Ruminant GIT Part 1 Flashcards
Herbivores have digestive apparatus that is able to digest high-fiber plant material such as
Cellulose and hemicellulose
Fermentation
- complex carbs get broken down by microorganisms into simple molecules
- prod. Methane (end product)
Glandular part of stomach
Abomasum
Ileocolic orifice lacks
A sphincter
Pillars are
Grooves on inside of stomach
Grooves
Depressions on outside of stomach
Cow’s main prehension organ
Tongue
Small ruminant main prehension organ
Lips
Transverse ridge of tongue
- prone to injury
- prone to bacterial infections
Papillae
- filiform and conical: mechanical
- fungiform and vallate: taste
Esophagus
- striated skeletal m.
- stratified squamous epithelium
- peristaltic/antiperistaltic movement
Stomach development
- developed from embryonic gastric spindle
- @ birth, abomasum= 60% stomach (b/c no need for fermentation since calves consume milk)
- @ 2 months rumen and reticulum= 80% stomach
Total capacity of ruminant stomach
60L
Rumen
- 7th/8th ICS to pelvic inlet
- from abd roof to abdominal floor
- dorsal sac in paralumbar fossa
- ventral sac covered by superior wall of great omentum
Reticulum location
- cranial to rumen
- left of midline
- under 6th-8th ribs
- above xiphoid process?
Reticulum openings
- cardia
- reticulomasal
Ruminoreticular fold
- incompletely divides reticulum and rumen
Parts of gastric groove (3)
- reticular groove
- omasal groove
- abomasal groove
Gastric groove
- bypass tube for milk when calf is suckling
- closure of muscular lips w/ relaxation of reticulo-omasal orifice and omaso-abomasal orifice covert groove into closed tube
- chemical receptors from mouth sensitive to milk salts and stimulate vagal reflex that closes groove
- copper and nicotine sulfate used for abomasal de-worming meds
Ruminal contraction controls
- regulated by vagus n. (Clin sig: vagal indigestion)
- controlled by gastric center in Medulla Oblongata
- usually seen on L side paralumbar fossa
3 phases of ruminal contraction
1) biphasic reticular contraction
2) contraction of dorsal ruminal sac
3) contraction of ventral ruminal sac
Primary contraction of rumen
- mixing and circulation of digesta
- 3 phases
Secondary ruminal contraction
- ingesta flows from ventral blind sac to dorsal blind sac; then dorsal blind sac to ventral blind sac; eructation;
-
One ruminal contraction cycle is how long
1 minute
Movement of ingesta
- ventral sac, cranial sac, reticulum, reticulo-omasal orifice, omasum, omaso-abomasal orifice, abomasum
Grain and remasticated roughages fall into
Ventral sac of rumen
Organs on left side
- rumen
- spleen, cranial sac, and reticulum
