Rumen microbes play an essential role in the digestion of ruminant animals like cattle. The rumen contains billions of microbes, including bacteria, protists, and fungi, that break down plant fibers like cellulose which ruminants cannot digest on their own. Major cellulolytic bacteria that degrade cellulose include Firmicutes, Bacteroidetes, Fibrobacter succinogens, and Ruminococcus albus. Changes to the microbial community, such as a rapid increase in Streptococcus bovis from a grain-rich diet, can cause acidosis and harm the animal. The microbes produce volatile fatty acids as end products that the ruminant can absorb to gain energy from its plant-

1. Rumen microbes
PRESENTED BY
၃ဂုဏ်ဏဇ-၁ HNIN WUT YEE
၃ဂုဏ်ဏဇ-၂ EI YATI AUNG
၃ဂုဏ်ဏဇ-၃ Mhuu Neichi

2. What is a Ruminant?
• A ruminant is any hoove animal that digest its
food in two ways.
• By eating the raw material and regurgating a
semi digested form known as cud.
• Then eating the cud a process called ruminating.
• Eg. Giraffe, Cattle, Goat, Sheep, Camel, Dear
and Cow.

3. Digestion
• The digestion process in Ruminants begins by chewing
its food in mouth.
• Ruminant do not completely chew the food they eat but
just consume or gulp as much as they can.
• After the food is broken down into smaller particles it is
swallowed and passes through the esophagus using
muscle contraction known as peristalsis.

4. • Ruminants have four
compartment stomach.
• They are Rumen, Reticulum,
Omasum and Abomasum.
• The stomach of a ruminant
occupies ¾ of abdominal cavity.
DIGESTION

5. • First compartment of a ruminant animal.
• Digestion and fermentation vat.
• Most feed collects here after being swallowed.
• Cellulose is broken down here with help of microbes.
• Contain anaerobic microbes .
• Absorption of VFA.
RUMEN

6. • Second compartment of the stomach.
• Collect smaller digesta particles and move them
into the omasum while the larger particles
remain in the rumen for further digestion.
Reticulum

7. Omasum
• The omasum is a globe-shaped structure
containing leaves of tissue (like pages in a
book).
• It absorbs water and other substances from
digestive contents.
• Feed material (ingesta) between the leaves
will be drier than ingesta found in the other
compartments.

8. • The abomasum is the only compartment
lined with glands.
• These glands release hydrochloric acid and
digestive enzymes, needed to breakdown
feeds.
• The abomasum is similar to a non ruminant
stomach.
Abomasum

9. Belching Rumination
• Digestion produces 30 to 50 quarts
of gas per hour in the rumen.
• Carbon dioxide and methane are
the main gases present.
• Cows must release this gas to avoid
bloating.
• Under normal conditions, swelling
from gas formation causes the cow
to belch and release the gas.
• Cows may spend 35 to 40 percent of
each day ruminating (cud chewing).
• The amount of time spent
ruminating depends on the diet.
• Little ruminating occurs when cows
eat grain or finely ground rations.
• But when eating long hay, cows may
ruminate for several hours.

10. • The rumen is home to billions and
billions of microbes including
bacteria, protists, fungi and viruses.
• In just 1 millimeters of rumen fluid
you can find 25 billions bacteria, 10
millions protozoa and 10 thousands
fungi.
MICROBIAL POPULATION

11. RUMEN BACTERIA
• MOSTLY ANAEROBIC
• DEGRADE
• Cellulose
• Starch
• Soluble carbohydrates
• Acidophilus
• Protein and
• Other compounds
• Some produce CH 4 ,CO² and H²

12. CLASSIFYING RUMEN BACTERIA BY ENERGY SOURCE
• Cellulolytic bacteria
Cellulose
• Primary constituent of plant cell walls.
• A chain of glucose units bound by beta 1-4 linkages.
• Can only be digested by microorganisms
• Digestibility determined by lignification.
COMMON CELLULOLYTIC BACTERIA
• Firmicutes
• Bacteroidetes
• Fibrobacter succinogens
• Ruminococcus albus
• Clostridium lochheadii

13. Bacteria
• Gram positive
• Anaerobic
• Dominant bacteria in
rumen
• Convert cellulose into
glucose
Firmicutes
• Gram negative
• Anaerobic or Aerobic
• Dominant bacteria in
rumen.
• Convert cellulose into
glucose.
Bacteroides
Fibrobacter
succinogens
Ruminococcus albus
• Gram negative
• Anaerobic
• Hydrolyze cellulose
into sugar.
• Ferment sugar to
VFAs.
• Gram positive
• Anaerobic
• Hydrolyze cellulose
into sugar.
• Ferment sugar to
VFAs.

14. • If a cow is changed from forage to a grain diet, the gram positive
bacterium Streptococcus bovis grow rapidly in the rumen.
• The normal level of S.bovis about 10⁷ cells/g but if large number
of grain are fed abruptly numbers of S.bovis can quickly rise to
over 10¹⁰ cells/g.
• S.bovis is a lactic acid bacterium.
• Lactic acid is a much stronger acid than VFAs.
• Lactate production can cause acidosis which can causes
inflammation rumen epithelium, hemorrhaging in the rumen
and death of the animal.
Dangerous changes in rumen microbial community

15. Rumen Fungi
Rumen protists
• The rumen also has ciliated protists.
• Many of these protists are obligate anaerobes
and rare among eukaryotes.
• Protists are not essential for rumen fermentation
.
• Some protists are able to hydrolyze cellulose
and starch and ferment glucose with the
production of the same VFAs.
• Rumen protists also consume rumen bacteria
and smaller rumen protists thus play a role in
controlling bacterial density in the rumen.
• Anaerobic fungi also inhabit the
rumen and play a role in its digestive
processes.
• Rumen fungi are flagellated and
thallus form and can ferment
cellulose to VFAs.
• Neocallimastix, for eg. is an obligate
anaerobic fungus that ferments
glucose to formate, acetate, lactate,
ethanol, CO² and H².
• Rumen fungi play an important role
in the degradation of polysaccharides
other than cellulose, including lignin,
hemicellulose and pectin.

16. • The food chewed mixed with saliva enters
the first two stomach chambers, the
reticulum and rumen.
• The reticulum and rumen work together to
separate solids and liquids.
• Contractions push solid food particles back
up into the rumen, while liquids are drained
into the reticulum.
• Specialized microbe species live in the
rumen and help ruminants break down
cellulose..
• Liquid digesta in the reticulum is passed into
the omasum where nutrients and water are
absorbed into the blood stream.
• After the abomasum, digesta moves through
the large and small intestines.

17. thank
you