Withdraw time for MGA is 48 hours. Buffers can be used when adapting cattle to high grain diets or when feeding concentrates such as wheat at high levels. Various buffering agents include sodium bicarbonate, limestone, sodium bentonite, and magnesium oxide. Yeast cultures do not appear to affect digestibility, however, yeast cultures appear to alter the shape of the degradation curve causing a reduction in the lag phase before digestion commences. Therefore the digestibility is not changed but the rate of degradation is increased.
More research is needed to evaluate the most appropriate situations for the use of yeast cultures.
There are numerous strategies based on the number of implants and combinations of implants that can be used from weaning to slaughter. Implant suitability depends on cattle age, sex, frame size, weight, days on feed, projected rate of gain, and implant history. The duration values in the following table reflect manufacturer's recommendations and industry practices. Classification of implants for weaned calves with regard to active ingredients and duration of use. Total gain can be improved if cattle are re-implanted over time.