Ruminants GI Tract Flashcards
What does ruminants GIT do?
Efficient digestive apparatus to digest high-fiber plant material like cellulose/ hemicellulose (microorgs breakdown)
Fermentative digestion
Ruminare
To chew over again
Fermentative Digestion
Complex carbs are broken down by microogs into simple molecules –> fermentation vat (large container)
How many microogs are in the GIT?
Over 200 species
10% play an important role in digestion
Wha does enteric fermentation produce?
Methane (CH4) as an end product, it’s belched/ eructed by the animal –> greenhouse gases
What are the 2 turns on the spiral colon?
Centripetal loop (inward)
Centrifugal loop (outward)
Which part of the ruminant stomach is glandular?
Abomasum
Connecting peritoneal of the GIT?
Omentum suspends the stomach
Mesentery suspends the intestines
What is the main organ of prehension for the cow and small ruminants?
Tongue –> indiscriminate eaters
Lips
How much saliva does bovine secrete?
100L/ day
Lingual fossa
Caudal 1/3 of the tongue, elevated
Transverse groove starts it –> because the mucosal lining is soft its prone to injury and harbors bacteria
Diastema
Space between teeth with different functions –> pull tongue through space to look in mouth
Papillae of the tongue
Mechanical- conical, filiform papillae
Taste- fungiform and vallate papillae
What are the 5 salivary glands?
Buccal SG
Labial
Parotid (well developed)
mandibular (monostomatic and polystomatic)
What are the muscular layers of the stomach called?
Grooves (outside)
Pillars (inside)
thickening of the muscularis layers
Esophagus
Stratified muscles
Stratified squamous
Peristaltic and antiperstatic movement
Stomach compartments
Rumen, reticulum, omasum and abomasum
Developed from embryonic gastric spindle
Total capacity: 60L
How is the stomach changed from birth?
@ birth abomasum is 60% of stomach because calf needs enzymes from mother to to digest milk
By 2 months rumen and reticulum are 80%
Stomach capacity for ox and small ruminants
Rumen: ox 80%, SR 75%
Reticulum: ox 5%, SR 8%
Omasum 8%, 4%
Abomasum: 7%, 13%
What is the location of the rumen?
From 7th- 8th ICS to pelvic inlet
From abdominal roof to abdominal floor
Most of the left side of the abdomen
What is the location of the reticulum?
Cranial to rumen
Left side of midline
Under 6th, 7th, and 8th ribs
Above the xiphoid process
Characteristics of the reticulum
Honeycomb appearance
2 openings: cardia and reticulomasal orifice
Incompletely divided from rumen by the ruminoreticular fold
Gastric groove structure
Extends from cardia to abomasum
3 parts: Reticular, omasal and abomasal groove
How is the gastric groove used?
Bypass tube for milk in suckling young
Closure of muscular lips with relaxation of reticulo-omasal orifice and the omaso-abomasal orifice will convert the groove into a closed tube
What triggers groove closure?
Chemical receptors in mouth and pharynx, sensitive to milk salts stimulate the vagal reflex
Whats used for abomasal deworming medication?
Copper and nicotine sulphate
Ruminal contractions
Mixes and moves ingesta from one compartment to the next (belching/eruption)
Regulated by the vagus nerve and controlled by gastric center in medulla oblongata
Where are contractions usually heard?
Left side @ the paralumbar fossa 1-3 every minute
Primary ruminal contraction
Mixing and circulation of digesta in an organized manner
3 phases: biphasic reticular contraction –> contraction of dorsal ruminal sac –> contraction of ventral sac
Secodary ruminal contraction
Ingesta flows from the ventral blind sac to the dorsal blind sac –> dorsal sac (eructation) and to the ventral sac
Leds to eructation of gases
Ingesta
Grain and re-masticated roughages fall into the ventral sac of the rumen
Bottom to top: grain/ yesterdays hay, todays hay, gases
How does ingesta move?
Cranial sac –> reticulum (reticulo-omasal) –> omasum (omaso-abomasal orifice) –> abomasum
Sacs of the rumen
LEFT
Dorsal sac in left paralumbar fossa
Ventral sac covered by greater omentum
What structures are located on the left side of the abdominal cavity ?
Spleen
Cranial sac
Reticulum
What structures are seen on the right side of the abdominal cavity?
Descending duodenum
Right lobe of pancreas
Superficial wall of the great omentum
Liver and gallbladder
Part of abomasum and omasum
Ruminal Tympany (bloat)
Excessive accumulation of fermentation gases within the reticulorumen
Failure of eructation
Can develop rapidly and be life-threatening due to pressure on heart, lungs and diaphragm
Clinical signs of ruminal typani
Asymmetrical abdominal distention
Most pronounced in left paralumbar fossa
Tachycardia and Dyspnea
Free gas bloat
Mechanical or functional disturbance anywhere along the path of the eructation mechanism
Frothy bloat
Ruminal gases trapped in small bubbles within abdominal viscous digesta
Trocarization doesn’t work
What are the causes of frothy bloat?
Esophageal dysfunction
Intraluminal: foreign body (choke)
Tumor
What else can ruminal tympani lead to?
Ruminal motility dysfunction
Muscular inactivity (hypocalemia)
Reticular adhesion (TRP, abomasal ulcers/ ditenstion, peritonitis)
Vagal nerve injury
Abnormal rumen environment
Lactic acidosis
Where is trocarization of the rumen done?
Left paralumbar fossa because its retroperitoneal, and dorsal aspect is cutaneous
What are the borders for trocarization?
Cranial: last rib
Caudal: cord of the flank (EAO comes down and forms the cord of the flank)
Dorsal: back muscles
Traumatic Reticuloperitonitis (TRP)
Sporadic disease caused by perforation of the reticulum by ingested foreign material
Contamination of body cavities or organs
Rarely in sheep/ goats
What are the outcomes of TRP?
Peritonitis
Reticular abscess formation
Liver puncture and abscessation
Pericarditis, pulmonary abscessation
What other structures are affected by TRP?
Diaphragm (28-60% of cases)
Pericardia (6-8% of cases)
How do you treat TRP?
Medical management (parenteral antibiotics)
Magnet (prevents migration)
Surgery
Surgery for TRP
- Exploratory laparotomy (left, opening the abdominal cavity via ventral midline)
- Rumenotomy: removing foreign objects and identify perireticular abscesses
How do you diagnose TRP?
Rod test
Slope test
Abduction
Bottle neck (advanced, edema of neck)
Lactic Acidosis (Rumen overload, grain overload, engorgement toxemia, ruminitis, et.)
Rapid production and absorption of ruminal organic acids and endotoxins
Animal over consumes a meal of readily fermentable carbs (finely ground grains)
What are the signs of lactic acidosis?
Anorexia
Complete rumen stasis
Abdominal pain (grunting, distension)
Diarrhea (grey, bloody, foamy)
What other conditions come with lactic acidosis?
Dehydration
Metabolic acidosis: blood pH <7.2
Hypocalcemia
Damage to rumen wall
Bacterial and mycotic organisms invade surface epithelium
endotoxic shock
Endotoxic shock
Toxins released during destruction of large numbers of gram-neg organisms from rumen
Treatment for lactic acidosis
Mild cases recover without treatment
Empty rumen: oral lavage, rumenotomy
Oral antacids (magnesium carbonate or hydroxide)
Correct dehydration
