Ruminants

• Ruminants, such as cows, have developed unique gastrointestinal tract that is adapted for digesting plant material.

  The process begins in the mouth where forage is rapidly ingested and then regurgitated as a bolus during rumination.

  Rumination is a process that reduces particle size and exposes fibrous carbohydrates to bacterial fermentation.
• • The rumen is the primary site for microbe fermentation. It retains long fibrous particles in a fibrous mat, stimulating rumination.
  • Microbial fermentaion produces volatile fatty acids (VFAs) which are a cows primary energy source.
  • The rumen allows for microbial growth which is protein-rich, and the eructation of gases like CO2 and methane.
• • The reticulum, which has a honey-comb appearance, works in conjunction with the rumen for the bacterial fermentation of cellulose.
  • The omasum is responsible for absorbing water, minerals and VFAs. It traps large particles, contributing to the selctive retention of large particles in the rumen.
• • The abomasum functions similarly to a monogastric stomach.
  • HCl is secreted to kill bacteria and digestive enzymes are seceretd to aid in the digestion of carbohydrates and proteins that escaped rumen fermentaion. It also aids in the digestion of microbial proteins produced by the rumen.
• • The small intestine is the site of enzymatic digestion of proteins, carbohydrates, and lipids.
  • The absorption of water, minerals, amino acids, fatty acids and glucose also takes place.
• The caecum and colon are involved in the fermentation of unabsorbed digestion products by a bacteria population and the absorption of water, leading to the formation of faeces.