Respiratory: physical examination in Horses (Equis) | Vetlexicon
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Respiratory: physical examination

ISSN 2398-2977



  • The first step in gathering information on suspected pathology of the respiratory tract.

Print off the Owner factsheets on Exercise intolerance / poor performance testing and Normal parameters and vital signs to give to your clients. 


  • Provides an overview of the patient and the condition.
  • May indicate in which areas more detailed examinations are required.


  • Can only view, listen to or palpate externally.


  • 5-10 min.




  • Held on halter.


Core procedure


Step 1 - Examinations

External nares
  • For any sign of discharge, trauma or deformity.
  • Listen to breath sounds (feel expiratory breaths on hand) and assess symmetry of airflow from right and left nares.
  • Note presence of any abnormal breath odor.
  • Note presence of nostril flare.


  • For signs of ocular discharge.
  • Mucous membran color, eg cyanosis.
  • For any signs of pain, swelling or anatomical disruption that may indicate respiratory pathology, eg sinuses   Paranasal sinus: facial distortion - nasal discharge  .
  • Percussion of paranasal sinuses is unreliable but increased resonance may indicate thinning walls, or a dull sound may indicate filling with fluid or soft tissue.
  • Check crowns of teeth for damage or impacted ingesta.
  • Nasolacrimal duct should be patent (catheterize and infuse saline to confirm)   Nasolacrimal duct: lavage  .


  • Palpate cartilage structure and musculature.
  • Look for evidence of previous surgery, eg ventriculectomy (Hobday) or laryngoplasty scar.
  • Perform 'slap' test   Larynx: slap test  .
  • Perform arytenoid depression test .

Parotid region, guttural pouch and intermandibular space

  • Palpate parotid region for pain or swelling in lymph nodes or salivary gland.
  • Disease of the guttural pouch rarely causes external distension.
  • If it is seen, eg guttural pouch tympany   Guttural pouch: tympany  it is deep to the parotid salivary gland   Neck: pharyngeal swelling 03  .
  • Occasionally mycosis of guttural pouch causes pain on palpation deep to base of ear (if bony structures become involved).
  • Palpate submandibular lymph nodes.

Step 2 - Palpate trachea

  • Palpate trachea to check for abnormal cartilaginous rings.
  • Stimulate cough.

Step 3 - Assess breathing

  • Select normal environment without disturbing horse.
  • Pulmonary function may worsen at night, ie daytime examination might not reveal true severity of problem.
  • Rate: watch costal arch when standing behind and to one side of horse (can be difficult to see in a normal horse), or feel expiratory airflow from nostril on hand. Normal: horses 8-12/min; ponies 15-20/min.
  • Depth: normally shallow. Dyspnea causes exaggerated movements of costal arch, intercostal and abdominal muscles; active nostril dilatation; anal 'pumping'.
  • Pattern: normally duration of inspiration and expiration are approximately equal. Abnormal patterns:
    • 1. Fast and deep: physiologic, eg exercise or anxiety; pathologic, eg pyrexia, anemia, acidosis.
    • 2. Slow and deep: severe airway obstruction.
    • 3. Fast and shallow: anxiety painful breathing, eg fractured ribs or pleuropneumonia; restrictive lung disease, eg interstitial pneumonia   Lung: pneumonia - interstitial (foals)  and pulmonary fibrosis; lesions that limit lung expansion, eg pleural effusion , pneumothorax .
    • 4. Slow and shallow: CNS depression; compensation for metabolic alkalosis.
    • 5. Cheyne-Stokes: cyclical increase and decrease in respiratory rate and depth due to CNS disease or hypoxia.
  • Inspiratory dyspnea is caused by obstruction to extrathoracic airways, eg tracheal collapse   Trachea: collapse  and by limited thoracic expansion, eg pleural effusion .
  • Expiratory dyspnea is caused by obstruction of intrathoracic airways, eg RAO   Lung: recurrent airway obstruction (RAO)  .
  • Heave line: linear depression ventral to external abdominal oblique muscles caused by hypertrophy due to chronic severe expiratory dyspnea.

Step 4 - Listen for abnormal sounds

  • Coughing: reliable indicator of pulmonary disease. Not always present.
  • Wheezes and crackles: may be heard near nostrils.
  • Grunts or groans: sudden loud expiratory sounds indicate pain.

Auscultate over trachea at level of thoracic inlet as well as thorax.

Can use re-breathing bag to accentuate respiratory sounds as makes animal breathe deeper and faster.

Step 5 - Feed from ground

  • Observe for discharge increased by gravity.



Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Andrews F M (1997) Poor performance and field evaluation of the respiratory system. Vet Clin N A Equine Pract 13 (3), 589-600 PubMed.
  • Savage C J (1997) Evaluation of the equine respiratory system using physical examination and endoscopy. Vet Clin N A Equine Pract 13 (3), 443-462 PubMed.
  • Traub-Dargatz J (1997) Field examination of the equine patient with nasal discharge. Vet Clin N A Equine Pract 13 (3), 561-588 PubMed.
  • Moore B R (1996) Lower respiratory tract disease. Vet Clin N A Equine Pract 12 (3), 457-472 PubMed.
  • Hinchcliff K W & Byrne B A (1991) Clinical examination of the respiratory system. Vet Clin N A Equine Pract (1), 1-26 PubMed.
  • Morris E (1991) Dynamic evaluation of the equine upper respiratory tract. Vet Clin N A Equine Pract (2), 403-416 PubMed.