1. Colin Mitchell BVM&S CertEP MRCVS Scott Mitchell Associates
Laminitis
Colin Mitchell BVM&S CertEP MRCVS
Scott Mitchell Associates

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

3. What is laminitis ? “itis” = “inflammation”
“laminae” = “a thin flat membrane”
So… “inflammation of a membrane in the horses foot”
Debilitating, sometimes devastating disease.

4. Where are the laminae?
The structures that connect the hoof wall to the pedal bone

5. Structure of the foot……..

6. Structure of the foot……..

7. Structure of the foot……
The pedal bone is housed within the hoof capsule
It’s the laminae which hold the two together

8. The laminae
Arranged in vertical rows from the coronary band running down to the ground

9. The laminae Insensitive layer on inside of hoof wall
Sensitive layer next to pedal bone

10. laminitis It’s a very sensitive and well organised network
Hoof laminae
Pedal bone laminae

11. laminitis When there is inflammation of the laminae, they swell
Then they weaken.
Hoof laminae
Pedal bone laminae

13. In mild cases this may not occur
In severe cases the pedal bone will be pushed out of alignment and possibly through the bottom of the foot

14. What causes laminitis? 1. Too much…. 2. The sick horse 3. Other causes
A. grass
B. grain
C. Weight (obesity)
2. The sick horse
Severe infections
Post foaling problems
Cushing’s disease
3. Other causes
Concussion
Excessive weight bearing foot
Stress / Drugs / Cold weather
Most causes are nutrition related

15. The Digestive System Sugars and starch are broken down in the
large intestines by good bacteria

16. A. Too much…. GRASS
Take a field

17. A. Too much…. GRASS
add the sun

18. A. Too much…. GRASS
Plenty rain

19. A. Too much…. GRASS
And….
Fresh new grass, full of sugars

20. A. Too much…. GRASS
Add a horse

21. A. Too much…. GRASS A 500kg horse can And Eat 65kg grass a day
That’s 3kg sugar!
And

22. A. Too much…. GRASS
Grass growing quickly has large amount of fructans in.
- produced by photosynthesis. But horses can’t break it down

23. cereals are high in starch…..
B. Too much ……GRAIN
Any overfeeding can cause laminitis :-
Daily overfeeding by owner
Raiding the feed bin
cereals are high in starch…..
Current thinking that XS protein does not cause laminitis

24. Fructans and (excess) starch
Not broken down by bacteria in the horse’s caecum
Rapidly fermented in the horse’s gut causing an acid environment.
This kills the good bacteria
ACID

25. Fructans and (excess) starch
endotoxins.
constrict
Aaargh!!
ACID

26. Loss of blood supply to the feet
Cells die
Signs of disease, heat, pain etc

27. C. Too much weight (obesity)
Metabolic
Intestinal environment

28. C. Too much weight (obesity)
A horse in good condition
Rounded rump
Ribs felt easily but not seen
Fit not fat
Lean not thin

29. 2. The sick horse
Any disease that causes horses to be sick can cause laminitis
Release of toxins into the blood stream
We look for the underlying cause
river

30. 2. The sick horse Post-foaling, mares with retained afterbirths
Endotoxins

31. 3. Other causes
Concussion

32. 4. Other causes
Excessive weight bearing

33. Equine Cushing’s Syndrome
Common problem in older horses and ponies (average 19yo)
Hormonal abnormality which leads to many and varied clinical signs
Laminitis
Long curly coat
Weight loss/redistribution
Lethargy
Drinking/urinating too much
Bulging fat pads above the eyes
Susceptible to infections
Requires life long management (expensive)

34. Causes of Cushing’s disease
Growth of pituitary gland in the brain
Lack of ‘Dopamine inhibition’ from the hypothalamus
Leads to excess of ACTH
Production of excess cortisol by the adrenal glands on the kidneys
Circulates around the body causing trouble!

35. Equine Metabolic Syndrome
Poorly understood condition
Cortisol is produced by fat cells in the abdomen
Related to body’s inability to use its own insulin, and regulate glucose levels
“insulin resistance” – like obese people
Young, fit or overweight horses
Severe laminitis, unresponsive to therapy

36. (3) Signs of laminitis Try and pick up cases as early as possible
History
Stance of the horse
Heat in the feet?
Increased/bounding digital pulses
Evidence of ‘founder’

37. Clinical Picture

38. Clinical Picture ‘Obel grading’
0 – no lameness at trot on hard surface
1 – Stilted in trot on hard surface and on turn
2 – Stiff at walk and doesn’t like turning
3 – Reluctant to walk on hard surface and difficult to lift leg
4 – May lie down, coercion to move especially on hard surfaces

39. Digital Pulses Can be felt at the fetlock
or 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!

40. Evidence of ‘founder’

41. Radiography – X-rays
Used to monitor the progress of the condition – may need to take several sets over time

42. Radiography
Normal
Dorsal hoof wall and pedal bone parallel and no evidence of ‘founder’
Normal degree angulation of the bottom of the pedal bone with the sole of the foot
Horse still shod

43. Radiography Mild 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

44. Radiography Moderate changes
Wide gap developing between the hoof wall and pedal bone
Evidence of ‘founder’ or
sinking of the pedal bone
Further increase in the angle of the pedal bone to the sole

45. Radiography Moderate/severe changes
Again we see rotation and founder with the tip of the pedal bone now very close to the sole of the foot

46. SEVERE CASE
Pedal bone rotated and dropped to the point of emerging through the bottom of the sole of the foot

47. First aid Treatment Remove initiating factor Box rest
Deep bed or sole support
Feeding – good quality forage. Don’t starve

48. Sole support

49. Styrofoam pads
Styrofoam pads – similar action to sole support system whereby foam moulds to the feet to supply good support

50. Veterinary / farrier treatment
Pain relief
Improve circulation
Sole support
Foot trimming/Dorsal wall resection
Abscess treatment

51. Pain Relief

52. Improving Circulation
Vasodilators – drugs which have a direct action to open up blood vessels supplying the laminae
Acepromazine – ACP
Isoxuprine
Glyceryl trinitrate
Anticoagulants – drugs which prevent small blood clots forming in the circulation
Aspirin
Heparin

53. Foot trimming
Attempt to re-establish the normal position of the pedal bone within the foot

54. Dorsal wall resection
Salvage procedure used when more conservative methods have failed
Removal of the front (or dorsal) wall of the hoof completely
This eliminates the forces acting to pull apart the laminae from the pedal bone at the front of the foot

55. 1. Avoid obesity Avoid your horse getting too fat
Should not have fat deposits around the crest, tail head, sheath, udder
You should be able to feel ribs
Trevor. Lost 50kg

56. Feed according to work done
If horses are fed calories in excess to their daily requirements they will put on weight
exercise
calories

57. Use a weight tape Maintain your horse at a sensible weight
Weigh out the hay and hard feed

58. 2. Avoid over eating Foods rich in sugars or starches
Cereals, cereal based feeds, coarse mix, rapidly growing grasses
If you do use them, feed little and often

59. Restrict access to grazing
For susceptible horses, not every horse
Esp. spring & autumn
Remove droppings frequently to avoid worms
Limit time out
Grazing muzzles

60. Feeding for extra work When you do need more energy dense feeds
Use high fibre, low starch feeds
Consider using soya or corn oils – slow release energy
Oil is safer as it contains no sugars or starch. Rupert

61. 4. Probiotics
Friendly bacteria
Improves fibre digestion

62. Founderguard Virginiamycin In feed antibiotic
Reduces acid build up during fermentation of starch and sugar

63. Methionine/Biotin supplementation
Promotes good horn growth by supplying the building blocks which may be lacking
Long term improvement – takes 9 months for new horn to grow out
Improved quality and strength of hoof should help chronic laminitic horses
Different preparations available but all similar and perform the same task

64. 5. Avoid the other causes Excessive concussion on roads
Feet regularly trimmed and balanced
Treat other diseases
Illnesses that cause toxaemias
Cause of weight bearing laminitis
Cushing’s disease