Yes, but its very unlikely that any show cattle are on it (legally). Zilmax is a more potent beta agonist than optaflexx. It's currently used in the high plains in some of the larger feedlots. Zilmax costs around $6500 per bag (pure zilpaterol). Therefore, only larger feedlots can justify feeding it (one bag will feed 20-30000 head). Zilmax is priced according to choice-select spread. As choice-select spread narrows, zilmax is priced higher. To my knowledge, no feed companies have it included in a show feed. However, I would guess it would become more available in the future.