White muscle disease is the result of degeneration of skeletal and cardiac muscles of lambs. It is most common in areas where lambs receive good quality feed and are fast growing. It is usually an acute disease that manifests itself in fast growing lambs at three to eight weeks of age. The disease is a manifestation of lack of Selenium, Vitamin E or both. There are Selenium deficienct areas within the country, predominately in the states of Wisconsin, Illinois, Indiana, Michigan and Ohio in the north central region of the United States.
Selenium is also deficient in the Northwest, Washington and Oregon.
While the leg muscles are generally affected first, any muscle area including cardiac muscle may be affected. Chronic or borderline deficiencies may result in lung edema resulting in increased pneumonia problems. It is quite common for the disease to show up after forced exercise, vaccination procedures, sorting, weaning, fitting or being chased by dogs or children. Diagnosis is based on clinical symptoms of stiffness, swollen hindquarters or lambs may simply be down. Animals are generally bright and alert and will continue to eat and drink if possible.