1 / 28

Ruminant - PowerPoint PPT Presentation

  • Uploaded on

Ruminant. Animal Nutrition. Herbivores. How do herbivores eating grass/ plant material digest this food? Grass is low in energy – how does this affect their eating habits? Cellulose cell wall – need access to the energy store. Ruminants.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about ' Ruminant' - tablita-lee

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript


Animal Nutrition


  • How do herbivores eating grass/ plant material digest this food?

  • Grass is low in energy – how does this affect their eating habits?

  • Cellulose cell wall – need access to the energy store


“Ruminants are earth’s dominant herbivores, due in part to the evolution within this group of a mechanism utilizing microorganisms to digest plant components not susceptible to attack by ruminant enzymes.” (Hungate 1975)

deer, moose, antelope, giraffe, caribou, cow, sheep, goat

Food passes the reticulum and enters the rumen

Fermentation occurs in the rumen

Food passes back into the reticulum

Sent up the oesophagus to be re-chewed

Passes back down oesophagus into the reticulum

Moves into the omasum

Passes into the abomasum



  • Structure and function of the stomach is the major difference between monogastrics and ruminants.

  • Multi-compartmented stomach – reticulum, rumen, omasum, abomasum.

Mouth, esophagus, liver, pancreas, gall bladder, small intestine, and large intestine have functions similar to monogastrics.


  • Openings to oesophagus, rumen and omasum

  • Lining has a honeycomb structure.

    • Catches and holds hardware consumed by animal.

    • Hardware can be removed with rumen magnet!


  • Large, anaerobic fermentation vat.

  • 75% of feed intake is digested by the rumen

  • Cows rumen has 160 litre capacity


  • Houses microorganisms.

    • Protozoa – 100,000 per gram of rumen fluid.

    • Bacteria/fungi – 100 million per gram of rumen fluid.

  • Functions of microorganisms.

    • Digest fibre to make Volatile Fatty Acids (VFA’s), make microbial protein, and make vitamins K and B-complex.

  • VFA’s absorbed in rumen.


Lined with millions of papillae (short projections on wall of rumen) needed for absorption.


  • Rumen saturated with gases and in constant motion.

  • Contractions occur at a rate of 1-3 per minute.

    • Serve to mix contents, aid in eructation of gases, and move fluid and fermented feedstuffs into the omasum.


  • Ruminants are well known for “cud chewing”.

  • Rumination involves:

    • Bolus of previously eaten foodstuff carried back into the mouth by reverse peristalsis

    • Fluid in bolus is squeezed out with the tongue and reswallowed

    • Bolus is rechewed and reswallowed

  • Rumination may occupy about 1/3 of a ruminant’s day

Eructation belching
Eructation (belching)

  • Fermentation of foodstuffs in the rumen generates enormous quantities of gas (CO2 and methane)

    • 30-50 litres per hour in adult cattle.

    • 5-7 litres per hour in adult sheep or goats.

  • Belching is how ruminants get rid of fermentation gases:

    • Anything that causes a hindrance to belching can be life threatening.

    • Bloating can result in death from asphyxiation.

Reticulum again
Reticulum (again)

  • Contains microorganisms (like the rumen).

  • Provides additional area for fermentation.

  • As fermentation by microorganisms proceed and feedstuffs are digested, smaller and more dense material is pushed into the reticulum (from which it along with microbe-laden liquid is ejected into the omasum).


  • A heavy, hard organ with a lining that has many folds (leaves)

  • Function not well understood.

    • Believed to produce a grinding action on foodstuffs.

    • May absorb residual VFA’s water and salts.


  • The true, glandular stomach.

    • Secretes acids and functions very similarly to monogastric stomach

    • Pepsinogen, rennin, lipase enzymes

    • Acid kills micro-organisms

  • Unique feature is that it secretes lysozyme.

    • Enzyme that efficiently breaks down bacterial cell walls.

    • Needed to break down the large quantities of bacteria that pass from the rumen.


  • Food is first chewed, then enters the rumen

  • In the rumen, cellulolytic bacteria and protozoa breakdown cellulose into cellobiose and glucose (sugars)

  • these sugars are then fermented, producing volatile fatty acids (acetic, proprionic, and butyric)


  • food passes from the rumen into the reticulum, where it is formed into small portions called ‘cuds’

  • cuds are regurgitated into the mouth where they are chewed again – ‘rumination’

  • these solids are now finely divided and very well mixed with saliva; they are swallowed again, but this time the material enters the abomasum, an organ more like a true stomach, where ‘true’ digestion begins and continues into the small and large intestine


The fermentation reaction:

cellulose --> acetate, propionate, butyrate, CO2, CH4, H2O

three main products that benefit the animal

i) Volatile fatty acids: acetate, propionate, butyrate

these pass through the rumen wall and are absorbed

propionate – used for carbohydrate biosynthesis

acetate, butyrate – used for energy

ii) microbial cells – contributes protein to ruminant’s diet – probably the main source of protein

many rumen bacteria can use urea as a sole N source; often part of cattle feed to promote protein synthesis (cheap meat)

iii) Heat – important to the ruminant’s thermoregulation

Rumen microflora
Rumen Microflora

The rumen contains bacteria and protozoa

  • Bacteriodes succinogenes, and Ruminococcus albus = main cellulose digesting bacteria

  • Some population differences depending on diet and location

Managing the ruminant diet
Managing the Ruminant Diet

  • Sudden change from high cellulose diet to high glucose diet can be fatal

  • Bacteria digesting glucose produce lactic acid which kills other bacteria and the acidic environment damages cells

  • Change to high protein diet should be gradual

Carbohydrate digestion
Carbohydrate digestion

  • Cellulose broken down by micro-organisms into simple sugars

  • Simple sugars are used by the micro-organisms

  • Fermented to produce VFA’s (acetic, proprionic and butyric acid)

  • 75% absorbed through rumen wall

Carbohydrate digestion cont
Carbohydrate digestion cont…

  • Remainder used as energy by the bacteria or pass into the abomasum

  • Saliva buffers the acid (150-200 litres per day!)

  • 90% of sugars and starches in the diet are digested by the rumen the rest passes into the intestines

Protein digestion
Protein Digestion

  • Two types of proteins

    • Rumen Degradable Protein (RDP)

    • Undegradable Protein (UDP)

  • Microorganisms break proteins down into peptides and amino acids, ammonia, organic salts and CO2

  • RDP is converted to microbial protein – some is used by the microbes and some passes out of the rumen and is used by the animal (bacteria pass out of the rumen and are digested)

Protein digestion cont
Protein digestion cont…

  • Excess ammonia is absorbed into the blood and processed by the liver into urea

  • UDP passes through the rumen into the abomasum and intestines and is broken down by enzymes

Lipid digestion
Lipid Digestion

  • Short chain absorbed directly from the rumen, long chain pass through to intestines

  • Broken down into fatty acids and glycerol

  • Broken down by bacterial lipase

  • Micro-organisms synthesis some fatty acids which are present in body fat and milk of ruminants

  • Too much fat will over load the micro-organisms