GIT MCQ (2)

Forestomachs

• The forestomachs consist of the rumen, reticulum, and omasum.
• Lined by stratified squamous epithelium.
• Examination of plant contents within the rumen can indicate toxicities.

Ruminal Tympany (Bloat)

• Over-distension of the rumen & reticulum with fermentation gases.
• Primary bloat (frothy bloat): gases trapped within the rumen content.
  • Caused by:
    • Plants with high soluble proteins (e.g., white clover, alfalfa, red clover)
    • High grain diets (less salivation, saliva has anti-foam properties)
• Secondary bloat (free gas bloat): blockage in the eructation mechanism.
  • Causes:
    • Obstruction in the esophagus
    • Vagal indigestion: rumen motility inhibited due to vagal nerve damage
  • No foam, just excessive gas.

Bloat Death

• Pressure from the expanding rumen compresses the thorax, compressing the vena cava.
• This leads to poor venous return and cardiac arrest.
• Grossly the animal found dead on its back with abdominal distension and marked congestion of head & neck.
• A "bloat line" on the esophagus at the thoracic inlet may be present, with cranial congestion.

Foreign Bodies

• Trichobezoars (hair balls)
• Phytobezoars (plant balls)
• Lead substance poisoning
• Sharp metals

Sharp Metal Fate

• Deposited directly into the reticulum:
  • Localized reticulitis
  • Penetrated reticulum, diaphragm, and pericardial sac (Traumatic Reticulopericarditis)
  • Penetrated reticulum, damaging the vagus nerve (Vagal indigestion)

Forestomach Inflammation

• Causes:
  • Extension from oral & esophageal infections
  • Grain overload (ruminal lactic acidosis)
• Pathogenesis:
  • Sudden change to high CHO diet, overgrowth of gram + bacteria.
  • Increased lactic & dissociated fatty acids lower pH below 5, leading to ruminal atony and damage to mucosa.
  • Fluid moves from the blood into the rumen.
• Sequelae:
  • Sudden death from dehydration, acidosis, and endotoxemia
  • Bacterial rumenitis: Fusobacterium necrophorum
  • Healed ulcers (stellate scars)
  • Liver abscesses: may rupture into vena cava, causing fatal septic embolism
  • Mycotic rumenitis: well-demarcated, circular hemorrhagic infarcts, can become systemic (placentitis & abortion)

Acute Gastric Dilation & Volvulus (GDV)

• Large dog breeds.
• Large meal (dry or highly fermentable).
• Gas buildup causing functional obstruction of cardia & pylorus.
• Dilation leads to rotation on its mesenteric axis (volvulus).
• Compression of diaphragm, vena cava, affecting venous return and cardiac output.

Abomasal Displacement

• Left abomasal displacement:
  • Mostly in dairy cows, older, high producers
  • Postcalving period, common GI disorder requiring surgery (seldom fatal)
• Right abomasal displacement:
  • 15% in cows and calves.

Gastric/Abomasal Impaction

• Low quality roughage
• Low water intake
• Poor mastication
• Vagal nerve damage ("vagus indigestion")
• Pyloric stenosis

Gastric Dilation and Rupture

• In horses:
  • Fermentable CHO
  • Secondary to intestinal obstruction, equine dysautonomia
  • Distinction: ante mortem from post mortem rupture

Gastric Ulcers

• Imbalance between acid secretion & mucosal protection (gastric mucosal barrier).
• Epithelial necrosis, erosion, ulceration, bleeding, perforation, peritonitis.
• Causes:
  • Local mucosal injury
  • High gastric acidity
  • Local ischemia (stress ulcers)
  • Steroids & NSAIDs (aspirin)
  • Helicobacter (bacterial infection)
• Main signs:
  • Hematemesis
  • Melena
  • Anemia
  • Abdominal pain

Gastritis

• Cattle, sheep, & goats:
  • C. septicum (Braxy or bradsot)
  • C. perfringens type A (Abomasitis with ulceration)
  • Mycotic infections
• Dogs & cats:
  • Uremia
  • Chronic gastritis & Hypertrophy
  • Helicobacter

Parasitic Diseases

• Ruminants:
  • Haemonchosis
  • Ostertagiosis
  • Trichostrongylosis
• Equine:
  • Gastric bots
  • Trichostrongylosis
  • Draschia megastoma
  • Habronema

Congenital Anomalies

• Atresia:
  • Absence of a normal opening.
  • Atresia ani (absence of anus)

Intestinal Displacements and Malposition: Hernias

• Protrusion of an organ through a natural or artificial opening.
• Internal:
  • Diaphragmatic hernia (through the diaphragm)
• External (have a hernial sac):
  • Ventral
  • Umbilical
  • Scrotal

Hernia Sequelae:

• Strangulation (interference with blood flow)
• Adynamic ileus
• Perforation

Torsion & Volvulus

• Rotation of the organ around its long axis.
• Mesenteric lipomas can wrap around the mesentery or bowel, causing strangulation.

Intussusception

• Telescoping of one segment of bowel into another adjacent section.

Enteritis

• Inflammation of the intestines:
  • Enteritis: inflammation of the small intestine.
  • Typhlitis: inflammation of the cecum.
  • Colitis: inflammation of the large intestine.
  • Enterocolitis: inflammation of all intestines.
  • Gastroenteritis: inflammation of the stomach and small intestines.
  • Proctitis: inflammation of the rectum.

Diarrhea & Dysentery

• Diarrhea: increase in stool mass, frequency, and/or fluidity.
• Dysentery: painful, bloody diarrhea.

Pathogenesis of Diarrhea

• Malabsorption: defective digestion/absorption.
• Osmotic diarrhea: exerted by luminal solutes.
• Hypersecretion: excessive intestinal fluid secretion induced by enterotoxins.
• Exudation: increased capillary or epithelial permeability.

Types of Enteritis:

• Catarrhal: viral diseases
• Hemorrhagic: bacterial diseases
• Fibrinous/fibrinonecrotic: mycotic diseases
• Ulcerative: protozoal diseases
• Proliferative/hyperplastic: parasitic diseases
• Granulomatous: non-infectious disease entities

Explore the anatomy of forestomachs and the critical conditions related to ruminal tympany in cattle. This quiz covers primary and secondary bloat, their causes, and the consequences of untreated bloat leading to death. Test your understanding of these vital concepts in bovine health.