Poor performance

• Poor performance can be caused by different body systems which may or may not show signs...

  • Musculoskeletal
  • Respiratory
  • Gastrointestinal
  • Reproductive
  • Cardio
  • Neurological
• respiratory causes of poor performance include...

  • Upper respiratory conditions
  • Recurrent laryngeal neuropathy
  • Dorsal displacement of the soft palate
  • Pharyngeal collapse
  • Lower respiratory diseases e.g., mild equine asthma
• mild equine asthma cases are normal at rest, but may have a slight wheeze on exertion so be sure not to miss this
• Atrial fibrillation is a cause of poor performance in horses with high athletic demand e.g., Racehorses and event horses
• what group of diseases is the most common cause of poor performance?

  musculoskeletal
• • A history suggestive of tiring, exercise intolerance or poor recovery rates would indicate a thorough cardiorespiratory auscultation both before and immediately after exercise.
• • A history suggestive of gastric disease including poor condition, poor appetite and issues associated with girthing and ridden exercise should make you consider gastroscopy
• A pattern in behaviours seen in mares during the summer months should alert you to think about oestrus associated behaviours and cyclicity.

  • some mares are obvious when in oestrus but others can be subtle
• While lunging in a lameness examination what else can you can listen for?

  respiratory noise
• As with a standard lameness examination we will inspect the limbs for signs of effusion, swelling and heat with a focus on likely foci of bilateral lameness. In these cases you will spend more time examining and manipulating the axial skeleton to identify signs of pain or dysfunction.
• When assessing the head perform a lateral flexion. After assessing the head, move caudally along the axial skeleton applying deep, sustained pressure onto the epaxial muscles (strip of muscles down the dorsal spinous processes) of the thoracic and lumbar spine. Assess the tone, symmetry, pain and you can apply pulsatile pressure to assess ability to ventral flex.

  • Stay away from the hindlimbs as this is where they are most likely to kick

  The epaxial muscles are the muscles above the ribs/transverse processes which are responsible for spinal stability and lateral flexion
• Abnormalities you might see with a

  sternal lift are…

  • Lack of response
  • Transient response that cannot be maintained
  • Overt objection to dorsiflexion
• sternal lift = Sustained pressure applied to the sternum to encourage dorsiflexion of the cranial thoracic spine.
• Keep moving caudally to palpate the sacroiliac region with deep palpation either side of midline. This is not a very specific test but abnormal responses include…

  • Horses with discomfort in this region often “shrink” towards the floor and hyperextend the region
  • Some horses show a marked pain response and can kick out
• how long should a horse maintain a sternal lift or a dynamic response to lumbar-sacral pressure?

  20 seconds
• Next, assess the dynamic response when pressure is applied to the skin on either side of the tail base (lumbar-sacral test)

  A) lumbosacral

  B) ischii

  C) no response

  D) maintain

  E) pain

  
• Effusions and passive range of motion can be helpful for high motion joints e.g., distal interphalangeal joint, metacarpophalangeal, tarsophalangeal joints, radiocarpal and middle carpal joint, but is less helpful for low motion joints e.g., the tarsometatarsal joint, distal intertarsal joint and proximal interphalangeal joint due to the small joint spaces

  • Palpation is challenging for some soft tissues: e.g., the proximal suspensory ligament
• Multi-limb lameness is easily overlooked by owners when it is (nearly) symmetrical as it may not be obvious when the horse is ridden or worked on a soft surface. The lameness evaluation allows you to put different stresses on left and right limbs simultaneously…

  • Lunging
  • More weight and more torsion on the inside limb
  • It would make weight bearing lameness cases more lame on the inside leg of both circles
  • Flexion tests
  • Increased pressures of joint fluid so can help identify subclinical or mild disease
• Always include a ridden assessment as this adds lots of benefits. Observe the horse in its usual tack with its usual rider but consider the use of a ”test” rider for cases where rider influence isn’t helpful.

  • Some lameness cases become more obvious or more consistent when ridden
  • Allows better understanding of the presenting complaints of the rider
  • Important to investigate diseases of the axial skeleton (tack and rider increase the biochemical demand here)
  • Can offer another (slightly biased!) opinion to the outcome of diagnostic analgesia
• Diagnostic analgesia includes….

  A) palmar digital

  B) abaxial sesamoid

  C) tarsal

  D) lateral plantar

  
• A significant response to diagnostic analgesia is usually the appearance of lameness in the contralateral limb!
• The proximal suspensory ligament and tarsometatarsal joint are the most likely foci. They are also very closely associated which means the tarsal region can be diagnostically challenging.

  • Anaesthesia of one can improve the other
  • Medication injected in one can help the other!

  With imaging, it can be helpful to block each structure in turn, but takes multiple visits. Compromise involves acquiring images of both (and often both structures have abnormalities)
• Neurectomy = Permanent (usually) desensitisation of the ligament
• Fasciotomy allows the ligament to swell outwards overcoming compartment syndrome
• Axial skeletal disease is often seen concurrently with hind limb lameness
• For refractory cases of tarsal and proximal suspensory ligament disease, a neurectomy of the deep branch of the lateral plantar nerve and plantar fasciotomy may help. This is a popular surgical procedure for a more “more curative” therapy. There are some contraindications…

  • Horses with marked ligament degeneration as the procedure can accelerate ligament degradation e.g., abnormal hock conformation
  • Competition legality as this currently falls into the same category as palmar digital neurectomy (however vets can now state if the horse if able to compete)
• First line treatments are often medical for cases of tarsal and proximal suspensory ligament disease e.g., intraarticular steroids
• fill in the blanks

  A) bilateral foot

  B) small tarsal

  C) proximal suspensory

  D) carpal

  E) fetlock

  F) tarsal