Mycotoxins — fungal toxins that contaminate grain and feed ingredients — cause chronic welfare harm in pigs by impairing immune function, damaging reproductive systems, and causing liver disease.
Mycotoxin welfare harm is chronic, invisible, and cumulative. Pigs consuming contaminated feed do not show dramatic acute symptoms — instead, their immune function is suppressed, reproductive performance declines, liver enzymes rise, and growth rates fall. These changes are easily attributed to other causes, making mycotoxin welfare harm frequently unrecognized. The reproductive effects of zearalenone are particularly severe: sows show signs resembling estrus at inappropriate times, have impaired conception rates, and produce smaller litters. The immune suppression from DON makes pigs more vulnerable to bacterial and viral pathogens, compounding welfare harm. Climate change is worsening mycotoxin exposure as the geographic range of mycotoxin-producing molds expands. Routine feed testing and proper grain storage are the primary welfare-protective interventions available to pig producers.