Ten multiparous lactating Alpine or Saanen goats were used to test the effects of recombinant bovine somatotropin (bST) on galactopoiesis and metabolism. Treated goats were injected daily with 5 mg bST during 28 d. Supplementation with bST significantly increased yields of milk, fat, and protein compared with controls (28.6, 41.6 and 23.7%, respectively). Voluntary feed intake was not increased. During the first week of treatment, percentage of fat was increased (+4.2 g/kg; P < 0.05), but percentage of protein was decreased (-1.6 g/kg; P < 0.05) in the bST group. Supplementation with bST enhanced NEFA concentration and reduced urea concentration in plasma (P < 0.05), whereas β-hydroxybutyrate and glucose concentration in plasma remained unchanged (P > 0.10). The proportion of long-chain fatty acids in milk tended to increase in wks 1 and 2, but the trend was reversed in wks 3 and 4. Yields of milk fatty acids were higher for goats in the bST-treated group, particularly for the long-chain fatty acids in wks 1 and 2 (P < 0.05) and the short-chain fatty acids during wks 3 and 4 of bST supplementation (P < 0.01). When regression residuals were used, individual variations in response to bST were noticed (from 13 to 40%;P < 0.05).