Guide to Australian Endurance Vetting

Metabolic Parameters

Parameters Checked

  1. Mucous membranes
  2. Capillary and jugular refill
  3. Skin recoil
  4. Heart sounds
  5. Gut sounds
  6. Muscle tone

Mucous Membranes

  • A = Clear pink and moist
  • B = Moist pink, fawn
  • C = Injected, pallid, tacky, dry
  • D = Muddy, blue, purple, toxic line – elimination
  • Clinical significance.
    • Assessment of dehydration – moist or dry
    • Assessment of colour –
    • Pale – anaemia or low blood pressure
    • Salmon pink and moist – normal
    • Injected or dark reflects poor tissue perfusion due to dehydration, poor oxygen supply and/ or onset of toxaemia

Capillary and Jugular Refill

  • 1 = Less than 1 second
  • 2 = 1-2 seconds
  • 3 = 2-3 seconds
  • 4 = Greater than 3 seconds – elimination
  • Clinical significance of prolonged CR reflects:
    • Poor blood pressure
    • Poor tissue perfusion
    • Dehydration
    • Toxaemia

Skin Recoil

    • Additional parameter to assess metabolic status.
    • Always taken at the point of the shoulder. No half scores.
    • 1 = Less than 2 seconds
    • 2 = between 2-3 seconds
    • 3 = between 3-4 seconds
    • 4 = Greater than 4 seconds
    • Clinical significance:
      • Unreliable
      • Dehydration
      • Differing response depending on site of test & wetness of skin
      • Can be prolonged in normal horses

Skin Recoil Practicalities

  • Always taken at the point of the shoulder.
    • Important to allow comparison, as the result can be different, depending on the location of the test
    • Should not be performed on the horses neck, or the shoulder blades
  • Can vary depending on if the hair is clipped or wet
  • Can vary with age
  • Unreliable and should be interpreted in light of other metabolic parameters
  • Should not be an isolated parameter used to indicate issues

Heart Sounds

  • A = Normal rhythm and intensity
  • B = Variable rhythm, increased intensity
  • C = Pronounced dysrhythmia, onset of murmurs
  • D =serious murmurs, or arrhythmias– elimination
    • Second degree AV block is acceptable.
    • Atrial fibrillation; pathological murmurs (pan systolic); ventricular extra systoles are unacceptable.

Gut Sounds

  • A = Normal and active
  • B = Slight decrease
  • C = Marked decrease
  • D = Absent – elimination
  • Clinical significance.
  • May be normal
  • Louder – increased activity with gas production or diarrhoea
  • Diminished
    • may be normal with strenuous activity (flight and fright reflex)
    • due to loss of water content in colon (impaction)
    • due to impending ileus
    • Absolute loss of gut sounds that fail to recover is significant

Gut Sound Practicalities

  • Listen to the four quadrants for normal sounds
    • Emphasis is placed on the small intestinal sounds as ileus can be a common problem in endurance horses, so early detection and management is important
    • Can be slow if the horse has recently come off course due to exercise, or less cooling of the horse
    • If in doubt a re-examination can be requested to ensure the horse recovers sufficiently, prior to the next loop, or completion/signing off the logbook

Muscle Tone

  • Gluteal muscles should be soft and supple to palpate
  • The muscles will be swollen, hard and painful where myositis is present
  • Fasiculating muscles and shivering should be interpreted in light of the environmental temperatures and other metabolic parameters
  • Critical part of musculo-skeletal examination to assess tie-up.
    • A = Supple, elastic, fluid wave
    • B = Firm, doughy
    • C = Fasciculation/altered tone
    • D = Cramped, flaccid, twitching, swollen – elimination

Metabolic Profile


Overall Interpretation of Metabolic Parameters

  • The elimination of a horse on metabolics should not be based on one parameter, but the overall picture and a number of parameters which indicate the horse is developing metabolic compromise
    • E.g. high heart rate (but under 60), B/C for mucous membranes, >2 capillary refill, low or absent gut sounds. Especially if no improvement prior to re-examination
  • Horses with synchronous diaphragmatic flutter (thumps), exertional rhabdomyolysis (tie-up) and colic encountered at the vet gate are automatically eliminated and sent for treatment