[Catecholamine and cortisol concentrations in plasma from cattle at parturition].

Cows with spontaneous parturition (n = 8) and cows with flumethasone (n = 3) or prostaglandin (n = 3) induced parturition were used in this study. Catecholamine concentrations from cows in the periparturient period were measured in order to evaluate the stress of birth on the dam and the calf. The plasma content of both norepinephrine and epinephrine in late pregnancy was not different from control values in the 3rd to 6th month of pregnancy (norepinephrine 3.27 +/- 0.99 nmol/l plasma and epinephrine 0.98 +/- 0.45 nmol/l plasma), though both parameters appear elevated in the pregnant group. Norepinephrine concentrations rose to a value of 4.50 nmol/l immediately after birth, whereas epinephrine levels did not show an increase post partum. In two neonates norepinephrine and epinephrine values were 2-3 times higher than in the dams and decreased to the values of the dams within 48 hours. Synthetic glucocorticoids can mimic the increase of cortisol, which leads to birth. Cortisol concentrations in the cows remained unaffected by induction of parturition by prostaglandins. Newborn calves showed values of about 330 nmol/l, which also declined within 48 hours to values similar to those measured in the dam (9-28 nmol/l). As stress and exogenous glucocorticoids may affect antibody production, the IgG-content of the colostrum was examined. Prostaglandin induction of birth did not alter the IgG-content of colostrum, but flumethasone produced a decrease of about 14.5%. It is therefore concluded that pre-term birth induction does not produce negative effects on the supply of IgG.