Equine GIT

Question 1

What is different in the equine stomach compared to other species?

Answer 1

• 2 distinct regions of mucosa
• Squamous and glandular epithelium
• Separated by margo plicatus
• 5-15 litre capacity

Question 2

Describe the equine small intestine

Answer 2

• 10-30m long
• 3 parts (duodenum, jejunum, ileum)
• Loosely coiled
• Long mesenteric attachment, no fixed position

Question 3

List some of the common diseases of the small intestine in the horse

Answer 3

• Parasitic infestation
• Diarrhoea
• Impactions
• Twists and strangulation
• Infiltrative bowel disease (malabsorption)

Question 4

Describe the equine large intestine

Answer 4

• Adaptation to high roughage diet
• Microbial digestion and water absorption
• Made up of caecum, large colon, small colon
• Ventral colon and caecum have taenia and haustra

Question 5

What is the function of the taenial bands?

Answer 5

• Muscular bands

- Important in mixing and moving ingesta

Question 6

What is the function of the sacculations/haustra?

Answer 6

Increase surface area

Question 7

Describe the equine caecum

Answer 7

• Blind ending sac
• 2 muscular valves controlling entry and exit of ingesta
• 25-35litre capacity
• Major site for microbial digestion of cellulose, absorption of water and electrolytes
• Pacemaker for motility

Question 8

Describe the equine large colon

Answer 8

• 4 regions: RVC, LVC, LDC, RDC
• Capacity for 55-130 litres
• Major site for microbial digestion of cellulose, absorption of water and electrolytes

Question 9

Describe the equine small colon

Answer 9

• Storage of faeces and absorption of remaining water

- Narrow diameter

Question 10

What is the clinical importance of the equine large colon?

Answer 10

• Narrow diamter, common site for impactions

- Esp. miniature horses

Question 11

Describe the diet and feeding habits of the horse

Answer 11

• Grazing diet
• Need high fibre
• Trickle feeders - graze continuously for up to 17 hours a day
• Not designed to eat lush grass or cereals

Question 12

What is the fate of cellulose and hemicellulose in the horse?

Answer 12

• Cannot be digested

- Breakdown by bacteria

Question 13

What is the fate of carbohydrate, protein and fat in the diet?

Answer 13

• Digested and absorbed in small intestine
• Starch to glucose and galactose
• Oligopeptides to dipeptides, tripeptides and AAs
• TAGs to fatty acids and monoglycerides

Question 14

What is the fate of fructans in the diet?

Answer 14

• Not digested in SI or stomach
• Pass into LI
• Digested by bacteria
• Produces acidic environment
• Alters LI bacterial flora
• Can lead to pathological disease

Question 15

Where does water absorption take place in the horse?

Answer 15

• Caecum

- Large colon

Question 16

Describe what can be felt in a rectal palpation

Answer 16

• Start top middle (12 oclock) move anticlockwise
• Aorta at top
• Then caecum on RHS (sacculations, taenia, large diameter, can feel body)
• Then small colon (small diameter, 2 taenial bands, faecal balls)
• Pelvic flexure (variable diameter, no sacculations, no taenial bands, indentable contents, can move avross midline)
• Caudal edge of spleen (against body wall, smooth, sharp border, no palpable masses)
• Nephrosplenic ligament (between spleen and left kidney)
• Caudal pole of left kidey (smooth margins, against spleen)

Question 17

What are the classes of cause for abdominal disease?

Answer 17

• Diet
• Anatomical predisposition
• Motility disturbances
• Infection
• Parasites
• Ulceration
• Other organs/systems (false colic)
  (DAMIPOU)

Question 18

What does colic refer to?

Answer 18

Abdominal pain

Question 19

Give examples of how diet can cause colic

Answer 19

• Rapid change in diet, microflora take time to adapt

- Increased gas production = predisposed to colic

Question 20

Give an example of an anatomical predisposition that may lead to colic

Answer 20

Inguinal hernia in a foal

Question 21

Give an example of a motility disturbance that may cause colic

Answer 21

Box rest

Question 22

What should you look out for on physical examination of a horse presenting with colic?

Answer 22

• Overall impression of horse
• TPR
• Mucuous membranes
• Pulse quality, CRT, digital pulses
• Gastrointestinal sounds
• Abdominal distension
• Skin turgor (not always accurate for hydration status)

Question 23

What diagnostic tests may be carried out in a horse presenting with colic?

Answer 23

• Blood sample
• Nasogastric intubation
• Faecal examination
• Abdominal paracentesis
• Ultrasonography
• Endoscopy
• Radiography
• Rectal palpation