Understanding selenium and vitamin E deficiency causing white muscle disease in lambs and sheep.
White muscle disease causes significant welfare impairment and mortality in affected lambs. Skeletal muscle disease presents with weakness, inability to rise, a stilted gait, and progressive deterioration. Affected lambs cannot suckle normally, face starvation, and are highly susceptible to hypothermia. The muscle pain associated with myodegeneration is significant.
Cardiac involvement is particularly devastating — lambs may be found dead with no prior signs of illness, representing sudden death from cardiac failure. Where cardiac disease is suspected (sudden deaths of previously healthy lambs), post-mortem examination and tissue selenium analysis confirm the diagnosis.
Prevention through selenium supplementation of ewes 4-6 weeks before lambing is highly effective. Selenium-responsive areas should be identified through soil and blood analysis. Supplementation can be given via subcutaneous injection (barium selenate slow-release products), oral drenching, or inclusion in mineralised compound feeds. Therapeutic treatment of affected lambs with selenium/vitamin E injection provides welfare improvement but should be dosed carefully — selenium toxicity is possible with overdose.