Conformation Flashcards
what is conformation?
overall body shape or form
what does form and function determine in a horse? (2) what does it affect? (2)
determines:
how the horse moves; how it withstands impact-related stress
affects: beaty and presence, health and soundness
what are 3 general aspects of a horse with good conformation?
- nice to look at
- comfortable to ride
- easier to train and perform
what is mainly evaluated when determining conformation? why? (2)
the skeleton;
1. it is the scaffolding for muscle and fat
2. it is the basis for good or poor conformation
what determines the skeletal conformation of a horse? (2)
- genetics
- environment (nutrition, exercise, health)
what do different breeds share despite their overall different dimensions?
common conformational traits
what is similar in great performance horses regardless of breed? give an example
musculoskeletal systems; example being that good quality muscling is wanted in both QH and arabians, but that good quality will look different
what does balance mean in conformation?
each part is proportional to all other parts
how many roughly equal sections with a horse with good conformation have their body divided into? what are these sections?
roughly equal and balanced thirds
1. point of shoulder to the withers
2. the withers to the point of the hip
3. the point of the hip to the point of the buttock
should you always look for balanced and equal thirds in young horses? if not what end usually grows first?
no; they are not always in balance; back end usually grows first
what is meant by the trapezoid you look at when evaluating a horse’s conformation?
includes the slope of the shoulders and hip to the length of the back (which we want to be short) to the underline (we want to be long)
what is yielded by a long underline?
longer, ground-covering stride
what does a short back do?
yields hind end power to the front, allowing both front and back to move in unison
what are the 5 criteria used when selecting a horse?
- structural correctness (of skeleton)
- balance (equal thirds)
- muscling (based on purpose)
- type (must look lile breed)
- size (fit for potential buyer/rider)
what is meant by structural correctness of horses?
bone structure of the horse
what is the usualy site of lameness in the skeleton that carries 65% of the horses weight?
the forelimbs
what is referred to by “type”? give an example
characteristics that separate one breed from another; how arabians have a dished profile
what is meant by the more “typy” a horse is?
the more it resembles the ideal of the breed
in what two ways does muscling vary? give an example
by mass and volume, or how much and what type of muscles; for example QH have a lot of fast twitch muscles but arabians have a lot of slow twitch
when looking at a horse from the rear, what should be the widest part due to muscling?
stifle to stifle (knee to knee)
what three things are ideal in terms of muscling?
- tie in low and clean to hocks and knees (no muscle below hock and knees, just ligaments)
- smooth appearance
- athletic tone or “fit” looking
what are 3 common comformational characteristics?
- prominent withers (composed of the dorsal spinous processes of T3 and T4)
- long sloping shoulder which forms a 45 degree angle between the scapula and the ground
- width of chest, depth of girth, and spring of ribs (to indicate heart and lung capacity)
what is yielded by the angle of the scapula to the ground?
a longer stride
in terms of topline and underline of horse, what do we want and why?
short back, long underline; to couple back end to front end and yield strength
what is the hip or croup on a horse?
the point of the hip to the point of the buttock
what does the length of the hip allow for the horse (2)
- allows hindlegs to reach under horses body
- generate force
when evaluating straightness and soundness of the fore and hind limbs, what is looked for? (2)
- clean and straight
- lower slope angle
what doe the fore and hindlimbs do for the horse?
absorb concussion
describe the ideal knee (2)
- large and broad, look at the articulating surface and tendon attachment
- flat, clean, and square with no bump or swell
describe the ideal cannons (2)
- short and strong for stability
- well defined tendons
describe the ideal fetlocks
strong, clean, free from swelling
what is the hind legs main job?
propulsion
what aids in the hind legs main function of propulsion?
a long gaskin with greater area for muscle attachment to yield max range of action
describe the ideal hock (2)
- clean
- well-defined
what is the ideal slope angle of the pasterns?
50 degrees relative to the ground
what is unsoundness?
and defect in form or function that may interfere with usefulness; can be acquired OR congenital
what is a blemish?
an ACQUIRED physical defect that does not interefere with usefulness of the horse, but may diminish value
what is a syndrome?
has no known etiology
what is the most common cause of chronic forelimb lameness in pleasure horses?
navicular syndrome
what body type increases predisposition to navicular syndrome?
large body, little feet
although there are different theories or definitions for the origin of navicular syndrome, what are the two most accepted theories?
that it is a vascular or degenerative process
what is another name for navicular syndrome?
caudal heel pain
what action causes stress on navicular structures and can leade to navicular syndrome? compare to how horses should walk
a toes first landing can cause stress; horses are supposed to walk heel to toe
how does navicular syndrom usually present?
in both feet at the same time; will observe alternating lameness
name three categories of developmental orthopedic disease (DOD) in horses
- bone problem in growing horses (formerly epiphysitis)
- metabolic bone diseases
- more generally, DOD, or all general growth disturbances resulting from any alterations in normal bone growth or formation
what can cause predisposition to DOD in horses?
athletic activity such as racing, dressage, jumping, roping, or cutting
in what kind of breeds is DOD generally observed? give two examples
in large, fast growing, light horses (QH and thoroughbred)
why does DOD occur? (3)
- due to a failure of growing cartilage to become properly ossified
- then the lack of calcification of the cartilage leads to it becoming thickened or enlarged,
- the increased cartilage thickness inhibits nutriton of the underlying cartilage, which may result in damage
what is the simple definition of laminitis?
inflammation of laminae in the foot
what is the complex but more accurate definition of laminitis?
failure of attachment of the epidermal laminae connected to the hoof wall from the dermal laminae attached to the distal phalanx
what are laminae responsible for?
suspending the distal phalanx within the hoof wall
what causes laminar failure?
downward forces of the weight of the horse and the force from the tension of the DDFT, which can result in catastrophic rotation/displacement of the distal halanx
although the pathogenesis is still controversial, what are the 3 main diseases that are known to cause laminitis?
- those associated with sepsis or endotoxemia (infections)
- equine metabolic syndrome
- supporting limb lameness
describe equine metabolic syndrome
body can’t metabolize carbohydrates, resulting in insluin dysregulation
describe supporting limb lameness
mechanical stress of overcompensation (one leg lame, put more weight on other leg, then that leg lame too)
for laminitis associated with sepsis/endotoxemia, what is the most common cause? give three examples and why
diseases associated with gram-negative bacteria; grain overload, postparturient metritis, colic; the endotoxins released into the bloodstream have a systemic effect
when laminitis is associated with equine metabolic syndrome, in what kind of horses is it observed?
overweight horses and ponies
what exacerbates laminitis due to equine metabolic syndrome and why?
grazing lush pastures, have lots of soluble carbohydrates that lead to insulin dysregulation
what does the insulin dysregulation of equine metabolic syndrome cause and what does this result in?
low level of systemic inflammation; results in a lower threshold to other insults associated with laminits
describe laminitis due to supporting limb lameness (2)
- animals supporting excessive amount of weight on one limb due to injury on cotnralateral (opposite) limb
- little known of pathophysiology, but decreased laminar blood flow may play a role
what is the underlying cause of laminitis? what is the NEW agreed upon reason for this cause?
failure of attachment of laminar basal epithelial cells (LBEC) of epidermal laminae to underlying dermal laminae; new theory is that this is due to dysregulation of hemidesmosomes
what are hemidesmosomes?
adhesion molecules of laminar basal epithelial cells that attach the cells to underlying matrix molecules
what may occur in the early stages of laminitis that may injure laminar basal epithelial cells?
significant increase of inflammatory mediators (cytokines) and enzymes
what might be involved in laminar basal epithelial cell dysfunction, resulting in laminitis, from a vascular origin?
hypoxia and ischemia due to aberrant vascular flow
