LaminitisLaminitisColin Mitchell BVM&S Colin Mitchell BVM&S

CertEP MRCVSCertEP MRCVS

Scott Mitchell AssociatesScott Mitchell Associates

ContentContent

1. What is laminitis?1. What is laminitis? 2. What causes laminitis?2. What causes laminitis? 3. Signs of laminitis.3. Signs of laminitis. 4. Treatment of laminitis.4. Treatment of laminitis. 5. Management and prevention 5. Management and prevention

strategies.strategies.

What is laminitis ?What is laminitis ? ““itis” = itis” =

“inflammation”“inflammation” ““laminae” = “a thin laminae” = “a thin

flat membrane”flat membrane” So… “inflammation of So… “inflammation of

a membrane in the a membrane in the horses foot”horses foot”

Debilitating, Debilitating, sometimes sometimes devastating disease.devastating disease.

Where are the laminae?Where are the laminae?

The structures that The structures that connect the hoof connect the hoof wall to the pedal wall to the pedal bonebone

Structure of the foot……..Structure of the foot……..

Structure of the foot……..Structure of the foot……..

Structure of the foot……Structure of the foot……

The pedal bone is The pedal bone is housed within the housed within the hoof capsulehoof capsule

It’s the It’s the laminaelaminae which hold the two which hold the two togethertogether

The laminaeThe laminae

Arranged in Arranged in vertical rows from vertical rows from the coronary band the coronary band running down to running down to the groundthe ground

The laminaeThe laminae

Insensitive layer on inside of hoof Insensitive layer on inside of hoof wallwall

Sensitive layer next to pedal boneSensitive layer next to pedal bone

laminitislaminitis

It’s a very sensitive It’s a very sensitive and well organised and well organised networknetwork

Hoof laminaePedal bone laminae

laminitis

Hoof laminae

Pedal bone laminae

When there is inflammation of the laminae, they swell

Then they weaken.

inflammation

In mild cases this In mild cases this may not occurmay not occur

In severe cases the In severe cases the pedal bone will be pedal bone will be pushed out of pushed out of alignment and alignment and possibly through possibly through the bottom of the the bottom of the footfoot

What causes laminitis?What causes laminitis? 1. Too much….1. Too much….

A. grassA. grass B. grainB. grain C. Weight (obesity)C. Weight (obesity)

2. The sick horse2. The sick horse Severe infectionsSevere infections Post foaling problemsPost foaling problems Cushing’s diseaseCushing’s disease

3. Other causes3. Other causes ConcussionConcussion Excessive weight bearing footExcessive weight bearing foot Stress / Drugs / Cold weatherStress / Drugs / Cold weather

The Digestive SystemThe Digestive System

Sugars and starch are broken down in thelarge intestines by good bacteria

A. Too much…. GRASSA. Too much…. GRASS

Take a field

A. Too much…. GRASS

add the sun

A. Too much…. GRASS

Plenty rain

A. Too much…. GRASS

And….

Fresh new grass, full of sugars

A. Too much…. GRASS

Add a horse

A. Too much…. GRASS

And A 500kg horse canEat 65kg grass a dayThat’s 3kg sugar!

A. Too much…. GRASS

Grass growing quickly has large amount of fructans in.- produced by photosynthesis. But horses can’t break it down

B. Too much ……GRAINB. Too much ……GRAIN

Any overfeeding can cause laminitis :-Any overfeeding can cause laminitis :-

1.1. Daily overfeeding by ownerDaily overfeeding by owner

2.2. Raiding the feed binRaiding the feed bin

cereals are high in starchcereals are high in starch…..…..

Fructans and (excess) Fructans and (excess) starchstarch

Not broken down Not broken down by bacteria in the by bacteria in the horse’s caecum horse’s caecum

Rapidly fermented Rapidly fermented in the horse’s gut in the horse’s gut causing an acid causing an acid environment.environment.

This kills the This kills the good good bacteriabacteria

ACID

Fructans and (excess) Fructans and (excess) starchstarch

endotoxins.endotoxins.

constrictconstrict

ACID

Aaargh!!

Loss of blood supply to Loss of blood supply to the feetthe feet

Cells die Cells die Signs of disease, heat, Signs of disease, heat,

pain etcpain etc

C. Too much weight C. Too much weight (obesity)(obesity)

MetabolicMetabolic Intestinal Intestinal

environmentenvironment

C. Too much weight C. Too much weight (obesity)(obesity)

A horse in good A horse in good conditioncondition

Rounded rumpRounded rump Ribs felt easily but Ribs felt easily but

not seennot seen Fit not fatFit not fat Lean not thinLean not thin

2. The sick horse2. The sick horse

Any disease that Any disease that causes horses to causes horses to be sick can cause be sick can cause laminitislaminitis

Release of toxins Release of toxins into the blood into the blood streamstream

We look for the We look for the underlying causeunderlying cause

2. The sick horse2. The sick horse

Post-foaling, mares Post-foaling, mares with retained with retained afterbirthsafterbirths

EndotoxinsEndotoxins

3. Other causes 3. Other causes

ConcussionConcussion

4. Other causes4. Other causes

Excessive weight Excessive weight bearingbearing

Equine Cushing’s Equine Cushing’s SyndromeSyndrome

Common problem in older horses and Common problem in older horses and ponies (average 19yo)ponies (average 19yo)

Hormonal abnormality which leads to many Hormonal abnormality which leads to many and varied clinical signsand varied clinical signs LaminitisLaminitis Long curly coatLong curly coat Weight loss/redistributionWeight loss/redistribution LethargyLethargy Drinking/urinating too muchDrinking/urinating too much Bulging fat pads above the eyesBulging fat pads above the eyes Susceptible to infectionsSusceptible to infections

Requires life long management (expensive)Requires life long management (expensive)

Causes of Cushing’s Causes of Cushing’s diseasedisease

Growth of Growth of pituitary glandpituitary gland in the in the brainbrain

Lack of ‘Dopamine inhibition’ from the hypothalamusLack of ‘Dopamine inhibition’ from the hypothalamus Leads to excess of ACTHLeads to excess of ACTH

Production of excess Production of excess cortisolcortisol by the by the adrenal glands on the kidneysadrenal glands on the kidneys

Circulates around the body causing Circulates around the body causing trouble!trouble!

Equine Metabolic Equine Metabolic SyndromeSyndrome

Poorly understood conditionPoorly understood condition Cortisol is produced by fat cells in the Cortisol is produced by fat cells in the

abdomenabdomen Related to body’s inability to use its Related to body’s inability to use its

own insulin, and regulate glucose levelsown insulin, and regulate glucose levels ““insulin resistance” – like obese peopleinsulin resistance” – like obese people Young, fit or overweight horsesYoung, fit or overweight horses Severe laminitis, unresponsive to Severe laminitis, unresponsive to

therapytherapy

(3) Signs of laminitis(3) Signs of laminitis

Try and pick up cases as early as possibleTry and pick up cases as early as possible HistoryHistory Stance of the horseStance of the horse Heat in the feet?Heat in the feet? Increased/bounding digital pulsesIncreased/bounding digital pulses Evidence of ‘founder’Evidence of ‘founder’

Clinical PictureClinical Picture

Clinical PictureClinical Picture

‘‘Obel grading’Obel grading’0 – no lameness at trot on hard surface0 – no lameness at trot on hard surface

1 – Stilted in trot on hard surface and on 1 – Stilted in trot on hard surface and on turnturn

2 – Stiff at walk and doesn’t like turning2 – Stiff at walk and doesn’t like turning

3 – Reluctant to walk on hard surface and 3 – Reluctant to walk on hard surface and difficult to lift legdifficult to lift leg

4 – May lie down, coercion to move 4 – May lie down, coercion to move especially on hard surfacesespecially on hard surfaces

Digital PulsesDigital PulsesCan be felt at the fetlockCan be felt at the fetlock or at the back of the pasternor at the back of the pastern

It is personal preference which site is used but remember that the horses pulse is slow and you may not feel every pulse initially so keep feeling for a while!

Evidence of ‘founder’Evidence of ‘founder’

Radiography – X-raysRadiography – X-rays

Used to monitor Used to monitor the progress of the the progress of the condition – may condition – may need to take need to take several sets over several sets over timetime

RadiographyRadiography

Dorsal hoof wall and pedal bone parallel and no evidence of ‘founder’

Horse still shod

Normal 10-15 degree angulation of the bottom of the pedal bone with the sole of the foot

Normal

RadiographyRadiographyMild changes

Small divergence between dorsal hoof wall and pedal bone

Increased angle of the bottom of the pedal bone to the sole of the foot

RadiographyRadiographyModerate Moderate

changeschangesWide gap developing between the hoof wall and pedal bone

Evidence of ‘founder’ orsinking of the pedal bone

Further increase in the angle of the pedal bone to the sole

RadiographyRadiographyModerate/severe changes

Again we see rotation and founder with the tip of the pedal bone now very close to the sole of the foot

Pedal bone rotated and dropped to the point of emerging through the bottom of the sole of the foot

SEVERE CASE

First aid TreatmentFirst aid Treatment

Remove initiating Remove initiating factorfactor

Box restBox rest Deep bed or sole Deep bed or sole

supportsupport Feeding – good Feeding – good

quality forage. quality forage. Don’t starveDon’t starve

Sole supportSole support

Styrofoam padsStyrofoam pads Styrofoam pads – similar Styrofoam pads – similar

action to sole support action to sole support system whereby foam system whereby foam moulds to the feet to moulds to the feet to supply good supportsupply good support

Veterinary / farrier Veterinary / farrier treatmenttreatment

Pain reliefPain relief Improve Improve

circulationcirculation Sole supportSole support Foot Foot

trimming/Dorsal trimming/Dorsal wall resectionwall resection

Abscess Abscess treatmenttreatment

Pain ReliefPain Relief

Improving CirculationImproving Circulation

VasodilatorsVasodilators – drugs – drugs which have a direct action which have a direct action to open up blood vessels to open up blood vessels supplying the laminaesupplying the laminae Acepromazine – ACPAcepromazine – ACP IsoxuprineIsoxuprine Glyceryl trinitrateGlyceryl trinitrate

AnticoagulantsAnticoagulants – drugs – drugs which prevent small blood which prevent small blood clots forming in the clots forming in the circulationcirculation AspirinAspirin HeparinHeparin

Foot trimmingFoot trimming

Attempt to re-establish Attempt to re-establish the normal position of the normal position of the pedal bone within the pedal bone within the footthe foot

Dorsal wall resectionDorsal wall resection Salvage procedure Salvage procedure

used when more used when more conservative methods conservative methods have failedhave failed

Removal of the front Removal of the front (or dorsal) wall of the (or dorsal) wall of the hoof completelyhoof completely

This eliminates the This eliminates the forces acting to pull forces acting to pull apart the laminae apart the laminae from the pedal bone from the pedal bone at the front of the footat the front of the foot

1. Avoid obesity1. Avoid obesity

Avoid your horse Avoid your horse getting too fatgetting too fat

Should not have fat Should not have fat deposits around deposits around the crest, tail the crest, tail head, sheath, head, sheath, udderudder

You should be able You should be able to feel ribsto feel ribs

Feed according to work done

If horses are fed calories in excess to their daily requirements they will put on weight

calories

exercise

Use a weight tapeUse a weight tape

Maintain your Maintain your horse at a sensible horse at a sensible weightweight

Weigh out the hay Weigh out the hay and hard feedand hard feed

2. Avoid over eating2. Avoid over eating

Foods rich in Foods rich in sugars or starchessugars or starches

Cereals, cereal Cereals, cereal based feeds, based feeds, coarse mix, coarse mix, rapidly growing rapidly growing grasses grasses

If you do use If you do use them, feed little them, feed little and oftenand often

For susceptible horses, not every horse

Esp. spring & autumn

Remove droppings frequently to avoid worms

Limit time out

Grazing muzzles

Restrict access to grazing

Feeding for extra workFeeding for extra work

When you do need When you do need more energy dense more energy dense feedsfeeds

Use high fibre, low Use high fibre, low starch feedsstarch feeds

Consider using Consider using soya or corn oils – soya or corn oils – slow release slow release energyenergy

4. Probiotics4. Probiotics

Friendly bacteriaFriendly bacteria Improves fibre Improves fibre

digestiondigestion

FounderguardFounderguard

VirginiamycinVirginiamycin In feed antibioticIn feed antibiotic Reduces acid build Reduces acid build

up during up during fermentation of fermentation of starch and sugarstarch and sugar

Methionine/Biotin Methionine/Biotin supplementationsupplementation Promotes good horn growth Promotes good horn growth

by supplying the building by supplying the building blocks which may be blocks which may be lackinglacking

Long term improvement – Long term improvement – takes 9 months for new takes 9 months for new horn to grow outhorn to grow out

Improved quality and Improved quality and strength of hoof should help strength of hoof should help chronic laminitic horseschronic laminitic horses

Different preparations Different preparations available but all similar and available but all similar and perform the same taskperform the same task

5. Avoid the other 5. Avoid the other causescauses

Excessive concussion on roadsExcessive concussion on roads Feet regularly trimmed and balancedFeet regularly trimmed and balanced

Treat other diseasesTreat other diseases Illnesses that cause toxaemiasIllnesses that cause toxaemias Cause of weight bearing laminitisCause of weight bearing laminitis Cushing’s diseaseCushing’s disease