On 4-point trimming

On 4-point trimming On4-point trlmmlft~ Previous the wear pattern in wild Previousstudies studiesdescribing deScribing thenatural naturalhoof OOofwear ~m~n wildhorses hOrsesthe' revealed a consistent 4-point pattern of()fcontact between the hoof capsule and revealedacons~ 4-poitltpattent c()llb,l.ctbetweeilth,e ~oof,~ and the ground. Based on these findings, the 4-point trim technique was introduced in the ground;,BasedOll~tindillgS.the4-pointtrlm~,W~~¢tdIDtfie late natural method of trimming the hoof wall of domestic horses. l~1980s 19808asasaa'~'~of~gth,e~oofwaU/of~ h~The 'Ibe 4-point trim has gained popularity, both as a technique assumed to prevent injury Dr. Loic M. Dejardin was named the Zan4-point trim baSgaID.ed popnlarlty~botba&a tec~assutnedtp~t ~ Dr. Loic M. Dejardin was named the Zan- and as a treatment. dman and as a treatIJletlt " ",' '" ""';utilize """ pared ,','",,', ;'" '" ," ,.," dmanAward Awardwinner winnerafter afterparticipating participating . • In following the 4-point toe totofacilitate breakover ininaaproject ,In'foUowiogth,e 4-pointtrim, trim,farriers farri~rS uUHzeaa~,toe breakove( projectentitled entitledPhotoelastic PhotoelasticStress Stress in trimmed totoreduce of loading Analysis , inthe thestride. stride.Also, Ahio,the thequarters quartersare aret:QnUned redUcethe tOe,amount amount;()n~i AnalysisofofEquine EquineHoof HoofStrains StrainsFollowFollowthe thinnest part of the hoof wall. The method, mimicking (weight/stress) ing (weight/stress)onOllthethinnest Pa.toftheboof waU·'ntemet1iod;lniO)ickjhi ing4-Point 4-PointTrim. Trim.GraysonGrayson-Jockey JockeyClub Club the natural wear pattern for wild horses, creates a hoof with ground contacts provided provided$28,492 $28,492totofund fundthe thestudy studyas as the,natl.mIlwear~ forWi1~ ~s.located t.t"eatesabOOfWith ""'~p~ .'" .C6ntacts concentrated atatfour respectively above pillars (thickpart concentrated fourpoints, points, respectively~ abovethe' heels'",and (~. partofoftheir theirslate slateofofprojects projectsfor for1997-98. 1997-98. the wall). est parts of estpatfSofthew.t,llk ,,', '",,;:.,; ,'""",;',', "" "",,," ' From Because seemed to bebefollowing "trimming" resulting from Grayson-JockeyClub ClubResearch Research FromGrayson-Jockey Becauseititseet)ledto foUowipgthe themethod ~ofpf'~'~~gfrom Today, June 2000. has been assumed to be helpful in maintaining a a natural forces, the 4-point trim Today, June 2000. natural forces. the4-point trim has ~,~ tobe~ii.~ healthy, hoof. However, little scientific information is available healthy.balanced t>alrulC(ld,bOO{. JlQweyer.totQ'date _littlesci~ lijf~~iS:avai1ab1e, patterns in normal hooves. Moreover, the effect of 4-point ononOOofwall hoof wall strain ~~in~,hoc;We$:~.~e~()f+pQint has not been determined. trimming on those strain patterns trimming OIl those strain l'attems ba$~~~ """':"('> ...., ' Inconsistent clinical results have been anecdotally which, ..along InConsistentc1itlicalresW:ts~ve ~, ", '" " reported, ''.VlJ.ch ~Ohg on when and how to perform the 4-point with the lack of clear guidelines with the laclie U.Dejardin, Dejan'lin,designed an experiment that utilized sophisticated stress inducing machinery tbatutilized so· bisticatedstress indu ....... ~ ........and , strain measurement tech. . p . cmg~"""·~I., to reduce variations inherent to hoof size and to standardize the trimming niques oiques to reduce vlUiaticinsinherent to. hoof size thus allowing meaningful comparison between specimens as well as technique, technique. thus allowing me3ningful~ be trimming patterns. Variations included imitation ofofaccidentally excessive trim··::.······· l trimming p;lttems. Variations i1l<::~imlta4()fi / ' G I' \ ",,>toe, .. ming nrlngasaswell wenasashoof hoofwear wearpatterns patternsassociated associatedwith with.softer terrain. qua1er :. I ! 2O"JIoof ..... " : hoof lengltl ...... The results ofofthis study showed that, regardless of the trimming pattern, the The results this study sbowed 1:blt. ~glU"dless ..... - ........... ... /~' l . .... _were distinguished in a apattern strain U strainfield fiddepicenters epicentmwere diStlnguisbedin ~that corresponds to the free edge edgeofofthe !bethird thirdphalanx. phalanxThe .. Thefunctional functionalalignment alignm.entbetween the third phalanx and the for hoof health. thehoof boofwall wallisisa afundamental fundatnentalconsideration considerati?Jlinintrimming .' Schematics illustrating the 4-point trimAlthough laminar stress measurement was not a part of the study, the Schematics illustrating the 4-point trimAlthough laminar stress rfieasuremen.t was -not ming researchers could bebeassumed mingalgorithm algorithmused usedininthis thisstudy. study.The The researchersnote notethat, that,"it "ifcould assUmedthat thatthe thestrain concentration over the length pillars lengthofofeach eachpoint pointOf Ofcontact contactreprereprepillarS·asaswell asasthe thesignificant significan.~increase increaseininshear shearstrain magnitude following sented could be associated with disruptive stresses on the trimming," sented20% 20%ofofthe thetotal totalhoof hooflength. length. trimming;' could be associatt:d with disi:uptives~, laminae. . lan:linae.However, However, The another possibility would bebethe opposite, i.i.e.,e~.that strain increase might stimulate Theheight heightofoftoe toeand andquarter quartertrims trimswas was another possibility would the opposite, ~ ~.·i1lcrea$e·mightstimulate mm. The toe points were approximately 5 is not breached, in a healthier approximately 5 mm. The toe pOints were growth growthand, and,asaslong longasasintegrity integrityofofthe thelamina lruninais ~hed.result centered foot. "';not ..... , ' :resW:t . in a healUUer centeredbetween betweenthe thetip tipofofthe thefrog frogand and foot. the thetip tipofofthe thetoe toewhile whilethe theheel heelpOints points This scientific knowledge Thisstudy studymight mightbebedescribed describedasasa acase caseofOfincreased ~scierllific knowledge having value not in what it says about "conventional wisdom" having value not in what it says about "conventkmal wisdom'~but butwhat ""hiltititdoes does not on the study, the notsay. say.The Theauthors authorsconclude concludethat, that,"Based "BaSedsolely ~y<>ri theresults resultsofofthis thisstudy~ the long-term long·tennclinical clinicalimplication implicationofofthe the4-point 4-pOinttrim ttimcan cannot botbebeinferred inferredand remains remains open opentotointerpretation. interpretation,Indeed, Indeed.asassuggested sugges~ininprevious preViousstudies, stUdies,the thedistribution dis'lributioriofof ,6, heel wall and sole changes with environmental factors such load between the hoof (... 6. load between the boof wall and sole cbimg'eSWith enviror)mentalfactors suchasas , hee' the hardness of the ground surface." the hardness of the ground surface." Also, indicated that quarter Also,the thestudy studyindicated thatthere thereisislittle li~correlation correlatioobetween betweenthe thedirections difections ofofprincipal loe principalstrain strainand andthe theoverall ov~orientation orientatiOnofofhoof boofwall wallinner innerstructure. strUcture.The The importance importanceofofthis thislack lackofofcorrelation correlatioohas basyet yettotobebedetermined, determined,but butleads leadstoto speculation a protective mechanism Diagram speculation.that thatititrepresents represent$aprotective mechanismagainst againstcracking. cracking: Diagramofofthe thegeneric generichoof hooftemplate template although the 4-point trim does achieve The researaches state that, illustrating changes in strain distribution The ~~state that, althOugh the 4-point trim does acbievethe theaim aimofof illustrating changes in strain distribution redistributing strain over the thickest parts of the hoof wall, the effect of this to trimming. The strain epicentersdue redis'lributing strain over the thickest parts oftbehoof wall. the effect of thispattern pattern due to trimming. The strain epicentersmight bebeeither from all the hooves and from various trimmight eithernegative negative(i.(i.e.,e.,encourage eIlcouragedisruptive disruptivelaminar laminarstresses) stresses)ororpositive positive from all the hooves and from various trim(i.(i.e.,e.,stimulate ming stimulatehoof boofgrowth). growth). mingpatterns patternshave havebeen beensuperimposed superimposed on the A paper ononthe generic template using a normalA paper on thestudy studyhas basbeen beencompiled compiledbybyDrs. Drs.Dejardin, Dejardin,Arnoczky, Amoczky,Gary Gary the generic template using a normalization izationprocedure. procedure.Note Notethe thestrain strainconcenconcen- L.L.Cloud, Cloud,and andJohn JohnA.A.Stick. Stick.The Theauthors authorsalso alsoacknowledged acknowledgedthe theexpertise expertiseand and tration assistance trationabove abovethe thecontact contactpoints pointsfollowing following assistanceofofDarryl DarrylPaterson, Paterson,Application ApplicatiOllEngineer, Engineer,Dr. Dr.Bari BariN.N.Oliver Oliverfor forhis his 4-point assistance 4-pointtrimming. trimming. assistancewith withstatistical statisticalanalysis, analysis,and andStephanie StephanieBormin Borminfor forassistance assistanceinincalibracalibration. tion.

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