Page 400 - The Veterinary Laboratory and Field Manual 3rd Edition

Pathology/cytology 369

The number and type of samples required 5 Examine the head of the animal and note the
from a post-mortem will depend on the species colour of the mucous membranes and the
examined and the nature of the disease(s) sus- position of the eyes (if sunken into the skull
pected (see Tables 10.1–10.10 in Chapter 10 for this is often a sign of malnutrition/dehydra-
diseases associated with specific clinical signs). tion as the fat pad behind the eye shrinks).
The following technique is suggested for a basic Find and incise the superficial lymph nodes
field necropsy. Detailed procedures for perform- (these may be enlarged and have an abnor-
ing a more comprehensive necropsy are outlined mal texture in many localized or systemic
in Appendix 2. infections).
6 Open the mouth and cut along the inner
margins of the mandibles, free the tongue
Performing the necropsy
and open the pharynx to examine the teeth,
1 Place the dead animal (carcass) on its back tonsils and salivary glands.
and secure it in position using blocks of 7 Cut into the muscles of the neck to expose
wood or rocks (that is, place wedges under the trachea and oesophagus. Examine the
the pelvis/shoulders to provide balance). glands of the neck including the thyroid
At the laboratory, there may be access to a glands.
post-mortem facility with specialized tables, 8 Open the nasal cavity and look for abnormal
winches and other equipment but, due to changes in the turbinate bones (atrophic
logistical challenges, most necropsies are rhinitis in pigs/tumours/foreign bodies). In
done in the field. For poultry carcasses, it is horses open and examine the guttural pouch
generally preferable to remove or wet some and check for the presence of fungal hyphae,
of the feathers, especially those over the discharge and so on.
sternum, prior to beginning the necropsy. 9 Using a sharp knife open up the rib cage
2 Using a sharp knife, make an incision in the by cutting posteriorly along the abdominal
skin from the midline of the throat to the wall.
pelvis. In birds it is usually necessary to cut 10 Examine the abdominal and thoracic con-
around the sternum. When cutting into the tents and note any abnormal colouration,
abdomen and thoracic cavity check to see abnormal location of organs or the presence
if the air sacs are clear, these can become of excessive peritoneal fluid/ascites/peri-
thickened and cloudy in birds with respira- tonitis. Examine the peritoneum (colour/
tory disease. texture) and the mesenteric lymph nodes.
3 Make deep incisions at the axillae and In birds the colour and texture of the air sacs
the hip joints, to make the limbs lie flat. should be examined.
Examine the subcutaneous tissues and the 11 Examine the location, colour and texture
superficial lymph nodes. Incise the lymph of the lungs and heart. If there is excessive
nodes (axillary, precrural, inguinal and pop- fluid around the heart (pericardial fluid)
liteal), examine the structure and note any or in the thoracic cavity (pleural/medias-
abnormality. When cutting through the hip tinal) collect a small amount (5–10 ml)
joints it may be necessary to incise the round using a sterile needle and syringe. This fluid
ligament (which secures the hip socket in can be submitted for cytological examina-
place). tion and microbiology. Note the volume,
4 Note the contents of the hip joint capsule colour and viscosity (thickness) of any fluid
and the presence of any excess fluid. collected.

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