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1 Western Beef Resource Committee Cttle Producer s Lirry Nutrition Section CL318 Supplementtion Strtegies for Grzing Beef Cttle C. P. Mthis, New Mexico Stte University D. W. Bohnert, Oregon Stte University J. E. Swyer, Texs A&M University In grzing opertions, there re times when forge qulity nd vilility re limited nd ruminnts re unle to consume enough nutrients from psture forge to fulfill requirements. During such situtions supplementl feeding is necessry to meet production gols. Numerous commercil feed supplements re ville to producers, who hve n unlimited numer of options for the development of custom supplements. It my e difficult to decide which supplement type (i.e., energy, protein, etc.) est fits the gols of the livestock production system. A fundmentl understnding of ruminnt nutrition is helpful in mking these decisions. It is lso importnt to choose delivery method tht provides the trgeted mount of desired nutrients to ech niml in the herd nd minimizes input costs. The ojectives of this puliction re to id producers in deciding the supplement type needed for grzing eef cttle nd to descrie the chrcteristics of supplement delivery methods. Generl Ruminnt Nutrition Ruminnts re different from pigs nd humns in tht they hve rumen tht llows for fermenttion of ingested feedstuffs efore it reches the stomch (clled the omsum in the cow). The rumen provides n optiml environment for the existence nd growth of microorgnisms. Rumen microorgnisms hve their own nutrient requirements. To fulfill these requirements they rek down or digest feed consumed y the niml nd use it for energy to support microil growth. At the sme time, rumen microorgnisms relese voltile ftty cids tht re used y the ruminnt s the mjor source of energy (clories). The odies or cells of the microorgnisms eventully pss out of the rumen. Once they rech the smll intestine they cn e digested y the ruminnt, nd since these cells contin pproximtely 50 percent protein, they contriute to the protein supplied to the niml. This symiotic reltionship llows ruminnts to utilize forges much more efficiently thn nonruminnts. However, this reltionship lso dds to the complexity of predicting nd effectively meeting the nutrient requirements of ruminnt nimls. Ruminnts must hve energy to survive; nevertheless, it is the microorgnisms in the rumen tht must unlock (digest) the energy in the forge to mke it ville to the ruminnt. In order to digest forge, the microorgnisms must hve nitrogen tht is primrily found in protein. Generlly, when protein is supplemented to grzing cttle it is to ensure tht the rumen microes hve enough nitrogen to digest forge efficiently. The vilility of forge nd its chemicl composition (primrily crude protein content) re the first fctors tht must e considered in developing n effective grzing nutrition progrm. If the ojective is to meet the nutrient requirements s economiclly nd efficiently s possile, the first limiting nutrient must e identified nd supplemented in cost-effective mnner. The decision to feed protein supplement, energy supplement, or comintion supplement, should e dependent on forge supply, protein content, nd cow ody condition. Protein Supplementtion The primry fctor limiting cttle performnce on forge diets is energy intke. However, intke of mture or dormnt forges is often limited ecuse these forges hve n indequte mount of crude protein. An 318-1

2 Forge DM intke, % of BW Forge CP content, % DM Fig. 1. Forge dry mtter (DM) intke reltive to the forge crude protein (CP) content. (Adpted from Moore nd Kunkle, 1995) exmple of the reltionship etween crude protein content of forges nd forge intke is presented in Fig. 1. Intke declines rpidly s forge crude protein flls elow out 7 percent, reltionship ttriuted to deficiency of nitrogen (protein) in the rumen tht limits microil ctivity. For exmple, in Fig. 1, t crude protein content of 5 percent, forge intke is out 1.6 percent of ody weight. However, when forge crude protein is 7 percent, forge intke is 44 percent higher t out 2.3 percent of ody weight. Becuse forge is the primry source of energy, improved forge intke oosts energy intke nd demonstrtes why correcting protein deficiency is usully the first supplementtion priority. Protein supplements not only stimulte forge intke ut my enhnce the microil digestion of forge s well. When the enefits of improved forge intke nd improved digestion re comined, it is evident tht energy intke cn e gretly enhnced. In Tle 1, the estimted impct of protein supplementtion on energy sttus of 1,200-pound cow is shown. Forge intke incresed 31 percent in response to 2 pounds of protein supplement, resulting in 49 percent increse in totl digestile nutrients (TDN; n estimte of energy) intke y the cow. The forge crude protein content threshold elow which n intke response is oserved vries with forge type nd with the individul niml used for evlution. Tle 1. An exmple of the impct of protein supplementtion on the energy sttus of 1,200-pound cow. Unsupple- Supplemented mented Increse, % Forge crude protein, % 5 5 Forge TDN, % Supplement CP, % 42. Supplement TDN, % 76 Supplement intke, l 2.0 Forge intke, l Totl dily intke, l Totl diet CP, % TDN intke, l Adpted from McCollum Totl digestile nutrients. Tle 2. Averge improvement in low-qulity forge intke in response to vrious concentrtions of crude protein. Improvement in forge intke ove Supplement protein content, % unsupplemented, % Less thn to to Greter thn Heldt Evidence of this vrition in intke level mong forges with similr crude protein content is seen in Fig. 1. However, 7 percent protein is useful guideline to follow when evluting the potentil for n intke response to protein supplementtion. Numerous commercil protein supplements re ville, with the mjority rnging from 15 to 40 percent crude protein. A review y Heldt (1998) ctegorized supplements sed on the protein content to evlute the impct of supplementtion on low qulity forge (< 7 percent crude protein) intke (Tle 2). Therefore, if the ojective is to optimize intke nd digestion of lowqulity forges, supplements should contin more thn 30 percent crude protein, lthough, supplements contining less thn 30 percent crude protein my still yield slight enhncement in forge intke. Energy Supplementtion When protein needs re met, performnce my still e limited y indequte energy intke. This sitution my occur during periods of high nutrient requirements or when forge vilility is low. Most energy limittions cn e mnged with proper gzing mngement. However, directly incresing energy intke with n energy supplement (low protein, high energy) my e cost-effective in some scenrios. Energy supplements typiclly cost less per ton thn protein supplements, ut the responses to energy supplementtion cn e vrile, mking results less predictle. A common result of feeding supplementl energy sources is the sustitution effect. Sustitution occurs when the supplementl feed reduces forge intke. One of the chief concerns when providing energy supplements to grzing eef cows is the strch content of the supplement. Reserch hs demonstrted tht when high strch supplements (i.e., corn, grin sorghum, whet, rley, etc.) re fed to cttle consuming forges (especilly when protein is deficient), forge intke nd digestion re often suppressed, ultimtely reducing the energy derived from the sl forge diet. Therefore, to truly supplement energy to grzing cttle, highly digestile fier sources (i.e., soyhulls, whet rn, whet middlings, nd corn gluten feed) re generlly most desirle. Anytime sustitution occurs, the energy intke of the niml my not e incresed to the desired level ecuse 318-2

3 of concomitnt reduction in forge intke. As generl rule, 1 pound of n energy-dense feed reduces forge dry mtter intke y 0.5 to 1 pound. Feeding high levels of hy my lso result in sustitution. As the mount of hy fed dily increses, forge intke from the psture will decrese ecuse hy will replce psture forge. Generlly, pound of hy replces out pound of psture forge. Deciding Wht Percent Protein to Feed Supplementl feeds for livestock re often clssified s energy or protein supplements y considering the percentge protein lone. This is ecuse the primry feedstuffs used in supplements re generlly etween 75 nd 90 percent TDN, yet the protein content of the high protein feedstuffs, such s cottonseed mel or soyen mel, re three- to five-fold higher thn grins such s corn nd milo. Becuse of this reltionship, the primry difference in nutrient content of 20 percent nd 40 percent protein supplement is the protein concentrtion, not energy. Thus, supplements re often ctegorized s protein or energy supplements sed on the protein content lone. Developing cost-effective supplementtion progrm is dependent upon identifying the nutrient most limiting to productivity nd providing the limiting nutrient(s) t the lowest cost (for more informtion on supplement pricing, see CL309). If protein is deficient (i.e., < 7 percent crude protein), supplements should e evluted sed on cost per pound of protein. Similrly, if forge supply is limited nd energy is deficient, supplements should e evluted sed on cost per pound of TDN (energy). Sometimes oth energy nd protein re limiting, so lnced pproch to provide supplementl protein nd energy is recommended. Generlly, high protein feedstuffs re more expensive thn grins or energy yproducts. Since high protein feedstuffs re more expensive per ton, they re more expensive thn low protein supplements. However, it is criticlly importnt to evlute potentil supplements sed on cost per unit of nutrient needed. Fig. 2 provides simple guide to using forge qulity (protein content; estimted sed on color), supply, nd cow condition to help decide wht percent protein is needed in supplement. This decision guide my e useful in developing lowcost supplementtion progrm ut is only generl guide nd is not s ccurte s mesuring ctul forge qulity nd quntity to develop strtegic supplementtion progrm for specific clss of cttle. Fig. 2. Beef cow supplement decision guide.* *This decision guide is generl tool nd is not s ccurte s mesuring ctul forge qulity nd quntity to develop strtegic supplementtion progrm for specific clss of cttle. Frequency of Supplementtion Feeding frequency (dily vs. three times per week vs. once week) of some supplements my ffect niml response. Feeding smller mounts of protein or energy supplements more frequently decreses the potentil for negtive impcts on forge intke. However, scientists t New Mexico Stte University nd Texs A&M University hve shown (Tle 3) tht hnd feeding high-protein supplements once week results in no significnt reduction in performnce when Tle 3. Comprison of supplementing the sme totl mount of cottonseed cke (41% CP) to yerling heifers once weekly vs. three times weekly during the winter-spring dormnt seson of two consecutive yers. Component Yer 1 Yer 2 Times fed/wk Amount fed/feeding, l/hd Protein fed/feeding, l/hd No. of heifers/tretment Averge initil weight, l Averge dily gin, l Conception rte, % Adpted from Wllce nd Prker

4 Tle 4. Comprison of grin cues for supplementing energy to yerling heifers either dily or twice weekly for 156 dys during the winter-spring dormnt seson. Component Tril 1 Tril 2 Times fed/wk 2 7 Amount fed/feeding, l/hd TDN fed/feeding, l/hd No. of heifers/tretment Averge initil weight, l Averge dily gin, l Conception rte, % Adpted from Wllce nd Prker, Totl digestile nutrients. compred to feeding supplement three times per week (Wllce nd Prker 1992) or dily (Huston et l. 1999). Additionlly, trnsporttion nd lor costs re reduced with less frequent distriution. New Mexico Stte University reserchers hve lso demonstrted (Tle 4) tht heifer performnce (weight gin nd conception rte) significntly declined when the frequency of energy supplementtion ws decresed from dily to twice per week (Wllce nd Prker 1992). These findings indicte tht protein supplements (i.e., 30 percent crude protein) cn e delivered s infrequently s once or twice per week, while energy supplements ( 20 percent crude protein) should not e fed less frequently thn every other dy. Supplement Delivery To efficiently meet production gols, it is importnt to choose delivery method tht provides the trgeted mount of desired nutrients to ech niml in the herd. Idelly, this is chieved with minimum of input costs for lor, equipment, nd supplementl feed. A vriety of fctors influence the usefulness of prticulr delivery method. Hnd-Feeding vs. Self-Feeding Supplement delivery methods my e rodly clssified s self-fed or hnd-fed systems. Hnd-feeding implies tht the supplement is regulrly delivered to the nimls in form nd mount tht is immeditely consumed. Self-fed supplements re mde ville in ulk mounts t infrequent intervls, with the expecttion of continuous, low-level consumption y livestock. Self-fed supplements re designed to limit intke so tht nimls consume only smll portions of the ville feed t ech mel. Intke my e limited y the supplement s physicl form (e.g., tus or locks), pltility fctor (slt, phosphoric cid, etc.), or comintion of these methods. Self-fed supplements hve severl dvntges. They cn reduce lor costs ecuse delivery times re designed to e less frequent thn hnd-feeding. However, if livestock re checked t times other thn feeding, the svings in lor nd ssocited costs my e less thn expected. Tle 5. Lor cost comprison of hnd-fed nd self-fed supplements for one week. Feeding frequency 3X per 1X per Item Dily week week Self-fed Vehicle cost Feeding, $ Checking cows c, $ Lor cost Feeding d, $ Checking cows e, $ Totl dily cost Vehicle, $ Lor, $ Totl weekly cost, $ Self-fed supplement delivered to the psture y the feed deler. Vehicle cost of $0.36/mile; ssume 30-mile round-trip. c Assumes cows re checked minimum of twice weekly. d Lor cost of $9/hr. Feeding requires 1 hr driving nd 1 hr feeding. e Checks require 1 hr driving nd 0.5 hr oserving cows. For supplements tht re trgeted for more thn pound per dy consumption, weekly delivery my still e required due to lck of feed unk volume or the desire to keep feeds fresh. If supplements re to e consumed t low mounts (e.g., minerl supplements), then selffeeding my e most cost effective. Another dvntge of self-feeding systems is tht nimls cn consume supplement every dy. This is minly n dvntge with energy or minerl supplements, which re most effective when delivered dily, nd less importnt for protein supplements tht cn e delivered s infrequently s once or twice per week. Therefore, when supplementing protein the lor required for hnd-feeding cn e similr to self-feeding (Tle 5). Bsed on this comprison, if self-fed protein supplement costs significntly more thn hnd-fed supplement, ny lor cost svings my e offset. However, for energy or minerl delivery (which require every dy or lternte dy feeding), self-fed supplements my e more economicl even t higher price per ton ecuse oth lor nd trnsporttion costs re reduced. Furthermore, in rough or poorly ccessile res, self-fed supplements my e the only vile solution since the producer my hve limited ility to deliver feed to the nimls. Supplementl feeds re designed to provide given level of nutrients to ech niml in the herd. Much of the vrition in response to supplementtion progrms hs een ttriuted to vrition in supplement intke y individul nimls (Huston 2000). Reserchers t Montn Stte University compiled intke dt from oth sheep nd cttle under wide vriety of environments nd supplement formultions. Their results indicted tht 5 percent of hnd-fed nimls filed to consume ny supplement, while 19 percent of self-fed nimls did not consume ny supplement (Bowmn nd Sowell 1997)

5 The totl vrition in supplement intke ws twice s high for self-feeding compred to hnd-feeding. This my result in sustntil vrition in response to supplementl feeding progrm since mny nimls fil to consume the trgeted mount, while others consume in excess. Intke vrition lso occurs with hnd-fed supplements, ut the vrition is generlly less drmtic. Depending on the cceptnce of the supplement nd the effectiveness of the intke limiter, more vrition in niml performnce my occur with self-fed supplements. Supplement intke vrition depends on fctors unique to ech opertion. However, producers should e wre of the potentil for lrger vriility in self-fed supplement intke, nd therefore, more vriility in performnce responses to self-fed supplements. Hnd-feeding is often used s method to control livestock loction nd movements. This my e n dvntge or disdvntge, depending upon circumstnces. When nimls ecome ccustomed to coming to vehicle nd receiving feed, they my e esier to gther nd/or check. However, on pulic lnd or privte lnd with esements, nimls my egin following ll vehicles, which cn e prolem. In this sitution, selffed supplements my e more desirle. Supplement Form The prcticlity of supplement delivery systems on prticulr rnch is often strongly influenced y the form (e.g., cue, lock, liquid, tus) of the supplementl feed. The vrious forms of supplements ech offer dvntges nd disdvntges. This section will cover the forms of supplements ville, how they re fed, nd importnt considertions for producers regrding ech form. Dry feeds re primrily composed of dry ingredients (some dry feeds include smll mount of molsses to improve pltility nd inding chrcteristics) comined to meet nutrient specifictions. These feeds my e further processed into vrious forms or left s n unprocessed mix (mels). A potentil dvntge of ll dry feeds is flexiility in formultion. Once nutrient specifictions re determined, formultion sed on the lest cost comintion of ingredients cn e creted to minimize cost. For exmple, if cottonseed mel ecomes expensive, then nother protein source such s sunflower mel might e esily sustituted into the formul. Individul types of dry feeds lso offer some dvntges nd disdvntges. Cues/Cke/Pellets Cues, cke, or pellets ll refer to essentilly the sme feed form. Cues, the most common form of dry feed used for hnd-fed rnge protein supplements, re ville in vriety of sizes (5/8-inch to 1-inch; round or octgonl). They my e ordered in ulk for distriution y ulk feeder or purchsed in scks. Bulk feeds reduce the lor ssocited with hndling nd often reduce the unit price of the supplement, ut they require reltively lrge initil investment in storge nd equipment. Pellet feeding llows some control over livestock distriution, s nimls cn usully e enticed to desirle feeding re. Cues often re fed on the ground, which cn e difficult in snow or mud. For hnd-fed supplements, cues usully hve the lowest vrition in supplement intke y nimls (Bowmn nd Sowell 1997). This is especilly evident when feed is provided three or fewer times per week (Huston 2000). A few mnufcturers offer self-fed cues tht include n intke limiter (usully slt). As with other self-fed supplements, feeder is required. This type of selffeeding system my e cceptle under some conditions. However, nimls my develop tolernce for the intke limiter nd increse intke over time. With selffed cues, it is difficult for producers to djust intke y dding slt, ecuse prticle size differences will result in sorting. Blocks Blocks re generlly dry ingredients in pressed or extruded form nd re essentilly lrge cues (33.3 to 50 pounds). These locks offer similr dvntges for formultion flexiility s other dry feeds. Blocks offer n intermedite option etween true selffed system nd hnd-fed system. They cn e mnufctured with vrying degrees of hrdness to influence supplement intke. Hrder locks reduce intke, while softer locks llow greter intke. Depending on the trgeted intke mount, proper hrdness cn e determined, nd the locks cn e used s self-fed supplement. Blocks tht re excessively hrd my result in poor consumption or even tooth dmge nd loss, while extremely soft locks my encourge over consumption of supplement. Regrdless of the delivery frequency, old locks should e completely eten efore the new ones re delivered to ensure dequte nutrient intke. Individul niml consumption of locks my e more vrile thn cues or mels of the sme formultion (Kendll et l. 1983). However, the numer of non-eters is still reltively low nd similr to cues (Bowmn nd Sowell 1997). In principle, lock feeding llows more timid nimls the opportunity to consume the supplement, since they cn wit until other nimls hve left the feeding re. The compct size nd shpe of locks my mke hndling esier, often reducing lor nd milege requirements. For exmple, if more locks cn e loded thn cues, then producers my not need to return to the storge site when delivering feed to severl res of the rnch. Liquid Feeds Liquid feed use hs grown significntly in the pst 20 yers. Liquid feeds for psture use 318-5

6 re lmost exclusively self-fed products nd hve mny of the sme dvntges nd disdvntges of other selffeeding systems. Mny liquid feed delers offer delivery service, which cn eliminte the lor nd hndling requirements ssocited with supplementtion (s shown in the Tle 5). However, feed delers ccount for their delivery cost when pricing these products so tht rnchers must crefully exmine the cost of lor nd cost per unit of nutrient delivered to ssess the vlue of this delivery form. Pricing of these supplements must e done on DM sis in order to ccount for differences in moisture content of liquid compred to dry supplements. A potentil drwck with liquid feeds is the limited numer of ingredients tht cn e utilized in formultions. While this my stilize prices, it lso reduces the opportunity to tke dvntge of less expensive commodities. Although suspension technologies re improving, it is still difficult to incorporte mny dry ingredients into liquid feeds. Therefore, most protein sources used in liquid feeds contin high proportion of non-protein nitrogen nd highly solule nturl proteins. Non-protein nitrogen (NPN) sources such s ure or liquid fermenttion yproducts my provide n excellent opportunity to reduce overll feed costs y 5 to 15 percent. It is importnt to rememer tht the utiliztion of NPN my e limited with low qulity diets (NRC 1985). Non-protein nitrogen occurs nturlly in mny feedstuffs (n exmple is lush psture, such s whet) nd is well utilized in the rumen if dequte energy is present in the diet. New technology in liquid feed formultions hs incresed the vilility of feeds with high proportion of dded ft, high-qulity energy source. Although smll mounts of ft cn e dded to dry supplements, liquid feeds cn incorporte higher ft concentrtion. This my mke liquid feeds ttrctive energy supplements, especilly when the reduced lor requirement of liquid supplements is compred to dily delivery of dry energy supplements. As with other self feeding systems, liquid supplement intke is more vrile thn tht of hnd-fed supplements. When dt from severl studies of groupfed nimls were compiled, the percentge of nimls tht did not et ny liquid feed rnged from 17 to 49 percent (Bowmn nd Sowell 1997). In New Mexico Stte University tril conducted over 2 yers, 17 percent of the cows did not consume ny liquid supplement. Supplement intke rnged from 0 to 5.4 pounds per dy (Pulsipher 2000), which is consistent with the rnges reported in other studies. This indictes tht while the verge performnce of herd my e similr mong liquid feeds nd dry feeds, the uniformity of individul niml performnce response my e lower with liquid supplements. Very few reserch trils hve ttempted to directly ddress this question. Tus Hrdened molsses locks re often referred to s tus or soft-pours nd shre some chrcteristics with oth locks nd liquid feeds. This type of supplement is generlly mde from molsses se, such s liquid feed, ut is cooked or chemiclly hrdened to crete lock-type feed pckged in steel, plstic, or fier continers. These supplements cn incorporte higher percentge of dry ingredients thn liquid feeds. Due to the mount of molsses in the formultion, tus typiclly hve lower mounts of dry feedstuffs thn pressed locks. Tus re self-fed supplements. As nimls lick the tu, sliv softens the surfce nd llows the nimls to scrpe off the softened portion. Intke is dependent on the rte of softening. Hrder tus re designed for slower consumption (lower intke) nd do not soften esily. However, incresing lock hrdness to reduce intke of molsses locks lso increses intke vriility (Kendll et l. 1983). When compred with hnd-fed dry supplements or liquid feeds under vriety of conditions, molsses locks hd the highest vrition in individul niml intke (Tle 6; Bowmn nd Sowell 1997). Molsses tus re more environmentlly resistnt thn pressed locks; therefore, tus cn e delivered less frequently. These tus generlly re etween 125 to 250 pounds. However, since livestock must e checked periodiclly, the totl lor cost ssocited with feeding tus my not e significntly less thn feeding dry supplements once per week. Conclusions Supplementl feeding ccounts for significnt economic input to most eef production enterprises. It is importnt tht money is only spent on nutrients tht re limiting niml performnce. There re mny pproches to strtegiclly providing supplementl nutrients. The primry considertions when purchsing or formulting supplements for grzing cttle re estimting nd udgeting forge supply nd estimting or mesuring forge crude protein content. Although not ll forges nd cttle will respond the sme to supplementtion, the Beef Cow Supplement Decision Guide (Fig. 2) my Tle 6. Intke vriility nd proportion of non-eters of hndfed dry cues or locks nd self-fed tus or liquid supplements. Hnd-fed Self-fed Item dry cues or locks tus or liquids Intke rnge, l Non-eters, % 5 19 Adpted from Bowmn nd Sowell Bsed on trget consumption of 2 l/hd/dy. Estimted intke rnge includes the middle 97% of nimls consuming supplement (some extremes my occur)

7 serve s eneficil tool to help producers determine wht percent protein supplement mount might e most cost-effective. A vriety of supplement types re ville to livestock producers. The most efficient nd effective supplement delivery system depends on individul circumstnces nd my vry from rnch to rnch. For energy nd minerl supplementtion, self-fed delivery methods re proly more lor efficient since these supplements should e consumed dily or every other dy. With energy supplements, lrge quntities re usully supplied, nd even with self-fed supplements the supply my need to e replenished frequently. When feeding protein supplements, less frequent feeding (once or twice week) cn e s effective s dily delivery, nd lor costs my e reduced to levels similr to tht of self-fed supplements with less intke vrition. Cues, locks, tus, nd liquids hve different dvntges nd disdvntges. The overll enefit of using prticulr supplement form depends on the individul sitution. Supplement delivery methods nd forms cn e rnked (1= est) sed on severl different criteri: Intke vriility: 1. Hnd-fed (cues nd locks) 2. Self-fed (tus nd liquids) Flexiility of lest cost formultion: 1. Cues 2. Blocks 3. Tus 4. Liquid feeds Lor ssocited with delivery: 1. Liquid feeds (deler filling feeders) 2. Tus 3. Blocks 4. Cues (hnd-fed) The primry gol of ny supplementtion progrm is to deliver trgeted mounts of specific nutrients in uniform nd consistent mnner to generte predictle results. Vriility in supplement intke is mjor cuse of vrile performnce responses to supplementl feeding progrm. Some systems my deliver nutrients more precisely, ut the costs nd enefits of ech system should e evluted. Literture Cited Bowmn, J. G. P., nd B. F. Sowell Delivery method nd supplement consumption y grzing ruminnts: A review. J. Anim. Sci. 75: Heldt, J. S Effect of vrious supplementl crohydrte sources on the utiliztion of low-qulity tllgrsspririe forge. Ph.D. Disserttion. Knss Stte University, Mnhttn, KS. Huston, J. E Frequency of feeding supplements to cttle. Proc Plins Nutrition Council Fll Grzing Conference. pp Huston, J. E., H. Lippke, T. D. A. Fores, J. W. Hollowy, nd R. V. Mchen Effects of supplementl feeding intervl on dult cows in Western Texs. J. Anim. Sci. 77: Kendll, P. T., M. J. Ducker, nd R. G. Hemingwy Individul intke vrition in ewes given feedlock or trough supplements indoors or t winter grzing. Anim. Prod. 36:7. McCollum, F. T Supplementtion strtegies for eef cttle. Texs Ag. Ext. Ser. Pul. B Moore, J. E., nd W. E. Kunkle Improving forge supplementtion progrms for eef cttle. In: 6th Annul Florid Ruminnt Nutrition Symposium, Ginesville, FL. pp NRC Ruminnt Nitrogen Usge. Ntionl Acdemy Press, Wshington, DC. Pulsipher, G. D Supplementl nutrients for eef cows nd heifers consuming low-qulity forges. Ph.D. disserttion, New Mexico Stte Univ., Ls Cruces. Wllce, J. D., nd E. E. Prker Rnge supplements wht we hve lerned. New Mexico Cttle Growers Short Course. pp Issued in furthernce of coopertive extension work in griculture nd home economics, Acts of My 8 nd June 30, 1914, y the Coopertive Extension Systems t the University of Arizon, University of Cliforni, Colordo Stte University, University of Hwii, University of Idho, Montn Stte University, University of Nevd/Reno, New Mexico Stte University, Oregon Stte University, Uth Stte University, Wshington Stte University nd University of Wyoming, nd the U.S. Deprtment of Agriculture cooperting. The Coopertive Extension System provides equl opportunity in eduction nd employment on the sis of rce, color, religion, ntionl origin, gender, ge, disility, or sttus s Vietnm-er vetern, s required y stte nd federl lws. Second edition; 2006 Updte 318-7