[Thyroid hormones in cesarean-delivered suckling calves after birth and in the first days of life--maternofetal relations and early postnatal adaptation reactions].

Caesarean section delivered suckler calves and their dams from the mother cow herd were used for this investigation. Jugular venous blood samples taken immediately after delivery from the cow and the calf and in the calf at 24 hours and at 48 hours of postnatal age as well were analyzed for T4, FT4, T3 and FT3 by luminescence enzyme immunoassay. Strong correlation between the thyroid hormone values of the cow and those of the calf could be found. Higher thyroid hormone values were measured in calves increasing further at 24 hours of age and then decreasing a little at 48 hours of age with higher values in female than in male calves. A strong correlation existed between T3 and heart rate of the calves.