How should vitamin, mineral and amino acid feed additives be compared?

Compare the active substance, chemical form, assay, carrier, particle characteristics, bioavailability assumptions, stability, impurities and authorised conditions of use. For blends or premixes, calculate the contribution at the final feed inclusion rate rather than comparing headline percentages. Specify analytical methods and tolerances and account for process and storage losses through a justified formulation approach. Local maximum levels, species restrictions and labelling rules take priority over generic marketing claims.