Performance of zeranol implanted lambs

Eighteen South African Mutton Merino ram lambs, four months old were divided by mass stratification into two groups, (A and B), similarly 18 wether lambs of the same age and breed were divided into groups C and D. The lambs in group A and C were each implanted with 12 mg zeranol. The lambs were fed individually and during a six week experimental period average daily gain (ADG) feed ingested, feed conversion, profit and carcass grading were determined. Zeranol treatment had no significant (p >0,05) effect although the implanted wether lambs showed improved values for all parameters investigated. The ram lambs had a significantly (p <0,01) higher ADG and ingested significantly (p< 0,05) more feed than the wether lambs. Zeranol treatment of wether lambs tended to reduce the difference between wether and ram lambs.