EVALUATION OF A SUSTAINED RELEASE BOLUS TO SUPPLY TRACE ELEMENTS AND VITAMINS TO BEEF CATTLE

SUMMARY An intraruminal bolus containing copper, cobalt, selenium, manganese, zinc, iodine, sulphur, vitamin A, vitamin D3 and vitamin E was evaluated in young steers on one farm and steers and heifers on another farm. When given at the recommended dose of two boluses per animal a significant liveweight response was recorded in steers on both farms but not in the heifers. The bolus treatment raised blood selenium concentrations in cattle on both farms and plasma copper concentrations in cattle on one farm. A transient increase in plasma vitamin B 12 concentrations was observed in cattle on one farm but plasma zinc concentrations were unaffected by treatment on both farms. The effective life of the supplement in providing additional copper and selenium was shown to be at least 43 weeks in steers on one farm.