Changes

In cases of mild, acute BVD, lesions are rarely seen. When disease is more severe, the lymph nodes may appear swollen, there may be erosions and ulcerations of the gastrointestinal tract tract and serosal surfaces of the viscera may show petechial and ecchymotic hemorrhages³⁹.

In cases of mild, acute BVD, lesions are rarely seen. When disease is more severe, the lymph nodes may appear swollen, there may be erosions and ulcerations of the gastrointestinal tract tract and serosal surfaces of the viscera may show petechial and ecchymotic hemorrhages³⁹.

The pathology associated with mucosal disease is much more striking³⁴. Oral, lingual and buccal erosions are observed, and buccal lesions often coalesce to form larger areas of necrosis and sloughed epithelium. Oesophageal lesions present similarly. The gastrointestinal tract often shows characteristic pathology, but post-mortem examination must be performed soon after death so that these are not masked by autolytic changes. In the rumen, ulceration is rare but congestion and oedema may be seen along the pillars, and papillae can be reduced in size. Several discoid erosions of around 5mm in diameter appear in the abomasum, with hyperaemia of the surrounding mucosa and petechiation of the submucosa, particularly at the pylorus. Abomasal erosions occasionally enlarge and ulcerate.  

The pathology associated with mucosal disease is much more striking³⁴. Oral, lingual and buccal erosions are observed, and buccal lesions often coalesce to form larger areas of necrosis and sloughed epithelium. Oesophageal lesions present similarly. The gastrointestinal tract often shows characteristic pathology, but post-mortem examination must be performed soon after death so that these are not masked by autolytic changes. In the rumen, ulceration is rare but congestion and oedema may be seen along the pillars, and papillae can be reduced in size. Several discoid erosions of around 5mm in diameter appear in the abomasum, with hyperaemia of the surrounding mucosa and petechiation of the submucosa, particularly at the pylorus. Abomasal erosions occasionally enlarge and ulcerate. Oval erosions can be seen along the antimesenteric surface of the small intestine, overlying the lymphatic tissue of the Peyer's patches and measuring 2-5 centimetres in length. The erosions become larger (10-20 centimetres) and more numerous towards the terminal ileum, and the exposed surfaces varies in appearance. In more chronic lesions, food is seen to adhere to the underlying submucosa, and in acute disease the exposed surface is acutely congested and often haemorrhages into the gut lumen. In the large intesting, the mucosal folds may be thickened, giving the organ a stiped appearance inwardly. Petechiation and erosions are occasionally seen alonf the folds, and the large intestinal contents are watery, dark and foul-smelling.

 

 

 

expose the antimesenteric surface, will reveal oval erosions

(2 cm to 5 cm long) that overlie the lymphatic tissue in Peyer's

patches. The erosions may vary from two to three to 30 to 40.

Towards the terminal ileum the erosions can become extensive

and may be up to 10 to 20 cm in length. The exposed

submucosal surface of the erosions can vary from the chronic

lesion, with food adhering (Fig 7), to the acutely congested

one often with interluminal haemorrhage.

In the large bowel, there may be congestion of the mucosa

which gives a thickening to the mucosal folds and a striped

appearance. There may also occasionally be petechial

haemorrhages and small erosions along the folds. The

contents are dark, watery and often foul smelling.

Gross lesions seldom are seen in cases of mild disease. (Brownlie, 1985).

==Treatment and Control==

==Treatment and Control==