7. Dissect the liver
Using a sterile scalpel, make a stab incision through the liver capsule allowing a swab to be passed into the tissue.
Make multiple slices through the liver to detect any abnormalities that may not be visible on external examination. Collect a 1 x 2.5cm fixed section. Collect 50 grams (3 x 3cm) of fresh liver for biochemistry.
8. Dissect the intestines
Cut 2.5cm long tubes of duodenum and jejunum. Make a small cut in each end of the tube to allow the ends to curl in the formalin to prevent the tube from collapsing. These two sites are good indicators of parasitic burdens.
Expose the ileo-caecal junction by lifting the small intestines over the dorsal aspect of the carcase. Collect a 2.5cm tube of ileum into formalin. This site is commonly affected in salmonellosis, parasitism and Johne’s disease. Collect 50 millilitres of ileal contents for bacterial culture and enterotoxaemia ELISA testing.
Collect a 2.5 x 2.5cm piece of caecum and colon into formalin. Do not scrape the surface.
9a. Examine the abomasum
Examine the abomasum for the presence of Haemonchus parasites or hyperplasia and nodular changes common associated with ostertagiosis. Collect a 1 x 2.5cm piece of tissue into formalin.
9b. Examine the rumen
Test rumen pH (normal 5.5–7.0). Examine contents for intact leaves of poisonous plants e.g. Gastrolobium). If ARGT is suspected, collect 50mL of rumen fluid for an annual ryegrass toxicity (ARGT) ELISA test.
9c. Examine the forestomachs
Empty the forestomachs and examine the ventral rumen mucosa for evidence of rumenitis. The ventral pillars are often affected, however most cases of rumenitis are not apparent on gross examination. Collect 1 x 2.5cm sections of rumen, omasum and reticulum into formalin.
10. Dissect the kidneys
Cut the kidney into two halves along the sagittal plane. Trim a 1cm section into formalin.
If copper or lead toxicity is suspected, submit the other whole half kidney chilled.
11. Take samples of muscle tissue
Slice the hindlimb muscles looking for areas of pallor suggestive of nutritional myopathy. Collect 1 x 2.5cm samples from two muscle groups. Vitamin E and selenium levels are measured in plasma and liver. Do not submit fresh muscle for this purpose.
12. Collect faecal samples
Collect 50g of faeces for faecal worm egg counts, bacterial and mycobacterial culture.
Contact the DPIRD Diagnostic Laboratory Services (DDLS) duty pathologist or your local field veterinary officer to discuss the case, sampling and charge exemptions.