VETERINARY JURISPRUDENCE

KEY NOTE ON PM EXAMINATION OF ANIMALS AT FIELD LEVEL

August 6, 2020

1091

KEY NOTE ON PM EXAMINATION OF ANIMALS AT FIELD LEVEL

Necropsy of animal carcasses is an important tool in diagnosis of diseases and ultimately their control. It also becomes extremely relevant in addressing vetero-legal cases. Therefore, a veterinarian must have the basic knowledge of the post mortem techniques, recording of lesions, their interpretation, collection of proper sample for laboratory examination, and writing of report.Here I am furnishing the standard formate laid down by VCI.
Post-mortem report consists of two parts- A. Post-mortem record, and B. Post-mortem examination as given in the standard format for PM prescribed by vci . The first part i.e. post-mortem record is having information related to animal and is supplied by the owner or person requesting post-mortem examination. Actually, it is a part of request form of the case for post-mortem examination. This is necessary for the identification of animal. It should be filled in before conducting postmortem examination. The proper record will be helpful in establishing accurate diagnosis based on post-mortem examination.

Necropsy examination

• Post-mortem Examination (PM) of carcass is conducted by Veterinarian or a Veterinary
Pathologist to ascertain the cause and nature of disease in fatal cases of diseases. The term
autopsy is preferred in human medicine for PM examination and necropsy in Veterinary
Medicine.
• Autopsy means seeing with one‘s own eyes. • Necropsy means seeing a carcass.
• Autopsist is one who conducts the PM examination

Types of necropsy

• Partial necropsy
o In case of rabies only the brain of the ‗carcass‘ is examined for diagnosis. Here
only a part of the body (head) is opened for the purpose. Other parts of the body
are not opened.
• Complete necropsy
o All parts of the body are thoroughly examined to arrive at an aetiological
diagnosis.
• Cosmetic necropsy
o Examination of the carcass is done with very less mutilation. Cuttings and
incisions are sewed together and the body is washed to appear as nearly intact as
possible. It is done in case of pet and wild animals.

Necropsy as a factor in diagnosis
• Necropsy actually accomplishes to bring into open previously unseen or merely surmised
lesions and even certain etiological agents not observable from the animal‘s exterior.
Quite frequently, the necropsy may be compared with opening and reading a book, the
title of which conveys a certain meaning; but it is the text that really portrays the plot, the
sequence of events and the conclusions. The necropsy like the text book may reveal items
of a surprising or unexpected nature thus explaining previously unknown or baffling
events.
• Clinical diagnosis would be more accurate if the clinician follows the animal which failed
to respond to therapy to the necropsy.
• The veterinarian holds a district advantage over the physician in the matter of Post-
mortem diagnosis since he/she may employ euthanasia in order to hasten the process of
diagnosis.
Time of necropsy

• The post-mortem examination (PME) should be conducted as soon as possible after the
death of the animal. If delayed, various PM changes including autolysis and putrefaction
may set in which sometimes may confuse with morbid lesions and distort the diagnosis.
However, even if PM changes have advanced considerably, still from a stand point of
gross pathology the deterioration is not as serious as many believed. If the disease was one that could have been diagnosed originally by the gross pathological changes it probably
can still be diagnosed by distinguishing PM changes from morbid lesions.

Place of necropsy and site for disposal

• The veterinary practitioner needs but little space for the conduct of necropsies. For small
animals, a well ventilated room of the hospital may be set aside for euthanasia and for
necropsies. In large animals, the veterinarian should choose an outdoor large area least
likely to allow contamination to spread.
• Sanitary conditions and intended disposition of the carcass are factors which outweigh
convenience in deciding where to perform the necropsy. If there is any possibility that the
animal may have died of a contagious disease, it is imperative to avoid contamination of
ground accessible to susceptible livestock or their food.
• If the necropsy has to be performed near farm building or on ground from which livestock
is not excluded, it may be feasible to have an extremely deep bed of straw prepared on
which to place the carcass. The straw absorbs the fluids and can be burned or buried
afterwards.
• More frequently, it will be decided to transport the carcass to some distant field not used
for livestock atleast during the current year. If the animal is to be buried, a deep grave
layered with lime can be dug where the carcass can be easily rolled into, to be followed by
the contaminated layer of the earth.

Disinfectants —–

• Although not effective as steam / heat strerilisation, chemical disinfectants are usually
employed for necropsy instruments, boots and gloves as well as the tables and premises
connected with necropsy. To be effective any such disinfection must be preceded by
thorough mechanical cleaning. The commonly used chemicals are Lysol, cresol, chlorine,
quaternary ammonium compounds, mercury in the form of bin-iodide combined with
potassium iodide, iodophores, phenol etc. The choice of disinfectant to be used for the
disposal of carcass where the cause of death suspected to be infectious and contagious
(Anthrax) is quick lime.

Precautions ——

• Obtain written permission from the owner before post mortem examination. • Request from local police is a must in vetero-legal cases
• Conduct postmortem as early as possible to avoid putrefaction.
• Examine the smear from peripheral blood to rule out anthrax. Besides anthrax bacilli,
examination of blood smear may reveal blood parasites, other bacterial and/or postmortem
invaders.
• Postmortem examination should be done in day time to appreciate the accurate changes in the colour of tissues. This is not possible with artificial light.
• Conduct postmortem far away from animal houses and farm premises and preferably in a
government land to avoid litigation.
• Obtain history, symptoms and treatment done etc.
• Wear gloves, mask, aprons and gum boots to avoid contact with zoonotic agents. • Record the postmortem findings immediately.
• Bury the carcass in deep ditches layered with lime. Carcass can be burnt to ashes if
incinerator is available.

Note before necropsy ——–

• Ruminants: Place the carcass on the left side to avoid the interference of rumen during
examination.
• Horses: Place the carcass on the right side to avoid the interference of colons during
examination.

NECROPSY TECHNIQUES AND OBSERVATIONS
Steps in Necropsy
1. Record the kind of animal and to whom it belongs.
2. Write the precis of the case.
3. Carry out the external examination of the carcass. Then proceed to internal examination.
4. Secure the carcass on its back.
5. Make incision in the mid ventral line from chin to anus going round about the external
genitalia in male and incision is also made on the medial aspect of all legs and flay the
skin.
6. Examine the subcutaneous tissue.
7. Open the cavities of the body. Look for exudates, transudate etc.
8. Examine the position of the organs.
9. Separate lungs from heart and palpate for any abnormalities. Incise and examine the lungs.
10. Examine the pericardial sac. Open the pericardium, examine the nature of contents.
11. Cut through heart and the vessels. Examine the wall and chambers for the nature of
content, valves and the lumen of vessels.
12. Examine the diaphragm.
13. Examine the abdominal visceral organs-liver, spleen, kidneys, adrenals, pancreas before and after incising the organs.
14. Open the bile ducts and gall bladder and examine.
15. Divide the kidney symmetrically by longitudinal incision. Remove the capsule, examine
the cortex, medulla and pelvis.
16. Open the mouth to examine the gum, tooth, tongue and buccal cavity. Then open and
examine esophagus.
17. Open the nasal cavity and examine. Examine the pharynx, larynx, trachea and bronchi.
18. Open the stomachs/forestomachs and abomasum (ruminants) and examine the nature of contents and the wall.
19. Open the intestine. Examine the contents and the wall.
20. Open and examine the urinary bladder for the nature of content and the wall.
21. Examine the genital organs.
22. Open the skull and vertebral column to examine the brain and spinal cord.
23. Examine the skeleton and musculature.
24. Record the findings.
25. Summarize the appearances found.
26. Collect suitable materials for microbiological, histopathological, parasitological and
chemical examination as required.
27. Arrive at an etiological diagnosis based on the PM findings and the results of the materials examined.

PRECISE OF THE CASE

• This includes date of admission, ward, case number if treated in Veterinary Hospital or
admission as carcass with case number, date and time to death reported, date and time of
making PM, history with symptoms, treatment details and clinical diagnosis

A. POST-MORTEM RECORD
1. Species: Here one should write the species of animal such as bovine, porcine, equine, poultry, etc.
2. Date: Date of the post-mortem examination.
3. Case no.: The serial number of your post-mortem book. It shows cumulatively how many animals are examined by you in necropsy.
4. Breed: Mention the breed of animal, if known or supplied in the request form, such as Murrah buffalo, Jersey cattle, etc.
5. Age/Born: Age of animal or its date of birth. In case the exact age is not known then mention young, adult or chick, grower, adult in case of poultry.
6. Sex: Sex of animal (male or female).
7. Identification number/mark: It must be filled with utmost care; the number (tattoo number or brand number) should be the same as on animal. If the identification number is not available/illegible then write the characteristic mark of animal.
8. Owner: Here, the name of owner with complete address must be filled clearly. The address should be complete enough so that the report can reach the owner through post also.
9. Referred by: In this column, the name of Veterinary Officer/any other officer who referred the case for post-mortem examination should be written. Sometimes owner himself/herself is interested in post-mortem examination of animal; in such case the name of owner should be written.
10. History of the case: This includes the clinical illness of animal, duration of illness, epidemiological data, tentative diagnosis, therapeutic and preventive measures adopted. This is very important and information of this column has an important role in making the diagnosis.
11. Reported date and time of death: It should have the exact date and time of death of animal. Sometimes, it is difficult to note the exact time then one can write morning, noon, evening, midnight etc. to approximate the timings of death of animal. In some large farms, it is very difficult to record information with regard to each individual animal/bird so here one can write “previous night” as time of death.
12. Date and time of post-mortem examination: Pathologist conducting post-mortem examination should write here the exact time and date of the post-mortem examination. The above information is very important to arrive any conclusive diagnosis. The correct information enhances the specificity of post-mortem diagnosis. Some points might be looking like insignificant but one should not overlook them and write as correct as information he/she can gather from the owner’s request letter/form.
B. POST-MORTEM EXAMINATION
It includes the observations made by the pathologist conducting postmortem examination. This part of report should be filled in as soon as possible after the post-mortem examination. It is advisable that one should record some points on a small paper or diary during postmortem examination and fill them in report after the conduct of postmortem examination.
1. External appearance: Record the lesions observed in intact animal before its opening. One should place on record the side of animal lying down, lesions on skin, external parasites, trauma etc.
2. Subcutaneous tissue and musculature: The observations made after removal of skin, on subcutaneous tissue and muscle should be included in this column.
3. General observations after opening the carcass: It contains the general information or lesions present in abdominal and thoracic cavity such as accumulation of fluid, pus, blood, clot of blood, post-mortem changes such as pseudomelanosis, etc.
4. Respiratory system: Record the lesions observed in respiratory system right from external nares, nasal passage, trachea, bronchi and lungs alongwith mediastinal lymphnodes.
5. Cardiovascular system: Record the lesions present in heart, aorta, arteries, veins and lymphatics.
6. Digestive system: Record the lesions observed in digestive tract from month cavity, esophagus, crop, proventriculus, gizzard (poultry), rumen, reticulum, omasum abomasum (ruminants), stomach, intestines, rectum, anus, cloaca, vent (poultry), liver, pancreas, gall bladder etc.
7. Urinary system: Place on record the lesions present on kidneys, ureter and urethra.
8. Genital system: Record the lesions present in ovaries, uterus, oviduct, cervix and vagina in females and testes, penis etc. in males. Be careful in recording lesions in this column as it should match with the sex of animal written in post-mortem record section.
9. Immune system: Record the lesions present in spleen, bursa, thymus, lymphnodes, respiratory associated lymphoid tissue (RALT), gut associated lymphoid tissue (GALT) etc. Careful recording of lesions in these organs will be helpful in diagnosis.
10. Nervous system: Place on record the lesions present in brain, spinal cord and nerves. Most of the pathologists overlook this system and often not taken pain to examine the brain. It should not be done and every effort should be made to examine and place on record the lesions present in this system.
11. Miscellaneous observations: Here one can record any missing observation which has not been covered above.
12. Post-mortem diagnosis: This is very important. Based on the history and lesions present in different systems, pathologists by using his experience and conscience conclude the diagnosis. He/she may also write suggestions alongwith diagnosis or some points to suggest the diagnosis and/or contain the disease in other animals.
13. Signature of officer conducting post-mortem: Each and every report must be signed by the officer doing post-mortem examination. Without signature of competent officer, it has no validity.
14. Place and date: The person signing the post-mortem report must also write date and place of post-mortem examination.
POST-MORTEM REPORT STANDARD FORMATE
POST-MORTEM RECORD
1.Species:
2. Date:
3. Case No.:
4. Breed:
5. Age/Born:
6. Sex:
7. Identification No.:
8. Owner with address:
9. Referred by:
10. History of the case:
11. Reported date & Time of Death:
12. Date and Time of post-mortem examination:
POST-MORTEM EXAMINATION (SECOND PAGE)
1. External appearance
2. Subcutaneous tissue and musculature
3. General observations after opening the carcass
4. Respiratory system 5. Cardiovascular system
6. Digestive system
7. Urinary system
8. Genital system
9. Immune system
10. Nervous system
11. Miscellaneous observations
12. Post-mortem diagnosis
Date:
Place:
Signature of officer conducting PM