An outbreak of monensin poisoning in adult turkeys.

Monensin, fed in excess of 200 ppm caused mortality in Triple 5 and Triple 6 turkeys aged 25 weeks old and over. Mortality commenced three to four days after administering feed containing monensin and ceased three to five days after it was removed. This concentration of drug did not have any detectable adverse effects on Triple 5 turkeys fed from day old, four weeks old, or 11 weeks old for periods of two weeks.