Page 401 - The Veterinary Laboratory and Field Manual 3rd Edition

370 Susan C. Cork

12 Once the thoracic and abdominal cavities a primary or secondary bloat but also remem-
have been opened the viscera (internal ber that the abdominal contents putrefy rapidly
organs) can be removed and examined and that gas production may be a post-mortem
systematically. In some cases, the viscera change. Open up the intestinal tract carefully,
should be weighed and the weight recorded note the presence of parasites. If possible collect
as part of the post-mortem. a sample of any worms present for identification
See also Appendix 2 and the videos of at the laboratory along with five to six cross-
avian and ruminant necropsy available on sectional pieces of intestine for histological
the website. examination. The former should be submitted
in alcohol (70%) and the tissues for histopathol-
ogy in 10% buffered formalin. If coccidiosis is
Examination of specific body systems
suspected take a smear from the mucus of the
In the next section, we will discuss the examina- jejunum or caecum and fix on a microscope slide
tion of each body system in more detail. Most (use a flame to heat fix or allow to dry and fix in
of the text refers to ruminants but where there methanol). Examine all of the lymph nodes and
are specific differences between ruminants and the ileocaecal valve. Some diseases, for example,
other species these are outlined. Johne’s disease (Mycobacterium avium paratubercu-
losis), cause characteristic changes at this point
so this area should be submitted for histological
Gastrointestinal system examination.
(see Figures 8.3 and 8.4) In birds (see Figure 8.4) the anatomy of
the gastrointestinal tract depends on the spe-
Remove the intestines/stomach from the body cies examined. The chicken (Gallus gallus) has a
cavity by tying the oesophagus and the rectum storage area, the crop (at the distal end of the
with two pieces of string 2 cm apart at each point oesophagus), which should be examined for
to be detached. Make an incision between the signs of impaction or inflammation. The caeca
pieces of string and remove the intestines and are paired and should be examined for lesions
stomach(s) into a tray. The liver can be removed associated with coccidiosis (see also Chapter 3).
at the same time. Note the colour and size of the
liver and whether or not the gall bladder is empty Cardiovascular system (see Figure 8.5)
or full. Examine for the presence of liver fluke or
tape worm cysts. These may only be an inciden- Examine the heart and the pericardium. Look for
tal finding but their presence could be important. signs of trauma such as haemorrhage or colour
Describe any gross lesions and remove a section change (Figure 8.5). Remove the heart and open
of liver for histology and for microbiology (1 × up the atria and ventricles. Examine the valves
1 × 1 cm sections). Open the stomach(s) and for signs of emboli and inflammatory change.
examine the contents. Check for the presence Collect a section of heart muscle +/– valvular
of foreign bodies, for example, wire, plastic and material/blood vessel for HP. Examine the major
so on. If poisoning is suspected keep a sample vessels in the body for signs of parasitic migra-
of the stomach/rumen contents and store in a tion (for example, strongyles in the mesenteric
labelled plastic bag. It may also be important to vessels of horses) or evidence of inflammatory
collect samples of suspect feed/plants for toxi- changes. In freshly dead animals, especially pigs
cology tests. In ruminants, note the presence of and small animals, it is often useful to collect
excessive gas in the rumen, this may indicate heart blood for microbiological examination

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