Ruminants like cattle, goats and sheep have a specialized four-chambered stomach that allows them to digest cellulose from plant matter. In the first chamber, the rumen, microbes break down cellulose and produce volatile fatty acids, methane and carbon dioxide. These products are then absorbed. Proteins are also broken down by microbes into amino acids and ammonia. Lipids are hydrolyzed into fatty acids and glycerol. Absorption of nutrients occurs in the rumen and small intestine. The end products that are absorbed include volatile fatty acids, amino acids, and fatty acids and glycerol.

1. Digestion & Absorption of
Foodstuffs in Ruminants
Md.Redoan Akond Sumon
Scientific Officer
BLRI Savar Dhaka
redoanakond@gmail.com
8801747481116

2. Introduction
 Ruminant animals efficiently utilize roughages
because of their unique ability of digestion .
 Foods are digested, absorbed, and utilized in
animal body.
 Finally converted to activity and valuable
animal products. eg. Milk, Meat etc.

3. Digestion ?
• Larger food particles converted to
simpler food particles
• Easily absorbed
Absorption ?
• Nutrients transferred from the lumen of the
gastrointestinal tract to the blood.

4. Ruminants
• Herbivore
mammals Eg.
Cattle, goat,
sheep, deer
• Feed on plant -
cellulose

5. Digestive System of
Ruminants
 Need cellulase to digest cellulose
 But ruminants do not produce
cellulase
However their digestive system are
specially adapted to carry out
cellulose digestion

6. Ruminants..
• Has a stomach with 4 chambers:
1. rumen
2. reticulum
3. omasum
4. abomasum
• Carry out rumination – process of
regurgitating food and rechewing it

8. Fig. Stomach

10. Ruminants..
• the saliva of a cow contains no
salivary amylase
•To digest the plant material,
herbivores need to depend on
the cellulase-secreting
microorganism in its digestive
system

11. Ruminants..
 Rumen
- first & largest compartment
- contain bacteria that produced
cellulase for the cellulose
digestion
- function as the fermentation
chamber

12. Organisms in rumen

13. Ruminants..
 Reticulum
- also contains bacteria for
digestion
- content of reticulum called cud
- regurgitation occurs
- has a ‘honeycomb’ wall

14. Ruminants..
 Omasum
- reswallowed cud will be sent
here
- large particle are broken
down by peristalsis
- water is removed

15.  Abomasum
- true stomach of the ruminants
- gastric juice containing
digestive enzymes
- HCl and pepsin
Ruminants..

16. Flow of food in ruminant
mouth
oesophagus
rumen mouth
omasum
reticulum
abomasum
regurgitationfermentation
curd
swallow
swallow
- H2O
chyme

17. Plant tissues contain about 75% CHO
Cellulose, hemicellulose, starch and
water-soluble carbohydrates
Attacked by the rumen microorganism
except lignin
 80% undergo microbial
fermentation
 20% enzymatic digestion
Carbohydrate Digestion

18. Carbohydrate ….
Primary fermentation
Occur outside the microbial body
Carbohydrates−−−−−−−−−−−−−−−−−−−Monosaccharaides
Secondary fermentation
Occur inside the microbial body
Monosaccharaides−−−−−−−−−−−−−−−−−−−−−→ Volatile
fatty Acid + CH4 +CO2 +H2O

19. Carbohydrate.....
Maltose Isomaltose
Cellubiose Glucose
Glucose-1-phosphate Glucose-6-phosphate
Uronic acid Fructose-6-phosphate Fructose
pentoses Fructose-1,6 phosphate
Pyruvate
Hemicellulose
Pectins
Pentosans
Frutans
Sucrose
Cellulose Starch

20. Carbohydrate….
Formate Acetyl Coenzyme A Lactate Oxaloacetate Methylmalonyl CoA
O2 H2 Acetoacetyl CoA Lactyl CoA Malate
Methane Hydroxybutyryl CoA Acryl CoA Fumarate
Acetyl phosphate Crotonyl CoA Propionyl CoA Succinate Succinyl CoA
Butyryl CoA
Acetate Butyrate Propionate
Fig3; Conversion of pyruvate to volatile fatty acids in the rumen
Pyruvate

21. End product of CHO digestion
1.Volatile Fatty Acid
– Acetate -65% (60-70%)
– Propionate-20% (15-22%)
– Butyrate-12% (10-15%)
- Valeric acid
-Isovaleric acid
- Isobutyric acid
2. CO2, CH4, H2, N2 etc.

22. Absorption of CHO
• VFAs are directly absorbed into the blood
from the rumen wall & intestinal tract
• Monosaccharides are absorbed from the
small intestine

23. Digestion of protein
• No proteases in saliva
• Bacteria & Protozoa responsible
• Enzymes also involved

24. Sources of Rumen Nitrogen
• Feed
– Protein nitrogen
• Feed Protein
– Non protein nitrogen (NPN)
• Usually means urea
• Endogenous (recycled) N
– Saliva
– Rumen wall derivatives

25. Digestion of protein

26. Protein Pathways in the Ruminant

27. Fate of Dietary protein
 Fermentation in the reticulo-rumen by
ruminal microbes
 Enzymatic hydrolysis in the small
intestine
 Excretion of indigestible protein in feces

28. Ruminal Protein Degradation
• Fermentative digestion – enzymes of
microbial origin
– MO proteases & peptidases cleave peptide
bonds and release AA
– AA deaminated by microbes, releasing NH3 and
C-skeleton
– MO’s use NH3, C-skeleton and energy to
synthesize their own AA

29. Digestion of lipids
• Lipase enzymes helps to break down lipids
• Rumen microbial population hydrolyzes
triaglycerides & galactolipids, & releasing FFA
• Glycerol & galactose fermented to VFA
• USFA hydrogeneted to SFA
• FFA, VFA are absorbed from intestinal tract

30. Vitamin-Mineral absorption
Fat soluble vitamins the small
intestine and are transported in the blood.
water soluble vitamins the gastro-
intestinal tract
Minerals through the gastrointestinal
tract, but mainly in the duodenum and
jejunum.

31. Digestive Process - Ruminants
Nonprotein N
(NPN)
Feed
proteins FatsCarbohydrates
Cellulose Starches
Hemicellulose Sugars
Microbial protein
(essential AA)
Volatile fatty
acids (VFA’s)
VFA’s
RUMEN/
RETICULUM
RUP
Microbial protein
Poly Peptides
OMASUM
ABOMASUM
SMALL
INTESTINE
Peptides
Amino acids
Fats
Fatty acids &
glycerol
Glucose
Glucose
RDP
RUP
LIVER
RDP
Glucose
= microbial action; = main site of absorption = some absorptionRDP = rumen degraded protein; RUP = rumen undegraded protein;

32. End products
Carbohydrate Volatile Fatty Acid in rumen & monosaccharaides in
small intestine
Protein Ammonia, kito acid in rumen and mono & di-peptide
amino acid in small intestine
Fat Volatile Fatty-acid in rumen
Fatty-acids & glycerol in small intestine

33. THE END
Any
questions?