Founder Articles

8/12/2019 Founder Articles

1/22

Founder Articles

Laminitis: Facts, Myths, and Common Sense

Laminitis: Prevention & Treatment

Laminitis: A major and Unsolved Problem for orses

!"#ine Laminitis: An U$date on %ts Ca#ses

ee$ i'ital Fle(or Tenotomy as a Treatment for Chronic Laminitis

Laminitis

)rass Fo#nder


2/22

Laminitis: Facts, Myths, and Common Sense

by Andrew Parks, VMB

Laminitis and the %nformation A'e

A "#ic* )oo'le search at the time of +ritin' $rod#ced almost --,--- lin*s abo#t e"#inelaminitis. This re$resents an enormo#s amo#nt of information. %t comes from all sorts of so#rcesincl#din' veterinarians, farriers and horse o+ners. Unfort#nately, there is no "#ality control onm#ch of this information, and an enormo#s amo#nt of it is $ersonal o$inion. Anybody readin'these re$orts is li*ely to come a+ay +ith many "#estions as +ell as ans+ers beca#se often theadvice different articles offer a$$ears conflictin'. /hat ca#ses laminitis0 %s laminitis the same asfo#nder0 /hat ty$e of emer'ency is laminitis0 M#st a horse +ith ac#te laminitis be treated +iththis dr#' or that dr#'0 Sho#ld % ta*e the shoes off of a horse +ith ac#te laminitis0 o % have toa$$ly fro' s#$$orts to a horse +ith ac#te laminitis0 Sho#ld % soa* the feet of a horse +ith ac#telaminitis0 Sho#ld a horse +ith laminitis be stall rested or +al*ed0 /hat does it mean to s#$$ortthe boney col#mn0 M#st % starve a horse +ith ac#te laminitis to ma*e it lose +ei'ht and $reventrec#rrence or e(acerbation of its c#rrent disease0 Are all cases of laminitis the same0 oes a

horse +ith laminitis have to be shod in a certain +ay0 oes laminitis al+ays have devastatin'conse"#ences0 Unfort#nately, many of these "#estions do not have definitive ans+ers. o+ever,over the last 12 years m#ch has been learned abo#t this disease, and it is the intent of this articleto e(amine both this $ro'ress and some of the controversies that remain.

/hat is Laminitis and /hat Ca#ses %t0

Laminitis is a syndrome in +hich the e$idermal and dermal lamellae +ithin the hoof are dama'ed.%f the dama'e to the lamellae is severe, the e$idermal lamellae se$arates from the dermallamellae and the distal $halan( dis$laces +ithin the foot. Fo#nder is a lay term that is consideredto be a synonym for laminitis by veterinarians. Laminitis is considered ac#te +hen it has been$resent for less than three days and the distal $halan( has not dis$laced. Laminitis is consideredchronic after the distal $halan( has dis$laced. %f the disease has been $resent for over three

days, b#t dis$lacement of the distal $halan( has not occ#rred, it is considered s#b3ac#te.

/hen disc#ssin' the ca#ses of the laminitis, it is necessary to differentiate bet+een ris* factorsassociated +ith the disease and the $atho$hysiolo'y of the disease. 4is* factors are factors that+hen $resent in the history of a horse indicate that the develo$ment of laminitis is a reco'ni5ed$otential se"#el. !(am$les of s#ch ris* factors incl#de colic, colitis, overfeedin' on 'rain or l#sh'rass and metritis. These are conditions that are fre"#ently associated +ith endoto(emia.

Additionally, there are other ris* factors s#ch as $rolon'ed +or* on hard s#rfaces +itho#tade"#ate foot $rotection, often called road fo#nder, $rolon'ed +ei'ht3bearin' on a sin'le limbbeca#se of a $roblem in the contralateral limb, !"#ine C#shin's Syndrome and injection ofsteriods.

The $atho$hysiolo'y of laminitis that occ#rs follo+in' systemic disease has been the s#bject of

many st#dies, b#t is still not clearly defined. Theories over the last 1- years incl#de diminishedblood s#$$ly to the foot, endoto(emia and inflammation, abnormalities of coa'#lation andabsor$tion of to(ins. C#rrently, the balance of the evidence $oints to+ards a 'enerali5edinflammatory res$onse to +hich the lamellae +ithin the foot are $artic#larly s#sce$tible. %t has notbeen determined +hether this is related to the +ei'ht3bearin' f#nction of the foot or some otherfactor.


3/22

o+ o % *no+ %f My orse as Laminitis and /hat Sho#ld % o0

The $rinci$le sym$tom of ac#te laminitis is the ac#te onset of lameness. The severity oflameness varies 'reatly, from barely detectable, to a stiff 'ait, to bein' #nable to move. Thehooves are #s#ally +arm, the horse may be rel#ctant to $ic* #$ a limb and the di'ital $#lses are$rono#nced. The horse may be breathin' ra$idly from the $ain or the effort to +al*. The disease

most fre"#ently affects both forelimbs, b#t any combination of limbs may be affected. %f yo#s#s$ect yo#r horse has laminitis based on the s#dden develo$ment of lameness that is evident ata +al* that involves m#lti$le limbs, yo# sho#ld call yo#r veterinarian immediately. A veterinarianma*es the dia'nosis based on a $hysical e(amination. 4adio'ra$hs at this sta'e in the diseasemay sho+ no abnormalities, b#t are fre"#ently ta*en to $rovide a baseline sho#ld the condition+orsen. Laminitis is not a five min#te emer'ency, nor is it a disease that sho#ld +ait #ntil the ne(tday to be treated. Treatment in the first fe+ ho#rs can ma*e an enormo#s difference.

orses +ith chronic laminitis #s#ally have a $rior history of the disease that the o+ner is a+areof, b#t this is not al+ays the case. A'ain the $rinci$le sym$tom is lameness, b#t horses +ithchronic laminitis #s#ally have chan'es in the sha$e of their hoofs that incl#de a dro$$ed sole,concavity of the dorsal hoof +all, e(cessive heel 'ro+th com$ared to the toes and #neven 'ro+thrin's. Additionally, radio'ra$hs demonstrate chan'es in the distal $halan(, the hoof ca$s#le and

the relationshi$ bet+een the t+o. Chronic laminitis is not #s#ally an emer'ency, b#t an ac#tee(acerbation of chronic disease may re"#ire $rom$t treatment.

o+ Sho#ld a orse /ith Ac#te Laminitis 6e Treated0

Treatment of horses +ith ac#te laminitis is divided into treatment of the $reci$itatin' disease if$resent, medical thera$y and s#$$ortive thera$y. Treatment of $reci$itatin' disease is beyond thesco$e of this disc#ssion. Medical thera$y is the mainstay of the treatment of ac#te laminitis.Unfort#nately, of all the medications available that have been tried in ac#te disease, none have#ne"#ivocally been $roven to be beneficial. Therefore, clinicians treat horses +ith ac#te laminitisbased on e(tra$olation of the theories #nderlyin' the $atho'enesis of the disease, *no+led'eabo#t ho+ these dr#'s affect normal horses, from in vivo and in vitro e($erimental models andtheir o+n clinical e($erience. These dr#'s are $rimarily aimed at $rovidin' relief from $ain,

controllin' inflammation, im$rovin' blood s#$$ly and $reventin' coa'#lation in the vessels +ithinthe di'it. The a#thor $rimarily #ses $henylb#ta5one to control the $ain and limit inflammation,ace$roma5ine to im$rove the blood s#$$ly and MS7 also to limit inflammation. 7f these,$henylb#ta5one is the only one that clinically demonstrates an obvio#s and immediate effect, b#teven the #se of $henylb#ta5one is controversial in some "#arters beca#se the $ain relief it$rovides enco#ra'es a horse to stand and8or move aro#nd. A sensible com$romise is to #seeno#'h $henylb#tat5one to limit discomfort, b#t not to $romote e(cessive #se of the limbs. 7therclinicians #se oral iso(s#$rine and to$ical nitro'lycerine to increase di'ital blood flo+, systemicas$irin and he$arin to red#ce coa'#lation +ithin the di'ital vasc#lat#re, and $ento(i$hylline for itsanti3endoto(ic and rheolo'ic effects. Additionally, fl#ni(in 96anamine or *eto$rofen are #sedinstead of or in conj#nction +ith $henylb#ta5one.

S#$$ortive thera$y is directed at limitin' stresses that ca#se dis$lacement of the distal $halan(

and controllin' limb edema. This is best achieved by removin' the shoes if $resent anddistrib#tin' the +ei'ht across the 'ro#nd s#rface of the foot by standin' on sand or $eat, $ac*in'the soles of the feet +ith silicone $#tty or ta$in' Styrofoam bloc*s to the bottom of the feet. %tsho#ld be noted that not all clinicians a'ree +ith removin' the shoes beca#se of the $otential ris*for increasin' the inj#ry as the shoe is removed. %f a horse does not res$ond favorable to thesemeas#res, the heels may be raised and the brea*over moved $almarly +hich is most easilyachieved by a$$lyin' a commercial c#ff and +ed'e $ad combination 9Modified 4edden Ultimate.Limb edema sho#ld be controlled +ith $ress#re banda'es. Additionally, it a$$ears that coolin' thefeet, #s#ally by standin' the horse in chilled +ater, limits lamellar $atholo'y. o+ever, soa*in'the feet $er se is not considered desirable. A $reci$itatin' condition may dictate ho+ an ac#tely


4/22

laminitic horse is fed, b#t in the absence of s#ch re"#irements, it is $r#dent to avoid feedin' 'rainand $rovide 'ood "#ality 'rass hay. !(ercise is contra3indicated in horses +ith ac#te laminitis.

o+ Sho#ld a orse /ith Chronic Laminitis 6e Treated0

The mainstay of the treatment of chronic laminitis, in contrast to the treatment of ac#te laminitis,

is s#$$ortive thera$y in the form of corrective shoein'. There are many shoein' techni"#es thathave been advanced for the treatment of chronic laminitis, each of +hich has its o+n advocates.These incl#de heart3bar shoes, e''3bar shoes in conj#nction +ith silicone $#tty or one of t+ocommercial shoes, the Al#min#m Fo#r Point 4ail shoe and the !"#ine i'it S#$$ort System. %t isnot $ossible to say one techni"#e is #ne"#ivocally better than the others for several reasons.Firstly, there are no 'ood controlled st#dies in the literat#re that com$are the different techni"#es.Secondly, not all laminitic horses are the same beca#se the mor$holo'ical and str#ct#ral chan'esin the feet differ bet+een horses, s#''estin' that they re"#ire different treatment. Thirdly,individ#al clinicians have fo#nd different techni"#es to +or* for them. So rather than foc#s on thety$e of shoe, it is better to foc#s on the $rinci$les that are most li*ely to lead to recovery. Shoein'the laminitic horse sho#ld be done +henever $ossible +ith the aid of radio'ra$hs beca#se theshoe sho#ld be $ositioned in relation to the distal $halan(, and not the sha$e of the distorted hoofca$s#le. The dorsal sole sho#ld not be trimmed thinner than normal thic*ness 9abo#t 2 mm.

The 'ro#nd s#rface of the foot sho#ld be reali'ned to the distal $halan(. The toe and brea*overof the shoe sho#ld be moved $almarly to decrease stress in the dorsal hoof +all and easemovement. Part or the entire 'ro#nd s#rface of the foot bet+een the branches of the shoe isrecr#ited for +ei'ht3bearin'. %f trimmin' the heels to achieve re3ali'nment of the distal $halan(increases the lameness, the heels of the shoe may be elevated. !ach of the techni"#esmentioned above meets most or all of these objectives. Limited e(ercise may +ell be beneficial tothe convalescin' horse, b#t the ret#rn to e(ercise sho#ld be 'rad#al and caref#lly monitoredbeca#se the de'ree of comfort e(hibited by a horse recoverin' from laminitis fre"#ently belies theseverity of the resid#al dama'e to the lamellae.

Medical thera$y is fre"#ently necessary to control $ain, and the most commonly #sed anal'esicis $henylb#ta5one. For those horses +ith !"#ine C#shin' Syndrome, treatment +ith $er'olide orcy$rohe$tadine is indicated, and the former a$$ears to be more effective. )ood "#ality 'rass hay

sho#ld be $rovided, b#t it is reco'ni5ed that this may not be s#fficient so that a balancedcom$lete ration may be added to the diet. There are many food s#$$lements available that are$#r$orted to enhance the ret#rn of a more normal hoof, b#t there is no scientific evidence toconfirm or ref#te their #se.

S#r'ery is occasionally indicated in the treatment of horses +ith chronic laminitis. ee$ di'italfle(or tendon transection is indicated in horses that contin#e to rotate des$ite other thera$e#ticmeas#res and in horses that have ac"#ired fle(#ral deformity s#bse"#ent to the disease. %nhorses in +hich the distal $halan( becomes infected, s#r'ical debridement is indicated.

Pro'nosis for the Laminitic orse

Laminitis is a devastatin' disease, b#t not all horses that develo$ laminitis are devastatin'ly

affected. %n fact, the severity of laminitis is hi'hly variable, and the co#rse of the disease e"#ally#n$redictable. Therefore, acc#rately $redictin' the o#tcome is diffic#lt, b#t some 'enerali5ationscan be made. The severity of the clinical si'ns in the ac#te sta'es of the disease reflects theseverity of the lamellar inj#ry, and therefore, at this sta'e of the disease the $ro'nosis is inverselyrelated to the clinical si'ns. o+ever, some horses that e(hibit severe lameness that do notdevelo$ dis$lacement of the distal $halan( have s#ccessf#l o#tcomes. %n horses +ith chroniclaminitis the $ro'nosis for both f#t#re athletic $erformance and s#rvival has been correlated +iththe de'ree of rotation. o+ever, in the a#thor;s e($erience the severity of the lameness, thean'le of the solar mar'in the distal $halan( forms +ith the 'ro#nd and the thic*ness of the sole


5/22

are better '#ides for s#rvival, b#t the de'ree of rotation that $ersists des$ite treatment is a fair'#ide for the ret#rn to athletic $erformance and the necessity for lon' term corrective shoein'.

There are many reasons that the treatment for laminitis fails, and the 'reatest of these is theinitial severity of the disease. o+ever, ina$$ro$riate a$$lication of corrective shoes, $remat#reret#rn to e(ercise and not holdin' to re'#lar shoein' intervals +ill all ne'atively im$act the

s#ccess of treatment. Additionally, the occ#rrence of com$lications s#ch as se$sis of the distal$halan( and secondary fle(#ral deformities of the distal inter$halan'eal joint +orsen the$ro'nosis.

S#mmary

Most of the research over the last 12 years is related to the $atho$hysiolo'y of laminitis, and+hile the $ict#re is incom$lete, o#r #nderstandin' has been 'reatly advanced. 4esearch into thetreatment la's behind o#r #nderstandin' of the $atho$hysiolo'y of the disease, b#t the latter isnecessary to lay the 'ro#nd+or* for the former. o+ever, collective clinical e($erience for thetreatment of laminitis as a +hole has increased, and there are many $rod#cts, $artic#larlyshoein' or s#$$ortive devices, on the mar*et that +ere not available 12 years a'o. %n the case ofany individ#al horse, it is still necessary for the clinician to inter$ret each horse se$arately and

incor$orate $ersonal e($erience in the treatment.

*ey+ords: laminitis .$osted: 8


6/22

Laminitis: Prevention !reatment

LAM"#"!"S

Prevention And !reatment

!very day veterinarians across the co#ntry see h#ndreds of cases of laminitis, a $ainf#l diseasethat affects the horse>s feet. /hat is es$ecially alarmin' is that some cases are $reventable. %nfact, it may be that +e are *illin' o#r horses +ith *indness.

Consider that a common ca#se of laminitis is overfeedin' 33 a mana'ement factor that is normally+ithin o#r control.

6y learnin' more abo#t laminitis and its ca#ses, si'ns and treatments, yo# may be able tominimi5e the ris*s of laminitis in yo#r horse or control the lon'3term dama'e if it does occ#r.

LAM"#"!"S $%F"#%$

Laminitis res#lts from the disr#$tion 9constant, intermittent or short3term of blood flo+ to thesensitive and insensitive laminae. These laminae str#ct#res +ithin the foot sec#re the coffin bone9the +ed'e3sha$ed bone +ithin the foot to the hoof +all. %nflammation often $ermanently+ea*ens the laminae and interferes +ith the +all8bone bond. %n severe cases, the bone and thehoof +all can se$arate. %n these sit#ations, the coffin bone may rotate +ithin the foot, bedis$laced do+n+ard 9?sin*? and event#ally $enetrate the sole. Laminitis can affect one or all feet,b#t it is most often seen in the front feet conc#rrently.

The terms ?laminitis? and ?fo#nder? are #sedinterchan'eably. o+ever, fo#nder #s#allyrefers to a chronic 9lon'3term conditionassociated +ith rotation of the coffin bone,

+hereas ac#te laminitis refers to sym$tomsassociated +ith a s#dden initial attac*,incl#din' $ain and inflammation of thelaminae.

CA&S%S

/hile the e(act mechanisms by +hich the feet are dama'ed remain a mystery, certain$reci$itatin' events can $rod#ce laminitis. Altho#'h laminitis occ#rs in the feet, the #nderlyin'ca#se is often a dist#rbance else+here in the horse>s body. The ca#ses vary and may incl#de thefollo+in':

i'estive #$sets d#e to 'rain overload 9s#ch as e(cess 'rain, fr#it or snac*s or abr#$t

chan'es in diet.

S#dden access to e(cessive amo#nts of l#sh fora'e before the horse>s system has had

time to ada$t@ this ty$e of laminitis is *no+n as ?'rass fo#nder.?

To(ins released +ithin the horse>s system.

i'h fever or illness@ any illness that ca#ses hi'h fever or serio#s metabolic dist#rbances

has the $otential to ca#se laminitis, e.'., Potomac orse Fever.


7/22

Severe colic.

4etained $lacenta in the mare after foalin'.

!(cessive conc#ssion to the feet, often referred to as ?road fo#nder.?

!(cessive +ei'ht3bearin' on one le' d#e to inj#ry of another le' or any other alteration of

the normal 'ait.

ario#s $rimary foot diseases.

6eddin' that contains blac* +aln#t shavin's. Prolon'ed #se or hi'h doses of corticosteroids.

'"S( FAC!)'S

Factors that seem to increase a horse>s s#sce$tibility to laminitis or increase the severity of thecondition +hen it does occ#r incl#de the follo+in':

eavy breeds, s#ch as draft horses

7ver+ei'ht body, cresty nec*s

i'h n#tritional $lane 9feedin' lar'e amo#nts of carbohydrate3rich meals

Ponies, Mor'ans, miniat#re horsesand don*eys Unrestricted 'rain bin'es, s#ch as +hen a horse brea*s into the feed room 9if this

ha$$ens, do not wait #ntil sym$toms develo$ to call yo#r veterinarian33 callimmediately so corrective action can be taken be*ore tissue dama+e ro+resses

orses +ho have had $revio#s e$isodes of laminitis

7lder horses +ith C#shin'>s disease

S"-#S

Si'ns of acute laminitisincl#de the follo+in':


8/22

Lameness, es$ecially +hen a horse is t#rnin' in circles@ shiftin' lameness +hen

standin'.

eat in the feet.

%ncreased di'ital $#lse in the feet 9most easily $al$able over either sesamoid bone at the

level of the fetloc*.

Pain in the toe re'ion +hen $ress#re is a$$lied +ith hoof testers.

4el#ctant or hesitant 'ait 9?+al*in' on e''shells?. A ?sa+horse stance,? +ith the front feet stretched o#t in front to alleviate $ress#re on the

toes and the hind feet $ositioned #nder them to s#$$ort the +ei'ht that their front feetcannot.

Si'ns of chronic laminitismay incl#de the follo+in':

4in's in hoof +all that become +ider as they are follo+ed from toe to heel.

6r#ised soles or ?stone br#ises.?

/idened +hite line, commonly called ?seedy toe,? +ith occ#rrence of seromas 9blood

$oc*ets and8or abscesses.

ro$$ed soles or flat feet.

Thic*, ?cresty? nec*. ished hooves, +hich are the res#lt of #ne"#al rates of hoof 'ro+th 9the heels 'ro+ at a

faster rate than the rest of the hoof, res#ltin' in an ?Aladdin3sli$$er? a$$earance.

!'%A!M%#!

The sooner treatment be'ins, the better the chance for recovery. Treatment +ill de$end ons$ecific circ#mstances b#t may incl#de the follo+in':

ia'nosin' and treatin' the $rimary $roblem 9laminitis is often d#e to a systemic or

'eneral $roblem else+here in the horse>s body.

ietary restrictions@ sto$ feedin' all 'rain3based feeds and $ast#re. Feed only 'rass hay

#ntil advised by yo#r veterinarian. Treatin' +ith mineral oil via a naso'astric t#be to $#r'e the horse>s di'estive tract,

es$ecially if the horse has overeaten.

Administerin' fl#ids if the horse is ill or dehydrated.

Administerin' other dr#'s s#ch as antibiotics to fi'ht infection@ anti3endoto(ins to red#ce

bacterial to(icity@ and anticoa'#lants and vasodilators to red#ce blood $ress#re +hileim$rovin' blood flo+ to the feet 9corticosteroids are contraindicated in laminitis, as theycan act#ally ca#se laminitis or e(acerbate e(istin' cases.

Stablin' the horse on soft 'ro#nd, s#ch as in sand or shavin's 9not blac* +aln#t and

enco#ra'in' the horse to lie do+n to red#ce $ress#re on the +ea*ened laminae.

7$enin' and drainin' any abscesses that may develo$.

Coo$eration bet+een yo#r veterinarian and the farrier 9techni"#es that may be hel$f#l

incl#de corrective trimmin', fro' s#$$orts and thera$e#tic shoes or $ads.

Bo#r veterinarian may be able to advise yo# on ne+ thera$ies that may incl#de standin'

yo#r horse in ice +ater to $revent the onset of laminitis after a $redis$osin' ca#se s#chas a retained $lacenta or a *no+n 'rain overload.

L)#-.!%'M )&!L))(


9/22

Some horses that develo$ laminitis ma*e #neventf#l recoveries and 'o on to lead lon', #sef#llives. Unfort#nately, others s#ffer s#ch severe, irre$arable dama'e that they are, for h#manereasons, e#thani5ed.

Bo#r e"#ine $ractitioner can $rovide yo# +ith information abo#t yo#r horse>s condition based onradio'ra$hs 93rays and the animal>s res$onse to treatment. 4adio'ra$hs +ill sho+ ho+ m#ch

rotation of the coffin bone has occ#rred and may also ill#strate abscesses or 'as acc#m#lationthat +ill affect the thera$y of yo#r horse.This +ill hel$ yo# ma*e a decision in the best interest ofthe horse and hel$ the farrier +ith the thera$e#tic shoein'.

MA#A-%M%#!

%t>s im$ortant to note that once a horse has hadlaminitis, it may be li*ely to rec#r. %n fact, a n#mber ofcases become chronic beca#se the coffin bone hasrotated +ithin the foot and the laminae never re'aintheir ori'inal stren'th. There may also beinterference +ith normal blood flo+ to the feet as +ellas metabolic chan'es +ithin the horse. !(tra care is

recommended for any horse that has had laminitis,incl#din':

A modified diet that $rovides ade"#ate

n#trition based on hi'h3"#ality fora'e,di'estible fiber 9beet $#l$ and oil. Avoide(cess carbohydrates, es$ecially from 'rain.

4o#tine hoof care, incl#din' re'#lar trimmin'

and, in some cases, thera$e#tic shoein'9additional radio'ra$hs may be needed to monitor $ro'ress.

A 'ood health3maintenance sched#le, incl#din' $arasite control and vaccinations, to

red#ce the horse>s s#sce$tibility to illness or disease

Possibly a n#tritional s#$$lement form#lated to $romote hoof health 9biotin s#$$lements

are $o$#lar for $romotin' hoof 'ro+th.

Avoid 'ra5in' l#sh $ast#res, es$ecially bet+een late mornin' and late afternoon ho#rs,

since $lant s#'ars are the hi'hest d#rin' these times. 4estrict $ast#re inta*e d#rin's$rin' or anytime the $ast#re s#ddenly 'reens #$.

S&MMA'/

The best +ay to deal +ith laminitis is $reventin' the ca#ses #nder yo#r control. Dee$ all 'rainstored sec#rely o#t of the reach of horses. %ntrod#ce yo#r horse to l#sh $ast#re 'rad#ally. 6ea+are that +hen a horse is ill, #nder stress or over+ei'ht, it is es$ecially at ris*. Cons#lt yo#re"#ine $ractitioner to form#late a 'ood dietary $lan. Provide 'ood, ro#tine health and hoof care. %fyo# s#s$ect laminitis, consider it a medical emer'ency and notify yo#r veterinarian immediately.

For more information, contact yo#r veterinarian.

American Association of !"#ine Practitioners


10/22

Laminitis: A ma0or and &nsolved Problem *or 1orses

by 2ritten by: 23A3 Moyer, $VM

%IT47UCT%7I

Laminitis 9often called fo#nder is a #ni"#e disease, +hich commonly affects horses, $onies,don*eys and m#les. %t has been dia'nosed in 5ebras and some cloven3hooved animals. %t hasbeen reco'ni5ed as a major $roblem in the horse +orld for cent#ries. %t is a reasonably fre"#entca#se of lameness in the less severely affected as +ell as a le'itimate reason for h#manee#thanasia in the more severely affected. The horse ins#rance ind#stry reco'ni5es it as one of

the most common reasons for an ins#rance claim. Bet the disease, for all its im$ortance, history,research and concern, remains an #nsolved dilemma.

The +ord laminitis means inflammation 9th#s the s#ffi(Jitis of the laminae. Laminae are the softtiss#e str#ct#res that e(ist bet+een the hoof +all and the #nderlyin' coffin bone 9or Hrd $halan(.Thin* of the laminae and lamellar str#ct#res li*e elcro, attachin' and s#s$endin' the coffin bone+ithin the hoof ca$s#le. Consider the hoof +all to be li*e a fin'er or toenail, the laminae to be thenail bed 9the soft and very sensitive tiss#e #nder the nail and the coffin bone to be the very smallbone at the ti$ of a fin'er or toe. 7bvio#sly, the similarity ends +ith re'ard to f#nction and load.

Most recently, based on $revio#s +or* done in A#stralia, another definition for laminitis has beenoffered as s#ch: a fail#re of the attachment bet+een the Hrd $halan( and the inner as$ect of thehoof +all. 7ne of the many dilemmas in this com$le( disease is #nderstandin' ho+ this critical

attachment is dama'ed and8or destroyed.

/AT APP!IS0

Fail#re of the lamellar attachment res#lts in loss of the s#s$ension of the coffin bone +ithin thehoof ca$s#le. Th#s the coffin bone descends 9rotates, sin*s or both to+ard the bearin' s#rface.The $rocess res#lts in shearin' and tearin' of arteries and veins, in +hich case livin' tiss#e diesin the absence of o(y'en3rich blood flo+. The tiss#es, +hich once #nited the str#ct#res, aresheared and cr#shed, +ith the end res#lt bein' $ain and lameness. isa'reement bet+eenscientists and investi'ators e(ists +ith re'ard to +hat destroys the attachment. Conventionalthin*in' for years +as that of a vasc#lar disorder, that is, somethin' ca#sed the vessels toconstrict and th#s start the cascade of events. More recent +or* s#''ests $rimary dama'e 9to(icto ori'in0 to the attachment via loss of the chemical and molec#lar bondin' follo+ed by $hysical

dama'e to the associated vessels. /e do *no+ that a m#ltit#de of events can set #$ this event.

/e also *no+ that j#st abo#t any $rimary or'an or or'an system dama'e has been *no+n toinitiate laminitis. This +o#ld incl#de $roblems involvin' the 'astrointestinal, res$iratory,re$rod#ctive, renal 9*idney, endocrine 9hormonal s#ch as C#shin';s Syndrome,m#sc#los*eletal, inte'#mentary 9s*in and imm#ne systems. %nde$endent to(ic events are *no+nto ca#se this 9for e(am$le, blac* +aln#t shavin's. This can also involve to(ins $rod#ced bybacteria s#ch as Salmonella. ario#s metabolic disorders are classic e(am$les: 'rain overload9'rain fo#nder and the in'estion of certain 'rasses at certain $hases of 'ro+th 9'rass fo#nder.


11/22

ario#s dr#'s have been im$licated 9steroids b#t not $roven. 6ased on observational st#dies,stress 9+hich is diffic#lt to define has been s#''ested to initiate laminitis 9for e(am$le, horsese($osed to heavy sho+in' sched#les +ith 'reat shi$$in' distances, chan'es in environment andfeedin' $ractices, etc.. /or*in' for lon' $eriods of time on hard s#rfaces has been named as aca#se 9road fo#nder@ even drin*in' cold +ater follo+in' +or* on a hot day has been s#''ested.Unilateral 9one limb laminitis can occ#r +ith $rolon'ed and #ne"#al +ei'ht bearin' 9for e(am$le,a horse recoverin' from a $ainf#l fract#re on the o$$osite le'. Pit#itary adenomas 9beni'n t#morof the $it#itary 'land can affect the normal $rod#ction of certain hormones. 7lder horses +ith this$roblem have a hi'her incidence of laminitis. An e"#ally lar'e cate'ory of ca#ses is sim$ly#n*no+n. Many horses, to the best of the involved horse o+ner;s *no+led'e, are fo#nd in thisstate +ith no history of illness, chan'e in environmental or n#tritional stat#s, etc.

The above is a sim$lified and brief s#mmary of the dama'e and ca#ses, b#t it sho#ld be a$$arentthat a m#ltit#de of initiatin' factors e(ists. %t also $rovides the investi'ators a very com$le(disorder that is diffic#lt to st#dy for the follo+in' reason: it is obvio#sly a very com$le( $roblem@animal +elfare iss#es ri'htf#lly e(ist that $rohibit the +holesale creation of the $roblem to allo+st#dies beca#se of the $ain@ horse research is very e($ensive@ and lastly and sadly, horseresearch is not at all +ell3s#$$orted by the horse3o+nin' $#blic or 'overnment 9horses are notconsidered to be either food animals or a necessity. This $roblem does not have an e"#ivalent inother s$ecies. All of the above ma*e investi'ation diffic#lt.

FACTS

%t is necessary to $oint o#t several established facts in order to #nderstand +hy this is s#ch afr#stratin' disease to treat and mana'e. 6y the time the o+ner or careta*er is a+are that a$roblem e(ists 9$ain, rel#ctance to move or lameness, the $roblem is very +ell established. Thatis, the $ain associated +ith laminitis follo+s the destr#ctive $rocess. Th#s, a develo$mental$hase e(ists in the absence of any obvio#s $roblems. A st#dy $erformed decades a'o indicated aE13ho#r delay, on avera'e, from the initiation of the $rocess #ntil the involved horses +ere notedas havin' $roblems. These +ere even horses +ho +ere bein' very caref#l and fre"#entlyobserved. Altho#'h that st#dy involved a $artic#lar method to create the disease and does notreflect ho+ "#ic*ly or slo+ly this mi'ht ha$$en +ith other ca#ses, it is im$ortant to #nderstand

that a la' time definitely e(ists from the be'innin' #ntil it is reco'ni5ed.

4eco'nition is another $roblem beca#se it is a f#nction of h#man observation and th#s co#ld bemonths for t#rned3o#t horses livin' on their o+n. Pain is not al+ays an acc#rate meas#re of thede'ree of destr#ction either. %n other +ords, a 'iven Kvictim co#ld a$$ear to be fairly comfortableand still have si'nificant and $ermanent dama'e. orses can s#stain very little lamellar dama'eand re'ain so#ndness beca#se healin', if it does occ#r, is often incom$lete. This means that thetiss#e arran'ement and th#s stren'th of the s#s$ension is often $ermanently lost. Therefore, thefoot remains a mechanical ris* and is li*ely to be a $roblem in the f#t#re. 4ec#rrence and otherfoot3related conditions 9for e(am$le, +all se$aration, foot abscesses and sole br#isin' mayfollo+ the ori'inal e$isode. Some horses +ith laminitis may have other $roblems, +hich mas* thedia'nosis s#ch as colic, diarrhea, central nervo#s system disorders, etc., and th#s the dia'nosisis not made at the time. There a$$ears to be no a'e 9+ith the e(ce$tion of the $roblem bein' rarein yo#n' horses or se( $redilection, altho#'h certain breeds, body ty$es and #sa'e a$$ear tohave a hi'her incidence 9$onies, Mor'ans, heavy sho+ horses, 'aited horses +ith e(cessivelylon' feet, Standardbred stallions and others. And lastly, it is a fact that no one treatment orcombination of treatments for this $roblem e(ists that #niformly $rovides 'ood res#lts.

7P%I%7I

My observations thro#'h the years, +hich may or may not be correct, indicate the follo+in': ali*ely candidate for laminitis is the #nder3+or*ed, over+ei'ht individ#al. 6esides bein'over+ei'ht, these horses are basic Ka$artment3d+ellers. Sho+ horses 9and other s$orts


12/22

re"#irin' little in the +ay of fitness, broodmares and stallions 9es$ecially Standardbreds are atris*. 4acehorses, end#rance horses, three3day event horses and +ild horses have, in mye($erience, a lo+ incidence. Ponies +ith laminitis are 'enerally easier to mana'e than horses@Thoro#'hbreds and Arabians are 'enerally harder to mana'e, as there is very little foot to +or*+ith. 7ver+ei'ht #arter orses on the sho+ circ#it are, in my o$inion, "#ite s#sce$tible anddiffic#lt to mana'e. orses +ith $rolon'ed and serio#s illnesses 9$roblems li*e colic, diarrhea,#terine infections and retained membranes follo+in' foalin' are $artic#larly hi'h on the list are ata si'nificant ris* of develo$in' laminitis.

P4!S!IT%I) S%)IS

%t is im$ortant to state and #nderstand that horses do not read anyone;s notes, boo*s or e3mails,th#s the $resentin' si'ns % disc#ss ne(t are 'enerally b#t not al+ays +hat is observed. Mostaffected horses are rel#ctant to move, es$ecially +hen t#rned. The front feet 9+hich are #s#allythe most often involved may be more diffic#lt to $ic* #$. )enerally the discomfort is 'reatest inboth front, altho#'h one may be +orse than the other. The $#lse is #s#ally bo#ndin' 9stron'er$#lse $ress#re than normal and is best a$$reciated +here the s#$erficial artery $asses over thebac* of the fetloc* on both sides. The more $ainf#l horse may ado$t an abnormal stance 9hindand front feet $ositioned in front of the #s#al vertical $lane. Us#ally resentment or a $ainf#l

res$onse to $ress#re from hoof testers e(ists j#st in front of the ti$ of the fro'. A'ain, it isim$ortant to $oint o#t that these si'ns +ill vary from one horse to the ne(t. A #sef#l clichN e(ists:horses sho+in' a s#dden onset of lameness in either front or all fo#r feet are fo#ndered #ntil$roven other+ise. 6e+are that the si'ns of laminitis can easily be mas*ed or missed by thesit#ation or disease that created the event 9colic, for e(am$le.

/AT S7UL B7U 70

The very first thin' to do is call yo#r veterinarian. The second thin' to do is call yo#r veterinarianOAttem$t b#t do not force the horse into a comfortable environment. /hat not to do0 o not doanythin' +itho#t instr#ctions. o not treat the $roblem yo#rself +ith advice from yo#r nei'hbor,yo#r stac*ed collection of horse ma'a5ines, yo#r Merc* eterinary Man#al or advice off of the%nternet. o not $#ll the shoes #nless instr#cted to do so by a $rofessional. Avoid shi$$in' the

horse #nless yo# have no choice. Al+ays *ee$ in the forefront of yo#r mind the fact thatsomethin' ha$$ened to tri''er the event, and therefore ine(act or ina$$ro$riate treatment of thelaminitis $roblem co#ld $otentially be harmf#l to the s#ccess of correctin' the disease $rocessthat hel$ed create the laminitis. This is not a time to KPlay etO

/AT T7 !P!CT F47M T! !T!4%IA4%AI

The $rocess +ill be'in +ith a 'eneral $hysical e(amination and a$$lication of dia'nostictechni"#es to determine the dia'nosis or dia'noses. The total $ict#re is im$ortant beca#sesomethin' ha$$ened to create the disorder. This $rocess +ill involve a disc#ssion of recenthistory in the horse;s life in an attem$t to discover the initiator. %n many instances, the ca#se +illel#de the o+ner and e(aminer. 4adio'ra$hs 93rays of the involved or s#s$ected feet +ill #s#allybe $art of this e(amination. %t is im$ortant to $oint o#t that an absence of radio'ra$hic evidence at

this sta'e of the $roblem does not mean the horse is not fo#ndered J recall the la'3time as$ect ofthis disease $rocess 9that is, si'nificant chemical and molec#lar dama'e occ#rs before str#ct#ralchan'es are a$$arent and th#s chan'es a$$arent on an 3ray film.

The initial treatment can and sho#ld vary +ith each case, beca#se no t+o horses or sit#ations areali*e. %f the ori'inatin' disease is $resent, treatment +ill be desi'ned in an attem$t to mana'e it.

Attem$ts +ill be started to control $ain@ the choice of medication +ill vary. iet and environmentalconcerns sho#ld be addressed. o+ the involved feet are handled +ill de$end entirely on theindivid#al case and foot. This co#ld incl#de shortenin' the toe len'th@ a$$lyin' Styrofoam, ta$ed3


13/22

on $ads or boots@ corrective shoein' or stayin' +ith the $resent shoein' J it al+ays varies. 7thertreatment considerations may be delayed #ntil the films are inter$reted, laboratory res#lts arereceived and res$onse to day3one treatment is eval#ated.

As the case develo$s, treatment and mana'ement evolves and is determined by assessin' thede'ree of dama'e, $ain, farrier e($ertise, costs, local environment and availability and

+illin'ness of labor. 6e f#lly a+are that any Kbattle $lan may have to be altered to s#it thechan'in' sit#ation and that the $rocess has a si'nificant head start on treatment.

L7I)3T!4M MAIA)!M!IT

First of all, very little fact#al information e(ists +ith re'ard to assessment of the vario#streatments and mana'ement $ractices that have been #tili5ed. %n some cases, the de'ree andseverity of dama'e e(ceeds the ability to fi( it or comfortably live +ith it. 4e'ardless of thethera$y #sed or even the s#ccess of s#ch thera$y at the time, rec#rrin' foot $roblems are veryli*ely. Treatments can be e($ensive es$ecially over time. %ndivid#al cases can be very laborintensive. %t is best to thin* in terms of ho$in' for a comfortable e(istence as o$$osed to a ret#rnto normal and athletic f#nction.

The varieties of treatments in the chronic case +ith str#ct#ral dama'e are "#ite varied. M#lti$lemethods and techni"#es e(ist +ith re'ard to corrective trimmin' and shoein'. oof +allreconstr#ction techni"#es have e(isted for years, b#t +ith +ide variation in o#tcomes 9in somecases the sit#ation is made +orse. C#ttin' the dee$ fle(or tendon, in selected cases andsometimes tem$orarily, can attain mechanical relief. A myriad of chronic3#se medications havebeen #sed to decrease $ain 9the most commonly #sed +o#ld be $henylb#ta5one Kb#te b#t onesho#ld be a+are that most any medication #sed on a lon'3term basis co#ld $otentially createother medical $roblems. %t is also im$ortant to note that even +ithin the same fo#ndered horsethe selection of treatments and mana'ement may vary bet+een the feet. Consideration for thes#rface 9livin' environment may be *ey to s#ccessf#l mana'ement. S#rfaces may incl#de drybeach sand, $eat moss, r#bber, 'ravel3li*e materials and other reasonably for'ivin' $rod#cts.The bottom line is sim$ly that no one system of shoein' and care has s#ccessf#lly s#rfaced asbein' best.

L7I)3T!4M C7IS!U!IC!S 7F LAM%I%T%S

Toe +all se$aration 9seedy toe and deformities 9#s#ally in the form of $arallel rin's are acommon se"#ella. Sin*in' of the coffin bone +ithin the ca$s#le is a very diffic#lt conse"#ence+ith re'ard to treatment and mana'ement. %n some instances, de$endin' on the de'ree ofrotation or dis$lacement of the coffin bone +ithin the hoof ca$s#le, $enetration of the sole by theti$ of the coffin bone occ#rs. This is also a very diffic#lt and life3threatenin' com$lication. S#ch anevent invariably leads to bone infection. %n some advanced cases, com$lete loss of the hoofca$s#le occ#rs. eformity of the lo+er limb 9contract#re is not #n#s#al in those horseschronically affected. Perha$s the most common sit#ation is that of rec#rrin' $ain and lameness Jrecall that the s#s$ension system may be $ermanently affected, creatin' a mechanical $roblem.Sole3br#isin' and abscess formation #nder the hoof +all and8or sole occ#r +ith some fre"#ency.

%n s#mmary, beca#se of the dama'e to the laminae and the often3e($erienced incom$letehealin', a variety of $roblems can occ#r +ith fo#ndered horses.

Laminitis is a very #ni"#e $roblem. %t is one of the most diffic#lt $roblems facin' the horse +orld.%n the event that yo# as an o+ner e($erience this $roblem +ith yo#r horse, 'et veterinary hel$"#ic*ly. 4eco'ni5e that each case is different and th#s these are very diffic#lt $roblems tomana'e.


14/22

*ey+ords: laminitis, foot $roblems.$osted: 281E81--


15/22

ca#sed the laminitis, it can ma*e an a$$arent com$lete recovery or become a Ksin*er, thehallmar* si'n of chronic laminitis.

A Ksin*er is a horse +hose coffin bone has lost all attachment to the inner hoof +all and dro$$edto the bottom of the hoof. The chronic $hase can last indefinitely +ith si'ns ran'in' from$ersistent, mild lameness to contin#ed severe foot $ain, f#rther brea*do+n of the lamellae, adeformed or even slo#'hed hoof +allthe horse may even 'o do+n. %t is im$ortant to reali5e

that the $rocess +hich tri''ered the lamellae to brea*do+n be'ins to o$erate d#rin' thedevelo$mental $hase before the first si'n of foot $ain.

#rin' the develo$mental $hase, the s$ecific $roblems of the horse often have to be attended to#r'ently 9'rain overload, tyin' #$, retained $lacenta. Unfort#nately, the feet may not enter intothe e"#ation #ntil the si'ns of foot $ain a$$ear. 6y the time foot $ain is a$$arent, destr#ction ofthe lamellae is #nder +ay. %n other +ords, foot $ain is the o#t+ard si'n that lamellar destr#ctionis occ#rrin'. To +ait and see if foot $ain is the se"#el to another or'an system;s crisis is to missthe o$$ort#nity to $revent or at least lessen lamellar dama'e.

The Underlying Disease Processes that Cause Laminitis

Lamellar changes

/e believe that the lamellar chan'es of laminitis are ca#sed by a dist#rbance of a normally ti'htlycontrolled $rocess or str#ct#re in the horse;s body. The body $rod#ces certain en5ymes 9MMPin res$onse to the stresses and strains of normal e"#ine life, as +ell as to constant 'ro+th./hen called for, eno#'h MMP is $rod#ced to maintain the correct sha$e and orientation of+hatever str#ct#re is in needbone, joint or, in this case, lamellae. %t is $ossible that re$air ofthe lamellae, necessary for the hoof +all to 'ro+ $ast the stationary coffin bone, is the tar'et ofthe laminitis disease $rocess. /hen MMP en5ymes are not inhibited, they dislod'e the cells thatma*e ne+ lamellae from the basement membrane 9a delicate tiss#e layer that serves as the$rotective barrier bet+een the e$idermis dermis. The basement membrane then $eels a+ay insheets. 6eca#se the basement membrane is the *ey str#ct#re bet+een the lamellae and thecoffin bone, loss of the basement membrane leads to the fail#re of attachment bet+een the innerhoof +all and the coffin bone that is laminitis.

Circulatory Changes

An additional com$onent of lamellar anatomy to be affected by over$rod#ction of MMP is thelamellar ca$illaries. As the basement membrane disa$$ears, so do the ca$illaries. The loss ofthese ca$illaries may e($lain +hy resistance to blood flo+ +as increased H.2 times in horsesd#rin' early laminitis and also +hy blood by$assed the ca$illary bed, flo+in' instead thro#'h thelar'er arteries and veins. These t+o chan'es in circ#lation are +hat $rod#ces the Kbo#ndin'di'ital $#lses felt in the ac#te $hase of laminitis and are believed to occ#r as a res#lt of e(cessMMP.

This theory of laminitis based on the tri''erin' of MMP challen'es the alternative vie+ thatlaminitis develo$s beca#se of circ#lation chan'es in the foot. A c#rrent theory is that constrictionof veins and hi'h fl#id $ress#re bloc*s the flo+ of blood thro#'h the ca$illaries of the lamellae,

event#ally ca#sin' the lamellae to die. o+ever, o#r research has not $rovided any evidencethat vein constriction and hi'h fl#id $ress#re occ#r. /hat a$$ears certain in the li'ht of o#rresearch is that the disinte'ration of lamellae is ca#sed by the #ncontrolled release of e(cessMMP.

/hat tri''ers MMP release0 A factor $resent in c#lt#res obtained from the '#tj of the horse hasbeen demonstrated to activate MMP and ca#se lamellar se$aration in the laboratory. Thesec#lt#res contain Stre$tococc#s bovis, the $rinci$al bacteria res$onsible for fermentation of s#'arsd#rin' 'rain overload. /e are c#rrently investi'atin' the role of the S. bovis MMP activator innat#ral cases of e"#ine laminitis. %f it is able to cross the barrier of the '#t and enter the


16/22

circ#lation, it may be a ne+ Kca#se of laminitis. o+ do the tri''er factors of laminitis reach thelamellae0 There is no+ stron' evidence that the blood vessels of the foot are dilated d#rin' thedevelo$mental $hase of laminitis. Laminitis does not occ#r if these blood vessels are constricted,s#''estin' that the tri''er factors +ill only ca#se laminitis if:

they reach the lamellae +hen the blood vessels are dilated

they are at a hi'h eno#'h concentration

they occ#r over a lon' eno#'h time $eriod

Since blood vessels constrict as the tem$erat#re decreases, *ee$in' the feet of horses that are indan'er of develo$in' laminitis as cool as $ossible seems lo'ical. Trials to determine the effect ofa sl#rry of iced +ater a$$lied to the feet of horses are #nder+ay. Preliminary res#lts sho+ thathorses, #nli*e h#mans, do not re'ard e(tremely cold feet as #ncomfortable.

Conclusion

Laminitis, or the loss of attachment bet+een the lamellae of the inner hoof +all and the coffinbone, occ#rs in three $hases. The factors tho#'ht to ca#se laminitis 9MMP are at +or* in thefirst $hase, develo$mental, before foot $ain is a$$arent. 6eca#se these factors cannot enter thefoot and ca#se dama'e #nless the foot;s blood vessels are dilated, cold +ater sho#ld be

beneficial in the $revention of laminitis. %n addition, research has sho+n that there are chemicala'ents that can bloc* MMP and $otentially aid in the $revention and mana'ement of ac#telaminitis. Trials to test +hether these MMP inhibitors can indeed $revent or im$rove laminitis arec#rrently #nder+ay at the A#stralian !"#ine Laminitis 4esearch Unit at the University of#eensland.

Article Posted: Qan#ary, 1---

Co$yri'ht R GG=31--- American Association of !"#ine Practitioners. All ri'hts reserved.

American Association o* %4uine Practitioners


17/22

$ee $i+ital Fle5or !enotomy as a !reatment *or ChronicLaminitis

by !imothy -3 %astman, $VM, MPVM,

by Timothy ). !astman, M, MPM,and Clifford M. onnas, M, i$lomate ACS

The coffin bone is the $rimary bone +ithin the horse>s foot. The hoof ca$s#le encases this boneli*e a body in a coffin 9hence the name coffin bone. The laminae +ithin the foot are the softtiss#e str#ct#res that firmly attach the coffin bone to the hoof +all. Laminitis, in its sim$lest terms,

is inflammation of the laminae that attach the coffin bone to the hoof ca$s#le. This inflammationdecreases blood flo+ to the area of the laminar attachments. Local alterations in blood flo+ maybe the res#lt of a variety of systemic illnesses, s#ch as 'rain overload, colic, retained $lacenta,etc. /hatever the so#rce of the disease, laminitis #s#ally ca#ses cri$$lin' $ain in horses and is$otentially devastatin' to horse o+ners.

%n some instances, the laminar attachments become so com$romised that the coffin bone andhoof ca$s#le act#ally se$arate from each other. %f the normal $#ll of the dee$ di'ital fle(or tendone(ceeds the stren'th of the remainin' laminar attachments, the bone may rotate do+n+ard a+ayfrom the hoof +all. eterinarians consider the disease chronic if rotation occ#rs or if the conditionlasts for more than several days.

Most treatments for laminitis foc#s on im$rovin' blood flo+ to the foot, alleviatin' the $ain

associated +ith this condition, haltin' disease $ro'ression, and re3establishin' a f#nctionalrelationshi$ bet+een the coffin bone and hoof +all. eterinarians often #se vaso3dilatin' a'entss#ch as ace$roma5ine, iso(s#$rine, $ento(y$hyline, and nitro'lycerin in ho$es of im$rovin'blood flo+. Phenylb#ta5one 96#te commonly relieves $ain and decreases inflammation inlaminitic horses. A variety of recommended shoein' and trimmin' techni"#es attem$t to decreasethe amo#nt of tension on the coffin bone and redistrib#te $ress#re on the hoof>s +ei'ht3bearin's#rfaces.

%n s$ite of e(tensive research, n#mero#s a$$roaches to treatin' horses +ith laminitis aresometimes fr#stratin' and #nre+ardin'. A m#lti3factorial condition, laminitis involves several bodysystems and $revents a sin'le treatment re'imen from becomin' #niversally acce$ted oreffective. /hen the disease does not res$ond favorably to conventional thera$ies, o+ners oftent#rn to e#thanasia to end the intractable $ain of this condition.

The $#r$ose of the a#thors> c#rrent st#dy, $resented at AA!P>s


18/22

This retros$ective st#dy eval#ated the $roced#re>s effectiveness by obtainin' follo+3#$information on all horses +ith laminitis treated by dee$ di'ital fle(or tenotomy over a ten3or3more3year $eriod. Thirty3seven cases met the criteria for incl#sion in the st#dy. Seventy3seven $ercentof the horses that had the o$eration +ere still alive after si( months and =- s#rvived at least t+oyears. The res#lts are s#bstantial considerin' the severity of the laminitis and e(treme lamenessof all the st#dy horses $rior to s#r'ery. These horses had not res$onded to established medicaltreatments and many +ere facin' e#thanasia. The hi'h $ercenta'e of o+ner satisfaction +ith thes#r'ery seems to indicate the im$roved "#ality of life for these horses. Seventy3three $ercent ofo+ners said they +o#ld have the $roced#re re$eated in similar circ#mstances, E +o#ld not,and - +ere #ns#re. The st#dy also fo#nd that the severity of lameness and amo#nt of rotationevident on $re3s#r'ical 3rays did not infl#ence the o#tcome of the o$eration.

Previo#s st#dies have yielded conflictin' res#lts for the $roced#re. Some indicate the $roced#reis less effective early in the disease>s $rocess d#rin' the ac#te sta'es of laminitis. 7thers sho+ alac* of res$onse to any *ind of treatment in cases +here the coffin bone sin*s in the hoof ca$s#lerather than rotatin'. /hen the bone sin*s, the e(tensive loss of laminar attachments contrib#testo the disease>s severity.

orse o+ners sho#ld consider the cost of aftercare +hen contem$latin' tenotomy of the dee$

di'ital fle(or. The act#al o$eration is relatively ine($ensive beca#se the s#r'ery does not re"#ire'eneral anesthesia. !($enses acc#m#late from the essential corrective trimmin' and shoein'$erformed by a "#alified farrier at fo#r3+ee* intervals. %n rare instances, the horse>s toe +ill fli$ #$follo+in' tendon transection d#e to the loss of the s#$$ortin' str#ct#re. This conditionnecessitates a heel e(tension on the affected foot.

The severed tendon heals +ith scar tiss#e, leavin' an enlar'ed thic*enin' on the le' +here thetiss#e forms. Some horses may become so#nd eno#'h to res#me li'ht +or*, b#t most achieve$ast#re so#ndness and are best s#ited for breedin' $#r$oses. Altho#'h a #niversally effectivetreatment for laminitis is #nli*ely, tenotomy of the dee$ di'ital fle(or tendon may benefit selectedhorses +ith chronic laminitis +hich contin#es to deteriorate des$ite intensive medical thera$y.

Co$yri'ht R GG=31--- American Association of !"#ine Practitioners. All ri'hts reserved.

American Association o* %4uine Practitioners


19/22

Laminitis

by Andrew 13 Parks, VetMB

My horse had mild laminitis in the ast, but is rideable now3 Can you tell mehow to e5lain this disease to my *riends6

Commonly referred to as fo#nder, laminitis is the inflammation of the laminae in the foot. Thelaminae connect the coffin bone to the hoof +all, and laminitis occ#rs +hen there is disr#$tionbet+een these str#ct#res. The ca#se of laminitis is m#ch debated, b#t the res#lt is a decrease inblood flo+ to the laminae, cell#lar death, and laminar disr#$tion. Dee$ in mind this is a sim$lified

definition of a com$le( $roblem.

Laminitis is a se"#el to a variety of diseases, re$eated conc#ssion on hard 'ro#nd, inj#ry,n#tritional overloads 9'rain, l#sh 'rass or alfalfa, etc., abortion or retained $lacenta, certaindr#'s, or to(ins. !ven tho#'h yo# don;t necessarily thin* of laminitis res#ltin' from a horse;seatin' fresh 'rass or alfalfa hay, if a horse in'ests too m#ch 'rass, or alfalfa, it mi'ht be eno#'hto ca#se a 'astrointestinal #$set that starts a systemic res$onse. This combination of events canlead to laminitis.

Com$ensatory +ei'ht bearin' can ca#se laminitis. An e(am$le of this occ#rs if a horse +ith afract#re in the left front le' has to bear all its +ei'ht on the ri'ht front le'. The effort of bearin'that e(tra +ei'ht mi'ht dama'e the j#nction bet+een the dermal and e$idermal laminae in theri'ht foot, +hich in t#rn mi'ht lead to laminitis. 7nce the j#nction bet+een the dermal ande$idermal laminae is disr#$ted, the tiss#es be'in to $#ll a$art, li*e $#llin' the linin' o#t of a 'love.

%t;s been +ell doc#mented that horses ridden too lon' and too hard on roads are s#sce$tible to?road fo#nder.? This is different from stone br#isin', and it;s ca#sed by the mechanical tra#ma tothe laminaethe res#lt of re$eated $o#ndin' of the hoof on a hard s#rface.

Laminitis occ#rs in three sta'es. The first sta'e, called the $rodromal $hase, is the time bet+een+hen the horse eats the feed8'rass 9or becomes systemically ill and +hen he be'ins to sho+clinical si'ns of lameness. The #s#al time frame for this to ha$$en is a$$ro(imately


20/22

Treatment for laminitis varies de$endin' on the individ#al horse;s history, the e($erience of hisveterinarian, and the severity of the disease. %n e(treme cases, the horse ra$idly becomesseverely lame. At that $oint, a''ressive treatment sho#ld be initiated, +ith stall rest bein'mandatory. %n my o$inion, the shoes sho#ld be removed, if removal can be done +itho#t ca#sin'harm to the horse. Some additional s#$$ort m#st be $rovided to the bottom of the foot s#ch asfro' $ads 9lilly $ads or standin' the horse in dee$ beddin'. The reason yo# mi'ht harm thehorse by removin' a shoe is that if yo# $ic* #$ one foot for an e(tended $eriod of time, then theother foot +ill bear the e(tra +ei'ht and ca#se additional dama'e. Also, removin' the shoe andnails may ca#se more tra#ma to the foot that the shoe is removed from. %f yo# can;t 'et the nailso#t cleanly +hen yo# $#ll the shoe, then yo# end #$ ri$$in' the bottom of the foot, ca#sin' moretra#ma.

%n the ac#te $hase, many dr#'s are #sed to treat laminitis. %n chronic laminitis, fe+er dr#'s are#sed to treat the disease, b#t $henylb#ta5one still is administered to control $ain. The treatmentfor the deformation ca#sed by laminitis is thera$e#tic shoein'. The $ro'nosis in the ac#te $haseis hi'hly correlated to the de'ree of rotation. Phenylb#ta5one is the best anal'esic form#sc#los*eletal $ain and often is #sed in treatin' laminitis. %f laminitis is ca#sed by the horse;sbein' sytemically ill, 6anamine also +o#ld be #sed. 7f co#rse, the combination of these t+odr#'s +ill vary from case to case. There is a variety of medications aimed at the blood s#$$ly andthe inflammatory res$onse of the foot. Ace$roma5ine is a vasodilator that often is #sed on horsess#fferin' ac#te fo#nder.

Another vasodilator dr#' #sed in these cases is nitro'lycerin, +hich is a$$lied to$ically eitheraro#nd the coronary band or the $almaris arteries of the foot. e$arin, an anticoa'#lant,sometimes is #sed to im$rove the flo+ of blood thro#'h the small vessels in the foot. As$irin is#sed to $rohibit $latelet a''re'ation, +hich *ee$s arteries from clo''in'. Pento(y$hyline hasn#mero#s effects and is beneficial in treatin' endoto(emia. The dr#' also can hel$ cells 'etthro#'h dama'ed blood vessels. MS7, a free radical scaven'er, is yet another dr#' that is #sedto red#ce the inflammatory res$onse in the initial sta'es of laminitis.

Bo#r veterinarian +ill +atch the horse;s $ro'ress and recommend dr#'s accordin'ly.

%n 'eneral, in ac#te laminitis, as lameness +orsens and as radio'ra$hic evidence of rotation+orsens, the $ro'nosis for recovery diminishes. e$endin' on the severity of the laminitis, theo#tcome +ill ran'e from the horse;s recoverin' to a state +here it is rideable a'ain to e#thanasia.

9For more information on laminitis and the foot see The orse %nteractive for re$orts from the6l#e'rass Laminitis Sym$osi#m and the American Farriers Assocation ann#al meetin'.

Andrew H. Parks, VetMB, has an interest in lameness and is anassociate professor of Large Animal Medicine at the ni!ersity of "eorgia.

$osted: =8=81--1. Last #$dated: =8=81--1.


21/22

-rass Founder

by 'ichard Mansmann and Christine (in+

Preventin+ 7-rass Founder7

8Pasture.Associated Laminitis9

Laminitis, or fo#nder, is a $ainf#l and $otentially devastatin' foot condition that can affect anymember of the horse family 9horses, $onies, don*eys, and m#les. There are many differentconditions or sit#ations that can ca#se laminitis or increase the $otential for it to occ#r. Probablythe sin'le most im$ortant in 'ra5in' horses is #nrestricted access to l#sh $ast#re. %n a recentnation3+ide s#rvey, access to l#sh $ast#re +as felt to be res$onsible for almost 2- of all casesof laminitis. %n most $arts of the co#ntry, the ris* for $ast#re3associated laminitis, or ?'rassfo#nder,? is hi'hest in the s$rin' and early s#mmer, +hen $lant 'ro+th is 'reatest.

The reason l#sh $ast#re is s#ch a laminitis ris* is beca#se it is hi'h in sol#ble carbohydratessim$le s#'ars and starches that are readily bro*en do+n by the bacteria in the horse>s lar'eintestine. 7ne of the conse"#ences of ra$id brea*do+n of these carbohydrates is $rod#ction of as#bstance that, +hen absorbed into the bloodstream, can dama'e an im$ortant str#ct#re in thehoof: the basement membrane. This str#ct#re essentially forms the ?'l#e? that attaches the hoof

+all to the $edal bone, or coffin bone 9the bone at the base of the limb that is encased by thehoof. 6rea*do+n of the bond bet+een the hoof +all and the $edal bone is the basic $rocess thattri''ers the destr#ctive chain of events associated +ith laminitis.

7f the sol#ble carbohydrates fo#nd in 'rass, one of the most im$ortant is fr#ctan. St#dies havesho+n that fr#ctan levels in the $ast#re are hi'hest in the s$rin' and s#mmer months. 7n s#nnydays, fr#ctan levels 'rad#ally rise d#rin' the mornin', $ea*in' aro#nd noon. They then 'rad#allydecline and are lo+est j#st before da+n. So, the ris*iest time for a laminitis3$rone horse to be on$ast#re is bet+een late mornin' and late afternoon, in the s$rin' or early s#mmer.

%t is +orth mentionin' that s$rin'8early s#mmer is not the only time +hen 'rass fo#nder occ#rs.Altho#'h far less common, it can ha$$en d#rin' a mild, +et a#t#mn or after a dro#'ht@ in other+ords, any time rainfall, s#nli'ht, and daytime tem$erat#res are s#fficient to stim#late ra$id $lant'ro+th.

The 'ood ne+s is that $reventin' 'rass fo#nder is sim$le: limit the horse>s access to l#sh$ast#re. %n over+ei'ht or cresty3nec*ed horses and $onies, and in those that have had 'rassfo#nder before, it may be best to *ee$ the horse off l#sh $ast#re entirely #ntil the 'rass is moremat#re. The horse can then be 'rad#ally re3introd#ced onto $ast#re. %n the meantime, *ee$ thehorse in a dry lot and feed 'ood "#ality 'rass hay.


22/22

7ther o$tions for limitin' $ast#re inta*e incl#de restrictin' the horse>s $ast#re time to only a fe+ho#rs $er day 9if $ossible, avoidin' those hi'h3ris* ho#rs bet+een late mornin' and lateafternoon, #sin' a 'ra5in' m#55le, and fencin' off $art of the $ast#re to ma*e a small $addoc*.9A 'ra5in' m#55le is a stra$3on +ebbin' or leather m#55le that allo+s the horse to eat some'rass, b#t not a lot. The horse can drin* +ith the m#55le on +itho#t any diffic#lty.

%n s#mmary, $reventin' 'rass fo#nder is a sim$le matter of *ee$in' an eye on yo#r $ast#rethro#'ho#t the year and limitin' yo#r horse>s access or inta*e +hen the 'rass is l#sh.

This article +as ada$ted from Preventin' Laminitis in orsesa $ractical '#ide to decreasin' theris* of laminitis 9fo#nder in yo#r horse by rs. 4ichard Mansmann and Christine Din'. To learnmore abo#t this boo*let, 'o to+++.$a$er3horse.com.

title Preventin' )rass Fo#nder 9Past#re3Associated Laminitis1 a#thor 4ichard Mansmann and Christine Din'H 6io M, 6Sc, MACSc 9e" med, MetClinSt#d

Founder Articles

Documents

Transcript of Founder Articles