Clinical Examination of Farm Animals - CYF MEDICAL DISTRIBUTION

CHAPTER 5
difficult. Observation without restraining the tongue
provides a good opportunity for assessment of
mobility and evaluation of gross appearance. In the
gagged animal the tongue can be palpated in situ
without attempting to pull it forward. The caudal
part of the tongue – the dorsum – is thicker than the
more anterior part from which it is divided by a small
transverse sulcus. Idiopathic injuries to the tongue including
quite deep cuts are sometimes found on the
dorsum of the tongue of young calves. If the tongue is
infected or if a foreign body is present a foul odour
may be detected in the mouth. In cases of wooden
tongue caused by Actinobacillus lignieresii the tongue
is very firm and inflexible to the touch; the animal is
unable to advance it through the lips and excessive
salivation may be seen. Inability to withdraw the
tongue may be associated with damage to the 12th
cranial (hypoglossal) nerve or with cerebral damage
in areas of the brain which control hypoglossal function.
Paralysis of the tongue is seen in cases of botulism.
Ulceration of the tongue is seen in a number of diseases
including foot-and-mouth disease (Fig. 5.15), malignant
catarrh and mucosal disease.
CLINICIAN’S CHECKLIST – THE MOUTH
Ability to open the mouth
Ability to prehend, masticate and swallow food
Tongue – movements, texture and mucosal surface
Oral mucosa
Hard palate and dental pad
Teeth
Examination of the internal pharynx
and larynx
Examination of the internal pharynx and larynx
through the mouth can be achieved by manual palpation
in the gagged and carefully restrained animal.
A large rigid metal, rubber or plastic tube passed
through the gagged mouth will allow a limited view,
assisted by a good light, of the pharynx and larynx
(Fig. 5.16). A detailed examination can be readily
carried out endoscopically – the instrument is passed
through the ventral meatus of the nasal passages.
Using the fibreoptic endoscope, laryngeal function can
be closely observed. Advancement of the endoscope
allows examination of the trachea and oesophagus.
Patency or obstruction of the oesophagus can be detected
using a nasogastric tube or probang. The tube
can alternatively be passed through the oral cavity,
but even in the gagged animal risks being damaged
by the sharp edges of the cheek teeth.
Figure 5.15 Animal with foot-and-mouth disease showing large ulcer on
tongue.
Endoscopy of the nasal passages,
pharynx, larynx, trachea and oesophagus
Restraint and sedation of the patient
The patient should be placed in a crush with its head
restrained by a halter. Sedation is not always necessary
but should be used if the animal is at all fractious.
Fibreoptic endoscopes are very expensive and
easily damaged. They must always be used with caution
and the exact whereabouts of the objective part
of the instrument checked by frequent observation
through the eyepiece. If this is not done the instrument
may bend ventrally behind the soft palate before
passing into the mouth where it can be seriously
damaged by the teeth.
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