16. Anatomy of the abomasum, diseases of the abomasum (list), abomasal displacement: forms, incidence, etiology/causes, and predisposing factors

Question 1

Anatomy of the abomasum?

Answer 1

Anatomy of the abomasum

• The abomasum is the fourth chamber in the ruminant
• It functions similarly to the carnivore stomach as it is glandular and digests food chemically, rather than

mechanically or by fermentation like the other 3 parts of the ruminant stomach

• The abomasum differs in its position within the abdomen, depending on fullness of the other chambers of

the stomach, intrinsic abomasal activity, contractions of the rumen and reticulum (to which it is attached)

and pregnancy status

• It is located upon the abdominal floor, and it is divided in two parts:

o cranial (split into the pylorus and body) and the caudal one.

• It is covered by the lesser omentum, and it has around 15-20 folds inside
• The abomasum is like a hammock

o 2 openings, no other connections to its surroundings, loosely hangs

Question 2

Diseases of the abomasum?

Answer 2

Diseases of the abomasum

• Abomasal displacement
• LDA
• RDA (with/without torsion)
• Abomasal inflammation
• Abomasal ulcer
• Abomasal obturation
• Reflux syndrome

o Conclusion: all abomasal diseases can lead to the reflux syndrome, right sided abomasal

displacement could happen with torsion.

Question 3

Abomasal displacement?

Answer 3

Abomasal displacement

• = A condition in which the abomasum (4th stomach) is displaced from its normal position (right lower part of

abd cavity) into an incorrect position

o Left sided= displacement below and to the left or dorsal to the right

o Right sided= up between Si and right sided thoracic part

o E.g., goes under rumen and protrudes btw rumen and left thoracic part

Question 4

Ethiology/ causes of abomasal disease/abomasal displacement ?

Answer 4

Etiology/ Causes

• Multifactorial with nutrition as the main factor!
• Other influencing factors (predisposing)

o Breed: e.g., Holstein (dairy)

o Genetic background

o Anatomic factor

§ Changes in abdominal cavity- after calving

• The abdominal cavity is emptier with a lot of spare space= higher possibility of

displacement

o Metabolic disorders

§ ketosis, lipomobilisation

o Lactation (stage and number)

o Other diseases of the abomasum (ulcer, Abomasitis)

o Recurrent diseases: endometritis, mastitis, claw disorders etc.

Question 5

Incidence of abomasal displacement after calving?

Answer 5

Incidence of abomasal displacement after calving:

• Majority of abomasal displacements post calving occur within the first 6 weeks
• Clinically consequence could be either LDA/RDA