Ultrasonographic assessment of change in abomasal position during the last three months of gestation and first three months of lactation in Holstein-Friesian cows

Objective - To determine changes in abomasal position and dimensions during the last 3 months of gestation and first 3 months of lactation via transabdominal ultrasonography and determine whether surgical correction of left-displaced abomasum (LDA) by right flank omentopexy alters abomasal position within the abdomen in Holstein-Friesian cows. Design - Observational study. Animals - 20 heifers and 20 cows with no history of an LDA and 7 cows that had been treated for LDA via right flank omentopexy during an earlier lactation. Procedure - Ultrasonographic measurements were obtained 8 times during the last 3 months of gestation and first 3 months of lactation. Abomasal length, width, and volume were calculated from these measurements. Results - The abomasum was always wider than it was long and located predominantly to the right of the midline. The presence of a right flank omentopexy had no effect on the measured parameters. Abomasal length decreased and width increased during the last 3 months of gestation, resulting in a more transverse orientation of the abomasum within the abdomen. These changes appeared to be in response to cranial expansion of the gravid uterus. The abomasum returned to a more caudal and right sagittal position within 14 days after parturition. Conclusions and Clinical Relevance - Abomasal dimensions, position, and volume change markedly during the last 3 months of gestation and first 3 months of lactation. Results permit detection of abnormal abomasal position in ill cows and indicate that the preferred location for abomasopexy is 20 cm caudal to the xiphoid process and 5 to 10 cm to the right of the ventral midline.