Clinical Examination of Farm Animals - CYF MEDICAL DISTRIBUTION

CHAPTER 8
Left
ventral
quadrant
Right
ventral
quadrant
Figure 8.8 Ascites causing gross distension of the right and left ventral
quadrants of the abdomen. Posterior view.
2 minutes) or rumenostasis may cause a free gas
bloat and is associated with a number of conditions
including milk fever, carbohydrate engorgement
(ruminal acidosis) and painful conditions of the
abdomen. Hypermotility (more than five movements
every 2 minutes) is less common and conditions
include the development of frothy bloat, vagal
indigestion and Johne’s disease.
Differentiation of the A and B waves can only reliably
be made by detecting eructation. This can be
done by observation, listening or by auscultation
with a stethoscope over the trachea. External palpation
and observation of the reticulum is not possible.
Auscultation of reticular contractions can sometimes
be achieved by stethoscope auscultation over ribs 6
or 7 ventrally on the left side. A diphasic contraction
every 40 to 60 seconds at the start of the A cycle can
sometimes be detected. A rumbling sound followed
by a liquid pouring sound may be heard. Palpation
of the left abdominal wall may enable pain to be
localised, although reactions by fractious animals
may be misleading.
Pneumoperitoneum caused by intraperitoneal gas
may cause mild distension of the right and left sublumbar
fossae. This may occur following abdominal
surgery. Pneumoperitoneum is usually less tympanic,
and the normal rumen can be palpated
through the left sublumbar fossa. A diagnosis of ruminal
bloat can be supported if hyper-resonance is
present on percussion of the distended left sublumbar
fossa. Differentiation between frothy and free gas
bloat can only be achieved by attempts at decompression.
Decompression can be attempted either by
using a large 16 BWG (1.65 mm) 5 cm needle inserted
into the tympanic dorsal sac of the rumen through
the flank, or by passing a stomach tube into the
rumen per os (Fig. 8.10) or per nasum. Free gas bloat
can easily be decompressed. Frothy bloat simply
blocks the tube without decompression. In cases of
ruminal acidosis, the fluid volume of the rumen will
increase due to osmosis into the hypertonic rumen.
Ballottement of the rumen may reveal sloshing
sounds caused by the excess fluid.
Rumen fluid collection and analysis when pyloric
obstruction, ruminal acidosis or poor rumen function
are suspected may provide useful additional information.
The collection and analysis is described
under ‘Further investigations’.
There are several tests and signs that may support
a diagnosis of traumatic reticulitis. The animal may be
reluctant to move and stand with an arched back
(Fig. 8.11); it may be anorexic and pyrexic. Animals
that have progressed to a traumatic reticulopericarditis
may have additional cardiovascular signs,
including signs of congestive heart failure. The animal
may grunt when it moves or breathes due to pain
induced by parietal peritoneal irritation. The grunt is
produced by forced expiration against a closed glottis.
Grunts may be produced by thoracic as well as abdominal
pain. The detection of a grunt is improved
by auscultation with a stethoscope placed against the
trachea. Acondition should not be ruled out if a grunt
is absent, but if a grunt is present this indicates there
is anterior abdominal pain.
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