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Tanning Skins

Autopsy of a goat

FIRST PUBLISHED APRIL 1986
AUTHOR:
Dr. J.W. McDonald, District Veterinary Officer, Department of Agriculture and Rural Affairs, Alexandra, Vic 3714.
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Introduction

An autopsy is an examination of a body after death. A background knowledge of anatomy and pathology is required. This article presents a synopsis on both.

It is unreasonable for goat owners to expect to learn how to autopsy goats from a few pages like this. However, the goat owner should know something about goats inside as well as out. The inside of an animal is important because very often a postmortem or autopsy on a dead animal is vital in saving the lives of many other animals in the herd.

Competent and capable goat owners may do autopsies and discuss with their private Veterinary Practitioners such things as specimen selection and diagnosis. However this is very much a personal relationship and ability issue between those involved.

An autopsy is only one tool in the complex business of diagnosis and disease control. Other facets include predisposing causes, medicine, pathology, laboratory testing and, of course, experience. Dabble a little if you will, looking inside the occasional death, but for the disease outbreak or flock production problem, consult the expert.

The primary purpose of this article is to show the broad approach to an autopsy, how complicated it can be and to know your limitations. The secondary purpose is to encourage more autopsies in the goat industry, preferably by Vets and Veterinary Laboratories.

Specimen Selection

Rationale of an autopsy is to systematically dissect and examine a carcase to detect departures from normal and to determine the nature and cause of these abnormalities. The affected specimen is excised and placed in a plastic bag for chilling in the fridge before transporting on ice in an esky to your Vet or on his advice to a Regional Veterinary Laboratory.

External Examination

First, examine the carcase from the outside. When the animal is lying on its side with evidence of struggling - leg scratch marks in the ground, this indicates such diseases as pulpy kidney, some poisonings and brain diseases.

A carcase lying on its chest hows the animal died quietly such as with milk fever, exposure, starvation or dehydration. If the carcase is bloated and decomposing quickly, this points towards a clostridial disease or death with a high fever.

Examine the skin, feet, nose, mouth, eye and conjunctiva, anus, vagina, udder, testicles and penis. Any abnormalities should be noted for further examination during the autopsy.

Equipment

All autopsies should be done wearing rubber gloves. If the hands are scratched, punctured, or even chapped, they can be invaded by many different kinds of dangerous micro-organisms, some of which are normally found in, a goat. Many micro-organisms that cause disease in the dairy goat also cause disease in man such as anthrax, Q fever and leptospirosis. It is not necessary to cut the skin away from a goat to be postmortemed, but the person may wish to remove it to get it out of the way. If the skin is removed, a layer of subcutaneous muscle can be seen which acts as a sling for the organs inside. A good broad bladed knife with a coarse sharpening steel are essential. Scissors and a pair of secateurs or a bone saw complete the kit. Have a few plastic bags on hand for specimens.

Opening Method - reflect the legs, abdominal wall and ribs

A quick simple method is to cut under the armpit until the front leg can be folded back, then cut into the hip joint and thigh muscles and ventral abdominal skin until the hind leg can be folded back along with the skin between the front and hind legs. Cut the abdominal wall down along the last rib, along the backline to the pelvis and reflect downwards. Cut along the cartilages between the ribs and the breast-bone, fold the ribs back so they break at the backline. If the goat is aged, it is difficult to cut the cartilage between the ribs and breast-bone, so use pruning secateurs or a bone saw.

Photo 1: Opening the goat

Udder, Lymph Nodes

If the animal is a milker, the person doing the postmortem will notice that the udder is a cutaneous (skin) organ. It does not go any deeper than the medial suspensory ligament, which holds the udder up, and which can be seen, is very important for that reason.

The super-mammary lymph nodes, at the rear of the udder, should be evaluated for size. These lymph nodes, when enlarged, are indicative of the presence of infection in the udder. They can also be palpated in a live animal that is infected.

The normal udder is firm, and when cut, should ooze milk from every direction as the alveoli are damaged. A normal udder has a soft, spongy tissue, something like the tissue of the lung, and it should be a pale pink colour. Cutting down the teat canal will reveal Furstenburg's rosette, at the top of the teat where mastitis usually strikes first. Mastitis is indicated by darkening or gangrene, many small abscesses or just inflammation and clots in the milk.

Photo 2: Examining the head and neck

Head and Neck

Open the skin along the neck and under the chin and reflect back with the reflected front leg. It will be possible to see the lymph nodes under the jaw and determine if they show any swelling or sign of infection. Here too, it is possible to see the underside of the tongue, and the blending into the gullet and windpipe. The voice box will be seen as well, as the pointy tip or epiglottis, which through its action directs food down the gullet and air down the trachea, or wind pipe, which lies in front of the gullet.

The almost bony trachea (windpipe) will be quite obvious, and if it is opened longitudinally, its divisions into the bronchi can be seen. The thyroid gland (3 x 1 cm cylinders) can also be seen in the area of the voice box on both sides of the trachea. The small parathyroids, the calcium controllers of the body, can be seen, one on each side of the thyroid. More lymph nodes are found in this area, too, and evidence of swelling should be noted.

Inside the mouth the teeth should be smooth and all present. Teeth abnormalities include missing, worn or loose incisors and missing, overgrown or hooked molars with lacerations to the cheek and tongue. The tongue, eyes, nose and lips should be examined for departures from normal. If the goat died with nervous symptoms the head should be removed and chilled in the fridge until it can be forwarded to a Veterinarian.

Photo 3: The stomachs, caul fat and intestines

The Abdomen; Stomachs and Intestines

When the abdomen is opened, the stomachs may balloon out because of the gas inside. The rumen or paunch will be the most obvious compartment of the stomach. It is closely attached to the reticulum or honey-comb stomach and the oesophagus empties into both of the compartments. It empties into the reticulum of young animals and into the rumen of older animals. Under the rumen and reticulum, lies the omasum, or bible and finally the abomasum or true stomach, appears.

All compartments of the stomach should look clean and clear white in colour. Except for the multi-leafed, omasum and honeycombed reticulum, stomach linings are quite thin, almost transparent.

Inflammation of the stomachs and the intestines of the ruminant by arsenic poisoning or salmonella is quite obvious, and such afflictions may also be accompanied by grossly enlarged lymph nodes along the digestive tract. The abomasum empties into the small intestine, which, when it is removed and stretched out measures about 90 metres. The small intestine is usually fluid filled and if it is inflamed the animal probably had scours. The large intestine empties into the rectum, and the faecal material throughout the large intestine and into the rectum should look normal and gradually change in consistency from soft to pelleted.

The omentum or caul-fat should be a fatty web-like tissue. If the goat is emaciated there will be no caul-fat. Tapeworm cysts, the bladder-worm, or hydatids may be seen in the omentum, liver or lungs.

Uterus/Ovaries or Penis/Testicles

Between the intestinal mass and the spine rest the reproductive organs of the female. The uterus in a doe not in kid should be collapsed, and the fallopian tubes should circle around the ovaries, the ovaries will, in a mature doe, probably contain follicles ready to burst forth the ova or eggs. The ovaries are quite small in a goat. Behind the uterus lies the bladder which sometimes holds bladder stones. The buck is more susceptible to obstruction from bladder stones because of the S-bend path his urethra has to take from the bladder to the outside. The testicles should be firm with a thumb-nail sized gland on the bottom end. Swellings indicate disease such as Ovine Brucellosis. At this point it is better to remove the intestines to reveal other organs.

Photo 4 A cut kidney showing the layers

The Kidneys, Ureters and Adrenal Gland

Going forward from the bladder are the small (2mm) ureters, which drain the two kidneys into the bladder. The one on the right side is called the floating kidney, and it moves around the peritoneal or abdominal cavity, often being pushed by the rumen as it fills. The left kidney is under the peritoneum (lining of the abdominal cavity) and it is usually buried deep in fatty tissue. The kidneys are a very important indicator of health. They should be firm to the touch, not soft or spongy. They should be deep red in colour, and paleness or white spots are abnormal. If the kidney is cut in half, the outer edge should be a little darker than the centre. The outer layer is called the cortex. A cut kidney shows definite layers with the cortex on the outside. Abnormal kidneys are often pulpy or spongy with no layers visible. In the centre or hylus, kidney stones may sometimes be seen. The kidneys are filtering organs which manufacture urine out of the waste products of the blood. The centre portion of the kidney is the medulla. Resting behind each kidney is the 2-3cm long adrenal gland, an important hormone-producing gland. The adrenals are small and considered second to the pituitary gland (in the skull) in importance.

The Spleen

On the left side of the animal, fitting tightly against the lower portion of the rib cage, the spleen is probably the most important diagnostic organ of the body.

The spleen is well attached to the side of the rumen and is concerned with blood filtering and blood cell manufacture. It is a fairly large organ, and somewhat flat. Its normal colour is dark bluish red and many white speckles cover the surface, its texture is like that of the liver.

If the spleen is much enlarged, and if the white areas protrude, then there is evidence of abnormalities there. Because of its filtering capacity, the spleen is an excellent organ to have cultured to discover what micro-organisms were involved in the death of the animal.

Most normal organs, even after death, will return to normal shape after being depressed with the finger. If the depression remains, this is an indication of inflammation or dropsy.

The Liver

On the right side of the animal, fitted against the diaphragm (sheet muscle that divides the peritoneal and thoracic cavities), is the large and important liver. This organ is also important in diagnosing disease and is a good organ to have cultured.

The liver should respond to handling as the spleen does, with depressions returning to normal. It should be a deep red with no variations. The texture is moist and it cuts clean.

Attached to the liver is the gall bladder. It manufacturers a digestive agent (bile) for the intestines. The gall bladder should be comparatively small, and it will be full of bluish or greenish fluid, which, if the animal is being butchered for meat, can ruin the meat for eating. The gall bladder is attached to the liver by the bile ducts and it is easily removed with care.

The liver is also a principle organ in the metabolism of all food. Liver disease, jaundice or hepatitis may be suspected in an animal that shows a yellow colour to the membranes. White spots on the liver are also indicative of other infections.

If the liver is removed and the diaphragm cut further, entry to the thoracic cavity can be made.

The two most prominent organs there, of course, are the heart and lungs.

Photo 5: Opening the heart-sac

The Heart and Lungs

The lungs are attached to the trachea, which as it was mentioned earlier splits into the bronchi. These two bronchi, entering the lungs, are where lung worms will be found if they are present. The bronchi continue to split into smaller and smaller bronchi until the tiny alveoli are formed. The healthy lung is pale in colour, and it floats when put in water. Inflammation, scarring, inflexibility of tissue are all obvious abnormalities. Solid, greyish red areas in the lungs are evidence of pneumonia.

Between the lungs are two large lymph nodes. These two lymph nodes are a very important aspect in diagnosing pneumonia or even pluerisy in the animal being post mortemed. Generally, lymph nodes are found along the blood supply areas, since they filter the blood, and they are often found near the major organs. Enlarged and/or pus-filled lymph nodes always indicate infection - such as cheesy gland.

The heart is surrounded by a very tough tissue, the pericardial sac. The heart itself is quite muscular, with the left side being more muscular than the right. The goat heart lies almost squarely in the centre of the chest, its longitudinal axis almost vertical, and with the right ventricle on the right and a little nearer the head than the left.

The right ventricle, which pumps blood to the lungs, is thin compared with the rest of the organ. It may not be possible to tell by opening the heart whether or not the valves have been working properly but it is rare for a goat to die of a heart disease.

It is important when autopsying a goat to check all lymph nodes to look for evidence of internal abscesses. In case of Mycoplasma infection, the lymph nodes that are swollen may very likely have a yellowish colour to them.

The Bones and Joints

The bones should be strong and unbroken. The ribs are a good test for rickets and other bone disorders. The joints between the ribs and breast-bone should be only slightly enlarged. The ribs should break with a firm snap and should not bend. This will be more so in aged animals. Examine all the joints, are they swollen from the outside appearance? The joint fluid is scanty and clear yellow whereas with arthritis there is pus, blood or discolouration present. The joint surfaces should be smooth compared with rough surfaces and boney spicules in arthritic animals.

The Muscles

The muscles should be of normal size, colour and consistency. With white muscle disease due to selenium deficiency, the muscles of the thigh especially are swollen, hard and have white fibres; with blackleg or malignant oedema, they are swollen, black and have red jelly around them.

Other Organs

Organs such as the male accessory sex glands, pancreas, brain and so on have not been discussed but if they are swollen, discoloured or infected looking, then excise them, place in a plastic bag and be off to see your Vet.

CAUSE OF DEATH DISEASE

CLINICAL AND AUTOPSY SIGNS

SPECIMENS TO SELECT

Anthrax

Bloody discharge from mouth,nose and anus, blood doesn't clot. Be careful as can affect humans.

Blood smear, or an ear. (see your vet)

Leptospirosis

Jaundice, blood in the urine, fever, abortion and up to 40% mortality.

Fresh kidney, liver and urine.

Impaction

Swollen rumen, omasum or bible hard and swollen, dry contents.

Stomach and contents.

Enterotoxaemia

Inflamed small intestine, haemorrhages in the lining of the heart, rapid post modem decomposition and soft pulpy kidneys.

Intestine, kidney and brain.

Ostertagia

Masses of 15mm hairlike worms in abomasum, emaciation, hard pelleted faeces or sometimes scours if associated with stomach damage.

Abomasum and intestines.

Lungworm

100m x 1 mm worms in bronchi of the lungs causing red consolidation and pneumonia of lungs.

Lungs

Barbers Pole

Masses of 30mm red and white 1 mm thick worms in the abomasum causing anaemia (bottle jaw) wasting and hard dry faeces.

Abomasum and intestines.

Mastitis

Swollen hard udder with watery or flakey milk, associated lymph nodes may be swollen.

Udder and milk

Gangrenous mastitis

Skin of udder is dark red or black with blisters, milk is red and watery and udder tissue is hard and juicy with lymph nodes similarly affected.

Udder and milk

Coccidiosis

Blood stained scour, wasting and unthriftness. Common in 8 wk old kids or in animals recently from the bush.

Intestines and faecal samples.

Johnes Disease

Wasting, harsh coat and diarrhoea in older goats. Common in dairy goats but rare in fibre goats.

Intestines, blood and faecal sample.

Milk fever

Goat dies on chest with hind legs pointing out behind. Post mortem may show vomiting with rumen contents inhaled into lungs, faeces are usually dry and hard.

Blood sample

Pregnancy Toxaemia

Swollen yellow liver, whitish flakes in the fat depots with a large kid or multiple kids.

Blood, urine and liver samples.

Goitre

Iodine deficiency in late pregnancy on lush cover pastures. Swollen throat due to normal thyroid of 2cm x 1/2 cm, increasing to 10 to 20cm x 1 to 10cm.

Thyroid

White muscle disease

Hard, swollen thigh muscle with white streaks in affected muscle including the heart.

Muscle, blood

Tetanus

Animal dead on side with evidence of leg paddling, stiff legs and head thrown back. No particular autopsy abnormalities. Clinical diagnosis is by lock-jaw and prolapsed third eyelid.

No specimens are diagnostic.

Mycoplasmosis

Causes pneumonia, peritonitis and arthritis with excess fluid and fibrin in these areas

Abdominal fluid, joints, blood, lungs

Copper deficiency

Causes sway back in kids - no visible lesions. Causes wasting and anaemia in adult.

Spinal cord. Blood and liver samples for both conditions.

Cobalt deficiency

Swollen friable liver, wasting, anaemia, watering of eyes.

Blood and liver

Cheesy gland

Yellow - green pus in swollen lymph nodes around the body with extended infection into peritonitis or pneumonia.

Affected gland

Poisoning-Plant

Oleander, rhododendrons and azaleas cause gastroenteritis, paralysis and death.

Stomach and heart

Poisoning - Insecticides

Nervous, over excitement, salvation

Liver, blood

Poisoning - lead

Nervous dummy syndrome

Liver, blood

Poisoning - arsenic

Inflammation, abomasum and intestines

Brain, blood, Stomach contents

Liver Fluke

Hard liver with swollen bile ducts containing liver flukes.

Liver and flukes

© 1986 A.C.G.A.