Atlas of ovine pathology

Atlas of Ovine Pathology 9 788494 040290

Atlas of Ovine Pathology

Luis Miguel Ferrer José A. García de Jalón Marcelo de las Heras

Pathology of the digestive system

Sucker lamb

Septicaemic colibacillosis 1.29 - Septicaemic colibacillosis.

Septicaemic colibacillosis is characterised by a more acute clinical course than the enteric form. Many animals fail to progress to diarrhoea, and major symptoms include poor coordination (A), depression, confusion and recumbency; death occurs within a few hours (B).

A

1.27 - Enteric colibacillosis. Acute catarrhal enteritis. The yellowish content of these intestinal portions is much more watery than in the previous picture.

B

1.30 - Septicaemic colibacillosis.

Eyeball of a dead lamb (detail). Fibrin deposition is sometimes visible in the anterior chamber.

1.28 - Enteric colibacillosis. Initial stages of colibacillary diarrhoea. Examination of faeces may be of diagnostic value.

Yellowish, highly-mucous faeces are characteristic.

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Pathology of the digestive system

Sucker lamb

Septicaemic colibacillosis 1.29 - Septicaemic colibacillosis.

Septicaemic colibacillosis is characterised by a more acute clinical course than the enteric form. Many animals fail to progress to diarrhoea, and major symptoms include poor coordination (A), depression, confusion and recumbency; death occurs within a few hours (B).

A

1.27 - Enteric colibacillosis. Acute catarrhal enteritis. The yellowish content of these intestinal portions is much more watery than in the previous picture.

B

1.30 - Septicaemic colibacillosis.

Eyeball of a dead lamb (detail). Fibrin deposition is sometimes visible in the anterior chamber.

1.28 - Enteric colibacillosis. Initial stages of colibacillary diarrhoea. Examination of faeces may be of diagnostic value.

Yellowish, highly-mucous faeces are characteristic.

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Pathology of the digestive system

Sucker lamb 1.41 - Haemorrhagic enterotoxaemia. Open jejunum from a lamb with haemorrhagic enteritis.

Note blood debris in gut lumen due to the action mainly of Clostridium perfringens type C toxins.

Cl. perfringens type B strains may also occasionally be observed.

1.42 - Haemorrhagic enterotoxaemia. Open abomasum.

Note digested blood, which has turned a dark colour.

1.43 - Haemorrhagic enterotoxaemia. Kidney surface and section, showing softened appearance and subcapsular bleeding.

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Lamb dysentery 1.44 - Lamb dysentery. 12-day-old lamb. Perianal area stained with whitish faeces. Although faeces are initially whitish, they tend to darken as the disease progresses, due to blood content. This diarrhoea is common in lambs whose dams were not properly vaccinated against enterotoxaemia.

1.45 - Lamb dysentery. White diarrhoea. In its clinical phase, lamb dysentery is marked by the presence of white fluid faeces on the pen floor.

1.46 - Lamb dysentery. Distended intestinal loops containing whitish fluid faeces.

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Pathology of the digestive system

Sucker lamb 1.41 - Haemorrhagic enterotoxaemia. Open jejunum from a lamb with haemorrhagic enteritis.

Note blood debris in gut lumen due to the action mainly of Clostridium perfringens type C toxins.

Cl. perfringens type B strains may also occasionally be observed.

1.42 - Haemorrhagic enterotoxaemia. Open abomasum.

Note digested blood, which has turned a dark colour.

1.43 - Haemorrhagic enterotoxaemia. Kidney surface and section, showing softened appearance and subcapsular bleeding.

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Lamb dysentery 1.44 - Lamb dysentery. 12-day-old lamb. Perianal area stained with whitish faeces. Although faeces are initially whitish, they tend to darken as the disease progresses, due to blood content. This diarrhoea is common in lambs whose dams were not properly vaccinated against enterotoxaemia.

1.45 - Lamb dysentery. White diarrhoea. In its clinical phase, lamb dysentery is marked by the presence of white fluid faeces on the pen floor.

1.46 - Lamb dysentery. Distended intestinal loops containing whitish fluid faeces.

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Pathology of the digestive system

Sucker lamb 1.50 - Comparison of two lambs’ digestive tracts. Differential diagnosis: enterotoxaemia or dysentery (left) versus colibacillosis (right).

Cryptosporidiosis (Diarrhoea caused by Cryptosporidium parvum) 1.53 - Cryptosporidiosis. Animals with Cryptosporidium parvum infection. Feces are greenish, typically abundant and very watery, giving rise to marked dehydration.

Onset is usually in the first week of life, and the clinical course may extend over the following 2 or 3 weeks.

Infection is often combined with other intestinal agents (E. coli, Clostridium), which considerably aggravates morbidity and mortality.

1.51 - Colibacillosis and enterotoxaemia, combined lesions.

Mixed infection by E. coli and Clostridium spp. may occasionally arise. In such cases, some portions of the gut display catarrhal enteritis, with yellowish content, while other portions show evidence of haemorrhagic enteritis.

1.52 - Intestinal loops distended by gas formation. In lambs over 3 weeks old, the action of the epsilon toxin produced by Cl. perfringens types B and D may prompt symptoms resembling those of adult enterotoxaemia. In such cases, tympanism of the gut is accompanied by foul luminal content.

1.54 - Cryptosporidiosis. Subacute catarrhal enteritis. Blind gut containing greenish matter, and hypertrophy of mesenteric lymph nodes.

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Pathology of the digestive system

Sucker lamb 1.50 - Comparison of two lambs’ digestive tracts. Differential diagnosis: enterotoxaemia or dysentery (left) versus colibacillosis (right).

Cryptosporidiosis (Diarrhoea caused by Cryptosporidium parvum) 1.53 - Cryptosporidiosis. Animals with Cryptosporidium parvum infection. Feces are greenish, typically abundant and very watery, giving rise to marked dehydration.

Onset is usually in the first week of life, and the clinical course may extend over the following 2 or 3 weeks.

Infection is often combined with other intestinal agents (E. coli, Clostridium), which considerably aggravates morbidity and mortality.

1.51 - Colibacillosis and enterotoxaemia, combined lesions.

Mixed infection by E. coli and Clostridium spp. may occasionally arise. In such cases, some portions of the gut display catarrhal enteritis, with yellowish content, while other portions show evidence of haemorrhagic enteritis.

1.52 - Intestinal loops distended by gas formation. In lambs over 3 weeks old, the action of the epsilon toxin produced by Cl. perfringens types B and D may prompt symptoms resembling those of adult enterotoxaemia. In such cases, tympanism of the gut is accompanied by foul luminal content.

1.54 - Cryptosporidiosis. Subacute catarrhal enteritis. Blind gut containing greenish matter, and hypertrophy of mesenteric lymph nodes.

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Pathology of the digestive system

Feeder lamb and replacement ewes 2.15 - Tricobezoars in the abomasum of a replacement ewe lamb with ruminal acidosis. Barley grain overload and formation of black hairballs due to ingestion of pigmented wool resulting from a fibredeficient diet. Note absence of hay or straw.

2.16 - Phytobezoars (A) and tricobezoars (B). Abomasum (detail).

This frequent post-mortem finding may be attributed, among other things, to: fibre- or mineral-deficient diet, overcrowding or other stressful situations.

2.12 - Ruminal acidosis in a replacement ewe lamb.

Rumen contains abundant cereal grains; abomasal haemorrhage due to grain overload and acidosis.

2.13 - Ruminal acidosis. Rumenitis-multiple abscess complex. Ruminal acidosis favours the passage of ruminal bacteria that give rise to abscesses in the liver.

A

B 2.14 - Phytobezoars in the rumen. Numerous balls of plant fibres encrusted with mineral salts in a replacement ewe lamb fed an unbalanced diet.

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Pathology of the digestive system

Feeder lamb and replacement ewes 2.15 - Tricobezoars in the abomasum of a replacement ewe lamb with ruminal acidosis. Barley grain overload and formation of black hairballs due to ingestion of pigmented wool resulting from a fibredeficient diet. Note absence of hay or straw.

2.16 - Phytobezoars (A) and tricobezoars (B). Abomasum (detail).

This frequent post-mortem finding may be attributed, among other things, to: fibre- or mineral-deficient diet, overcrowding or other stressful situations.

2.12 - Ruminal acidosis in a replacement ewe lamb.

Rumen contains abundant cereal grains; abomasal haemorrhage due to grain overload and acidosis.

2.13 - Ruminal acidosis. Rumenitis-multiple abscess complex. Ruminal acidosis favours the passage of ruminal bacteria that give rise to abscesses in the liver.

A

B 2.14 - Phytobezoars in the rumen. Numerous balls of plant fibres encrusted with mineral salts in a replacement ewe lamb fed an unbalanced diet.

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Pathology of the digestive system

Feeder lamb and replacement ewes

A

A

B

B

2.37 - Coccidiosis. Subacute and chronic catarrhal enteritis. The gross appearance of the liver in coccidiosis may vary considerably, from thinning of the wall and formation of small nodules in the mucosa (A), to thickening of the wall and hypertrophy of mesenteric lymph nodes (B).

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2.38 - Coccidiosis. Chronic hypertrophic catarrhal enteritis. Intestinal mucosa (detail), showing thickening of wall and folding of mucosa in portions of the ileum (A) and caecum (B).

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Pathology of the digestive system

Feeder lamb and replacement ewes

A

A

B

B

2.37 - Coccidiosis. Subacute and chronic catarrhal enteritis. The gross appearance of the liver in coccidiosis may vary considerably, from thinning of the wall and formation of small nodules in the mucosa (A), to thickening of the wall and hypertrophy of mesenteric lymph nodes (B).

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2.38 - Coccidiosis. Chronic hypertrophic catarrhal enteritis. Intestinal mucosa (detail), showing thickening of wall and folding of mucosa in portions of the ileum (A) and caecum (B).

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