Diseases of the Forestomach

Question 1

What determines the development and height of ruminal papillae? What are potential
causes of short, clumped and/or hyperkeratotic ruminal papillae?

Answer 1

Proper diet and function of the oesophageal groove - starving ruminants have very short hardly there papillae

• clumped due to not enough roughage in diet
• keratinized due to lack of vitamin A

Question 2

What is the reference range for the pH of ruminal fluid?

Answer 2

5.5-7.5

Question 3

What is the significance of adherent ruminal mucosa several hours after death of a
ruminant?

Answer 3

this is abnormal and may reflect rumenitis or ruminal fibrosis

Question 4

What is meant by the term bloat?

Answer 4

= dilation of the rumen, ruminal tympany, hoven

• can be primary (acute) or secondary (chronic)
• 50% mortality rate

Question 5

What is primary or frothy bloat? What is its most common cause and why? What
causes primary bloat in feedlot cattle?

Answer 5

acute condition of the rumen in which stable foam forms and prevents eructation of fas

• often associated with consumption of succulent legumes (pasture bloat) because they are so full of water stimulate less saliva production = increased viscosity of ruminal fluid - foam
• may develop in feedlot cattle due to high concentrate and low roughage diets = also getting cattle from different areas on different diets

Question 6

What are the potential consequences of primary bloat? What post mortem lesions might
be found in a cow that has died of primary bloat?

Answer 6

often sudden death

• animals found lying on backs , sawhorse posture - abdomen markedly distended by gas
• bloat line = in oesophagus at level of thoracic inlet
• head/neck oedema and haemorrhage

Question 7

What is secondary bloat? What are possible causes of secondary bloat? What post
mortem lesions might be found in a ruminant that has died from secondary bloat?

Answer 7

• usually a chronic condition referable to a physical or functional obstruction preventing eructation of gas from the rumen
  -i.e. tumour, foreign body etc.
  Post mortem findings are the same as primary bloat but without the stable foam formation = physical obstruction instead sometimes

Question 8

What is meant by the term ruminal drinker?

Answer 8

another form of secondary bloat sometimes = failure of the oesophageal groove reflex in bucket-fed calves
- see similar problem in calves fed by stomach tube sometimes

Question 9

What is a trichobezoar? What may contribute to the formation of trichobezoars in the
forestomach of ruminants? What is their significance?

Answer 9

it is a foreign body = spherical mass largely composed of hair or wool
common in younger animals
- may be associated with inadequate dietary fibre, boredom, pica or skin disease

Question 10

What is a phytobezoar? What may contribute to the formation of phytobezoars in the
forestomach of ruminants? What is their significance?

Answer 10

• another foreign body = spherical mass largely composed of plant fibres
• may be due to rough feed or oral/dental disease that impairs mastication

Question 11

Outline the pathogenesis and potential consequences of traumatic reticuloperitonitis.

Answer 11

HARDWARE DISEASE: sharp foreign body perforates reticulum during contractions - perforates usually cranioventral direction - bacteria infect area and extend along the perforation track from the reticulum
- could be incomplete, reticulum, diaphragm (pneumonia), pericardial sac (congestive heart failure right side)
lots of other sequelae depending on how it penetrates/where it penetrates

Question 12

What is meant by the term vagus indigestion? What clinical signs are suggestive of
vagus indigestion? What are possible causes? What post mortem findings might suggest
a diagnosis of vagus indigestion?

Answer 12

= clinical syndrome resulting from a physical or functional outflow obstruction of the forestomach or abomasum -> distension of the rumen and reticulum
clinical signs: persistent ruminal atony irregular motility, gradual bilateral abdominal distension, inappetence and decreased milk production
causes: traumatic reticuloperitonitis, physical obstruction, damage to vagus nerve, pregnancy
post-mortem: rumen distended with watery fluid lacking odour, unmacerated food particles flot, omasum = v large and impacted with dry feed, sam with abosmasum

Question 13

What is the most common cause of rumenitis? Outline its aetiopathogenesis.

Answer 13

= inflammation of the rumen
Lactic Acidosis: grain overload
- due to dietary overload with rapidly fermentable carbohydrates - or sudden increase in amount of carbohydrates in diet = changing diet too quickly
- see a lot in dairy and feedlot animals
outline: photo

Question 14

What post mortem findings would support a diagnosis of ruminal lactic acidosis?

Answer 14

• Diagnosis can be difficult in acute phase

- most reliable is histo and looking for those ulcers whether old or new

Question 15

What are common secondary complications of ruminal lactic acidosis?

Answer 15

bacterial and fungal infections of different magnitudes may occur - fungal are often fatal

Question 16

Apart from lactic acidosis, what are other possible causes of rumenitis?

Answer 16

Viral: BVDV, Foot and mouth diseases etc.
Toxic: parasites = flukes and nematodes

Question 17

What are the most common parasites found in the rumen and reticulum of ruminants in
Australia? What is their clinical significance?

Answer 17

paramphistomum - conical flukes, found in the ruminal papillae

Question 18

What are the most common tumours that develop in the forestomach compartments of
ruminants? With which causal agents are these associated? What is the clinical
significance of tumours involving the forestomach compartments?

Answer 18

Papilloma - fibropapilloma - squamous cell carcinoma - lymphoma - fibroma
large lesions may be in strategic locations and cause secondary bloat of vagus indigestion
- there is often no clinical significance of most neoplasias