Hypopituitarism as the possible cause of prolonged gestation in cattle]

Multiple malformations were shown in a bovine fetus delivered at slaughter after a gestation period of 469 days. Hypoplasia of the adenohypophysis and a bilateral agenesis of the adrenal cortex suggest that the failure of initiation of parturition resulted from a fetal deficiency of ACTH and glucocorticoid hormones. ACTH, GH (growth hormone) and prolactin could not be demonstrated immunohistochemically within the adenohypophysis. However, TSH immunoreactive pituitary cells were demonstrable. Nevertheless, considering the extremely reduced size of the adenohypophysis a fetal deficiency of TSH is suspected. This view is supported by a bilateral hypoplasia of the thyroid gland. Additionally, the complex fetal endocrine dysfunction had led to a growth retardation of the fetus.