Concentrations of bovine somatotropin and insulin-like growth factor-I in serum and milk samples of crossbred dairy cows treated with prolonged-release bovine somatotropin (Kepekatan somatotropin bovin dan faktor-I tumbesaran seperti insulin dalam sampel serum dan susu lembu tenusu kacukan yang disuntik dengan somatotropin bovin lepas- berpanjangan)

Secretion of bovine somatotropin (BST) and insulin-like growth factor-I (IGF-I) was measured in lactating crossbred Sahiwal-Friesian dairy cows injected with prolonged-release bovine somatotropin (sometribove). The study showed an increase of two to threefold in both BST and IGF-I secretion in the blood serum. Serum BST and IGF-I increased significantly (p <0.05) on day 2 and remained high on day 9 as compared with the non-injected control. Both values decreased on day 14 after the injection. The mean values for serum BST concentration at day 2 and day 9 of cycle 8, and 14 days post-injection period were 6.3, 6.6 and 4.3 ng/mL respectively while the corresponding mean serum IGF-I values were