Digestive System Lecture II PDF

Digestive System Lecture II  Forestomach The forestomachs consists of : rumen reticulum omasum  lined by stratified squamous epithelium  Examination of plant contents within the rumen might give you some hints about tox...

Digestive System Lecture II  Forestomach The forestomachs consists of : rumen reticulum omasum  lined by stratified squamous epithelium  Examination of plant contents within the rumen might give you some hints about toxicities  Ruminal tympany(bloat) Over-distension of the rumen & reticulum with fermentation gases Types:  Primary  Secondary Layers of different substances develop. Muscular movements move and mix these layers Slurry contains bits of straw/hay mixed with liquid Solid/lighter bits are the parts that get regurgitated for re-mastication  Primary bloat (frothy bloat) gases is trapped in a form of bubbles within the rumen content. Causes: White Clover LEGUMES 1- Some plants have too many soluble proteins mixed with the fluid bubbles The bubbles don't burst because of the excess protein. 2- Feeding of high grain diets less salivation (saliva has anti-foam) Alfalfa Red Clover  Secondary bloat (free gas bloat)  Blockage in the eructation mechanism Obstruction in the esophagus Vagal indigestion: rumen motility is inhibited because of vagal nerve damage. No foam (just too much gas)  Can you think, Why do animals with bloat die? The pressure from the expanding rumen compresses the thorax compresses vena cava poor venous return cardiac arrest.  Grossly Animal found dead & rolled on back Abdominal distension Marked congestion of head & neck Bloat line” on esophagus at thoracic inlet (caudal (white) and the cranial (congested) mucosa of the esophagus (arrow) Rumen is greatly enlarged with food that contain many gas bubbles.  Foreign bodies Trichobezoar(hair balls) Phytobezoars(plant balls) Lead substances poisoning Sharp metals Fate of Sharp metals  These metallic objects get deposited directly into the reticulum: 1. Localized reticulitis 2. Penetrated reticulum , diaphragm, and the pericardial sac (Traumatic Reticulopericarditis) 3. Penetrated reticulum then damage vagus nerve (Vagal indigestion )  Inflammation of forestomach Causes Extension from oral & esophageal infections Grain overload (ruminal lactic acidosis) Pathogensis Sudden change to high CHO diet overgrowth of gram + bacteria ↑ lactic & dissociated fatty acids pH < 5 & ruminal atony & damages mucosa fluid moves from the blood into the rumen ▪ Sudden death from dehydration, acidosis & endotoxemia Grain overload, ovine: Marked hyperemia, erosion and multiple confluent vesicles of ruminal mucosa There are mutiple ulcers in the ruminal mucosa  Sequelae Bacterial rumenitis  Fusobacterium necrophorum  Healed ulcers (“stellate scars”) Liver abscesses  May rupture into vena cava fatal septic embolism Vena cava Abscess (1) rupture of a hepatic abscess into the caudal vena cava; (2) vegetative valvular endocarditis (tricuspid valve); and (3) jugular thrombosis Mycotic rumenitis  Well demarcated, circular hemorrhagic infarcts  Can become systemic placentitis & abortion Ulcers on the rumen pillars DDx (cattle & sheep)  Acute gastric dilation & volvulus(GDV)  Large dog breeds  Large meal (dry or highly fermentable)  Failure of eructation & pyloric outflow  Gas functional obstruction of cardia& pylorus dilation rotation on its mesenteric axis (volvulus)  Compression of diaphragm, vena cava venous return cardiac output  Abomasal displacement Left abomasal displacement:  mostly in dairy cows Older, high producers a Postcalving period  Common GI disorder requiring surgery (seldom fatal) Rigt abomasal displacement  15% in cows and calves The abomasum (a) is normally on the abdominal ventral midline but here, it is displaced to the right and dorsally.  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  2ary to intestinal obstruction; equine dysautonomia  Distinction: ante mortem from post mortem rupture  Gastric ulcers Important but less so than in humans 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 Ostertagiosis (lymphoid hyperplasia) Trichostrongylosis Equine Gastric bots Trichostrongylosis Draschia megastoma Habronema Gastric bots Description? Cause? Pathogenesis? Intestines Digestive System  Congenital anomalies Atresia  Absence of a normal opening  Atresia ani Lamb with no anus Intestine markedly distended with fecal material  INTESTINAL DISPLACEMENTS AND MALPOSITION HERNIAS protrusion of an organ through a natural or artificial opening  Internal  Diaphragmatic hernia (through diaphragm)  External (have an hernial sac)  Ventral  Umbilical  Scrotal  Sequelae  Strangulation (interference with blood flow)  Adynamic ileus  Perforation Strangulation cutting off the venous return congestion necrosis Bacteria Shock and septicemia  TORSION VOLVULUS Rotation of the organ around its long axis  Mesenteric lipomas wrap around the mesentery or the bowel strangulation  INTUSSUSCEPTION telescoping of one segment of bowel into another adjacent section  Enteritis Inflammation of intestines  inflammation of small intestine = enteritis  inflammation of cecum = typhlitis  inflammation of large intestine = colitis  inflammation of all intestines = enterocolitis  inflammation of stomach and small intestines = gastroenteritis  inflammation of rectum = proctitis  Diarrhea  An increase in stool mass, stool frequency, and/or stool 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  Catarrhal  viral diseases  Hemorrhagic  bacterial diseases  Fibrinous/fibrinonecrotic  mycotic diseases  Ulcerative  protozoal diseases  Proliferative/hyperplastic  parasitic diseases  Granulomatous  noninfectious disease entities