Body Condition Scoring Beef Cows

Transcription

1 Body Condition Scoring Beef Cows Lwton Stewrt Extension Animl Scientist Beef Cttle Ted Dyer Extension Animl Scientist Beef Cttle Introduction Reproduction is the most importnt fctor in determining profitility in cow clf enterprise. To mintin clving intervl of 365 dys, cow must re-reed in 80 to 85 dys fter clving. Mny cows in Georgi need higher level of condition t clving nd reeding to improve reproductive performnce. Poor reproductive performnce is directly linked to the percentge of ody ft in eef cows. Body condition scoring (BCS) is n esy nd economicl wy to evlute the ody ft percentge of cow. Cows cn then e sorted nd fed ccording to nutritionl needs. Body condition scoring cn e n effective tool for cttle producers who cnnot weigh cttle, nd it my e n even etter mesurement of cow condition nd reproductive performnce thn weight. Most studies show tht ody condition decreses t fster rte thn weight loss. Therefore, ody condition scoring cn estimte the proility of re-reeding. Beef cttle hve nutrient requirements in priority order for ody mintennce, fetl development, lcttion, growth nd reeding. The nutrient intke is distriuted in the ody of the cow to fill these nutrient requirements. As ech requirement is filled, the ville nutrient is shifted to the next lower priority. The reverse shift is lso ovious in eef cows. As nutrient requirements exceed intke, nutrients re shifted from the lower priority requirements to e sure tht higher priority requirements re filled. Beef cttle store excess nutrients s ody ft. The ft stores re moilized when the nutrient demnds exceed the ville intke. In times of severe nutrient restriction, muscle tissue is moilized once ft nd other nutrient stores hve een depleted. Reserchers hve determined tht certin mount of ody ft is required for the reproductive system to function. Indequte nutrition is most often the cuse of poor reproductive performnce. Developing nutrition progrm is esier nd more cost effective when ll cows on the frm cn e mnged in similr mnner. This is especilly true when ll cows on frm re mnged in single herd, which is often the cse with smll production units. Clving yerround will mke it very difficult to mintin dequte ody condition on ll cows t the criticl times. Importnce of Body Condition Scoring Body condition ffects oth cow nd clf performnce. Poor ody condition is ssocited with reduced income per cow, incresed post-prtum intervl, wek clves t irth, low qulity nd quntity of colostrum, reduced milk production, incresed dystoci, nd lower wening weights. Incresing post-prtum intervl will result in younger, smller clf t wening the next yer nd will result in lower incomes if sold t wening. Wek clves t irth my not get dequte colostrum nd re more susceptile to disese, reduced wening weights, reduced feedlot performnce, nd less desirle crcss trits. Reserch clerly shows tht cows in moderte ody condition will hve shorter intervl from clving to first estrus thn cows in thin condition. This supports the conclusion tht BCS is one of the most importnt fctors in determining susequent reproductive performnce. 1

2 Tle 1. Description of ody condition scores (BCS) (1 [thin] to 9 [oese]). BCS % Body Ft Detiled Description Clerly defined one structure of shoulder, ris, ck, hooks nd pins esily visile. Little muscle tissue or ft present Smll mount of muscling in the hindqurters. Ft is present, ut not undnt. Spce etween spinous process is esily seen Ft egins to cover loin, ck nd foreris. Upper skeletl structures visile. Spinous process is esily identified. Thin Borderline Foreris ecoming less noticele. The trnsverse spinous process cn e identified y plption. Ft nd muscle tissue not undnt, ut incresing in fullness. Optimum Ris re visile only when the niml hs een shrunk. Processes not visile. Ech side of the til hed is filled, ut not mounded Ris not noticele to the eye. Muscling in hindqurters plump nd full. Ft round til hed nd covering the foreris Spinous process cn only e felt with firm pressure. Ft cover in undnce on either side of til hed Animl smooth nd locky ppernce; one structure difficult to identify. Ft cover is undnt Structures difficult to identify. Ft cover is excessive nd moility my e impired. Ft (Source: NRC, 2000) (Adpted from: Herd nd Sprott, 1986) How to Body Condition Score To properly evlute ody condition for cttle, n oserver must e fmilir with skeletl structures nd with muscle nd ft positioning. Although there re severl methods ville to determine ody composition, mny cttlemen use scoring system tht involves rnking cttle on scle. This mnuscript will focus on the commonly used scle of 1 to 9, with 1 eing emcited nd 9 eing oese (Whitmn, 1975). Cttlemen cn esily oserve cttle under psture conditions to otin ody condition scores. Fmilirity with key skeletl structures listed in Figure 1 (p. 3) is required to pply n ccurte ody condition score. A description of ech condition score is listed in Tle 1. Body condition scoring is sujective mesurement, mening tht one producer my score slightly different thn nother. The producer cn gin experience using ody condition scores y identifying cttle into one of three ctegories: thin (1 to 3), orderline (4), optimum (5 to 7) or too ft (8 nd 9). Over time, s the producer ecomes fmilir with detils of ech specific ody condition score, these ctegories cn e further roken into ctul condition scores. Reserch reported y the University of Florid (Tle 2, pge 4) demonstrtes tht s cttle decrese from ody condition score of 5 to 4, they my hve reduced pregnncy rtes y s much s 30 percent. An dditionl 30 percent of pregnncies cn e lost when cttle drop from 4 to 3. Cttle tht receive BCS of 5 or elow my hve reduced pregnncy rtes. Although most cttlemen tend to keep cows on the thin side, cttle tht re oese (BCS of 8 to 9) my lso hve reduced pregnncy rtes. 2

3 Figure 1. Skeletl structures of cow used to evlute ody condition score. BCS 3 BCS 2 BCS 4 BCS 5 BCS 6 BCS 7 3

4 Tle 2. Reltionship of prity nd ody condition score to pregnncy rte (%). Body Condition Score t Clving Prity All > All (Re et l., 1993; University of Florid) (Scle of 1 [thin] to 9 [oese]) Tle 3 shows the impct of BCS on pregnncy percentge, clving intervl, clf performnce, clf price nd income. Cows in orderline ody condition (BCS of 4) hve gretly reduced pregnncy rtes, incresed clving intervls, lower clf dily gin nd gretly reduced yerly income. For exmple, cow clving in BCS of 4 will return n income of pproximtely $100 less thn cow clving in BCS of 5. If BCS is tken 90 dys prior to clving, the cows in orderline condition cn e properly supplemented to chieve BCS of t lest 5 t clving. In most cses supplementl feed costs will e pproximtely $25 to $35 for feed tht costs $100 to $150 per ton This is fr less money spent on feed thn would e lost if cows were llowed to sty in BCS of 4. The impcts re even greter for BCS of 3 nd is condition tht should never hppen with ny of the cows in the herd. When to Evlute Body Condition Mny eef producers re involved in diversified frming opertions. These opertions my comine cttle with row crops, poultry houses, timer nd mny other time consuming production prctices. Regrdless of the comintion, dditionl oligtions my limit the mount of time producers cn spend evluting ody condition. However, neglecting to properly oserve nd record ody condition cn hve sustntil impct on overll productivity nd profits. To properly identify cttle tht hve incresed nutritionl needs, producers should evlute ody condition s often s possile, ut minimum of three times (wening, 90 dys pre-clving nd reeding) per yer is preferred. Cttle tht re clving should hve enough ody condition to llow for reduction in ody mss due to weight eing lost during the prturition process nd fluids eing displced. Body condition score t clving time provides the est prediction of re-reeding performnce. Evluting BCS pproximtely 90 dys prior to clving llows sufficient time to djust the feed rtion to ensure cows re in dequte ody condition t clving. Wening Evluting ody condition t wening cn e useful to determine which cows or heifers need the most gin prior to clving. Since clves will no longer suckle, lctting cows will e le to dry off nd dd needed weight efore clving. The time period from wening to clving hs proven to e the esiest nd most economicl time to dd condition to cttle. Producers who fil to evlute ody condition nd djust the nutri- Tle 3. Reltionship of ody condition score to eef cow performnce nd income. BCS Preg. Rte (%) Clving Intervl (dys) Clf WA (dys) c Clf DG (l) d Clf WW (l) e Clf Price Income $/100 f ($/Clf) Yerly Income $/Cow g (Adpted from Kunkle et l., 1998; UF/IFAS Puliction SP-144. (Body Condition Score; scle of 1 [thin] to 9 [oese]). c (Wening Age; 240 dys for cows in BCS 5 nd 6 nd decresing s clving intervl increses). d (Dily Gin) e (Wening Weight; clculted s clf ge multiplied y clf gin plus irth weight [70 ls]). f (Averge price for similr weight clves during 1991 nd 1992). g (Clculted s income/clf times pregnncy rte times 0.92 [% clves rised of those pregnnt]). 4

5 tionl needs of the cow herd fter wening my hve difficulty dding condition lter in the production cycle. 90 dys Prior to Clving Assessing ody condition 90 dys prior to the eginning of the clving seson my e useful in preventing extended periods of nestrus. This score my e tken t wening in herds tht dely wening until clves re 8 to10 months of ge. However, wening clves t lest 90 dys prior to the strt of the clving seson is recommended. Cow nutritionl requirements re gretly lowered when non-lctting nd should llow the cow to chieve dequte ody condition t clving with miniml supplementl feeding. Nutrition cn then e djusted for cttle tht receive ody condition scores of less thn 5 fter this ssessment. Although chnges in weight cn e chieved, tke cre to prevent excessive weight gin immeditely prior to clving. Cows should e fed to clve in BCS of 5 to 6 nd heifers BCS of 6. Breeding After undergoing the stress of prturition, cttle will lose ody condition. The time period from clving to reeding is the most difficult in which to improve ody condition. This is why it is very importnt to ody con-dition score cows 90 dys prior to clving nd mke rtion chnges to chieve optimum BCS prior to clv-ing. Approximtely 90 percent of cttle in optimum ody condition will resume estrus cyclic ctivity 60 dys postprtum. Assessing ody condition t reeding my offer useful informtion tht my help explin reduced pregnncy rtes. Body Condition Score nd Clving Seson The clving seson in Georgi vries widely mong cttle opertions, ut most clves re orn from Sep-temer through Mrch. Clving seson hs lrge impct on phse of the cow s yerly production cycle in which ody condition score is most likely to e deficient. In the southest, cows clving in the fll months re likely to hve dequte ody condition score, so the winter feeding period usully egins shortly fter the clving seson egins. Therefore, cows re lctting throughout the winter feeding period. Incresed de-mnds of lcttion nd declining feed qulity during the fll months often cuses indequte ody condition y the strt of the reeding seson, which egins in erly- to mid-winter. The mjority of producers feed hy s the se diet during this period. Hy will likely require supplementtion nd the hy feeding period my lst throughout the reeding period for cows clv-ing during the fll. In contrst, cows clving in lte winter will e in lte gesttion nd erly lcttion dur-ing the winter feeding period. Body condition score t clving will hve to e monitored more closely thn fll clving cows s the cows will e fed hy through most of the lst trimester. Cows will likely e fed hy sed diet tht requires supplementtion during the erly lcttion period. However, supplementtion cn cese when hy feeding stops nd grzing ecomes ville. Cows should e le to increse ody condi-tion score when grzing lush spring growth of fescue, ryegrss, or smll grin psture. Incresing Body Condition Score from Clving to Breeding The esiest nd most economicl time to improve ody condition score is from wening to clving. In situtions where cows clve in less thn dequte ody condition, weight gin must e incresed rpidly following clving to chieve cceptle pregnncy rtes t the end of the reeding seson. The most difficult period to mintin ody condition is from clving to reeding. Body condition score nd rereeding rtes cn e improved in cows clving in less thn 5 condition score if fed to increse condition prior to the eginning of the reeding seson. Mture cows, however, will respond to supplementtion much etter thn first clf heifers. Tle 4 illustrtes the effects of ody condition score t clving nd susequent ody weight gin on pregnncy rtes of first clf heifers. Heifers tht clved in ody condition score of 5 or ove hd greter thn 90 percent pregnncy rtes when either gining weight or mintining weight. In heifers clving in BCS of less thn 5, pregnncy rte ws incresed from 36 to 67 percent y incresing dily gin from 0.7 to 1.8 pounds per dy. Even though incresing dily gins improved pregnncy rtes, the 67 percent pregnncy rte is not cceptle nd ws fr elow oth groups clving in condition score of 5 or greter. This study shows tht, for first clf heifers, ody condition score t clving is the key component to high re-reeding rtes. 5

6 Tle 4. Effects of clving BCS nd susequent weight gin on reproductive performnce of first clf heifers. Clving BCS Weight gin, l/d Pregnncy % < < > > Adpted from Bell, et l Weight gin = dily weight gins from clving to the strt of the reeding seson. Body condition score t clving is less criticl for mture cows. Certinly, it is idel to hve cows in ody condition score of 5 t clving through reeding. Acceptle re-reeding rtes, however, cn e chieved in mture cows tht clve in orderline (BCS of 4) condition if cows re fed to increse ody condition score to 5 t the strt of the reeding seson. A study evluted the effects of nutrient intke from the second trimester through the strt of the reeding seson. The first group ws fed to mintin ody condition score of 5 from the second trimester to the strt of the reeding seson. The second group ws fed to e BCS of 4 during the second trimester, nd then regin condition during the third trimester to BCS of 5 t clving. The third group ws fed to e in BCS of 4 from the second trimester through 28 dys postclving, nd then gin weight to e in BCS of 5 t the strt of the reeding seson. Tle 5 shows the ody condition scores nd Tle 6 shows the post-clving weight gins nd pregnncy rtes. All groups were in BCS of 5 just prior to the strt of the reeding seson s plnned. Acceptle pregnncy rtes occurred in ll groups. Cows tht clved in BCS of 5 to 6 lost weight from clving to the strt of the reeding seson; cows tht clved in BCS of 4.8 hd to e fed to gin 3.43 ls per dy to increse ody condition to mintin n cceptle re-reeding rte. Such rpid weight gin would require grin-sed or corn silge sed diet. Cows in BCS of less thn 5 t clving should e seprted from the rest of the herd nd feeding progrm designed to increse BCS should egin immeditely. The cows tht clved in BCS of 4.8 were only slightly elow the desired BCS of 5 nd cows clving in BCS of less thn 4 my not hve cceptle pregnncy rtes. Tle 5. Effect of restricted feeding on ody condition score of mture cows. Dys from clving -- Feeding Level Low-- Low-Low Adpted from Freetly et l., = mintin BCS of 5.5 from wening to reeding. Low-- = decline in BCS in second trimester nd regin BCS to five during third trimester. Low-Low- = decline in BCS during second trimester through 28 dys postclving, then regin BCS to five t reeding. Tle 6. Effect of restricted feeding on postprtum weight gin nd pregnncy rtes of mture cows. Item -- Feeding Level Low-- Low-Low- Weight gin, l/d Pregnncy rte, % Adpted from Freetly et l., = mintin BCS of 5.5 from wening to reeding. Low-- = decline in BCS in second trimester nd regin BCS to five during third trimester. Low-Low- = decline in BCS during second trimester through 28 dys post-clving, then regin BCS to 5 t reeding. Supplementl Feeding Bsed on Body Condition Score Grouping y Body Condition Score A ody condition scoring system is much more effective when cows cn e sorted nd supplemented reltive to trget ody condition score. The mount of sorting will depend on the vilility of pstures nd lor. Idelly, mture cows should e seprted into n dequte ( 5 condition score) nd indequte BCS group (<5 condition score). In ddition, first-clf heifers nd developing heifers should remin in seprte groups. Condition scores of heifers do not vry s gretly s those of mture cows, nd heifers cn usully e fed together. 6

7 Another option is to sort your cow herd into mture cows in condition score of 5 nd greter in one group nd heifers plus cows in condition score of less thn 5 in nother group. The primry enefit of grouping y ody condition is to reduce supplementl feeding costs nd implement more specilized mngement system for thin cows. Determining Needed Level of Supplementtion Body condition scores of cows must e determined prior to the eginning of supplementl feeding progrm. Body condition score hs significnt impct on the requirement for energy ut only smll effect on the protein requirement. Mny supplementtion progrms focus only on supplementl protein nd fll short of providing enough energy to mintin n dequte BCS. Energy rther thn protein is often the most limiting nutrient in Georgi forges. To increse ody condition, the first step is to determine how mny pounds cow needs to gin to rech the desired BCS. To increse one condition score, cow needs to gin out 75 pounds. A dry pregnnt cow would need pproximtely 375 pounds nd lctting cow 575 pounds of TDN (Totl digestile nutrients) ove mintennce to increse one ody condition score in 75-dy period. This would equte to pproximtely 6.5 pounds of corn per dy for dry pregnnt cow nd 10 pounds of corn per dy for lctting cow. Tles 7 nd 8 list the requirements for TDN nd crude protein for cows nd heifers in different ody condition scores. For exmple, cow tht is in ody condition score of 4 t 60 dys prior to clving needs to gin out 1.25 l per dy to rech condition score of 5 t clving. The next step is to determine if the feedstuffs ville on the frm will support this gin. For exmple, nutrient nlyses indicted tht the hy ws 10 percent crude protein nd 50 percent TDN. Assume tht dry cow will consume out 2.0 percent of ody weight per dy nd lctting cow will consume out 2.25 percent of her ody weight per dy in dry feed. Therefore, the dry cow in ody condition of 4 will consume out 24 ls of hy per dy. The 24 pounds of hy t 50 percent of TDN will yield 12 pounds of TDN. From the informtion in Tle 7, the cow needs 16 pounds of TDN. Therefore, the cow must e supplemented with 4 pounds of TDN per dy. There re mny grins, yproduct feeds nd supplements tht will work. The primry fctor in determining which supplement to use is price. The crude protein supplied y the 24 pounds of hy is out 2.4 pounds per dy, nd the cow requires 2.1 pounds per dy. Therefore, the supplementl feed does not hve to e high in crude protein, nd high energy, low crude protein feeds such s corn cn e used. In most cses, hy will not supply sufficient nutrients to increse ody condition score. Computer rtion lncing progrms re ville through Coopertive Extension. These progrms cn rpidly lnce diets for protein nd energy to chieve the desired ody condition score, ut n ccurte nlysis of feeds is needed to ccurtely lnce diet. Tle 7. Dily requirements of TDN nd crude protein for 1,200 l mture cow. Stge of production Lte gesttion Erly lcttion Adpted from NRC, ls of TDN ls of Crude Protein BCS 4 BCS 5 BCS 4 BCS Tle 8. Dily requirements of TDN nd crude protein for 1,000 l first-clf heifer. Stge of production Lte gesttion Erly lcttion Adpted from NRC, ls of TDN ls of Crude Protein BCS 4 BCS 5 BCS 4 BCS 5 Choosing Supplement A wide rnge of supplements cn supplement existing forge to mintin or increse ody condition score. Nutrients my include energy, protein, minerls nd vitmins. Minerls nd vitmins re not ltered significntly y BCS, so supplements will e chosen sed on their energy nd protein concentrtion. Fctors impcting type of supplement used will e nutrient content of forge, lcttion sttus, desired dily gin, cost of supplement, nd vilility of supplement. The only wy to get n ccurte ssessment of hy qulity is to hve the forge nlyzed for nutrient content. Type of supplement will then e dictted y how much protein nd energy supplementtion is required per dy to rech the desired performnce level. If energy is the 7

8 only limiting nutrient, most ny supplement will work. energy supplements such s corn grin will usully e the most economicl. If oth energy nd protein re required, then y-product with high level of protein such s corn gluten feed, distillers grins or whole cottonseed cn e used. Exmple supplementtion protocols re shown for lctting cows in Tle 9 nd for dry pregnnt cows in Tle 10. Tle 9. Hy qulity nd supplementtion required for 1,200 l lctting cow producing 15 ls of milk/dy Qulity of hy Crude Protein (%) TDN (%) Supplement Required Excellent 11.2 & over 58 & over None Good 9.5 to to 58 4 ls corn gluten feed or 3 ls corn nd 1 l soyen mel or 4.5 ls of 20% crude protein cues or 4 ls of whole cottonseed Fir to good 8.2 to to 53 6 ls of corn gluten feed or 5 ls of corn nd 1.5 ls soyen mel or 7 ls of 20% crude protein cues or 6 ls of whole cottonseed Poor to fir 7.3 to & under 8 ls of corn gluten feed or 6 ls of corn nd 2 ls soyen mel or 8.5 ls of 20% crude protein cues or 6 ls of cottonseed nd 2 ls of corn Very poor under & under 9 ls of corn gluten feed or 6.5 ls of corn nd 2.5 ls soyen mel or 10 ls of 20% rnge cue or 7 ls of whole cottonseed nd 2 ls of corn gluten feed Recommended feeding mounts ssumes cow is in BCS of 5. Tle 10. Hy qulity nd supplementtion required for 1,200 l dry pregnnt cow Qulity of hy Crude Protein (%) TDN (%) Supplement Required Excellent 11.2 & over 56 & over None Good 9.5 to to 56 None Fir to good 8.2 to to 53 3 ls of corn gluten feed or 3 ls of corn or 3.5 ls of 20% crude protein cues or 3 ls of whole cottonseed Poor to fir 7.3 to & under 4.5 ls of corn gluten feed or 4 ls of corn nd 0.5 l soyen mel or 5 ls of 20% crude protein cues or 4 ls of cottonseed Very poor under & under 6 ls of corn gluten feed or 5 ls of corn nd 1.0 l soyen mel or 6.5 ls of 20% crude protein cues or 5.5 ls of whole cottonseed The recommended feeding mounts ssumes cow is in BCS of 5. 8

9 By-product feeds re n incresing source of winter supplementtion in the southest. They re often priced competitively with corn nd oilseed mels. In ddition, some y-product feeds hve moderte protein content, which reduces feed costs compred with trditionl corn-soyen mel mixture or commercil protein supplement. In ddition, y-product feeds such s soyen hulls, whet middlings, corn gluten feed, distillers grins nd citrus pulp re low in strch ut high in digestile fier. These y-products cn e fed t higher levels thn corn efore forge intke nd digestiility is depressed. The high strch content of corn cuses negtive effect on digestion when supplementtion level exceeds pproximtely 0.5 percent of ody weight nd worsens s supplementtion level is incresed. When high levels of supplement re needed, low strch y-product feed is recommended. Self-controlled supplements such s molsses lick tnks nd hrd compressed molsses or high protein locks re populr choices ecuse of low lor requirements. These supplements re designed to e primrily protein supplements. In most situtions, cows require oth supplementl protein nd energy. Often, the hrd lock supplements cnnot e consumed in gret enough mounts to provide the desired level of energy. These supplements ecome less desirle s hy qulity declines nd supplement needs re incresed. Additionl energy my need to e supplemented when these products re fed. The liquid molsses-sed supplements cn e consumed t higher levels nd will more closely mtch requirements for energy thn hrd pressed locks. Consuming too much molsses, however, cn cuse decrese in forge digestiility nd intke. Grzing cows on winter nnul pstures is populr choice for mny producers in Georgi. Winter nnul pstures re high qulity, nd they provide extr energy nd protein for lctting cows while decresing the feeding of hy. Winter psture lone is too high qulity for most cows; limit-grzing provides the most efficient use of these high qulity forges for eef cows. Winter pstures contin pproximtely 25 percent crude protein nd 75 percent TDN nd cn meet supplementl protein nd energy needs. The most populr method of grzing cows on winter psture is limitgrzing few hours every dy. You cn get stisfctory results, however, y grzing s little s every other dy or just two or three dys per week. Reserch hs shown tht grzing lctting cows for 7 hours per dy for either two or three dys per week is s effective in mintining cow condition s grzing every dy nd is prticulrly effective for cows clving in the fll. Economics of Supplementl Feeding Providing supplementl feed to improve BCS for cceptle pregnncy rtes is n economicl prctice. In lmost every herd, first-clf heifers re the most difficult group to get re-red. It hs een estimted tht heifer tht does not re-reed fter clving costs the producer from $200 to $500. Reserch hs shown tht first-clf heifers hving BCS of 4 t reeding time will hve pregnncy rtes of pproximtely 50 percent, nd first-clf heifers hving BCS of 5 t reeding time will hve out 90 percent pregnncy rte. For exmple, producer hs group of 10 heifers in BCS of 5 t clving. If heifers re only fed poor qulity hy (8% CP nd 50% TDN) from clving to reeding, decrese of one condition score is likely. The recommendtion in Tle 10 suggests tht feeding 8 pounds of corn gluten feed dy will mintin BCS of 5. This would cost pproximtely $0.48 per dy or $28.80 for the entire feeding period if the gluten feed ws priced t $100 per ton. The producer cn provide supplementl feed to these 10 heifers for 60 dys prior to the strt of the reeding seson to mintin BCS of 5 t reeding time. In this exmple, we would expect four more heifers to ecome pregnnt compred with no supplementl feeding. This would sve $800, ssuming totl of $200 for ech dditionl heifer red. Using n exmple of corn gluten feed t $100/ton, the producer cn uy 8 tons of corn gluten feed with the $800 nd still rek even on dditionl feed costs. However, it would only tke pproximtely 2.5 tons of corn gluten feed to ccomplish this gol. This does not include dditionl enefits of higher wening weights nd erlier clving cows the next yer. Clerly, it is economicl to improve ody condition of lctting cows rther thn reduce feed costs nd hve reduced pregnncy rtes. Supplementl feeding must egin shortly fter clving, however. Witing until the reeding seson strts is too lte. Poor pregnncy rtes nd n extended re-reeding period is certin. Extended Breeding Seson Some producers elieve tht incresing the length of the reeding seson will result in high re-reeding rtes of cows in poor ody condition. Cows, however, will not re-reed t cceptle levels s long s they re in poor condition. This is clerly illustrted in Tle 11. Cows tht were in BCS of 4 or less hd only 58 percent pregnncy rte, despite 150 dys of 9

10 exposure to the ull. Cows tht do ecome pregnnt t the end of n extended reeding seson will wen smller clves nd will e unlikely to re-reed the following yer. Tle 11. Effect of ody condition score during the reeding seson on pregnncy. Body condition during reeding Item 4 or less 5 Percent pregnnt fter 150 dys Adpted from Sprott, Slvging the Breeding Seson When cows re in condition scores of less thn 5 t the strt of the reeding seson, incresing nutrition will improve pregnncy rtes ut not enough to mintin high pregnncy rtes nd yerly clving intervl. To chieve high ( 90%) pregnncy rtes nd mintin yerly clving intervl lterntive mngement strtegies will need to e implemented. The most effective mngement prctice is to wen the clf to remove the demnds of lcttion on the cow. This mngement prctice is often employed with first clf heifers. However, it is n effective mngement tool to increse rereeding rtes in mture cows. Erly Wening In most herds, first clf heifers usully hve the lowest ody condition t the eginning of the reeding seson. These heifers will likely need some cesstion of nursing y reduced exposure to the clf or y wening the clf to chieve high re-reeding rtes. Erly wening the clf t the initition of the reeding seson will led to high re-reeding rtes if dequte supplementtion is supplied. Removing the demnds of lcttion gretly reduces energy nd protein requirements. Erly wening must e done y the strt of the reeding seson to improve re-reeding rtes. Clves should e minimum of 30 dys old prior to wening. Tle 12 compres weights nd condition scores of heifers with clves wened t the strt of the reeding seson with those with clves wened t the end of the reeding seson. Weight nd BCS t the end of the reeding seson were greter for heifers with erly wened clves. Most importntly, heifers with clves wened t the strt of the reeding seson hd 90 percent re-reeding rte versus only 50 percent for heifers tht nursed their clf throughout the reeding seson. Another dvntge to erly wening is decresed feed costs of the cow. Cows will consume pproximtely 20 to 30 percent less feed fter erly wening compred to lctting cows nd gin significntly more weight thn lctting cows. Reserch hs lso shown tht TDN requirements re 50 percent less for dry first clf heifer to mintin equl condition scores s lctting first clf heifer. This would represent sustntil reduction in feed costs for fll clving cows, which re fed hrvested feeds through much of the lcttion period. The improvements in pregnncy rtes nd reduced feed costs mke erly wening the est option for cows tht re elow the desired ody condition score t reeding time. The disdvntge to erly wening is incresed feed costs nd mngement of the erly wened clf. Clves must hve ccess to high qulity winter nnul psture or should e fed high concentrte grin mix in drylot. Feeding progrms tht hve used winter nnul pstures plus n energy supplement hve een very successful for clves wened t less thn 80 dys old. Tle 13 shows dily gins of erly wened clves tht grzed ryegrss psture plus 1 percent ody weight dily of 16 percent crude protein supplement. Clves were stocked t pproximtely four clves per cre. Weight gins were similr etween the erly nd norml wened clves. The winter psture plus supplement progrm would work well for most cttle producers in Georgi. Tle 12. Effect of erly wening first clf heifers on weight nd ody condition score. Item Beginning of reeding seson End of reeding seson Wening c Norml wened, wt Erly wened, wt Norml wened, BCS Erly wened, BCS Adpted from Arthington, Initil weight ws collected t the strt of the reeding seson. c Finl weight ws collected t wening. 10

11 Tle 13. Effect of erly wening first clf heifers on clf weight. Item Erly Wened Norml Wened Initil weight, l c Finl weight, l Dily gin, ls Adpted from Arthington, Initil weight ws collected t the strt of the reeding seson. c Finl weight ws collected t wening. Mngement Fctors Affecting Body Condition Score Severl mngement decisions cn ffect the ody condition of the cow herd. Some of these include stocking rte, clving seson nd herd helth. Clving seson nd the durtion of the clving seson cn influence cow ody condition. Supplementtion must e well plnned for cows clving in the fll nd erly winter months, s most of the clving to re-reeding period will e on hrvested feeds. In ddition, shorter clving will llow the producer to feed the herd more efficiently, ecuse ll the cows in the herd will e in the sme stge of production. er-round clving will cuse significnt under- nd over-feeding unless clves re mnged s multiple groups. Adjust stocking rtes so dequte forge is ville to mintin dequte condition during the grzing seson. If hy or supplement must e fed every dry spell, the stocking rte is proly too high. Tret cttle for internl nd externl prsites. Georgi is n excellent environment for worms, nd the cows should e treted t lest once per yer. Summry A ody condition score of 5 to 6 t clving nd reeding time will result in cceptle pregnncy rtes. Heifers clving in ody condition score of less thn 5 will hve less thn optiml reproductive performnce, even when nutrition is gretly incresed fter clving. Cows re more responsive to incresed nutrition fter clving. Clerly, it is more economicl to improve ody condition rther thn reduce feed costs nd hve reduced pregnncy rtes. Supplementl feeding must egin, however, shortly fter clving to improve or mintin ody condition. Witing until the reeding seson strts is too lte to efficiently chnge BCS nd hve n impct on reproductive performnce, nd poor pregnncy rtes will likely result. Erly wening is proven mngement prctice to mintin high rereeding weights in cows nd heifers clving in less thn 5 ody condition score. Literture Cited Arthington, J. D Erly Wening A mngement lterntive for Florid Cttle Producers. University of Florid, IFAS, Florid Coop. Ext. Serv., Animl Science Dept., EDIS Puliction AN131. H. C. Freetly, C. L. Ferrell, nd T. G. Jenkins. Timing of relimenttion of mture cows tht were feed-restricted during pregnncy influences clf irth weights nd growth rtes. J. Anim Sci : Herd, D.B, nd L.R. Sprott Body Condition, Nutrition nd Reproduction of Beef Cows. Texs Agriculturl Extension Service. B Kunkle, W.E., R.S. Snd, nd D.O. Re Effects of ody condition on productivity in eef cttle. Deprtment of Animl Science, Florid Coopertive Extension Service, UF/IFAS. SP-144. NRC Growth nd Body Reserves. Nutrient Requirements of Beef Cttle. 7th ed. Wshington, D.D.: Ntl. Acd. Press. Re, D.O., W.E. Kunkle, P.J. Chenoweth, R.S. Snd, nd T. Trn Reltionship of prity nd ody condition score to pregnncy rtes in Florid Beef Cttle. Theriogenology 39:1143. Sprott, L.R. Body condition, nutrition, nd reproduction of eef cows. Texs Agriculturl Extension Service. B