Lecture 1

Question 1

What type of digestive animals are horses

Answer 1

Non-ruminant herbivores

Question 2

Digestive tract is divided into?

Answer 2

Foregut
- monogastric like

Hindgut
- ruminant like

Question 3

What is a rumen?

- positives? negatives?

Answer 3

large liquid sack

• less agile
• high microbial activity (nutritionally efficient)

Question 4

Major location of microbial activity

Answer 4

cecum and colon

- posterior to the small intestine

Question 5

Primary nutrient uptake location?

Answer 5

Small intestine

• duodenum and jejunum
• less in ilium

Question 6

Nutrient utilization is between

Answer 6

monogastrics (pigs) and ruminants (cows)

Question 7

Time for feed to move through digestive tract

Answer 7

65-75hrs (fast compared to some ruminants)

Question 8

Shape of jaw

Answer 8

lower is narrower than upper

- lateral grinding motion is limited (inefficient)

Question 9

Feature of teeth

Answer 9

both upper and lower incisors

- permits close grazing

Question 10

Features of lips

Answer 10

strong
mobile
prehensile (capable of grasping)

Question 11

Salivary glands

Answer 11

Parotid (90% of saliva)
Sublingual
Submaxillary glands

Question 12

Saliva functional components

Answer 12

Bicarbonate Buffers
- optimizes pH

Amylase
- begins carbohydrate digestion

Question 13

Stomach in contrast to bovine

• size
• time of emptying

Answer 13

10x smaller than bovine

1/3 the time to empty

Question 14

Stomach functional compounds

Answer 14

Small microbial population
- fermentation

Gastric HCl
- denatures dietary protein, allows for hydrolysis by pepsin

Gastric Lipase
- hydrolysis of fat

Question 15

2 main regions of stomach

- main structural difference?

Answer 15

glandular region
- protective layer from enzyme acids

esophageal region

• no protective layer
• surceptible to problems

Question 16

Small intestine proportional size

Answer 16

30% of digestive tract

Question 17

Pancreas secretes

Answer 17

Bile

• no gallbladder
• constantly secreted into small intestine

Question 18

Significant enzymatic hydrolysis in SI due to

Answer 18

Pancreatic Secreations

Question 19

Major site of nutrient absorption

Answer 19

duodenum and jejunum

- less in ilium

Question 20

Large intestine proportion of digestive tract

Answer 20

60% length of digestive tract

Question 21

Parts of large intestine

Answer 21

cecum
large colon
small colon
rectum

Question 22

Reason for high fermentation compared to monogastrics

Answer 22

Cecum larger than a cow

- replaces rumen

Question 23

Cecum

• role
• functional components

Answer 23

active population of bacteria and protozoa

- for fermentation of undigested feedstuffs including forage fibers

Question 24

Cecum efficiency

Answer 24

66% efficiency of cow

- for converting fiber to nutrients

Question 25

Microbial action

Answer 25

synthesizes

• vitamins
• volatile fatty acids (VFAs)
• amino acids

Question 26

Main site of water absorption in intestinal tract

Answer 26

Cecum

Question 27

Synthesized in large intestine that provides energy

- what %

Answer 27

volatile fatty acids

- 25% energy needs

Question 28

what happens to undigested dietary protein

- implications?

Answer 28

degraded to ammonia in large intestine

• amino acids from this little significance
• little active transport of amino’s in large intestine
• less able to improve amino acid profile of low quality protein than ruminants
• high quality required

Question 29

Microbial synthesis of vitamins

Answer 29

not adequate to meet requirements

- particularly during training

Question 30

When does cecum start functioning

Answer 30

15-24 months old

• limit ability to use forages
• acts like monogastric

Question 31

Initial location of protein digestion

- what enzyme

Answer 31

stomach

- pepsin

Question 32

Major site of protein digestion

Answer 32

small intestine

- liberated peptides and amino acids absorbed by “active transport”

Question 33

amino acids synthesized by microbial activity absorbed?

Answer 33

Cecum and large intestine

- by diffusion

Question 34

Young horses and protein

Answer 34

Requires dietary protein

• lacks cecal protein synthesis
• cecum doesnt function until 15-24months

Question 35

Amino acid that promotes growth of young horses

Answer 35

lysine

- connective tissue

Question 36

Protein in hay digestion

Answer 36

large intestine

• hay high in cellulose + hemicellulose
• limit protein release for young horses

Question 37

Major site of starch and other soluble carbohydrate digestion and absorption

Answer 37

small intestine

• actively absorbed
• as simple sugars

Question 38

Soluble carbs that reach cecum and large intestine

Answer 38

metabolized to volatile fatty acids

• acetate
• propionate
• butyrate

Question 39

Carbohydrate overload

Answer 39

excess reaches LI

- can upset GI tract

Question 40

insoluble fiber fate

Answer 40

metabolized to VFAs in large intestine

• cellulolytic bacteria numbers same as bovine
• protozoa differ greatly

Question 41

dietary fatty acid composition similar to?

Answer 41

fatty acid composition of body fat

- little microbial alteration

Question 42

fatty acid absorption

Answer 42

small intestine

Question 43

high fat diet tollerance

Answer 43

very good

• no gallbladder
• bile constantly released

Question 44

Phosphorus and calcium absorption

Answer 44

phosphorous = large intestine
calcium = proximal small intestine

excess dietary phosphorus reduces calcium but calcium has no effect on phosphorus