Pharmaceuticals, direct-fed microbials, and enzymes for enhancing growth and feed efficiency of beef.

This article provides a brief review of the types of products commonly used in one or more countries of North America to enhance the performance of growing beef cattle. Performance-enhancing products primarily target metabolism (e.g., anabolic implants, zilpaterol, and melengestrol acetate) or gut function (e.g., ionophores, low-level antibiotics, direct-fed microbials, and enzymes). Using currently available performance-enhancing products, rate and efficiency of growth typically are improved from 5% to 20% and 3% to 10%, respectively.