A note on the effect of monensin and amicloral in steer diets

Abstract

ABSTRACTThe effects of feeding monensin and amicloral at 33 and 1500 mg/kg of diet, respectively, were investigated in two experiments using 330-kg steers. Monensin and amicloral, either alone or in combination, increased the digestibility of organic matter and crude fibre compared with a control diet (P< 0·001). Crude protein digestibility was increased by monensin (P< 0·001). Use of monensin and amicloral, alone or in combination, increased molar proportions of propionic acid by 22% on average (P> 0·05), and monensin decreased butyric acid by 37% (P< 0·05).Ruminal ammonia concentrations were lower in steers fed monensin (P< 0·05). Steers fed monensin consumed 6 % less feed, gained 9 % more weight (P< 0·05) and utilized feed 14% more efficiently (P< 0·05) than control animals. Amicloral, either alone or with monensin, lowered feed intake by 11 % (P< 0·05), had no effect on average daily gain and improved feed efficiency by about 12% (P< 0·05). There were no treatment effects on any of the carcass parameters.