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6.1.3 Stage 3: Dissection and display
Dissect the carcass to display but not disturb the contents of the oral, thoracic and peritoneal cavities.
Note any accumulations of fibrin or fluid, the state of nutrition, presence of any carcass discolouration, presence of any organ or tissue colour, size or configuration changes.
Take a photograph of each cavity and close-up photographs of any changes in organs that you think are important
6.1.4 Stage 4: Internal organ examination and sampling
Examine organs in a systematic way and collect samples concurrently according to sampling protocol.
1. Abdomen: abdominal alimentary tract rumen, reticulum, omasum, abomasum, small intestine, large intestine, caecum, colon, rectum,
then: liver, gall bladder, spleen, pancreas,
mesenteries, omentum, diaphragm. But sample intestines first.
2. Oral cavity: tongue, larynx 3. Neck: oesophagus, trachea
4. Thorax: lungs, heart
These organs may be examined and sampled before or after removal from the carcass, as serves best.
5. Abdomen revisited
– adrenals, kidney, bladder, genital organs, foetus
6. Head - oral cavity, teeth, nasal cavities, middle ears
If protocol dictates, remove head to sample brain or brainstem
7. Feet and limbs
– soles, white line, interdigitum, swollen joints, other swellings, muscle, bone marrow
8. Spinal column
– spinal cord only if protocol dictates
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Figure 6.1: Necropsy examination sequence for shipboard necropsy
Variations to this procedure may be required for certain conditions where postmortem changes must be avoided for correct interpretation. If heat stroke is suspected measure core
temperature as soon as possible after death. If enteritis is suspected, exteriorize intestine as soon as abdomen is opened and collect samples for histology and microbiology.
6.2 Sampling protocols
Two protocols exist for sample collection, one for targeted sampling and one for comprehensive sampling. Targeted rather than comprehensive sampling is likely to be much
more commonly undertaken on routine voyages.
Guidelines for collection of samples are as follows:
Formalinised samples for histology
• Take samples from the margins of lesions to obtain normal and abnormal tissue in the one piece, plus separate pieces of normal and abnormal tissue from the same organ.
• Use ten volumes 10 buffered formalin to one volume of sample for three days at room temperature for fixation. Do not refrigerate. The volume of formalin can be reduced later
for transport of samples. • Samples from solid organs such as liver, kidney and spleen should not exceed 1 cm
thickness. Blocks of 2cm x 2cm x 1cm are best. Mesenteric lymph nodes, adrenals
and thyroids should be split. • Samples from intestines should be incised lengthwise to ensure penetration of fixative to
the inner surface. Short 3cm lengths of intestine are sufficient. For larger viscera such
as gall bladder, ruminoreticulum or abomasum take a 2cm x 2cm section of the wall.
• Samples of rumen should be ventral rumen and include a pillar
