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| − | ==Rumenal Acidosis== | + | ==[[Rumenal Acidosis]]== |
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| − | * Like bloat, rumenal acidosis is associated with mismanagement of feeding and involves cessation or depression of [[Rumination - Anatomy & Physiology|rumenal movements]] with development of a degree of tympany.
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| − | * More common in cattle and goats than in sheep due to differences in diet.
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| − | ===Clinical===
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| − | * Animals display signs of abdominal discomfort, but usually recover if treated.
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| − | * Acute disease can result in death if acidosis is severe.
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| − | ===Pathogenesis===
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| − | * Occurs following feeding of highly fermentable material, usually carbohydrate, in the form of concentrate or cereal
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| − | ** e.g. in barley beef feeding systems.
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| − | * An overgrowth of Gram positive bacteria results, breaking carbohydrate down very quickly.
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| − | ** Increased [[Volatile Fatty Acids - Anatomy & Physioogy|volatile fatty acid]] production decreases the [[The Rumen - Anatomy & Physiology|rumen]] pH to about 5.
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| − | *** [[The Rumen - Anatomy & Physiology|Rumen]] epithelium is damaged- ruminitis.
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| − | *** Osmotic effects of [[The Rumen - Anatomy & Physiology|rumen]] contents produce severe dehydration.
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| − | *** Death may ensue when the [[The Rumen - Anatomy & Physiology|rumen]] pH drops to 4.5 or below.
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| − | * Normal flora may invade the damaged wall of [[The Rumen - Anatomy & Physiology|rumen]] e.g. Fusiformis necrophorum.
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| − | ** Results in areas with mushy necrotic papillae.
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| − | ** Especially on pillars and ventral parts of [[The Rumen - Anatomy & Physiology|rumen]].
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| − | * Excess gas production may occur
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| − | ** Concentrate does not contain soluble proteins, therefore foam does not develop.
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| − | ** Only mild to moderate free gas bloat is likely- much of the rumenal distension which occurs with rumenal acidosis is due to fluid sequestration in the [[The Rumen - Anatomy & Physiology|rumen]].
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| − | ===Pathology===
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| − | ====Gross====
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| − | * Gross PM findings may be non-specific.
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| − | * Ruminal stasis/bloat leads to rumen distension
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| − | * [[The Rumen - Anatomy & Physiology|Rumen]] contents are porridge-like.
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| − | * Rumenitis may be present
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| − | ** Normal flora invading wall of rumen may enter blood as thromboemboli and travel in the portal flow to [[Liver - Anatomy & Physiology|liver]]
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| − | ** Focal abscesses are produced, which heal with sunken star-shaped scars.
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| − | * Overgrowth of Clostridia may cause endotoxic shock with widespread petechial haemorrhages.
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| − | ====Histological====
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| − | * Microvesicles may be present in the epithelium of the [[The Rumen - Anatomy & Physiology|rumen]] papillae.
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| − | ** Contain mainly [[Neutrophils - WikiBlood|neutrophils]]
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| − | * May be focal erosions/ulceration.
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| − | ===Sequelae===
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| − | * Scarring- necrotised papillae are replaced by smooth epithelium closely adherent to sub mucosa.
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| − | * Has economic significance since many barley beef livers are condemned at meat inspection.
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| − | * More persistent organisms can invade [[The Rumen - Anatomy & Physiology|rumen]] wall producing chronic infection.
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| − | ** These are often fungi, e.g. Mucor (see [[Forestomach Inflammation - Pathology#Mucormycosis|Mucormycosis]]).
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| | [[Category:Forestomach - Pathology]] | | [[Category:Forestomach - Pathology]] |