Displaced Abomasum

• This is much less dramatic than a displaced stomach in the dog, and develops chronically.
• Occurs most frequently in heavy yielders on high concentrate diets and in late pregnancy.
  • Rearrangement of abdominal viscera in pregnancy is thought to be an important aetiological factor.

Clinical

• Animals display general malaise and abdominal pain.
• Left flank bulges behind ribs
  • "Pings" on auscultation.
• Not usually acutely fatal, but results in loss of condition and emaciation if untreated.

Pathogenesis

• There are two manifestations of abomasal displacemet. In both the abomasum becomes trapped between rumen and abdominal wall.
  1. Ventral and to the left of rumen (LDA) - the more common presentation.
     • Most common in dairy cattle around parturition.
     • Abomasal atony and increased gas production lead to displacement
       • Is induced by the combination of a high concentrate diet, hypocalcaemia and increased volatile fatty acids from the rumen.
  2. To the right of rumen (RDA) - less common.
     • Constriction of blood vessels and trauma to the vagus nerve results in abomasal distenstion with blood-stained fluid and gas, congested mucosa and infarction.
     • The abomasum may rupture, causing peritonitis, shock and death.
• May be associated with secondary development of ketosis.