We examined whether the postoperative prognosis of beef cattle with left displaced abomasum (LDA) can be estimated from changes in laboratory parameters. Preoperatively, beef cattle with LDA showed increases in plasma glucose with decreased serum insulin in the glucose tolerance test compared to non-LDA cattle. Postoperatively, the cattle with LDA were retrospectively divided into two groups, good and bad prognoses. Although plasma glucose concentrations significantly increased either pre- or postoperatively, no difference was noted between the good and bad prognosis groups. Serum insulin concentrations in the bad prognosis group significantly decreased, compared to those in the good prognosis group. These findings suggest that beef cattle with LDA elicit disturbed glucose metabolite pre- and postoperatively, and serum insulin levels may predict their prognoses after surgery.