Effect of preoperative erythromycin or dexamethasone/vitamin C on postoperative abomasal emptying rate in dairy cows undergoing surgical correction of abomasal volvulus

Objective - To determine the effects of preoperative erythromycin or combined dexamethasone/vitamin C treatment on postoperative abomasal emptying rate in cows undergoing surgical correction of abomasal volvulus (AV). Study Design - Prospective, controlled, clinical study using a convenience sample. Animals - Lactating Holstein-Friesian cows (n=45) with AV were alternately assigned to 3 groups (n=15): group C: untreated (control); group E: erythromycin (10 mg/kg intramuscularly [IM]); group D: dexamethasone (0.02 mg/kg intravenously [IV]) and vitamin C (10 mg/kg IV). Methods - Drugs were administered 1 hour before surgical correction of AV. d-xylose solution (50%, 0.5 g/kg body weight) was injected into the abomasal lumen during surgery. Jugular venous blood samples for determination of serum d-xylose concentration were periodically obtained. Time to maximal serum d-xylose concentration (T _max-model) was pharmacokinetically determined. Results - Abomasal emptying rate was significantly (P<0.05) faster in group E (T _max-model=182±69 min; mean±SD) than in group C cows (T_max-model=237±64 min). Abomasal emptying rate was similar in group D (T_max-model=196±47 min) and group C. Both treatments improved postoperative milk yield within 1 day after surgery. Conclusion - Preoperative injection of erythromycin (10 mg/kg IM) is an effective method for ameliorating postoperative abomasal hypomotility in cows with AV. Clinical Relevance - Parenteral erythromycin can be recommended for preoperative treatment of cows with AV.