- Abomasal displacement and volvulus are common disorders of high-producing dairy cattle. Clinical signs include anorexia and decreased milk production. With abomasal volvulus, clinical deterioration is rapid. The most important diagnostic finding is a ping upon simultaneous percussion and auscultation of the abdomen. Conservative (ie, medical) treatment for left abomasal displacement may be successful, especially if the diagnosis is made early, but prompt surgery is always required for right abomasal displacement due to high risk for volvulus. Improved management techniques may help reduce the frequency of all three conditions in dairy herds.
- Because the abomasum is suspended loosely by the greater omentum and lesser omentum, it can be moved from its normal position on the ventral part of the abdomen to the left or right side (LDA and RDA, see below), or it can rotate while displaced to the right and lateral to the liver (abomasal volvulus). The abomasum can shift from its normal position to left displacement or to right displacement over a relatively short period (pendulous LDA). Abomasal volvulus can develop rapidly or slowly from an RDA. LDA and RDA result in partial ileus; abomasal volvulus leads to complete ileus and abomasal wall ischemia.
- Left displaced abomasum (LDA) is displacement of the gas-filled, distended abomasum to the left side of the abomasum, trapping it between the rumen and the abdominal wall
- Right displaced abomasum (RDA) is displacement of the gas-filled, distended abomasum from the ventral abdominal wall into the craniodorsal right abdominal cavity
- Abomasal volvulus is displacement of the gas-filled, distended abomasum from the ventral abdominal wall into the craniodorsal right abdominal cavity, secondarily creating a volvulus by vertical and horizontal rotation (abomasum, wrapped in the greater omentum)
Diagnosis and differentials
- The most important diagnostic physical finding is a ping on simultaneous auscultation and percussion of the abdomen, which should be performed in the area marked by a line from the tuber coxae to the point of the elbow, and from the elbow toward the stifle on both sides of the patient. The ping (detected during simultaneous percussion and auscultation) characteristic of an LDA is most commonly located in an area between ribs 9 and 13 in the middle to upper third of the left abdomen; however, the ping can be more ventral or more caudal, or both.
- Abomasal volvulus and RDA require immediate surgical treatment
- A patient with LDA can be medically treated with administration of spasmolytic and analgesic drugs; in addition, rolling a cow through a 180° arc after casting it on its right side corrects most LDAs. Additionally, it has been reported that movement during transport of the patient with LDA may result in return of the abomasum to its normal position. A major disadvantage of all nonsurgical approaches is that recurrence is very likely.
- Open (surgical) and closed (percutaneous) techniques can be used to correct abomasal displacements. LDA can be corrected surgically using right- or left-flank omentopexy, right-paramedian abomasopexy, combined left-flank and right-paramedian laparoscopy (a two-step procedure), or left-flank laparoscopy (a one-step procedure). Blind suture techniques (toggle-pin fixation or the “big needle” [blind-stitch] method), performed in the right-paramedian area, are percutaneous methods for correction of LDA.
- Patients with notable dehydration and metabolic derangements require IV therapy, typically administered as hypertonic saline (7.2% NaCl, 5 mL/kg, IV over 5 minutes).
- The prognosis after correction of simple LDA or RDA is good, with survival rates of 95%. Abomasal volvulus has a variable and less favorable prognosis (average survival rate of 70%); a high heart rate, moderate to severe dehydration, a longer period of illness, a large quantity of fluid in the abomasum, increased blood or plasma l-lactate concentration, and the presence of omasal-abomasal or reticulo-omasal-abomasal volvulus are associated with a poorer prognosis.