Use of the D-xylose absorption test to measure abomasal emptying rate in healthy lactating Holstein-Friesian cows and in cows with left displaced abomasum or abomasal volvulus.

We determined the abomasal emptying rates of Holstein-Friesian cows at different stages of lactation, with left displaced abomasum (LDA), or immediately after surgical correction of LDA or abomasal volvulus (AV). D-xylose (0.5 g/kg body weight [BW], 50% solution) was injected into the abomasum in healthy cows (group 1, 4-7 days in milk [DIM], n = 7; group 2, 90-120 DIM, n = 7; group 3, > 300 DIM, n = 7) and in cows with LDA (n = 10; group 4). D-xylose was injected into the abomasum during right flank laparotomy in cows with LDA (n = 22; group 5) and cows with AV (n = 15; group 6). The time to maximal serum D-xylose concentration was used as an index of emptying rate. The abomasal emptying rates for cows in groups 1, 2, and 3 were similar, whereas emptying was slower in cows with LDA and in cows after surgical correction of LDA or AV. The abomasal emptying rate of cows with LDA was slowed to a greater extent immediately after surgery, when compared to the rate obtained before surgery. There was no difference in abomasal emptying rate immediately after surgical correction between cows with LDA or AV. The results indicate that the increased incidence of LDA in the first month of lactation is not associated with an intrinsic decrease in abomasal emptying rate in healthy cows. Our findings also demonstrate that surgical correction further slows the emptying rate in cows with LDA.