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

On day 5, all pigs were given gentamicin through the drinking water for 6 d to treat the diarrhea. Culture of liver and lung tissue from pigs that died during this time confirmed exposure to Salmonella (S. infantitis), Actinobacillus suis, and Streptococcus suis. Several deaths due to mulberry heart disease prompted water treatment with vitamin E and selenium for 5 d (days 15 to 19) . A PRRSV challenge was confirmed on day 26 of the study after observations of lethargy, heavy breathing, coughing, sneezing, and decreased feed intake. Pigs were individually treated as described in the materials and methods section for symptoms for the remainder of the study. A timeline and result of all necropsies are listed in Table 5 ; results of all diagnostic testing are listed in Table 3 .