Animal Welfare and Epidemiology—Across Species, Across Disciplines, and Across Borders

In North America, there is strong interest in animal welfare issues by the general public, with shifts in government and corporate policies about animal care and use in a number of areas (for review, see Millman in this issue). Decisions about animal welfare are based on moral principles and scientific knowledge, and the relatively young discipline of animal welfare science struggles to keep pace with the demand for knowledge in this area. There is a need in the U.S. and abroad for research that provides guidance for on-farm animal welfare auditing and for identifying key farm factors that are associated with greater animal welfare. An epidemiological approach is warranted for such studies, and to date there has been limited attention to this approach, especially within the US.