physical measurements, and drought-stressed is hard to repair, Photo points such as thiskeep track of when livestock enter and leave whereas a cow herd can be bought when help range managers rains return. evaluate changes in veg-a pasture; what materials or chemicals are etation due to grazingused; revegetation or weed control treat- management.ments; and observations on cattle healthwhile in the pasture. This information willbe extremely useful in refining your graz-ing plans.To obtain more detailed information onrangeland monitoring contact ATTRA at 1-800-346-9140.Managing for droughtDrought is a natural ecosystem process.The concept of an average or normal pre-cipitation or temperature is a fabricationthat humans use to try to understand com-plex systems and attempt to predict behav-iors and outcomes. Whether in a humidzone or an arid environment, a producer Photo by Lee Rinehart, NCATwill experience relative wet and dry years.www.attra.ncat.org ATTRA Page 15
  16. 16. Plant toxicity • feeding one-third of the daily dry Graziers must pay careful attention to the matter requirement as long-stem negative health effects that certain plants grass hay before grazing lush pas- can cause in livestock. Plant toxicosis tures that contain greater than 50 occurs either through the ingestion of poi- percent alfalfa or clovers; sonous plants or forage plants that contain • planting a non-bloating legume like toxic substances due to environmental or Cicer milkvetch, sainfoin or birds- physiological conditions. Plant poisoning foot trefoil; and from water hemlock, nightshade or astraga- • feeding an anti-foaming agent, usu- lus can be significantly reduced by proper ally composed of fats, oils or syn- grazing management. These poisonous thetic surfactants. plants contain resins, alkaloids and organic acids that render them unpalatable. If the Organic producers should make sure that pasture contains enough good forage, there they do not feed prohibited materials. Any is little reason for the animals to select bad- treatments they use or plan to use must tasting plants. Contact your local Coopera- be listed in their organic system plan and tive Extension Service office for information approved by the organic certifier before on poisonous plants in your area. use. Your local Cooperative Extension Service office Grass tetany Contact your local Cooperative Extension Service office for information Grass tetany is caused by low blood levels of on poisonous plants, forage nitrate testing and locally adapted forages. magnesium (Mg). When succulent cool-sea- The USDA maintains an online database of local Cooperative Extension son grasses are grazed early in the spring, Service offices on its Web site at www.csrees.usda.gov/Extension/index. the condition can have a rapid onset. Symp- html. You will also find the phone number for your Cooperative Exten- toms include lack of coordination, stagger- sion Service office in the county government section of your telephone ing and eventually death. Grass tetany is directory. prevented by: • delaying spring grazing; The following section illustrates some of the more common and economically important • feeding a legume hay with spring environmentally or physiologically caused grass pastures since legumes are disorders. higher in magnesium than grasses; • providing a mineral supplement; Bloat and Livestock can bloat when they consume veg- • grazing early spring pastures with etative legume pastures such as clovers and less tetany-prone animal such as alfalfa. Bloat is a condition manifested by steers, heifers and cows with older the distention of the rumen, noticed as a calves, since pre- and post-partum severe protrusion on the animal’s left side cows are most susceptible to grass caused by fermentation gasses that are not tetany. able to escape. Legumes are high in pro- tein and the more immature the plant, Prussic acid the higher the concentration of proteins it Prussic acid, or hydrocyanic acid, is a toxin contains. These proteins are very rapidly that occurs in annual grasses such as John- digestible and produce gas very quickly, songrass, sorghum and sorghum-sudan faster than the animal can expel. Control is hybrids. When these grasses are stressed accomplished one of four ways: due to drought or frost, prussic acid lev- • ensuring the legume component is els accumulate and, if grazed by livestock, less than 50 percent of the pasture will cause salivation, labored breathing stand composition; and muscle spasms. Death can occur veryPage 16 ATTRA Pasture, Rangeland, and Grazing Management
  17. 17. quickly after consumption. Prussic acid most commonly affected plants are annualdoes not persist like nitrates do. Forage grasses such as the cereal grains includingthat has been ensiled or harvested as hay oats, wheat and barley; warm-season annualand dried to a less than 20-percent mois- grasses such as sorghum, pearl millet andture content is safe for consumption. Prus- corn; and broadleaf plants such as pigweed,sic acid poisoning can be prevented by: thistles, goldenrod and lambsquarters. In contrast to prussic acid, nitrate toxicity in • testing for prussic acid if conditions forage does not decrease with time. Nitrate are right; poisoning can be prevented by: • avoiding grazing for a week after the end of a drought since young plant • testing of suspected plant tissue tissue after a drought-ending rain prior to feeding; will be high in prussic acid; • harvesting or grazing suspected for- • avoiding grazing for a week after a ages several days to a week after the killing frost; end of a drought; • considering pearl millet as a warm- • beginning harvest or grazing of sus- pected forages in the afternoon after E season annual forage since pearl millet does not produce prussic the plants have had several hours of xcess acid; and sunlight since this helps the plants nitrates can metabolize nitrates; be deadly • avoiding turning hungry livestock into a suspect pasture. • chopping forage and diluting with to livestock and the clean hay; and most commonlyTesting for prussic acid requires timelydelivery to the lab, as cyanide levels decline • minimizing nitrogen fertilization. affected plants areafter the plant is harvested. Refrigerate but Contact your local Cooperative Extension annual grasses.do not freeze samples if you cannot get them Service office for information on forageto the lab right away. If mailing samples to nitrate testing.the lab, mail them on a Monday to reduceshipping time. Fescue toxicosisContact your local Cooperative Extension Another important condition to consider inService office for information on forage the South and Midwest is fescue toxicosis,prussic acid testing. which is caused by fungi growing symbioti- cally with the plant. Three distinct ailments can occur when livestock consume infectedNitrates tall fescue. Fescue foot results in fever, lossAll plants contain nitrates, which are the of weight, rough hair coat and loss of hoovesprecursor to plant proteins. Excess nitrates or tail switch. Bovine fat necrosis is a syn-will accumulate in the lower stems of some drome characterized by hard fat deposits inplants when plants are stressed. This can the abdominal cavity. Summer slump is evi-occur during a drought, heavy rain or long denced by fever, reduced weight gain, intol-period of cloudy weather. In effect, nitrate erance to heat, nervousness and reducedaccumulation occurs when photosynthe- conception. Fescue toxicosis can be reducedsis slows down. During this time the plant by:may not be metabolizing nitrates, but it will • seeding of legumes to dilute fescuestill be taking nitrates from the soil. The intake;result is a backlog of poisonous nitrates inthe plant stems. Concentrations of 1.5 per- • early close grazing of fescue tocent or more in plant tissue can be toxic reduce seed development;to livestock, and concentrations of less than • restricting nitrogen fertilization0.25 percent are considered safe. Excess to the summer when warm-seasonnitrates can be deadly to livestock, and the grasses are actively growing; andwww.attra.ncat.org ATTRA Page 17

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