Only US Food and Drug Administration (FDA)-approved drugs may be administered to animals. Aspirin (acetylsalicylic acid) is not FDA approved for use in animals or humans. Thus, it cannot be legally used to treat animals. Sodium salicylate is also not FDA approved and likewise cannot be used.
Read Executive Director Dr. Harry Snelson’s message in the latest issue of the Journal of Swine Health and Production at https://www.aasv.org/shap/issues/v33n1/v33n1exdir.html.