Effects of erythromycin on milk yield, rumen contraction rate and blood beta-hydroxybutyrate concentration in dairy cows
The objective of this study was to evaluate the beneficial effects of erythromycin (Emy), a prokinetic drug active at the level of the abomasum, duodenum and proximal duodenum, in dairy cows undergoing a lapa- roscopic repositioning of left abomasal displacement (LAD). A total of 71 German Holstein cows were randomly assigned into three groups. Cows of the group Emy1 received erythromycin once preoperatively (10 mg/kg; intra- muscularly). Animals of the group Emy3 were additionally treated twice after surgery at intervals of 24 h each (10 mg/kg; intramuscularly), while cows in the control group did not receive erythromycin. The milk yield of the patients was documented on Days 0, 1, 2, 3, 6 and 10 and the rumen contraction rate (RCR) was determined on Days 1 and 3. Additionally, the measurement of the concentration of beta-hydroxybutyrate (BHB) in whole blood samples was performed on Days 0, 1 and 3. Significant differences between the study groups regarding the cure rates, milk yield (in relation to Day 0); BHB concentrations and RCR could not be determined on the observation dates. With respect to a prudent use of antibiotics in livestock, the application of erythromycin as a prokinetic drug cannot be recommended for the present in cows undergoing a laparoscopic correction of LAD.