1. Digestive System
Ruminants

2. Dentition
Restraint

3. Dentition - Cattle 0 0 3 3 3 1 3 3 Incisors Pre-molars Molars
Deciduous: 20 (there are no deciduous molar and deciduous PM1)
0 0 3 (I C PM)
3 1 3
Permanent: 32 (No PM1)

4. Eruption – Deciduous Teeth
Age at eruption
1st Incisor (Di 1)
Birth – 2 weeks
2nd Incisor (Di 2)
3rd Incisor (Di 3)
4th Incisor (Di 4 or C)
1st Cheek Tooth (Dp 2)
Birth to few days of age
2nd Cheek Tooth (Dp 3)
3rd Cheek Tooth (Dp 4)

6. Deciduous
Permanent

7. Eruption – Permanent teeth
Age at eruption
I 1
18 – 24 months
I 2
24 – 30 months
I 3
36 months
I4 or C
42 – 48 months
1st cheek tooth P2
P3 second cheek tooth
18 – 30 months
P4 third cheek tooth
30 – 36 months
M2 fifth cheek tooth
M3 sixth cheek tooth

8. Cattle - Dentition 14 months: complete deciduous short and broad
bright ivory color
space between Di 1 incisors

9. How old? Rostral Rostral - lateral Teeth are longer and narrower
15 – 18 months
Teeth are longer and narrower
Not touching at upper corner

10. How old?
18 – 24 months
Eruption of one or more central incisors

11. How old?
30 months
At least one of
2nd pair of incisors

12. How old? I3: 36 months, I4: 42 months Peg teeth
Greater than 30 months old
Peg teeth

13. Dentition – Sheep and Goats
2 (0/4 incisors, 3/3 pre-molars, 3/3 molars) = 32
Animal under one year old: no permanent teeth
One year old (2 permanent teeth)
Two years old (4 permanent teeth)
Three years old (6 permanent teeth)
Four years old (8 permanent teeth)
Old animal, more than four years old

14. Permanent Tooth Eruption
Incisor (I1)1-1.5 years
Incisor (I2)1.5-2 years
Incisor (I3)2.5-3 years
Incisor (I4)3.5-4 years
Premolars1.5-2 years
Molar (M1)3 months
Molar (M2)9-12 months
Molar (M3)1.5-2 years

15. How old- Sheep? Broken mouth Wide spacing
Yearling, 2 yrs, 4 yrs, 6-8 yrs, 8-12 yrs
Broken mouth
Wide spacing

16. How old - Goats Deciduous – 10 months Deciduous – 2 weeks 10 yrs

17. Digestive System Cranial fermentors Caudal fermentors Forestomach
E.g. cattle, sheep and deer
digest and extract energy from cellulose
utilize the protein from fermentative microbes
Caudal fermentors
Cecal digestors
E.g. horses and rabbits
utilize dietary hexose sources directly

18. Digestive system calf Esophageal groove
first few weeks of life, the rumen, reticulum, and omasum are undeveloped
By pass reticulum and rumen and goes directly into abomasum
Grain and forage for rumen development ~ 3 weeks age

19. Fermentation Ecology Rumen inoculation
1 ml of rumen content: ~10 to 50 billion bacteria,1 million protozoa, variable numbers of yeasts and fungi
Cellulolytic (digest cellulose)
Hemicellulolytic (digest hemicellulose)
Amylolytic (digest starch)
Proteolytic (digest proteins)
Sugar utilizing (utilize monosaccharides and disaccharides)
Acid utilizing (utilize such substrates as lactic, succinic and malic acids)
Ammonia producers
Vitamin synthesizers: vitamin B and K
Methane producers

20. Fermentation Ecology Rumen pH between 6 and 7
Grain engorgement: pH <5.5
protozoal populations decrease
Products: Sugars -> VFA’s
acetic, propionic and butyric acids

21. Volatile Fatty Acids Acetic acid Proprionic acid Butyric acid,
is utilized minimally in the liver
oxidized throughout most of the body to generate ATP
Major source of acetyl CoA for synthesis of lipids.
Proprionic acid
is almost completely removed from portal blood by the liver
In the liver, proprionate serves as a major substrate for gluconeogenesis, which is absolutely critical to the ruminant because almost no glucose reaches the small intestine for absorption.
Butyric acid,
most of which comes out of the rumen as the ketone beta-hydroxybutyric acid
is oxidized in many tissues for energy production.

22. Ruminant Anatomy the rumen or paunch reticulum or "honeycomb,"
the omasum or “book,"
the abomasum or "true stomach."

23. Rumen – ‘Paunch’ largest of the forestomaches
sacculated by muscular pillars: dorsal, ventral, caudodorsal and caudoventral sacs
stratified squamous epithelium
fermentation vat (25 gallons)
Absorbs most VFA
Healthy cows: 1-2 minutes/contractions

24. Reticulum – ‘honeycomb’
Lies against the diaphragm
rumino-reticulum connected by tissue
Heavy objects fall
Hardware disease (traumatic reticuloperitonitis)
No enzymes secreted

25. Omasum - book broad longitudinal folds or leaves
absorbs water and other substances from digestive contents
Reduce particle size, ingesta between the leaves will be drier than in other compartments

26. Abomasum – true stomach
This is the only compartment (also called the true stomach) with a glandular lining
HCL and digestive enzymes (mucin, pepsinogen, renin, lipase), needed for the breakdown of feeds, are secreted into the abomasum

28. Digestive system - Ruminants
The small intestine
measures about 20 times the length of the animal
duodenum, jejunum, and ileum.
secretions of the pancreas and the gallbladder, which aid digestion
Most of the digestive process is completed here, and many nutrients are absorbed through the villi (small finger-like projections) into the blood and lymphatic systems.
Cecum
junction of the SI and LI, where some previously undigested fiber may be broken down
Function of cecum?
Large intestine
last segment of the tract through which undigested feedstuffs pass
absorption of water is the primary digestive activity occurring in the large intestine
Some bacterial digestion of undigested feed occurs

29. Function of digestive tract
Eructation (belching)
Large quantities of gas, mostly carbon dioxide and methane, are produced in the rumen
Rumination
35 to 40 percent of each day ruminating (cud chewing)
During rest periods, feed boluses (cud) are regurgitated for rechewing to reduce particle size and for resalivation.
Feed is more readily digested by rumen microbes as particle size is reduced
Motility of the rumen and reticulum
contractions mix the rumen contents, bring microbes in contact with new feedstuffs, reduce flotation of solids, and move materials out of the rumen
Saliva production
50 to 80 quarts of saliva
provides liquid for the microbial population, recirculates nitrogen and minerals, and buffers the rumen
buffer for helping to maintain a rumen pH between 6.2 and 6.8 for optimum digestion of forages and feedstuffs
Vomiting
Rare: suspect toxins

30. References Large Animal Clinical Procedures, Elizabeth Hanie. 2006
faculty.fortlewis.edu/LASHELL_B/Nutr2-Rumdigestion.pdf