Equine gut anatomy and physiology Flashcards
What are the problems of a grazing diet for horses?
Grass contains silicates - harder than enamel => rapid wear of teeth
Cellulose and hemicellulose in diet can’t be digested - required breakdown by bacteria in hindgut
Describe horse dentition
Lips and incisors grasp and prehend food
Large, ridged molars grind food
irregular molar surface for optimal grinding
rotational chewing
continued eruption throughout life = rate of wear
What is the effect of concentrate diets on horse dentition?
affects chewing movement and rate of wear => overgrowths
Why does saliva exit the mouth and nose in horses with choke?
food material stuck in oesophagus => saliva cannot go down oesophagus
Why can horses not vomit?
muscular sphincter controlling food moving into the stomach and preventing reflux - blocked stomach => death if no intervention
What is choke and what can cuase it?
food obstructing the oesophagus
caused by:
- dry food e.g., sugar beet
- food that is not properly chewed
- unsuitable types of food e.g., whole apples, potatoes, grooming brushes
What are the 2 distinct regions of the equine stomach?
squamous epithelium
glandular epithelium
what are the sphincters in the equine stomach?
powerful muscular sphincters:
- cardiac sphincter: stops food going back into oesophagus
- pyloric sphincter: controls food entering duodenum
Describe the clinical relevance of the equine small intestine
long mesenteric attachment and no fixed position => can form knots
Describe the digestion of carbs, protein and fat
Why are horses not designed for sugar diets?
fructans cannot be digested in the SI
passed onto LI where they are digested by bacteria => acidic environment => changes large intestinal bacterial flora
What are the common disreases of the equine SI?
parasites
diarrhoea
impactions
twists and strangulation
infiltrative bowel disease - malabsorption
What is the function of the equine large colon?
microbial digestion of cellulose and absorption of water and electrolytes
Where are sacculations and taenial bands found in the equine GIT?
ventral colon
caecum
what is the function of sacculations in the equine GIT?
increases SA for microbial fermentation?
What is function of taenial bands?
muscular bands important in the mixing and movement of ingesta
What is the function and anatomy of the equine small colon?
storage of faeces and absorption of remaining water
Narrow diameter => impactions
What structures can be felt via rectal palpation in the horse?
Left hemisphere:
Spleen - against body wall, smooth, sharp border
Caudal pole of left kidney - smooth margins and against spleen
Pelvic flexure - no sacculation or palpable taenial bands, indentable contents, can move to midline
Small colon- small diameter, 2 taenial bands, faecal balls
Right hemisphere:
Caecum - large diameter, gas/fluid/feed contents, sacculations, caudal and medial taenial bands run dorsal to ventral
What the possible causes of abdominal disease in horses?
diet
anatomical predisposition
motility disturbances
infection
parasites
ulceration
What diagnostic tests should be carried out in suspected abdominal disease in horses?
blood sample - hydration, infection, biochemistry, electrolytes
Nasogastric intubation
Faecal exam
Abdominal paracentesis
Ultrasound
What is the function of nasogastric intubation in horses?
Removal of liquid reflux as horses are unable to vomit
detection of gastric impaction
relieving choke
administer oral fluids/treatments
What should you analyse in a peritoneal tap of a horse with suspected abdominal disease?
colour
volume
turbidity
total protein
cell number and type
