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History

A four-month-old, female intact Jersey calf presented for vomiting, diarrhea, and decreased body condition of three weeks duration. Clinical signs began approximately one week post weaning from milk onto orchard grass and calf starter grain. The vomiting was not correlated with a specific event (e.g. post-prandial), was green, and appeared digested. The frequency of vomiting decreased once the patient was reversed to a predominantly milk-based diet. On physical examination, the calf was quiet but responsive, with a body condition score of 1.5/5. She was mildly tachycardic (140bpm), eupneic (40rpm), normothermic (102.0 deg F). Mucus membranes were pale pink and moist with normal capillary refill time. Rumen contractions were weak but present (1 per 2 minutes). No abnormal “ping” was noted on auscultation.

 

Images

The abomasum is abnormally positioned between the rumen and left abdominal wall and is both moderately enlarged and gas-filled. At the level of L2-L3, the pylorus (torus pyloricus labeled by white arrow in static image) is seen along the left ventrolateral abdominal wall, and the duodenum courses towards the right abdomen. The omasum is also abnormally located, to the left of midline. The rumen contains a medium amount of normally attenuating ingesta. The duodenum and other small intestinal segments are mildly enlarged, containing gas. The colon contains a small amount of fluid and gas.

Vomiting is attributed to left displaced abomasum. This diagnosis was confirmed via exploratory and de-rotation surgery

At birth, the abomasum is the most mature of the gastric chambers and may exceed 60% of the adult size, whereas the rumen and reticulum are relatively small. In the suckling ruminant, the forestomach is bypassed via closure of the reticular groove and milk is directed from the omasal canal into the abomasum. By the second month of life, the ruminoreticulum begins to have regular contractions. As solid food is introduced, the forestomach increases in both size and maturity (1). Normally, the rumen is the leftmost gastrointestinal structure, extending from the cardia to the pelvic inlet; the reticulum is much smaller and is cranially positioned, also left of midline. The omasum (third gastric chamber), lies to the right of midline, and the abomasum (fourth gastric chamber) extends transversely towards the right body wall (1,2). Abomasal displacement is reportedly due to reduced abomasal motility or increased gas production. As the lumen fills with gas and the rumen contracts, the abomasum crosses ventral to the rumen and into the left side of the abdomen.

Diagnosis of left displaced abomasum is typically made via physical examination and characteristic “pinging” in the left abdomen, although ultrasound (3,4) and radiography (5) have also been reported. In our case, diagnosis of LDA was not made on percussion and auscultation. Although this test is often diagnostic in adult cattle, the left-sided ping in calves can be subtle and is not pathognomonic for LDA (DDx: abomasitis, rumen ping, peritonitis) (4). We are not aware of a prior CT diagnosis of LDA. Lastly, treatment for LDA can be conservative (rolling) or surgical. As rolling is often temporary and has been associated with mesenteric volvulus, surgical correction is recommended

References

  1. Dyce KM, Sack WO, Wensing CJG. Textbook of Veterinary Anatomy. St. Louis: Saunders Elsevier, 2010: 680-693.
  2. Braun U, Schnetzler C, Ohlerth S, et al. Computed tomography of the abdomen of calves during the first 105 days of life:  Reticulum, rumen, omasum, and abomasum. Schweiz Arch Tierheilkd 2014;165(5):217-25.
  3.  Li XW, Xu QS, Zhang RH, et al. Ultrasonographic findings in cows with left displacement of abomasum, before and after reposition surgery. BMC Veterinary Research 2018;14:44. DOI 10.1186/s12917-018-1358-7.
  4. Oman RE, Streeter RN, Reppert EJ, et al. Left displacement of the abomasum in 4 beef calves. J Vet Intern Med 2016;30:1376-1380.
  5. Hawkins CD, Fraser DM, Bolton JR, et al. Left abomasal displacement and ulceration in an eight-week-old calf. Aust Vet J 1986;63(2):53-5.