Bovine somatotrophin stimulates milk production in red deer hinds

Abstract

To determine its potential as a tool for studies of growth in suckling red deer calves, bovine somatotrophin (bST) was administered to lactating red deer hinds. The present study used twice-daily machine milking of bST-treated hinds (n = 10, 54 mg bST for 2 weeks then 108 mg for 1 week) and compared the milk yield with that of saline-treated controls (n = 9). Treatment with 54 mg bST tended to increase milk yield by ~16% and the 108-mg dose increased (P = 0.013) milk yield by ~32%. Both doses of bST increased (P < 0.05 and P < 0.001, respectively) plasma insulin-like growth factor-1 concentration but did not affect total solids or fat content of the milk, nor was there any effect on body condition score or liveweight of the hinds. This shows that milk production in red deer hinds is increased by administration of bST, which makes it a suitable experimental technique for investigating the lactational biology of red deer.