Before post-mortem the outside of the pig should be examined
The general appearance and colour should be noted. Careful examination should be made for the presence of ectoparasites, mainly lice and crusts relating to mange. Lice will often leave a dead pig, so their absence does not mean they were not present in life. Any crusts should be retained and can be supplemented with deep skin scrapings and even punch biopsies to help get a diagnosis.
At the start the head should be examined; is the snout twisted? Is there ocular discharge? Then the body; are there udder swellings? Is the prepuce normal? Are the feet and coronary band normal? Is the rectum/vulva normal?
Single-handed post-mortem technique without a cradle
This is easiest if carried out in a series of steps.
1. Lie the pig on its left side and make a bold cut in the axilla, cutting all the skin and musculature so that the right front leg is totally reflected on to the ground.
2. Make a bold cut into the groin into the adductor muscles going straight into the hip joint and severing the ligament anchoring the femoral head into the acetabulum, so that right hind leg can be totally reflected (Fig. 3.3). The carcass should now be stable on its side.
3. Cut the skin from the opening around the hind leg along the ventral mid-line to the skin cut in the axilla (Fig. 3.4).
4. Cut the skin from this skin incision through the ventral mid-line, reflect the skin as a large flap to the spine so that it can be laid out behind the backbone as a flat surface with the skin on the ground. This can then be used to lay the internal organs on, rather than on the ground.
5. Cut the skin from the cranial point of the ventral skin incision, an incision should be made cranially to the symphysis of the mandibular rami.
6. Cut the skin from the caudal point of the ventral skin incision, an incision should be made caudally to the rectum/vulva.
Fig. 3.3. The upper and lower legs are reflected.
Fig. 3.4. The abdomen is opened.
7. The abdominal cavity should be opened carefully from the xiphisternum to the pubic symphysis. Samples can be taken from the peritoneal fluid and from the liver for bacteriology.
8. The abdominal musculature should be cut along the line of the last rib from the xiphisternum to the spine, so that the flank can be reflected and the internal organs revealed (Fig. 3.5). The liver will just be seen caudal to the xiphisternum with a small portion of the stomach. The rest of the abdomen will be filled with the greater omentum cranially and the jejunum caudally.
9. Two cuts should now be made through the diaphragm along both costalchondral junctions cranially and including the first ribs. In growing and fattening pigs these cuts can normally be carried out with a sharp postmortem knife. In adults a saw or a pair of garden loppers may be required. Then the whole sternum can be removed.
10. Multiple cuts should be made through the intercostal muscles between the ribs dorsally to the spine, so that each rib can be broken in a dorsal direction near to the spine. The heart, lungs and the rest of the thorax can then be examined in situ. Bacteriological samples can be taken at this stage. Heart blood can be aspirated.
Fig. 3.5. The liver, spleen, small and large bowel are visible.
11. A cut should be made between the mandibles so that the tongue can be grasped. It should be pulled using blunt dissection so that the whole ‘pluck’ can then be removed, i.e. the larynx, trachea, oesophagus, lungs and heart.
12. A cut at the caudal end of the oesophagus will remove the ‘pluck’ from the intestinal tract.
13. A cut should be made down both the trachea and the oesophagus to examine the internal mucosa.
14. The lungs, the mediastinal lymph nodes and the thymus should be examined carefully. The pericardium, the outside and the inside of the heart should be examined, paying particular attention to the heart valves.
15. The whole intestinal tract should be examined outside and inside. This should also include an examination of the liver, spleen, omentum and lymph nodes. The contents of the intestinal tract should be examined for nematodes and samples should be taken for bacteriology.
16. The rest of the carcass should be examined. This should include the adrenal glands, kidneys, ureters, bladder and urethra. Bacteriological samples can be taken at this stage. The uterus or male genital tract should also be examined. The contents of the bladder should be examined and a sterile sample should be taken if required.
Two-person post-mortem technique or single-handed technique using a cradle
The pig is laid in dorsal recumbency with the helper holding one leg to keep it upright or laid in the cradle. A skin incision is made from the chin straight down the ventral surface all the way to the anus. A small incision is carefully made through the abdominal musculature and the peritoneum caudal to the xiphisternum. This incision is then lengthened caudally to the pubic symphysis, making sure that the internal organs are not cut. Two cuts are made from the xiphisternum cranially through the costalchondral junctions so that the sternum can be removed. The internal organs can then be examined in situ. Bacteriological samples can be taken at this stage. The pluck and the intestinal tract can then be removed as described above.
The internal organs etc. to be examined in the abdominal cavity are: the umbilicus together with the whole internal peritoneal surface, the liver including the gall bladder, the spleen, kidneys and adrenals, the ureters, bladder and urethra, the uterus, fallopian tubes, ovaries and mammary glands, the testes, vesicular gland, bulbourethral glands and the penis.
The alimentary tract can be examined starting with: the tongue, lips, teeth, pharynx and oesophagus, the stomach (noting contents), the duodenum, jejunum and ileum, the colon, caecum and rectum, the mesenteric lymph nodes and the pancreas.
The respiratory tract and thoracic cavity can be examined starting with: the snout and turbinates, the larynx, trachea and lungs, the heart, thymus and mediastinal lymph nodes.
The neurological system can be examined after the cranium and the spinal column have been opened. Bacteriological samples can be taken at this stage. The brain, spinal column and peripheral nerves should all be examined.
