PLASMA-CATECHOLAMINES AND BLOOD-CHEMISTRY IN NEWBORN CALVES IN RELATION TO DIFFERENT OBSTETRICAL PROCEDURES AND TO NEONATAL OUTCOME

Each of 56 newborn calves born to primiparous heifers was classified in two different ways: first into one of four groups according to the way it was delivered and, secondly into one of three groups according to its neonatal acidotic stage. Blood samples from each animal were collected at 1, 10 and 30 min after parturition. Plasma catecholamines and blood chemistry parameters were measured to evaluate the calves' physiological functions and their responses to different forms of stress during calving. Both plasma noradrenaline (NA) and adrenaline (A) were significantly elevated (P < 0.01) 1 min postparturient in the heavy and normal extraction groups, respectively, when compared with the Caesarean section (C-section) group. These high values of catecholamines seen in both extraction groups may correlate to severe mechanical stress used during parturition. On the other hand, NA and A were significantly increased (P < 0.01) in the severe acidosis group (blood pH less than 7.0). Blood glucose levels in the heavy extraction group were significantly higher (P < 0.01) than in any other group. This may result from high levels of catecholamines that can provide a stimulating effect on carbohydrate metabolism. None of other blood parameters determined (enzymes and electrolytes) showed significant differences. This study has demonstrated that the catecholamine system in newborn calves responded sensitively to different forms of stress during delivery, even though different obstetrical procedures did not influence selected clinical enzymes and electrolyte concentrations.