Conformation

Conformation of what? The whole horse The axial portion of the horse, head, neck, spine The thoracic limbs, fore legs The pelvic limbs,hind end The individual parts of each of the limbs While every farrier should have a good understanding of overall conformation, we should be most expert on those areas we have the most impact on.

Side view of fore legs Upright Ideal Long Pastern Calf Knee Broken forward Bench Knee Upright

Side view of fore legs 1 2 3 4 5 6

Fore limbs Front View Ideal Turned out Turned In Base narrow turned out Base narrow turned in Knock Kneed Bow legged Turned out

A B C D E F G

Side view of hind limbs Ideal Sickle Hock Lack of angle to hock Camped under

Side view of hind limbs 1 2 3 4

Hind Limbs Rear View Ideal Base wide Base narrow Turned in Cow hocked

Hind Limb Rear View 1 5 4 3 2

Conformation Considerations How does the horse stand? Is the hoof loaded through the center of mass? How does the horse move? Does the load enter the hoof as close to center line as possible? Does the body move over the loaded limb and hoof on the midline of the limb and hoof? Does the leg rotate under moving load? Is the last point of contact with the ground on the midline of the hoof?

How does the Horse Stand A horse spends more time standing still than working. Should we shoe for this period or for the short period of time they work? Generally on the fore limbs the horse carries more load on the medial side of the hoof than the lateral. The majority have a slightly toed out stance. Generally on the hind limbs the load is carried more on the lateral side of the hoof partly due to a slight base narrow shape, though the limb will also have a toe out stance.

Is the Hoof loaded through the Center of Mass How the load is distributed to the hoof will depend on the alignment of the bones of the limb above When evaluating the load consider P.3 being able to pivot on three axis Pivot side to side, Medial/lateral balance Pivot front to back, Dorsal/palmar balance Pivot from attachment to body to ground, Proximal/distal balance

Three Axis of P.3.

How does the Horse move How the bones of the limb align will determine how the load will be transmitted through the limb to the ground Once muscles are activated to produce movement alignment of the joint faces will determine the direction of flight of the limb Movement begins from the center of mass and migrates outwards. Therefore misalignment of the Carpal joint will influence the direction of the lower limb Misalignment of the Metacarpo-phalangeal (Fetlock) will influence the direction of the digit

Does the load enter the midline of the hoof If the load does not enter the midline of the hoof, first contact with the ground will be to one side, more often lateral (Landing side) The last side of the hoof to contact will carry more of the load, more often medial (Loading side) The limb will be more to the medial when viewed from dorsal/palmar in the above case

Example of landing lateral This horse has a toe out conformation. Winging in, landing lateral, loading medial. The leg appears straight with a rotation high up

Toe Out Stance This horse has straight legs with a pronounced turned out rotation. At a low speed this horse will wing in and land lateral. At higher speed the rotation may be reduced due to activation of the muscles of the chest.

Does the load move over the midline of the leg and hoof Both the fore and hind limbs move towards the mid line of the body of the horse during movement. The higher the speed the more pronounced this is. However if there is a pronounced deviation at the distal end of the limb, load will not be aligned centrally over the hoof. Most common example would be Metacarpo-phalangeal (Fetlock) misalignment.

Severe Limb Deviation This horse has more than one deviation. The most serious is the inward rotation at the Metacarpo-phalange (Fetlock). The long bones and load align over the lateral. The hoof distorts medial.

Last point of contact with the ground Toe wear of the shoe or hoof is a good indicator of conformation deviations. Equal wear medial/lateral indicates best loading of hoof possible for that individual. Severe toe wear, fore or hind, often indicates disease of the hind limb.

Hoof Plasticity The hoof is a plastic wrapper enclosing the distal bones of the limb Hoof orientation is predicated primarily by the orientation of P.3. Orientation of P.3. is determined by tension of the Extensor branches of the Suspensory Ligament and Extensor Tendon, the Deep Digital Flexor Tendon, and other small ligaments When orientation of P.3. causes unequal load on the hoof distortion will occur

Hoof Distortion

Hoof Conformation Each of the parts can be considered individually Hoof wall, thickness, angle, shape White Line, thickness, colour Sole, concavity, thickness Frog, size, proportion width/length, texture Bars, size, length

Hock Rotation It is not unusual to have a slight rotation of the hock as the horse pushes off the hind leg. If the limb has a toe in stance the hock rotation will be pronounced. A slight toe out stance will more often give the ideal conformation when moving. Either too close or too wide behind will cause disease if the horse is worked hard.

Example of Hind Limb