Abstract
Objective—To determine the correlation between insulin concentrations and myoelectrical activity of the abomasum in cows with a left displaced abomasum (LDA).
Animals—14 dairy cows with an LDA at the onset of lactation.
Procedure—During surgical correction of an LDA, 3 pairs of electrodes were placed in the smooth muscle of the gastrointestinal tract (abomasal body, pars pylorica, and duodenum) of each cow. Electromyographic recordings were obtained once per day for 7 days. Samples were collected and tested to determine concentrations of insulin, glucagon, cortisol, glucose, β-hydroxybutyrate, and nonesterified fatty acids.
Results—All 14 cattle had high glucose and insulin concentrations at the time of admission, independent of ketosis. Concentrations of glucose and insulin decreased slowly after surgical treatment and were associated with a progressive increase in abomasoduodenal myoelectric activity. The 14 cows were allocated into 2 groups (suspected insulinresistant cattle, n = 7; suspected non–insulin-resistant cattle, 7) on the basis of persistent hyperinsulinemia during the postoperative period. Seven days after surgery, the abomasoduodenal myoelectric patterns were still significantly lower for the insulinresistant cows, compared with patterns for the non–insulin-resistant cows.
Conclusions and Clinical Relevance—Insulin resistance appears to be common in cows with an LDA. Analysis of results of this study reveals that abomasal atony in cows with an LDA depends on persistence of high serum concentrations of insulin. Results of this study could provide an explanation for a pathogenetic factor of LDAs and the frequent relapses of cattle affected by this condition. (Am J Vet Res 2004;65:1319–1324)
