Term
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Definition
| Inflammation of the laminae. |
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Term
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Definition
| Founder occurs when the bond between the hoof wall and the coffin bone fails, allowing the pull of the DDFT to rotate the coffin bone away from the hoof wall. |
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Term
| What is the only way to know that founder has occurred? |
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Definition
| Radiographic evidence of the rotation of the coffin bone is required. |
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Term
Can a horse have laminitis without foundering?
Can a horse founder without having laminitis? |
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Definition
- Yes, the laminae can be inflamed without founder occurring.
- No, laminitis will always precede founder |
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Term
| When a founder occurs, what else is affected besides the rotation of P3? |
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Definition
| Important veins and arteries are crushed between P3 and the sole of the hoof, especially the circumflex artery. |
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Term
| Does founder only affect the feet of the horse? |
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Definition
| No. Founder is a systemic disease that will affect most of the horses internal organs as well. |
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Term
| Does founder only affect the front feet? |
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Definition
- No. All 4 feet are affected. However, since 60% of the horses weight is on the front feet, these are generally more severely affected. |
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Term
| What is the primary reason that P3 rotates with a founder? |
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Definition
| The unresisted pull of the DDFT on P3. |
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Term
What are 5 major causes of founder?
Are these the only causes? |
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Definition
- Grain Founder
- Water Founder
- Road Founder
- Foal Founder
- Grass Founder
- No, numerous other things can cause founder. Trauma, hormones, black walnut shavings, and many other things. |
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Term
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Definition
| Founder caused by excessive grain consumption. The horse cannot digest the grain quickly enough. Undigested grain gets into the hindgut and ferments, which can cause founder. |
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Term
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Definition
| If an overheated horse ingests large amounts of water, it can founder. |
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Term
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Definition
Founder caused by foot concussion from working on a hard surface. |
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Term
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Definition
Founder that occurs to a mare after giving birth and retaining placenta. |
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Term
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Definition
- Founder caused by a horse eating too much lush pasture. - High fructan levels develop in grasses under certain growing conditions.
- This affects fat horses that may be insulin resistant more than fit horses. |
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Term
| What are the primary theories for the causes of founder? (5) |
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Definition
- Enzyme theory
- Inflammation theory
- Vascular theory
- Metabolic theory
- Traumatic theory
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Term
| What is the enzyme theory for founder? |
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Definition
| Some triggering mechanism, probably pharmacological to the hoof, activates the MMPs, which breaks down the attachment between the basement membrane and the basal cells, which allows founder. |
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Term
What is the inflammation theory?
(Founder) |
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Definition
Inflammatory mediators produce inflammation, and MMP production occurs later. A possible 2 step process.
Inflammation- MMP production - Founder |
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Term
What is the vascular theory?
(Founder) |
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Definition
- Issues with blood flow to the foot decreases oxygen delivery to the laminae.
- The laminae experience cellular death and breakdown.
- This results in vascular permeability and edema within the hoof. |
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Term
What is the metabolic theory?
(Founder) |
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Definition
| An insulin based reaction affects multiple bodily processes, leading to founder. |
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Term
What is the traumatic theory?
(Founder) |
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Definition
- Concussion to the hoof directly damages laminae.
- This, coupled with increased weight bearing decreases blood supply to the foot. |
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Term
What are basal cells?
(Founder) |
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Definition
| The last layer of the sensitive laminae. These attach to the insensitive basement membrane, which is the beginning of the insensitive hoof wall/stratum medium layer. |
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Term
| What is the basement membrane? |
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Definition
A tough, fibrous membrane that covers the primary and secondary epidermal layers from coronary band to the sole.
It separates the sensitive structures from the insensitive structures. |
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Term
| How much hoof growth occurs each month? |
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Definition
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Term
| What basically happens in founder? |
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Definition
Some 'trigger' activates MMP's, which dissolve the bond between PEL's and SEL's
The DDFT pulls on P3, and since P3 is no longer attached to the hoof wall, it rotates downwards and backwards into the hoof capsule. |
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Term
What are PEL's?
How many are in the average hoof? |
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Definition
Primary Epidermal Layers.
The average hoof has 550 to 600 epidermal leaves. |
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Term
What are SEL's?
How many are in the average hoof? |
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Definition
Secondary Epidermal layers.
Each PEL has 150-200 SEL laminae along its length. |
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Term
| What is acute laminitis/founder. |
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Definition
- A rapid onset occurrence, usually in the front feet.
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Term
| What are signs of acute founder? |
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Definition
- Strong digital pulse
- Grade 4/5 lame
- If forced to walk, will try to bear weight on hind legs
- Will load heels of the front feet, standing as though "Camped in Front"
- Hoof testers will indicate tenderness over the sole in front of the frog. |
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Term
| What is chronic laminitis/founder? |
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Definition
| A long term condition that will result in varying degrees of lameness, depending upon the degree of P3 rotation and the amount of damage to the foot. |
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Term
| What are signs of chronic laminitis? (4) |
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Definition
- Horse may be Grade 2 lame
- Flat sole, possible bulging sole due to P3 pressure
- Little or no toe growth
- Rings that separate at the heel and converge at the toe. |
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Term
| How should all founder cases be treated? |
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Definition
| A veterinarian should be consulted. |
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Term
| How is acute founder treated? |
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Definition
- Relieve pain with a soft heart bar shoe.
- Advise the owner to contact the vet. |
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Term
| How is chronic founder treated? (5) |
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Definition
- Leave the sole alone unless you have radiographs.
- Remove the dorsal surface to relieve DDFT pull on P3 and to ease in breakover
- Use the paper test to remove as much heel as possible
- Try to put the horse on a 6 week schedule.
- A heart bar shoe may be used. |
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Term
| What are some issues that can occur when open toe egg bar shoes are used for chronic founder? |
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Definition
- The toe is not supported
- Prolapsed soles can be an issue. |
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Term
| What is the popular definition of the cause of navicular syndrome? |
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Definition
- Many vets and laypeople consider any type of heel pain as navicuar. |
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Term
| What is the podotrochlear apparatus? (PTA) |
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Definition
- The PTA includes the following:
- Navicular bone
- Impar ligament
- Collateral sesmoidean ligaments (suspensory ligaments of the navicular bone)
- the navicular bursa
- the DDFT
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Term
| What is the most accurate definition of navicular syndrome? |
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Definition
Rooney's definition: Pathological changes of the navicular bursa, DDFT, and the ligaments and cartilages of the navicular bone. |
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Term
| What breeds most commonly experience navicular? (4) |
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Definition
- Thoroughbreds
- Quarter Horses
- Warmbloods
- Standardbreds |
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Term
| Which breeds rarely have navicular syndrome? (3) |
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Definition
| Ponies, Friesians and Arabians. |
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Term
| What age range is most often affected by navicular syndrome? |
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Definition
| Horses that are 7 to 14 years old. |
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Term
| What aspects of foot conformation can affect navicuar disease? (5) |
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Definition
- Small feet on a large horse, basic area loading
- Short straight pasterns - high concussion forces
- Long toes increases stress on the navicular bone via the DDFT.
- Dorso-Palmar Imbalance - underrun heels/broken back HPA
- Mediolateral imbalance |
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Term
| What are 5 assumed causes of navicular pain? |
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Definition
- Disruption of blood supply to the navicular bone
- A degenerative disease similar to athritis which affects the articular cartilage of the navicular bone.
- Navicular bursitis
- Damage to one or more of the navicular bone ligaments
- Adhesions from the DDFT to the navicular bone. |
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Term
| What is the most likely basis for navicular syndrome? |
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Definition
| Abnormal biomechanical stresses that are placed upon the PTA. |
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Term
| How does navicular syndrome manifest itself? (6) |
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Definition
- There is usually a chronic, progressive lameness which improves with rest but returns when exercise resumes.
- The horse may stumble
- Shuffling forelimb gait
- Shortened cranial stride phase
- Toe first landing
- May stand "Camped in front" with bilateral navicular
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Term
| What is the primary treatment consideration for the farrier when working with navicular syndrome? |
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Definition
| A veterinarian should be consulted. |
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Term
| Is a horse with PTA injury more likely to be lame in one foot or both? |
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Definition
| PTA injury is usually found in only one foot. |
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Term
| When is a horse with DDFT damage most likely to exhibit pain? |
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Definition
| When performing a tight circle |
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Term
| Horses with lameness caused by things other than navicular will be less likely to show lameness during what type of maneuver? |
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Definition
| They are less likely to show lameness when trotting in a straight line. |
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Term
| What are some conditions that may mimic navicular syndrome. (9) |
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Definition
- Chronic sole bruising (out of balance feet)
- Club feet or tendonitis
- P3 fractures, pedal osteitis
- Quarter and heel wall separation/tearing
- bar cracks
- Corns
- sheared heels
- collapsed/underrun heels
- foot out of C/P or L/M balance
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