VPB 121: Veterinary Physiology - II (2+1)

Digestion in ruminants stomach

DIGESTION IN RUMINANT STOMACH

Features of digestion in ruminants

• Gastro intestinal tract has colonies of microbes. As the animal grows the type of microbes gets modified according to the type of diet. Host animal and its populations of gut microbes interact. There is a complex interaction between the host animal and microbial population. Host animal does not produce enzymes degrading cellulose and other plant polymers, hence depends on metabolic activities of gut microbes to utilize the fibrous food. Microbial cellulose digestion is a slow process hence they are retained for longer period in the gut.

• Value of microbial products are more to the host (VFA/ Vitamin B Complex)
• They are well absorbed in rumen and lower stomach
• Ammonia and non protein nitrogen ,metabolized by microbes to synthesize good quality microbial protein which is later digested by the host.
• Large fibrous particles are selectively retained in the reticulo-omasal orifice for mechanical breakdown.
• Large quantity of gases produced by metabolism is readily expelled by eructation.
• Large output of saliva provides high buffering action against VFAs and also media for microbial growth.
• Toxic substances are detoxified during fermentation before getting into the small intestine.

Mechanical factor of digestion in ruminants

Mastication	Grinding of the food particles
Deglutition	Swallowing of patially graind food materials (Cud) from the mouth into oesophagus
Rumination	Chewing of the cud. This occurs in four phases
	Regurgitation: Reentry of cud, the liquid portion from the reticulum in to the mouth
	Remastication: Regrinding of the cud
	Reinsalivation: Additional salivary secretion to the bolus
	Redeglutition: Reswallowing of the bolus from the mouth into oesophagus
Eructation	Elimination of CO2 and CH4 from GI tract