Selenium toxicity in sheep flock: case study

Selenium, an essential trace element, acts as an antioxidant alongside vitamin E to prevent and repair cell damage. A deficiency can cause increased neonatal mortality, increased disease susceptibility, reduced weight gain and impaired performance, white muscle disease (WMD) in lambs and weaners, scouring, ill thrift, and reduced wool production in weaners and hoggets, as well as infertility or reduced conception rates in ewes (Robson, 2016). Selenium and vitamin E play crucial roles in immune function. The benefits have instigated the pharmaceutical companies to incorporate selenium in various livestock products, such as anthelmintic drenches, vaccines, and lick blocks etc. Given the widespread inclusion of selenium in sheep products, several overdose scenarios are possible which can lead to toxicosis. Acute toxicity in lambs can cause cardiac failure, resulting in lethargy, respiratory distress, neurological disturbances, and death within 72 hours (Glenn et al., 1964; Blodgett & Bevill, 1987).