Ministry of Agriculture and Fisheries, Ruakura Agricultural Research Station, Private Bag, Hamilton, New Zealand (Received 23 August 1974) The foetal adrenals are important in initiating parturition in sheep (Liggins, Fairclough, Grieves, Kendall & Knox, 1973) and goats (Thorburn, Nicol, Bassett, Shutt & Cox, 1972). Indirect evidence suggests that the foetal adrenals may be involved in the termination of pregnancy in the cow. Such evidence includes prolongation of pregnancy when foetal pituitary function is impaired (Kennedy, Kendrick & Stormont, 1957; Holm, 1958), and the induction of parturition by administering either corticotrophin (Welch, Frost & Bergman, 1973) or dexamethasone (Hunter, Welch, Fairclough, Barr & Seamark, 1974) to the foetal calf. Comline, Silver, Nathanielsz & Hall (1973) have noted a two- to threefold increase in foetal cortisol levels in prematurely calving cows. These authors conclude that this comparatively small rise in foetal cortisol levels casts doubt on whether the foetal adrenal cortex is