Clinical Examination of Farm Animals - CYF MEDICAL DISTRIBUTION

Clinical Examination of the Respiratory System
CLINICIAN’S CHECKLIST – THE
RESPIRATORY SYSTEM
History of the farm and patient
Observation at a distance
Identify the animals affected
At rest
Rising
Feeding
Exercise tolerance
Take temperatures of animals in group affected
Clinical signs observed
General clinical examination
Examination of the respiratory system
Upper or lower respiratory condition?
Severity of disease (pathophysiological assessment)
Breathing abnormalities
Palpation
Abnormal breath sounds on auscultation
Percussion
Further investigations
Aetiological agent
Bronchoalveolar lavage (BAL)
Paired serum samples
Nasal swabs
Faeces
Saliva
ELISA test for lungworm
Lesions
Ultrasonography
Radiography
Pathology
Lung biopsy
Thoracocentesis
Pathophysiology
Pulse oximetry
Acid/base blood gas analysis
Further investigations
A complete physical examination including auscultation
and percussion may be sufficient to characterise
respiratory disease. Sometimes additional
investigations may be helpful. The additional costs
must be considered carefully. Bronchoalveolar lavage
(BAL) is particularly helpful in cases of calf pneumonia
in which the identification of the aetiological
agent is required. Further investigations may include
serology, nasopharyngeal swabs, sampling for
lungworm larvae, fibreoptic endoscopy, radiography,
ultrasonography, blood gas analysis, thoracocentesis
and lung biopsy.
Bronchoalveolar lavage (BAL)
This is a simple technique and enables a bronchalveolar
sample to be obtained which can be used for the
rapid identification of viral antigens by indirect
fluorescent antibody tests (IFAT), bacteriological
culture and cytology. Sampling of severely affected
animals should be avoided because of the added
stress caused by the procedure. New acute cases are
ideal. This technique is usually used when there has
been an outbreak of pneumonia with high morbidity
and vaccination programmes are being contemplated.
In order to obtain an accurate profile of
the aetiological agent it is best to select up to five
animals for sampling.
Although this technique can be performed
through a fibreoptic endoscope, more rudimentary
equipment can successfully be used. The equipment
required is a 50 ml catheter tip syringe, disposable
gloves, a sterile 90 cm long flexible tube of small
(6 mm) diameter, 20 ml of warm sterile saline, viral
transport medium and topical local anaesthetic gel.
The technique is illustrated in Fig. 7.10. Local
anaesthetic gel is applied to the inner surface of a nostril;
2 minutes are allowed for anaesthesia. The distances
to the larynx and the base of the neck are both
measured and marked on the tube. The tube is gently
passed intranasally via the ventral meatus to the
larynx. Once the larynx is reached the tube is pushed
quickly forwards on inspiration to gain entry to the
trachea through the glottis. If successful, breathing
will be felt and heard at the end of the tube accompanied
by some mild coughing. Getting the tube into
the trachea and not the oesophagus may require repeated
attempts; if entry to the trachea has not been
successful the tube may have to be withdrawn a few
centimetres and advanced again. When it is in the
trachea, the tube is then advanced to the base of the
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