Lipid Metabolism In Ruminants

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(Isfahan University of Technology)
Animal nutrition on the rangeland (Part 2)
Prepared by Dr A. Riasi ariasi_at_cc.iut.ac.ir http
//riasi.iut.ac.ir
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Digestive system of ruminants

• Proper care of the land and its grazing animals
  requires a sound understanding of ruminant
  nutrition.
• Ruminant comes from the word rumen.

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Ruminant digestive physiology
Small intestine
Rectum
Rumen
Cecum
Esophagus
Reticulum
Omasum
Colon
Abomasum
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Digestive system of non-ruminants
Rectum
Colon
Stomach
Esophagus
Small intestine
Cecum
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Digestive system of non-ruminants
Rectum
Small intestine
Esophagus
Stomach
Cecum
Colon
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Digestive system of ruminants
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Digestive system of ruminants
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Advantage of pregastric fermentation

• Make better use of alternative nutrients
• Cellulose
• NPN
• Ability to detoxify some poisonous compounds
• Oxalates, cyanide, alkaloids

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Advantage of pregastric fermentation

• More effective use of fermentation end products
• Volatile fatty acids
• Microbial protein
• B vitamins
• Decrease in handling undigested residues
• In wild animals, it allows animals to eat and run

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Disadvantage of pregastric fermentation

• Fermentation is inefficient
• Energy
• Loss Amount ( of total
  caloric value)
• Methane
  5-8
• Heat of fermentation
  5-6

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Disadvantage of pregastric fermentation

• Fermentation is inefficient
• Protein
• Some ammonia resulting from microbial degradation
  will be absorbed and excreted
• 20 of the nitrogen in microbes is in the form of
  nucleic acids

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Disadvantage of pregastric fermentation

• Ruminants are susceptible to toxins produced by
  rumen microbes
• Nitrates
  Nitrites
• Urea
  Ammonia
• Nonstructural carbohydrates
  Lactic acid
• Tryptophan
  Methyl indole
• Isoflavonoid estrogens
  Estrogen

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Ruminant digestive process

• Nutrients absorbed from the digestive tract
  include volatile fatty acids, amino acids, fatty
  acids, glucose, minerals, and vitamins.
• These are used in the synthesis of the many
  different compounds found in meat, milk and wool,
  and to replace nutrients used for maintaining
  life processes including reproduction.

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Ruminant digestive process

• Digestion begins when an animal takes a bite from
  the pasture.
• As the animal chews the feed is formed into a
  bolus (a packet of food capable of being
  swallowed).
• Saliva is excreted, which further aids in
  swallowing and serves as a pH buffer in the
  stomach.

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Ruminant digestive process

• Ammonia can be absorbed into the animals system
  through the rumen wall, or can be consumed by
  bacteria to become microbial protein.
• If adequate and suitable VFAs are present, NH3 is
  incorporated into microbial protein otherwise,
  it is absorbed, particularly if the rumen pH is
  alkaline.

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Ruminant digestive process

• Once in the rumen, the feed begins to undergo
  fermentation.
• Millions of microorganisms ingest the feed,
  turning out end products which serve as a major
  source of nutrients for the animal.

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Ruminant digestive process

• Some of the principle products formed are
  ammonia, methane, carbon dioxide, and volatile
  fatty acids (VFAs).