Blood parameters, feed intake and milk yield were determined in 53 cows with a left displacement of the abomasum (LDA) on the day of surgery (ds; laparotomy and omentopexy) and during the following four days (d1-d4). Using histological methods severe (group SF), moderate (group MF) or no/mild (group NF) fatty liver was found in 32%, 40% and 28% of the patients, respectively. Moderate and severe fatty liver were found almost exclusively in cows in the first three weeks post partum. Post surgery, feed intake and daily milk yield increased steadily in cows of the NF- and MF-group; in cows suffering from severe fatty liver feed intake remained low (p < 0.05). On ds, mean serum levels of nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), total bilirubin, aspartate aminotransferase (ASAT), gammaglutamyl transpeptidase (GGT) and glutamic dehydrogenase (GLDH) in SF-cows were significantly (p < 0.05) higher and values of cholesterol significantly lower (p < 0.05) as compared to the NF- and MF-group; no significant differences were found between the groups in mean serum glucose concentrations. In the four day period following surgery, in all groups mean serum levels of ASAT, GGT, GLDH and cholesterol remained nearly unchanged, whereas total bilirubin, NEFA, BHB and glucose decreased significantly (p < 0.05). Apart from LDA, 55% of the patients were suffering from mastitis, endometritis or lameness. Within three weeks post surgery, 3 cows of the SF-group and 1 cow of the MF-group developed recumbency and liver coma, and were culled for that reason. In conclusion, post surgical convalescence of cows with LDA is clearly related to disturbances of energy metabolism and fatty liver. Therefore, successful treatment of cows suffering from LDA requires the effective treatment of excessive lipomobilization, ketosis and fatty liver along with the immediate surgical correction of LDA.