THE EFFECT OF DAILY INJECTIONS OF PROLONGED-RELEASE IMPLANTS OF RECOMBINANT PORCINE SOMATOTROPIN ON BEHAVIOR IN MARKET-WEIGHT PIGS

Animal behaviour frequency data were collected on 92 ad libitum fed Yo rkshire pigs (96 kg) allocated to one of three recominant porcine soma totropin (rpST) treatment groups (36 prolonged-release rpST implants a t 2 mg d-1 pig-1, 40 daily injection rpST pigs at 2 mg d-1, and 16 con trol or sham-injected pigs). From time-lapse recordings of animal beha viour, ethogram analysis revealed that of the 10 behaviours studied, i nvestigative behaviour, was the only trait affected by rpST treatment, with the daily injected pigs showing a slightly lowered percentage of time (P < 0.05) spent investigating their pen (7.3% d-1 vs. 13.6% d-1 in control and 10.1% d-1 in prolonged-release treatment group).