Postpartum adrenocortical function in dairy cows with dystocia submitted to cesarean section

The effects of the stress of dystocia on the adrenocortical function post partum in cows (n = 6) requiring a cesarean section were assessed by an adrenocorticotropic hormone (ACTH) stimulation test. Nine cows that calved normally were used as controls. The plasma glucocorticoid levels, before and 60 min after an intramuscular injection of 25 IU ACTH, were 4.4 +/- 0.5 (mean +/- SD) and 21.5 +/- 2.4 ng/ml 1 d post partum, 1.9 +/- 0.3 and 18.4 +/- 2.9 ng/ml 4 d post partum and 2.7 +/- 1.1 and 14.6 +/- 3.3 ng/ml 8 d post partum, respectively. Corresponding values of glucocorticoids in cows with normal calving were 4.5 +/- 3.6 and 18.1 +/- 5.2 ng/ml 1 d post partum, 1.7 +/- 1.3 and 13.2 +/- 5.5 ng/ml 4 d post partum and 1.9 +/- 1.7 and 14.6 +/- 3.3 ng/ml 8 d post partum. There were no statistically significant differences of the values between cows with dystocia requiring a cesarean section and cows with normal calving. The results indicate that dystocia requiring a cesarean section like normal calving does not lead to significant depression of the adrenocortical function post partum.