See the link to a recent article in The Land on selenium deficiency in sheep and cattle in the New England region of NSW Australia. Long acting selenium pellets can help prevent and treat selenium deficiency.
Selenium Deficiency in Central Tablelands – EMAI Vet Path has received numerous submissions from the Central Tablelands region, from both LLS district vets and private vets. Submissions have included clinical lambs and calves, from 6 weeks old to 18 months old. When selenium levels were tested in blood samples, both adults and young animals were equally as deficient, with young animals only showing clinical signs. Clinical selenium deficiency is most commonly associated with white muscle disease, and associated kidney damage or sudden death (heart muscle degeneration). Other signs may include ill thrift, infertility, respiratory distress (intercostal myonecrosis), lameness (skeletal muscle degeneration), reduced growth rate and lower wool production in sheep.
Diagnosis of selenium deficiency depends on thorough history taking, blood selenium levels (GSHPx) and histopathology of affected organs. In clinical cases, histopathology is characterised by cardiac and skeletal myocyte degeneration and necrosis which is polyphasic, with mineralization and some inflammation and regeneration. Kidneys may be severely damaged with myoglobin-associated acute tubular injury. In the field, the veterinarian may see necropsy changes including multifocal pale streaks in the muscles and heart with some mineralisation and dark kidneys.