Awesome-veterinary

Avian necropsy

Need for Avian Necropsy

A necropsy (postmortem examination) is performed to determine the cause of disease
by gross and microscopic examination of tissues and by conducting appropriate serologic and microbiologic examinations
A postmortem examination is indicated whenever there is a decrease in production
there are overt signs of illness, or there is an increase in mortality.

Limitations

Necropsy will not reveal all causes of disease because a high percentage of disease problems
Related to management, including

poor nutrition,
feed and/or water deprivation,
improper ventilation, poor sanitation,
chilling or overheating of birds, and overcrowding.

Such conditions often require an on-site investigation to determine the cause of the problem.
Necropsy is most likely to identify infectious disease processes, nutritional deficiencies, toxicities, parasitic disease, and tumors.

Equipment for Avian Necropsy

Necropsies can be performed with a limited amount of equipment
Required is a knife (4- to 6-inch)
bone shears, tissue scissors (preferably with sharp/blunt blades),
forceps with teeth, disposable gloves, disposable syringes (3 cc and 5 cc),
needles (20 gauge, 1 inch for wing vein blood collection, and 1 1/2 inch for heart blood collection),
sanitizer for cleaning instruments and table, tissue bottles with 10 percent neutral buffered formalin, black marker,
Labeling tape. If serum samples are collected, blood collection tubes and serum vial are also needed.

History of the Problem

Prior to examining the birds, a thorough history of the problem must be evaluated.
The more information provided about aviary conditions, environment, management practices, and flock history, the more likely the pathologist will be able to derive a diagnosis
The flock history should include: primary clinical signs, age, strain (or species), number affected, vaccinations, medications, recurrent aviary diseases, feeding problems, feed consumption, production, body weights, and mortality pattern
If the disease problem is in chicks, include the history of hatching and brooding procedures
In most cases, a list of possible causes of the problem (differential diagnosis) can be developed following the study of the complete history.

Examination of Live Birds

If the disease is a flock problem, closely examine the live birds in the aviary prior to necropsy
This examination should include
assessment of general appearance
feathering, weight, pigmentation of skin and shanks
Physical injuries, facial tissues, eyes, feces (droppings)
nasal and respiratory discharges, respiration, gait
leg/joint deformities, and external parasites.
Moisten the feathers with water containing detergent
If psittacosis (or another human pathogen) is suspected, the bird should be soaked in a 5 percent Lysol solution
and a laminar flow hood should be used while performing the necropsy.

With scissors, cut through one lateral commissure of the mouth and examine the oral cavity
Continue at the cut commissure and make a longitudinal incision through the skin of the neck to the thoracic inlet. Reflect the skin laterally.
Make a longitudinal incision in the esophagus and crop. Note the content and odor.
Make a longitudinal incision in the larynx and trachea and examine.

Incise the loose skin between the medial surface of each thigh and the abdomen. Reflect the legs laterally, and disarticulate the hip joints. Incise the skin on the medial aspect of each leg, and reflect it to expose the muscles and stifle joint.
Connect the lateral skin incisions with a transverse skin incision across the middle of the abdomen. Reflect the skin of the breast anteriorly, and of the abdomen, posteriorly.