INTRODUCTION
Ruminants, cloven-hoofed mammals of the order Artiodactyla, obtain their food by browsing or grazing, subsisting on plant material. Approximately 95% of the population of domesticated ruminants constitutes species: cattle, sheep, and goats, all of them belonging to the Bovidae family.
Dairy cows and other animals such as sheep, goats, buffaloes, camels, and giraffes are herbivores because their diets are composed primarily of plant material. Many herbivores also are ruminants. Ruminant animals can be recognized easily because they chew frequently even when they are not eating. This chewing activity, called rumination, is part of the processes that allow a ruminant to obtain energy from plant cell walls also called fiber.Ruminants have a unique digestive system that allows them to better utilize energy from fibrous plant material than other herbivores. Unlike monogastric animals such as swine and poultry, ruminants have a digestive system designed to ferment feedstuffs and provide precursors for energy for the animal to utilize. By better understanding how the digestive system of the ruminant works, livestock producers can better understand how to care for and feed the ruminant animal.
The ruminant digestive system uniquely qualifies ruminant animals such as cattle to make efficient use of high-roughage feedstuffs such as forages. Anatomy of the ruminant digestive system includes the mouth, tongue, salivary glands, esophagus, 4-compartment stomach (rumen, reticulum, omasum, and abomasum), pancreas, gall bladder, small intestine, and large intestine.
Gastro intestinal tract of a ruminant animal has colonies of microbes residing in it. As the animal grows, the type of microbes gets modified according to the type of diet. There is a complex interaction between the host animal and the microbial population which helps in digestion of different substrates. Ruminant animals do not produce sufficient enzymes to degrade cellulose and other plant polymers; hence they depend on metabolic activities of gut microbes to utilize the fibrous food. Since microbial cellulose digestion is a slow process, they are retained for a longer period in the gut of ruminant animal.
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