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Rotational GrazingJimmy Henning, Garry Lacefield, Monroe Rasnake, Roy Burris, John Johns, Ken Johnson, and Larry Turner

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cool- and warm-season grasses and le-gumes. However, only about one-thirdof the forages produced are actuallyused by grazing animals. In addition,much of the forage consumed is not ashigh in quality as it should be, result-ing in low animal output per acre of for-age grazed. This low-quality forageoccurs particularly in pasture in latespring and summer and in much of thehay that is produced.

Kentucky pastures are generally toolarge for efficient management. Withlarge pastures, the animal decides when,where, what, and how long to graze.Use of low-cost, versatile fencing toreduce pasture size can transfer deci-sion making from the animal to themanager and usually results in more ef-ficient utilization of available pastureand more control over pasture alloca-tion by quality and quantity based onanimals� needs.

Kentucky has great opportunity andpotential in animal-based agriculture,and better utilization of forage is thekey to realizing this potential. If pas-tures are managed for better production,captured in a higher-quality stage, andconverted more efficiently to high-qual-ity animal products, animal-based ag-riculture will without question increaseKentucky�s agricultural income.

Rotational grazing can help Ken- tucky farmers increase net profit

by increasing yield of animal productsper acre. At the same time, rotationalgrazing can:� reduce cost of machinery, fuel, and

facilities.� reduce supplemental feeding and

pasture waste.� improve monthly distribution and

pasture yield.� improve animal waste distribution

and use.� improve pastures� botanical compo-

sition.� minimize daily fluctuations in in-

take and quality feed.� allocate pasture to animals more ef-

ficiently, based on nutritional needs.

Farmers and ranchers who haveadopted improved grazing practices usea variety of terms for these practices.Just a few of them are controlled graz-ing, intensive grazing, management in-tensive grazing, rotational grazing, andintensive rotational grazing.

A rotational grazing program cangenerally be defined as use of severalpastures with one being grazed whilethe others are rested. Continuous graz-ing is use of one pasture.

Kentucky�s land and climate offerfarmers the opportunity to grow largequantities of high quality pasture from

High-quality pasture is essential forKentucky's cattle industry, but most fieldsare too big to be managed efficiently.

Much of Kentucky's land resource has roll-ing topography and would be used best byimplementing sound rotational grazingsystems for cattle.

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pounds of usable forage dry matter peracre in order for the quantity of pas-ture to not be a limiting factor in meet-ing the livestock�s nutritional needs,which can vary from animal to animal.The amount of forage in 1,000 to 1,500pounds can vary, too. It may representonly 4 inches of dense grass, or it mayrepresent 8 inches or more forage ifthe stand is thin and open.

Keeping an adequate supply of for-age before grazing livestock across thefull grazing season is challenging for allmanagers. A rotational grazing systemwill require the use of a mix of foragesto meet the seasonal needs of livestock.An almost infinite combination of for-ages can be used successfully in a graz-ing system.

Principle 2: Forage yield and qualityand pasture persistence can beoptimized.

Rotational grazing allows the man-ager to regulate the frequency and in-tensity of grazing to control quality,yield, utilization, and persistence ofpastures. A sound rotational grazingsystem has benefits for forage produc-tion and utilization. These benefits fallinto six main areas: yield, quality, re-growth, persistence, utilization, andnutrient cycling.

Yield: Moving to an improved grazingsystem will improve yield per acre be-yond that of continuous grazing. Im-proved grazing systems allow for quickdefoliation of the forage to a target re-sidual height followed by enough resttime to allow the forage to regrow to agrazable height. An improved grazingsystem also will allow alteration ofstocking rate to adjust to the forage�schanging growth rates. Continuousgrazing, on the other hand, does not al-low for adjustment for changing foragegrowth rate or for rest periods that al-low forage growth to occur. Continu-ous grazing will thus lead toovergrazing during slow-growth peri-ods, and overgrazed pastures will notyield their potential.

Continuous grazing has been com-pared to planting a field of soybeans andthen running a combine over the fieldall year long. Such a comparison makesit easy to see the negative effects of con-tinuous grazing on pasture yield. In con-trast, the graze/rest cycles of animproved grazing system allow formaximum regrowth of the forage, givenlimitations that may result from factorssuch as weather and soil fertility.Quality: Compared to continuous graz-ing, rotational grazing systems are morelikely to maintain pastures in an activelygrowing state than a continuous graz-ing system. Under continuous grazing,animals tend to return to the same arearepeatedly and allow other areas to be-come mature. The net result is that theoverall quality of the pasture declines.Under rotational grazing, selectivegrazing is limited, forage is more uni-formly grazed, and paddocks will re-grow more uniformly.

A sound rotational grazing systemis worthy goal for Kentucky producers.Such a system involves three principles:

Principle 1: Nutritional needs oflivestock can be met efficiently.

Rotational grazing helps managersmake the best possible match of quan-tity and quality between forage and thelivestock�s nutritional needs, which willvary with age, body size, livestockclass, and especially the productionlevel to be supported. Growing animals,lactating livestock, and livestock understress (cold temperatures, wet weather,etc.) need more nutrition than mature,nonlactating stock.

Pasture that is leafy and green andfree from antiquality factors (such asthe endophyte of tall fescue) will pro-vide both high protein and high energyfor grazing livestock. Pasture also mustbe made available in quantities that per-mit grazing animals to achieve their re-quirements.

Meeting the nutritional needs oflivestock is also a function of intake.Grazing stock need to consume foragedry matter equal to 2 to 3 percent oftheir body weight daily�a 1,100-pound cow can require 22 to 33 poundsof dry matter from pasture daily. Pas-tures should contain 1,000 to 1,500

Key Principles of Rotational Grazing

Rotational grazing allows the manager tomake the best possible match between ani-mal needs and forage production, as on thisreclaimed mine site in Perry County.

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lower nutritional needs. Following topgrazers with dry cows or other livestockwith lower feed needs is known asleader/follower or first-and-secondgrazing. This system allows for maxi-mum forage utilization as well as highlevels of animal output per acre.

Rotational grazing also gives an ad-vantage to legumes in grass-legumepastures (Figure 1). This advantage isbrought about by the quick and nonse-lective grazing of mixed stands. In

A study at the Forage Systems Re-search Center of the University of Mis-souri compared the forage quality ofcontinuously grazed orchardgrass-redclover pasture with similar pasturesgrazed in a six-paddock rotation. Afterthe start of the grazing season, pasturesin the rotational system had consistentlyhigher forage quality than those in con-tinuous grazing. Forage quality mea-sured at the beginning and end ofpaddock grazing sessions showed cy-clical fluctuation.

Forage quality differs in differentlayers of pasture, especially with le-gumes and to a lesser extent with for-age grasses. The upper half of an alfalfaor red clover canopy, for example, con-tains the majority of the leaf yield andstems that are much less mature thanthose in the lower half.

The forage quality of legumes ishigher in the top half of the pasture thanin the lower half. The crude protein inthe top 6 inches of an alfalfa canopycan be twice that of the lower 6 inches.Energy content follows a similar pat-tern, although it is not as large in rateof decline.

This layering of quality has practicalimplications. Removal of the top half formaximum gains is a technique called topgrazing. Stockers are excellent as topgrazers because they select the highestquality forage and maximize their aver-age daily gains. However, significantamounts of residual forage remains whentop grazing is used. This residual mate-rial, though lower in quality, is still valu-able for dry cows or other animals with

mixed stands, grass regrowth tends tobe faster than legume regrowth whengrazing heights are high.Regrowth: Rotational grazing andmanaging to maintain adequate root orstubble carbohydrate reserves and theproper residual leaf area will result inmaximum regrowth rates. Regrowth byforage species after defoliation is drivenby a combination of residual leaf areaand carbohydrate reserves. Both drivegrowth by supplying energy.

1.5"

3"

Rotational grazing keeps pastures higher inquality than continuous grazing and favorsthe growth and persistence of legumes.

Figure 1. Effect of grazing height on legume and grass regrowth in a grazed pasture. FromBlaser, et al., 1986. Virginia Polytechnic Institute Bulletin 86-7.

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Rotational grazing, with its grazeand rest cycles, allows carbohydrate cy-cling species (such as alfalfa, red clo-ver, big bluestem, switchgrass, andindiangrass) to maintain proper energyreserves to fuel regrowth. Rotationalgrazing can also benefit species thatrely more on residual leaf area (tall fes-cue, orchardgrass, birdsfoot trefoil)because grazing pressure can be man-aged to leave enough green leaf tissueto power regrowth.

Removing most of the available topgrowth of grasses leads to death andsloughing of large portions of grasses�fibrous root systems. Small root sys-tems lead to slow top growth and also

to less water infiltration and uptake.Persistence: Rotational grazing will re-sult in greater persistence of forage spe-cies that regrow from storedcarbohydrates and are sensitive to over-grazing or repeated defoliation. It alsowill aid in the persistence of speciesduring periods of drought stress. InUniversity of Missouri research, chang-ing the method of grazing from continu-ous to weekly or daily rotationsincreased the persistence of bigbluestem. Georgia researchers reportedthat repeated close grazing of endo-phyte-free tall fescue caused it to go outof stand. However, on those endophyte-free pastures that had 4 inches of re-

sidual growth maintained across theseason, the fescue survived.Utilization: In most pastures, there isa great deal of forage that is never con-sumed and eventually decays. Tradi-tional continuous grazing systems mayuse only 30 to 50 percent of the avail-able forage. The rest of the forage iseither trampled, soiled, or of little valuebecause it is overmature or dead. Mostof this loss occurs with underutilizedfall stockpiles and during periods ofrapid growth where there is surplusbeyond what is needed for cattle. Short-ening grazing periods to 3 to 7 days in-creases utilization to 50 to 65 percent;to two days, 55 to 70 percent; and toone day, between 60 and 75 percent.Nutrient Recycling: A ton of grass-le-gume forage harvested as hay removes40 to 45 pounds of nitrogen, 10 to 15pounds of P2O5, and 40 to 50 poundsof K2O. Grazing animals excrete intheir feces and urine between 70 and90 percent of the N, P, and K they con-

• The whole farm should be planned, followed by the devel-opment of the rotational grazing system as time and moneyallow. This approach will limit the number of times fenceswill need to be moved.

• Lanes can be a positive force in the system. They are neces-sary if there is a dairy, and they also:• make separating sick cattle easy.• make Al breeding much easier.• allow cattle to be put where they need to be.

• Two lanes side by side, rotated back and forth, will controlerosion.

• Lanes can also be a negative force:• 15 percent of the manure is left in the alleyway.• Cows will drink less if they have to travel far to water.

• Long, round corners make it easier to mow or crop whenfencing around the better soils on the farm; fence for thebest soils benefit.

• The squarer the paddock, the better. However, the smallerthe paddock, the less critical the shape.

• Mix warm-season and cool-season forages.• Both permanent and temporary fence should be used.

Fencing should not be put up all at once; it should be alearn-as-you-go process.

• The forages already on the farm should be used. A managershould not reseed with all new varieties until learning howto manage what is already there.

• Current resources should be used. It isn’t necessary tospend a lot of money in order to have water and fence.

• Fertilizing should be done where it will do the most good.• To make rotational grazing successful, managers must think,

make a plan, put a system in place, and then look to seewhich parts are working. The consistent part of setting upany rotational grazing system is the need to think, think,think!

General Comments on Designing Rotational Grazing Systems

A good rotational grazing system allows theuse of high-quality forages such as alfalfa,which requires rest periods after grazingand in the fall.

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Manure is more evenly distributedat higher stocking densities. When thetravel area of the animal is restricted,grazing and manure distribution areenhanced.

Maintenance of pasture fertilitybased strictly on manure may be easy

sume from forage. Manure can be avaluable resource in maintaining pas-ture soil fertility. Based on current fer-tilizer dollars, a beef cow excretes theequivalent of about $60 to $75 worthof fertilizer nutrients per year. For a100-cow herd, that would be $6,000 to$7,500 per year.

Pasture fertility represents a real op-portunity for Kentucky cattle produc-ers. Kentucky surveys show that soiltesting is done on only about 10 per-cent of pastures. Of the pastures thatare soil tested, 40 percent are below pHof 6.0, 45 percent are low in phospho-rus, and 35 percent are low in potas-sium. These low rates should be aconcern to managers for all types ofpastures but are especially critical forfields where legumes are to be estab-lished and grown. Ideally, plant nutri-ents should be applied to achievedesired levels of pasture production,and fertilizer should be applied to main-tain that level of production thereafter.

Rotational grazing provides bettermanure (fertility) distribution than typi-cal continuous grazing, in which mostof the manure and urine is distributedclose to shade and water. Research hasshown that soil-test P and K values areoften three to five times higher within50 feet of shade compared to averagelevels in the general pasture. Thesmaller paddocks and shorter distanceto water found in rotational grazing sys-tems improve manure distribution.

on some pastures and difficult on oth-ers. Realistic monitoring of pasture fer-tility through soil testing and grazingpractices that encourage more uniformdistribution should be considered keyto maintaining pasture fertility with re-cycled nutrients from manure and urine.

How to Know When to Move to Fresh Pastures

The right time to rotate pastures depends on many factors. Making the follow-ing six observations can help with the decision:

Look down. Has the present paddock been used as much as desired, or is theretoo much forage left? In general, most new graziers tend to overgraze pasture. Leavea little more forage than seems necessary; cattle will therefore need to be movedsooner.

Look ahead. Is the next paddock ready for grazing? How fast is pasture growth?Fast growth may indicate the need to speed up rotation or harvest some pad-docks for hay. Slow growth signals the need to lighten stocking rate, add acres, orfeed hay.

Look at the animals. Do they appear hungry, and are they in good condition?Livestock can let a manager know when they want to move, but their desire tomove may be too soon for high utilization. High-performing animals should bemoved more often.

Look behind. How fast is the last paddock regrowing? Periods of slow growthmay signal the need to slow the rotation, reduce stocking rate (by adding grazingacres or by selling or moving stock), or feed hay. Slowing the rotation (more daysper paddock) increases days per paddock and makes animals graze closer andgain less. Future regrowth from these “overgrazed” paddocks will be slower.

Look at the weather. Approaching rain can signal the need to move from purelegume to grass-based pastures to prevent pugging of the soil and damage to thelegume stand. Animals should be removed from johnsongrass and sorghum-sudantype pastures prior to frost.

Finally, look at the calendar. During the active growing season (April to Oc-tober), residual forage height should be managed to allow fast regrowth. On falland winter stockpiled pasture, graze longer and closer on each paddock to useforage that otherwise would be lost during the winter.

Rotational grazing enables managers touse high stock densities and short grazingperiods to increase utilization and decreaseanimal selectivity in grazing.

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In general, pasture soils should betested every three years.

University of Missouri researchershave conducted several studies over thepast five years on fertility and manuremanagement in pastures. Their work re-sulted in the following conclusions,summarized here:� Alleyway access to water can result

in a loss of manure nutrients frompasture, and this loss probably in-creases as the distance that cattlehave to travel for water increases.

� Shade trees are sites of manure accu-mulation, especially in slow rota-tions. (However, shade is importantin hot weather and is desired in mostsystems.)

� Grazing systems with more frequentrotations will result in more uniformdistribution of manure across a pas-ture and ultimately less fertilizer in-puts to maintain fertility.

� Fencing paddocks to minimize land-scape variation within them will fa-vor more uniform distribution ofmanure (for example, managersshould fence slopes separately fromdraws and ridgetops).

� Square paddocks generally result inmore even manure distribution thanpaddocks of other shapes.

� When setting up a grazing system,keep in mind that any landscape po-sition that looks cool and comfort-able to people will look the sameway to cattle. Setting up paddocksand rotations to minimize the num-ber of days that cattle can camp atthese sites will improve the unifor-mity of manure distribution over theentire pasture.

Principle 3: Economic profit can berealized through improvedefficiency and productivity oflivestock.

Rotational grazing produces eco-nomic profit by improving grazinglivestock�s efficiency and productivity.Rotational grazing systems allow themanager to optimize animal perfor-mance and forage utilization. In gen-eral, by changing from a continuousgrazing program to a rotational graz-

ing program, animal gain per acre canbe increased significantly while indi-vidual animal performance actuallymay be decreased slightly. In order tocapitalize on all the benefits of rota-tional grazing in terms of quality andquantity of pasture growth, farmersmust increase stock numbers.

Good management of pastures, pad-docks, and rotation schedules can leadto increased gain per acre. For example,workers in several states have foundthat rotational grazing will increase beefper acre from 35 to 61 percent (Table1). Increasing beef yield per acre canresult in a reduced forage cost perpound of gain. More beef per acre at alower cost of gain leads to greater po-tential profit.

Dairy net profit for rotational graz-ing in Pennsylvania was 72 percentgreater than continuous grazing ($129vs. $75, Table 2). Rotational grazing asa dairy farm enterprise was more prof-itable per acre than either hay or cornsilage, based on Pennsylvania budgets.

Finally, a study from the Universityof Georgia (Table 3) showed severalbenefits from rotational grazing com-

Table 1. Increase in gain per acre inrotational grazing compared tocontinuous grazing.

State % Increase

Arkansas 44

Georgia 37

Oklahoma 35

Virginia 61

Table 2. Dairy enterprise budgets per acre for pasture and forage crops.

IntensivePasture

ContinuousPasture Hay

CornSilage

Gross return in field $193 $112 $196 $313

Average storage loss 0% 0% 12% 13%

Gross return after storage $193 $112 $172 $273

Total costs $64 $35 $156 201

Profit $129 $75 $20 $58

Source: Farmer Profitability with Intensive Rotational Grazing. L. Cunningham and G.Hanson, Penn State University. 1995.Note: Feeding loss was not measured. Pasture was valued based on dry matternutrient value compared to the nutrient value and market price of dry hay.

Table 3. Effect of year-round continuous vs. rotational stocking of endophyte-free tallfescue and common bermudagrass mixed grass pastures at Central Georgia BranchStation, Eatonton, Ga., 3-year average.

Continuous Rotational Change, %

Stocking rate, cow-calf units/acre 0.50 0.68 +36

Calf weaning weight, lb 502 502 0

Total calf gain/acre, lb 251 342 +36

Cow pregnancy rate, % 94 93 0

Hay fed/cow, lb 2,390 1,690 -29

Source: Dr. Carl Hoveland, University of Georgia.

pared to continuous grazing. These ben-efits included an increase in stockingrate, total calf gain per acre, and a re-duction in hay fed per cow, and theywere realized without reducing calfweaning weight or pregnancy rate.

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• Use as much of the usable forage as ispossible to meet the nutritional needsof livestock and still allow forages toregrow.

• Make sure the soil fertility programdoes not limit either production orforage establishment goals for thefield.

• Have water in every paddock.• Construct good quality permanent

fences where needed.• Make paddocks as square as possible.• Have a good mix of cool- and warm-

season forages and a plan to use them.• Integrate the fencing system with live-

stock handling facilities so cattle canbe treated or moved to a handlingfacility from any paddock on the farm.

With the above goals in mind, follow-ing is a step-by-step procedure for settingup a grazing program:1. Start with a good aerial photograph,

the larger the scale, the better. Thesephotographs are available at the localFarm Service Agency office. Theagency has small scale maps or canorder larger scale maps. Just be sureyou have a scale map. A soils map isalso a valuable tool. A soils map, a listof descriptions, and some professionalguidance is available at the NaturalResources Conservation Service officein your county. A grid for countingacres is also handy. It will help youeven up the odd-size fields in totalacres.

2. Conduct a resource inventory. On youraerial photo, mark the property line,all roads, buildings, cattle-working ar-eas, milk parlors, other permanent fa-cilities, and existing water and shade.

3. Using the soils map, mark the majorsoils changes, considering both slopeand quality of the soils. Then, adjustthese lines to make them workable asmarkers for your first permanentfences.

4. Draw around any crop fields if they aredifferent from the soil breaks. You mayalso want to identify areas with differ-ent forages, such as alfalfa or warm-season grasses. Divide the farm alongexisting water sources.

Physical Components ofRotational Grazing Systems

A good rotational grazing plan willinclude four main physical components:forage supply, fence system, water sup-ply, and shade.

Forage SupplyA good rotational grazing system

begins with a forage system that allowsthe maximum number of grazing daysper year with forages that are suited tothe land, livestock, and manager�s abili-ties and desires.

Forage can be divided into two cat-egories: cool-season and warm-seasonspecies. These categories differ in theirseasonal ability to produce grazableyield. Cool-season species (tall fescue,orchardgrass, timothy, white clover)perform best in spring and after theweather cools down in the fall. Warm-season species (bermudagrass, eastern

gamagrass, alfalfa, annual lespedeza)perform better in summer.

Forages should be matched to soilsthat will maximize their yield andgrowth. For example, tall fescue andwhite clover are well adapted to thinsoils or steeply sloping sites that willhold water for growth during spring butwill dry out during summer. Thesefields would be poor sites for warm-season forages because they hold littlemoisture for summer growth, whichwould be the period of maximumgrowth for these species. In another ex-ample, highly productive forages such

as alfalfa should be planted on the deep-est, most productive soils.

Forage systems in Kentucky arebased on cool-season forages such astall fescue, orchardgrass, white clover,and red clover and have an abundanceof forage in the spring and most fallsbut are not productive in mid to latesummer.

The two biggest challenges in assem-bling a balanced forage system are main-taining supplies of quality forage inmidsummer and extending the grazingas long as possible into the fall and earlywinter. Many forages are available that

Goals in Designing a Grazing System

A good complement of cool- and warm-season forages is needed for a sound graz-ing system. This field of switchgrass in OwenCounty provides summer pasture for thesestockers and complements tall fescue,which is used in spring and fall.

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Your completed map should:• be a basic grazing system with wa-

ter in each field.• be divided based on productivity.• have enough fields to begin rota-

tional grazing.5. The next step gets more difficult and

requires a lot of patience. Subdividethe permanent fields in near-equalsizes, keeping the paddocks as squareas possible. Plan and plan again. Drawlines, think, erase, and try again. Evenwhen you start to fence, use temporaryfence so it will be easy to change. Try touse existing water if possible. Hope-fully by this time you will have 10 ormore paddocks and also will have nearlydoubled your farm’s productivity.

6. At this point you are already doing agood job of grazing, and it is time torefine the process. You should haveenough paddocks so that your cattlewill be moving every three days orless. Put water in every paddock. Thispractice will allow you to make thepaddocks as square as possible. Youshould also have shade in as manypaddocks as possible, especially thosethat will be grazed in the summer-time.

7. At some point you will want a systemthat will allow you to move your cattleto any part of the farm as you need to,and it will require a system of lanes. Alllanes should allow you to take a cowanywhere you need to if she has

trouble calving, is sick, or needs breed-ing. This system will also allow you tograze more than one herd at a time.These herds might be cows and stock-ers or heifers. Or, you may be usingmore than one bull. You may also wantto build some sorting squares to sepa-rate cattle as needed without movingthem to the barn. This system will letyou be in control of the grazing onyour farm and would make it easy tomove cattle to your handling facilities,chutes, or scales.

are productive in midsummer, but theyall seem to have disadvantages that ruleout their use for some producers. Alfalfa,for example, requires deep, well-drainedsoils and a high level of management forbest performance. Eastern gamagrassand other native warm-season perennialgrasses are slow to establish, and seedis expensive compared to other forages.Stockpiled tall fescue is the best forageto use to extend the grazing season intothe late fall and early winter. A balancedand well-planned grazing system willallow some acreage of tall fescue to betaken out of the summer forage rotation

(due to the presence of summer forages)and rested and fertilized for use in thelate fall.

A balanced forage pasture planshould attempt to match pasture growthto animal needs so a minimum needs tobe harvested and stored as hay or si-lage. Cow-calf systems will have thegreatest forage needs in the calving andbreeding season; forage needs will dropoff after weaning. Spring-calving herdsneed the quality and quantity of thespring and early summer pasture butmust rely on stored forage in late win-ter. Fall-calving herds rely more on hay

or silage and forage crops that providepasture during the fall and winter. Thesefall pasture options include stockpiledtall fescue, small grains, turnips or otherbrassicas, and annual ryegrass.

Stocker operations are usually eitherof two types:� buying in the spring and selling in

the fall.� buying in the winter, overwintering

on hay or stockpiled pasture, andthen turning out on spring pasture.

Both systems provide the freedomto sell all or part of the stockers as for-age growth slows. Stocker operationsare much more sensitive to forage qual-ity and quantity than cow-calf opera-tions because the cow�s milk helps tomaintain the calf performance.

A leafy, high-quality mix of grasses and le-gumes can be achieved through well-man-aged rotational grazing.

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Fence SystemRotational grazing usually relies on

an electrified system to subdivide largerpastures. Development of high-voltage,low-impedance electric chargers allowfencing of large acreages without los-ing voltage because of fence line veg-etation. These energizers sendhigh-voltage, short-duration pulsesdown the fence. Although 2,000 voltsis considered adequate to control moststock, most fence chargers and systemsshould start with around 7,000 volts onthe fence.

There is no standard system for com-parison of energizers, and every manu-facturer has a different scale. Joules arethe most common measure of power inenergizers. The joule rating is calcu-lated using a combination of voltage,amperage, and pulse duration, andchanging any of them affects the joulerating. Generally speaking, fencing sys-tem needs will grow, so obtain enoughenergizer capacity to cover futureneeds. Energizers come in mains, orplug-in units, as well as battery and so-lar units. It is best to use a plug-in ener-gizer, if possible, because it deliversmore charge (joules) per dollar spent.

A good ground is essential for theeffectiveness of any electric fence sys-tem. The ground system of the energizeris like radio antennae. A large radio col-lecting waves from a long distanceneeds a large antennae, and a large en-ergizer powering a lot of fence needs alarge ground system with a minimumof three 6-foot galvanized ground rods.These rods may be placed in the groundat an angle if there is less than 6 feet ofsoil. Ground rods should be driven in adamp place, if possible, such as underthe drip of the barn roof or in a low area.

There are two ways to build an elec-tric fence so it will work effectively.With the all-live system, every wire inthe fence is energized, and the conduc-tion of electrons back to the energizerdepends on the soil. This system is gen-erally effective in the southeasternUnited States because soils in this re-gion have high mineral content and ad-equate rainfall.

The other system is the hot groundsystem. This system has one or morefence wires connected to the positiveterminal of the energizer and the restof the wires connected to the groundterminal. This system works well insandy, arid areas�moist soil is notnecessary to deliver a charge. Also, in

an all-hot system, a limb or branch canfall across the wires, and the fence willremain energized. The main disadvan-tage of this system is that it requireshigh maintenance. If any charged wiretouches a ground wire, the whole sys-tem shorts out.

In Kentucky, the most economicalcontrolled grazing fencing system is of-ten one that includes a combination ofpermanent, electric, smooth, high-tensilewire fence and temporary portablepolywire (available on reels). An advan-tage of the reel is that it allows rapidsetup and takedown of fence for tempo-rary arrangements or strip grazing. Por-table fiberglass fence posts are oftenused with the portable braided wire, us-

Right: High-tensile electrified wire is a viableand economic alternative to conventionalfencing materials such as woven wire andis quicker to build.

Below: Temporary fencing materials such astread-in posts and electrified polytape al-low for quick subdivision of existing pas-tures.

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Table 4. Sample water requirements for cattle, gallons per head per day.

Temp, FGal/lb

DM500-lb Calf,

12 lb DMI750-lb Calf,16.6 lb DMI

1,100-lbDry Cow

1,100-lbNursing Cow

40 0.37 4.4 6.1 7.4 8.1

60 0.46 5.5 7.6 9.2 10.1

80 0.62 7.4 10.3 12.4 13.6

90 0.88 10.6 14.6 17.6 19.4

Source: Winchester and Morris, 1956.

ing one strand of wire for grazing of largeanimals and two strands for calves. Sinceit is electrified, high-tensile wire for thepermanent fence often can be installedusing low-tension techniques.Types of Fencing: Following is anoverview of several types of fence andtheir appropriate place in a controlledgrazing system:

The type of wire suggested for per-manent boundary fence installations isNew Zealand-type high-tensile wire.This is 12½-gauge high tensile smoothwire that is heavily galvanized (ClassIII). Also, smaller diameter high-tensilewire is now being used, particularly oninterior division or paddock fences. Thistype of wire includes 14½-gauge and 16-gauge thicknesses. The use of such wirehas implications for energizer selection(since smaller wire has a greater resis-tance to current flow) and in the lengthof fencing that can be energized.

For interior and temporary fences, amore flexible, low-tension wire is popu-lar. Small-diameter high-tensile wire

can be used, but many producers pre-fer a slightly softer grade of wire sinceit is somewhat easier to work with whenmoving and handling the fence. An ex-cellent alternative for temporary instal-lations is braided wire containingfine-gauge steel wires braided withpolyethylene strands into a wire, rib-bon, or tape. These wires work quitewell for installations of up to 1,200 feet.Because of the lower cross-sectionalarea of steel, energizer requirementsdiffer from those of smooth high-ten-sile wire. Some newer braided wireshave more steel (thus less resistance),so they can be used in longer runs.

Water SupplyWater is possibly the most impor-

tant, but least considered, nutrient forcattle. It is needed for virtually everybody function. Many factors influencewater intake. As air temperature in-creases above 40°F, water intake in-creases per pound of dry matterconsumed (Table 4).

Lactating cattle require more waterthan dry cows. At a constant temperature,cattle consuming more feed need greaterwater intake. Similarly, if water intake be-comes limited, feed intake will decrease,and performance will be limited. Lushpasture can be 70 percent or more waterand can decrease the amount of water thatmust be supplied in the water system, atleast on a short-term basis.

Water intake restrictions can resultfrom inadequate access of cattle to thewater source, water temperature, andwater quality. Quality is determined bytotal dissolved solids (TDS). HighTDS levels may not pose serioushealth risks but may decrease totalwater intake. Water exposed to directsunlight (tanks, ponds) can becomequite warm in the hot days of summer,resulting in lower intakes.

Regardless of why decreased waterintake occurs, performance will suffer.Cooling water has been shown to re-duce heat load and allow increased feedintake. Studies with dairy cattle haveshown the most acceptable water tem-perature to be in the 60° to 80°F range.Using insulated drinking receptacles orbuilding shades over the water tank canreduce heating from the summer sun.Insulated or heated waterers will beneeded for pasturing stockpiled forageduring late fall and winter.

The location of water in the grazingsite will greatly influence grazing dis-tribution. During hot weather, cattlecongregate nearer the water source, re-sulting in less use of pasture fartherfrom the water source. Research hasshown that the maximum distance cattlewill travel to water and not decreasegrazing uniformity is 800 feet. As traveldistance increases above this amount,pasture use decreases.

Electrified polytape (available in widths upto 1½ inches) is very visible and can be usedfor subdivision fencing for horse pasture.The twist in the polytape makes it flutter inthe wind, resulting in greater visibility.

12

Developing Water Sources: Each situ-ation is different, and flexibility is re-warded when it comes to developingwater sources.

Although there is a monthly cost,public water supplies many times are thebest solution to livestock water needswhen development, maintenance, andreliability are considered. At some pointin developing a management system, apressurized water system will become anecessity. It will provide water where itis needed instead of forcing the managerto work with a few water sites.

Consider using the raw water sourceof springs. They are an excellent sourceof water but are as different as grazingsystems. A stream of water the size of apencil and a large collection tank willwater a lot of cattle, even up to 70 to100 beef cows. Also consider ponds asa water source. Watering from tanksbelow ponds is strongly preferred towatering directly out of the pond. Thepipe should be installed under the damwhen building the pond. The pipe thencan go directly to a tank or to a collec-tion basin. Water can be pumped any-where on the farm.

ShadeShade is necessary to maximize per-

formance of cattle. Heat stress in theabsence of shade can have several ef-fects. Black-hided cattle, for example,can suffer from heat stress on brightsunny days in late summer when airtemperature is comfortable.

Cows with natural shade spend moretime grazing and less time standing thancows without shade. Natural shade fromlarge, well-canopied trees is the mosteffective. This type of shade interceptsradiation from the sun and provides

some air cooling through evaporationof moisture from leaves.

Artificial shade also will reduce heatstress, but attention must be paid to thetype, orientation, and square footage perhead. Hay or straw on wire are the besttypes of artificial shade because theyhave high insulation value, low bottomsurface reflectance, and loss of absorbedheat to the air by convection. Aluminumpanels painted white on top and blackon the bottom are also effective. Direct

heat from the sun is well reflected bythe white paint, and the black bottom ab-sorbs the heat from the ground and ani-mals. Snow fence or shade cloth mayalso be used, but they are less effectivethan the other materials mentioned here.Both let through some sun, thus not pro-viding complete shading. For maximumshading, the long axis of the artificialshade should be oriented on an east-westline. Most research shows that 45 to 60square feet per cow is desirable.

Layout and Design

Developing grazing systems involves subdividing large pastures into smallerpastures or paddocks (cells) that give the manager control over how long cattleare allowed to graze a particular area (paddock) before they are moved. There isno blueprint or single model to follow in setting up a grazing system that willprovide the manager with the greatest control. Every Kentucky farm is unique,and many different solutions are possible and workable.

Laying out or designing a pasture system involves making many decisions, in-cluding how many paddocks the system will have, their size, the location of watersources, lane placement, and livestock flow around working facilities.

The most important factor in developing a rotational grazing system isto develop one that is right for the farmer, the farm’s resources, and theland’s capabilities.

In most situations, the best way to start rotational grazing systems is to make afew simple or basic improvements in the current system. This first step will start thelearning process and allow the manager to develop the system at a comfortablepace. It will also minimize “improvements” that later prove to be less than optimal. Alot of progress is made by simply closing the gate between two pastures. Dividingan existing pasture in half is the start of a rotational grazing system.

Being flexible is key to putting rotational grazing systems together. The farmershould do what he or she thinks best, but be open to change—and plan, plan, andplan before driving the first post.

An effective water distribution system is keyto the grazing system. This permanent wa-ter tank was developed from a spring andprovides an inexpensive source of water ona Metcalfe County farm.

13

1

744'

Length

836'

888'

951'

1,007'

1,040'

87,122'43,560

L = 4 x W

L = 2 x W

Shapes

45˚

60˚ 60˚

60˚

45˚

Source: Garry Lacefield, University of Kentucky.

Pasture Number and Sizeditional cost of fencing, water, labor,and management.

University of Kentucky modelingstudies compared beef production onendophyte-free tall fescue using con-tinuous grazing, four paddocks, andeight paddocks. Beef production rangedfrom 683 pounds per acre for continu-ous grazing to 810 pounds per acre foreight paddocks. The most striking dif-ference was the four-paddock system,which showed an increase of 112pounds of beef per acre over the con-tinuous system. The eight-paddock sys-tem showed a 127-pound increase inbeef per acre over the continuous sys-tem. The rotational system increasedreturns by $77 to $103 per acre.

University of Missouri researcherscompared the effect of three-, 12-, and24-paddock systems on the performanceof beef cow-calf and stockers grazingcool-season grass and clover. When allcosts and returns were compared, thethree-paddock system resulted in $84.36increase above pasture, animal, and in-terest cost, the 12-paddock systemshowed a $115.43 increase, and the 24-paddock system showed an increase of$117.74. These results suggest that go-ing to 12 paddocks yielded a profit of$31. Going from 12 to 24 paddocks re-sulted in only a $2.31-per-acre increase.

Shape of individual paddocks is im-portant. Within practical limits, squarepaddocks are the most efficient com-pared with other shapes (rectangle, tri-angle, pie, etc.). Square paddocks allowanimals to obtain their daily ration offorages with a minimum of grazing time,effort, and trampling damage. Studieshave shown that square paddocks aremore economical to construct than othershapes (Figure 2). Having exactly squarepaddocks is not absolutely necessary, butavoid long, narrow paddocks. Wheneverpossible, fence across slopes rather thanup and down the slope.

One of the most frequently askedquestions by producers who want tostart a rotational grazing program is�How many paddocks should I have?�There appear to be contradictory an-swers:� One pasture can be grazed just as

efficiently as many.� Regardless of how many paddocks

there are, divide them again and moremoney can be made.

The truth lies somewhere betweenthese two extremes.

In general, one should consider start-ing with five to 10 paddocks in the ro-tational grazing program. This practicewill allow a paddock to be grazed inthree to 7 days and rested for 25 to 30days. In most cases, four paddocksshould be considered a minimum. Table5 contains several formulas that canhelp determine paddock number andsize.

Systems in the United States andNew Zealand have as many as 30 to 60or more paddocks. Many of these aredairy farms where pastures are changedafter each milking. Several studies havebeen conducted in the United States andgenerally show that for most beef op-erations the added benefit above 8 to12 paddocks may not be worth the ad-

Temporary or seasonal water systems canreduce distance traveled to drink and in-crease pasture utilization. Small to me-dium-sized tanks can easily be moved frompaddock to paddock.

Figure 2. Effect of pasture shape on amountof fencing needed around one acre.

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Table 5. Grazing mathematics.

• Stocking density is the stocking rate at a given point in time.In this example, 100 steers are grazing in a 5-acre paddock,which is a stocking density of 20 head per acre. Stockingdensity can be expressed as the number of pounds ofgrazing animals per acre at a given point in time (in thiscase, 10,000 pounds per acre).

number of animals grazing on a paddock

paddock size

100 head

5 acres

Example:Stocking density =

= 20 head per acre

Stocking density =

• Stocking rate and stocking density are often confused.Stocking rate applies to an entire grazing period (in thisexample, 32 days) or can be thought of as a season-long orwhole-farm statistic.

number of animals to be grazed

total acres grazed

100 head

40 acres

Example:Stocking rate =

= 2.5 head per acre

Stocking rate =

• Number of paddocks will be determined by the length ofthe rest and grazing periods.

• Acres required per paddock are determined by amount offorage needed each day by the grazing herd divided by thegrazable forage dry matter per acre.

• The number of acres needed per grazing cycle will vary withthe growth rate of the forage. As the growth rate slows, thenumber of acres required to supply 3% DMI and maintain 4days on and 28 days off a paddock will increase.

number of paddocks x acres required per paddock

8 paddocks x 5 acres per paddock

Example:Total acres required per grazing cycle =

= 40 acres

Total acres required per grazing cycle =

• Weight: weight per head, in pounds.• Percent DMI: percent dry matter intake, ranging from 2% to 4%.• Number: number of head to be grazed.• Days per paddock: amount of time that animals are to be

allowed to graze in a given paddock. Values can range from1 to 7 and up. To keep animals from grazing regrowth, keepdays per paddock to 7 or less.

• DM per acre: estimate of total forage dry matter availableper acre as the animals enter a paddock.

• Percent utilization: portion of the available forage per acrethat animals will consume during a grazing period. Im-proved grazing systems can result in utilization of 60% forgrasses and 75% for legumes.

weight x % DMI x number x days per paddock

DM per acre x % utilization

500 lb x 3% x 100 head x 4 days

2,000 lb per acre x 60%

Example:Acres required per paddock =

= 5 acres

Acres required per paddock =

• Days of rest: Values range from 10 or less for grasses duringperiods of rapid growth to 30 for legumes and even morefor periods of slow growth.

• Days of grazing: Varies from 1 to 7 and up. Shorter times on apaddock yield greater season-long utilization and less waste,selectivity, and regrowth grazing.

Number of paddocks = + 1days of rest

days of grazing

Example:Number of paddocks =

= 8 paddocks

+ 128 days rest

4 days grazing

15

Grazing ManagementGood grazing management achieves

the right balance between forage utili-zation and animal performance. Thegood manager stocks pastures heavyenough to graze available forage downto a target height that will allow formaximum regrowth (during the grow-ing season) while not compromising thelivestock�s nutritional needs. A goodmanager will observe pastures fre-quently for overgrazing andundergrazing and will periodically ad-just the stocking rate or movement ofcattle as needed. Guidelines for begin-ning and ending grazing heights andusual days of rest for several pasturecrops are contained in Table 6.

SummaryA sound rotational grazing system

is worthy goal for Kentucky producersfor three main reasons. Such a system:� helps managers efficiently use for-

age to meet the nutritional needs oflivestock.

� helps managers optimize forageyield, quality, and persistence.

� increases profit by improving graz-ing livestock�s efficiency and pro-ductivity.

The components of a good rotationalgrazing system are a balanced foragesystem, a electric fencing system, dis-tributed water supply, and adequateshade for livestock. These componentscan be designed and customized to fitthe needs of each farm.

Table 6. Guidelines for rotational stocking of selected forage crops .

Crop

Target Height (inches)

Usual Daysof Rest

BeginGrazing

End Grazinga

Alfalfa (hay types) 10-16 2-4 35-40

Alfalfa (grazing types) 10-16 2-4 15-30

Bahiagrass 6-10 1-2 10-20

Bermudagrass 4-8 1-2 7-15

Big bluestem 15-20 10-12 30-45

Caucasian bluestem(and other Old World bluestems)

10-20 4-6 14-21

Clover, white, and subterranean b 6-8 1-3 7-15

Clovers, all others b 8-10 3-5 10-20

Eastern gamagrass 18-22 10-12 30-45

Fescue, tall 4-8 2-3 15-30

Indiangrass 12-16 6-10 30-40

Johnsongrass 16-20 8-12 30-40

Kentucky bluegrass 8-10 1-3 7-15

Orchardgrass 8-12 3-6 15-30

Pearl millet 20-24 8-12 10-20

Ryegrass, annual 6-12 3-4 7-15

Sericea lespedeza 8-15 4-6 20-30

Small grains 8-12 4 7-15

Smooth bromegrass 8-12 3-4 20-30

Sorghum, forage 20-24 8-12 10-20

Sorghum/sudan hybrids 20-24 8-12 10-20

Switchgrass 18-22 8-12 30-45

Source: Excerpted from Forage Pocket Guide, Developed by Don Ball, Garry Lacefield,and Carl Hoveland. 1999.Note: These are merely guidelines. Stocking rates and growing conditions greatlyaffect forage growth. Also, the more closely pastures are grazed, the longer the restperiod generally needs to be for species that are sensitive to defoliation.aThe nutritional requirements of the livestock being grazed should be consideredwhen deciding when to end grazing. The closer a pasture is grazed, the lower foragequality will be toward the end of that particular grazing cycle. Greater residual heightsmay be desired for animals with higher nutritional requirements (for example, stockercattle vs. cows and calves).bClovers are typically grown in pastures in mixtures with grasses. White clover andsubterranean clover are quite tolerant of close defoliation; most other clovers are not.

16

Aftermath: Forage grown following aharvest.

Animal unit day: The amount of dry for-age consumed by one animal unit per24-hour period.

Carrying capacity: The maximum stock-ing rate that will achieve a target level ofanimal performance in a specified graz-ing method that can be applied over adefined time period without deteriora-tion of the ecosystem.

Continuous stocking: A method ofgrazing livestock on a specific unit ofland in which animals have unrestrictedand uninterrupted access throughoutthe time period when grazing is allowed.

Creep grazing: The practice of allowingjuvenile animals to graze areas that theirdams cannot access at the same time.

Deferred grazing: The delaying of graz-ing in a nonsystematic rotation withother land units.

Extensive grazing management: Graz-ing management that uses relativelylarge land areas per animal and a rela-tively low level of labor, resources, orcapital.

First-last grazing: A method of usingtwo or more groups of animals, usuallywith different nutritional requirements,to graze sequentially on the same landarea.

Forage allowance: The relationship be-tween the weight of forage dry matter perunit area and the number of animal unitsor forage intake units at any one point intime; a forage-to-animal relationship. Theopposite of grazing pressure.

Forage crop: A crop of cultivated plantsor plant parts (other than separatedgrain) produced to be grazed or har-vested for use as animal feed.

Grazing Terminology

Excerpted from Terminology for Grazing Lands and Grazing Animals, Forage and Grazing Terminology Committee, Dr. V. Allen, Chair, PocahontasPress Inc., Blacksburg, Virginia.

Forward creep: A method of creepgrazing in which dams and offspringrotate through a series of paddocks withoffspring as first grazers and dams aslast grazers. A specific form of first-lastgrazing.

Grazing land: Any vegetated land thatis grazed or has the potential to begrazed by animals.

Grazing management unit: The grazingland area used to support a group ofgrazing animals for a grazing season. Itmay be a single area, or it may have anumber of subdivisions.

Grazing pressure: The relationship be-tween the number of animal units or for-age intake units and the weight of foragedry matter per unit area at any one pointin time; an animal-to-forage relationship.The opposite of forage allowance.

Intensive grazing management: Graz-ing management that attempts to in-crease production or utilization per unitarea or production per animal through arelative increase in stocking rates, forageutilization, labor, resources, or capital.

Mixed grazing: Grazing by two or morespecies of grazing animals on the sameland unit, not necessarily at the sametime but within the same grazing season.

Mob grazing: In the management of agrazing unit, grazing by a relatively largenumber of animals at a high stockingdensity for a short time period.

Nonselective grazing: Utilization of for-age by grazing animals so all forage spe-cies and/or all plants within a species aregrazed.

Paddock: A grazing area that is a subdi-vision of a grazing management unit andis enclosed and separated from other ar-eas by a fence or barrier.

Pasture: A type of grazing managementunit enclosed and separated from otherareas by fencing or other barriers and de-voted, primarily by grazing, to the pro-duction of forage for harvest.

Put-and-take stocking: The use of vari-able animal numbers during a grazingperiod or grazing season with a periodicadjustment in animal numbers in an at-tempt to maintain desired sward man-agement criteria; that is, a desiredquantity of forage, degree of defoliation,or grazing pressure.

Rotational stocking: A grazing methodthat uses recurring periods of grazingand rest between two or more paddocksin a grazing management unit through-out the period when grazing is allowed.

Short-duration grazing: Not an accept-able term.

Stocking density: The relationship be-tween the number of animals and thespecific unit of land being grazed at anysingle point in time.

Stocking rate: The relationship betweenthe number of animals and the grazingmanagement unit used over a specifiedtime period.

Stockpiling forage: To allow forage toaccumulate for grazing at a later period.

Sward: A population of herbaceousplants characterized by a relatively shortgrowth habit and relatively continuousground cover, including bothaboveground and belowground parts.

Vegetative: Involving nonreproductiveplant parts (leaf and stem), the nonrepro-ductive stage in plant development.

Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability, or national origin. Issued in furtheranceof Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, C. Oran Little, Director of Cooperative Extension Service,University of Kentucky College of Agriculture, Lexington, and Kentucky State University, Frankfort. Copyright © 2000 for materials developed by the University of KentuckyCooperative Extension Service. This publication may be reproduced in portions or its entirety for educational or nonprofit purposes only. Permitted users shall give credit to theauthor(s) and include this copyright notice. Publications are also available on the World Wide Web at: http://www.ca.uky.edu.

This publication was made possibleby a grant from the Kentucky Departmentof Agriculture, Billy Ray Smith, Commissioner.