Digestion physio of horse (foals, adult and senior horses)

Question 1

What is unique to equine digestive physio?

Answer 1

They have the highest CF digestibility among monogastric species

Their metab is 3-4x slower than Ru so they need a longer daily feeding period to reach their daily feed intake

Question 2

Saliva (3)

Answer 2

40 L/day

No digestive enzymes

HCO3 acts as buffer for prox stomach

Question 3

Esophagus

Answer 3

Even if there is an incr in abd P- the sphincter cannot relax- therefore no chance of vomitting or regurgitation

pH is 5

Question 4

Stomach (5)

Answer 4

9% of GIT

8-10L capacity

Short emptying time: limited protein digesiton and bolus remians for 2-6 hrs

Microbial ferm of carbs- produces lactic acid– then abs by the SI

Pylorus- HCl secretion- therefore pH is lower 2.5-2.7

Question 5

pH of the glandular vs the non-glandular part

Answer 5

Glandular is 7

Non-glandular is 2-4

Question 6

Small intestine (4)

Answer 6

• Carbs– glucose that can be absorbed.

Alpha amylase is LOW which means that some undigested carbs pass to the LI

• Proteins: partly hydrolysed and aa’s are absorbed
• Fats: The lack of gall bladder means that there is continuous bile secretion- efficient emulsification
• Mineral abs- but not P as this is done by the colon

Question 7

Precaecum

Answer 7

Starch digestion

Oat> barkey > corn

Aided by grinding

Question 8

Caecum

Answer 8

16% of GIT

Fiber digestion

Question 9

Large intestine (3)

Answer 9

Microbiome- similar to rabbit

Carb digestion

Protein digestion

Question 10

Microbiome

Answer 10

Similar to rabbit

Bacteroides

Streptobacilli

Lactobacilli

Protozoa

Question 11

Carb digestion

Answer 11

Cellulose and the predigested caecal starcj and converted to VFA’s– heat production– sweating

Question 12

Protein digestion

Answer 12

AA’s and NH3– reutilized– protein synth– absorbed

Excess NH3 and NPN– liver– urea

**Note: NPN is contra in the horse

Question 13

Ideal feeding

Answer 13

Give feed 3 times a day, to avoid starch overload and give forages first- to limit starch fermentation

Morning: 1/3 oat and 1/4 hay

Noon: 1/3 oat and 1/4 hay

Eve: 1/3 oat and 2/4 hay

Question 14

Uniqueness of the foal

Answer 14

Initial source of E (in the first hour) come from carbs in the liver and glycogen in the muscles

From 2-4 hrs: the E comes from body fat

After 2-4 hrs: combo of carbs and fats

Higher gastric pH: newborns it is 4.1

Colustrum does not stim gastrin prod- means Ig’s are not dissolved

Question 15

Senior horses- problems (7)

Answer 15

1. Dental abnormalities
2. Metab disorders- PPID, EMS, Insulin resistance
3. Chronic low grade Dx- decr abs capacity
4. Chronic pain– decr grazing
5. Eq asthma- incr E requirements
6. Decr nEM: decr exercise and fat free mass
7. Cold intolerant