The effects of group size and subtherapeutic antibiotic alternatives on growth performance and morbidity of nursery pigs: a model for feed additive evaluation

Olsen, Kristin M; Gabler, Nicholas K; Rademacher, Chris J; Schwartz, Kent J; Schweer, Wesley P; Gourley, Gene G; Patience, John F

Determining pathogen presence, or the presence of agents/active infections, will involve identifying genetic material of a pathogen (generally through PCR), detecting an antigen (through ELISA or immunohistochemistry), or detecting a viable pathogen Figure 3 . Proposed necessary study components to be included and reported in studies evaluating alternatives to antibiotic growth promoters (AGP) for pigs. When critical information is included in reports of AGP alternative studies, the context of the study is better understood. This will aid in making comparisons across multiple studies and will lead to faster and more valuable conclusions about the effectiveness of AGP alternative products. through isolation (Christopher-Hennings et al., 2012) . Pathogen exposure is determined by measuring seroconversion, which confirms a prior infection or presence of a maternal antibody and is done by detecting antibody in the serum (Christopher-Hennings et al., 2012) . The specific procedure for defining health status via pathogen presence or exposure will likely depend on the nature of a study and the pathogens involved, and a strategy may need to be adapted for each study and pathogen of interest. It is also important to report the medical treatment regimen used if pigs need to be treated for illness.