The effect of monensin on carcass and wool traits of Merino lambs.

Forty Merino lambs were used to determine the effect of monensin (20 mg/day) on carcass and wool traits when fed at two energy levels. Monensin improved feed efficiency and decreased feed consumption significantly (P ≤0,05). Total body mass gains were not significantly raised. The effects on meat and carcass characteristics were insignificant. Blood glucose levels were slightly, but not significantly, raised by monensin. Wool production was not influenced significantly. As far as the volatile fatty acids in the rumen are concerned acetic acid was significantly lowered (P  ≤0,05) while propionic acid was raised (highly significantly at P ≤0,01). There was no significant effect on any of the other fatty acids or on the total volatile fatty acid concentration. No significant influence could be observed on the apparent digestibilities of dry matter and gross energy. The apparent digestibility of crude fibre was lowered and that of nitrogen highly significantly (P ≤0,01) raised by monensin. Nitrogen retention, however, was not significantly influenced.