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Created page with '==Bloat/Tympany== * When eructation fails, the rumen becomes distended due to the accumulation of gas …'
==Bloat/Tympany==
* When [[Eructation - Anatomy & Physiology|eructation]] fails, the [[The Rumen - Anatomy & Physiology|rumen]] becomes distended due to the accumulation of gas produced by the fermentation process. This distension is known as '''bloat''' or '''tympany'''.
===Clinical===
*The disease is acute and progressive and will result in death in a matter of hours.
===Pathology===
* In severe bloating, that the [[The Rumen - Anatomy & Physiology|rumen]] almost fills the abdomen.
** Diaphragm is displaced forwards, compressing the lungs.
** Posterior vena cava (lying dorsally) is also compressed, reducing the venous return to the heart.
** Respiration is depressed and animals die from anoxia.[[Image:oesophageal bloat line.jpg|thumb|right|150px|Oesophageal "bloat line" (Courtesy of Elspeth Milne)]]
*** Blood is dark (hypoxic) and clots poorly.
* The anterior parts of the body are often characteristically acutely congested.
** Oedema and subcutaneous haemorrhage of head and neck tissues.
** [[Oesophagus - Anatomy & Physiology|Oesophageal]] "bloat line" at thoracic inlet.
*** Congested and haemorrhagic cranially, pale caudally.
===Pathogenesis===
* There are two forms of bloat:
** '''Frothy bloat/ Primary bloat'''
*** Occurs following ingestion of large amounts of succulent green plant material. This is highly fermentable and produces large amounts of gas.
*** Material contains high levels of soluble proteins. These act as foaming agents by reducing surface tension but increasing surface viscosity of rumenal liquids and a stable rumenal foam forms.
*** The [[Volatile Fatty Acids - Anatomy & Physioogy|volatile fatty acids]] of the plant material consumed lower pH, optimising conditions for formation of froth.
*** Gas present in bubble form is insufficient to trigger eructation, and so the [[The Rumen - Anatomy & Physiology|rumen]] becomes distended.
** '''Free gas bloat/ Secondary bloat'''
*** May be:
**** '''Acute'''
*****Due to sudden [[Oesophagus - Anatomy & Physiology|oesophageal]] obstruction, for example by a solid foreign body (e.g. a piece of potato or turnip).
**** '''Chronic'''
***** Results from partial [[Oesophagus - Anatomy & Physiology|oesophageal]] obstruction/ compression, or from interference with the normal eructation mechanism, e.g. with:
****** partially obstructive foreign bodies
****** actinobacillosis in the oesophagus or [[Oesophageal groove|oesophageal groove]]
****** [[Oesophagus - Anatomy & Physiology|oesophagus]] or groove tumours
****** chronic inflammatory or adhesive disease of the [[The Reticulum - Anatomy & Physiology|reticulum]]
***** Some passage of gas is possible, so gas build-up and distenesion is more prolonged.
***** Interference with cardiac and respiratory function is seldom life threatening.
[[Category:Forestomach - Nutritional Pathology]][[Category:Cattle]]
* When [[Eructation - Anatomy & Physiology|eructation]] fails, the [[The Rumen - Anatomy & Physiology|rumen]] becomes distended due to the accumulation of gas produced by the fermentation process. This distension is known as '''bloat''' or '''tympany'''.
===Clinical===
*The disease is acute and progressive and will result in death in a matter of hours.
===Pathology===
* In severe bloating, that the [[The Rumen - Anatomy & Physiology|rumen]] almost fills the abdomen.
** Diaphragm is displaced forwards, compressing the lungs.
** Posterior vena cava (lying dorsally) is also compressed, reducing the venous return to the heart.
** Respiration is depressed and animals die from anoxia.[[Image:oesophageal bloat line.jpg|thumb|right|150px|Oesophageal "bloat line" (Courtesy of Elspeth Milne)]]
*** Blood is dark (hypoxic) and clots poorly.
* The anterior parts of the body are often characteristically acutely congested.
** Oedema and subcutaneous haemorrhage of head and neck tissues.
** [[Oesophagus - Anatomy & Physiology|Oesophageal]] "bloat line" at thoracic inlet.
*** Congested and haemorrhagic cranially, pale caudally.
===Pathogenesis===
* There are two forms of bloat:
** '''Frothy bloat/ Primary bloat'''
*** Occurs following ingestion of large amounts of succulent green plant material. This is highly fermentable and produces large amounts of gas.
*** Material contains high levels of soluble proteins. These act as foaming agents by reducing surface tension but increasing surface viscosity of rumenal liquids and a stable rumenal foam forms.
*** The [[Volatile Fatty Acids - Anatomy & Physioogy|volatile fatty acids]] of the plant material consumed lower pH, optimising conditions for formation of froth.
*** Gas present in bubble form is insufficient to trigger eructation, and so the [[The Rumen - Anatomy & Physiology|rumen]] becomes distended.
** '''Free gas bloat/ Secondary bloat'''
*** May be:
**** '''Acute'''
*****Due to sudden [[Oesophagus - Anatomy & Physiology|oesophageal]] obstruction, for example by a solid foreign body (e.g. a piece of potato or turnip).
**** '''Chronic'''
***** Results from partial [[Oesophagus - Anatomy & Physiology|oesophageal]] obstruction/ compression, or from interference with the normal eructation mechanism, e.g. with:
****** partially obstructive foreign bodies
****** actinobacillosis in the oesophagus or [[Oesophageal groove|oesophageal groove]]
****** [[Oesophagus - Anatomy & Physiology|oesophagus]] or groove tumours
****** chronic inflammatory or adhesive disease of the [[The Reticulum - Anatomy & Physiology|reticulum]]
***** Some passage of gas is possible, so gas build-up and distenesion is more prolonged.
***** Interference with cardiac and respiratory function is seldom life threatening.
[[Category:Forestomach - Nutritional Pathology]][[Category:Cattle]]