Selenium Toxicity in Domestic Animals

Selenium (Se) was essential for animal growth and health but had become toxic due to various sources like selenium-rich soil, water, and indiscriminate supplementation. Historical accounts, such as those by Marco Polo, noted Se toxicity causing hoof disease and hair loss in horses. Se toxicity in animals manifested as acute, sub-acute, or chronic, with severity depending on factors like chemical form and animal species, with horses being more susceptible than cattle. Toxicopathology included damage to skeletal muscle, heart, liver, spleen, and kidneys, with histopathological changes like endocardium disruption and hepatic necrosis. Preventive measures included high-protein feed, dietary supplements, and clean water to mitigate Se toxicity and improve livestock health, thereby reducing Se levels in the human food chain.