by Bas Van Luijk, Bas is the Head Veterinarian at East Coast Farm Vets Selenium levels in the soil are low in many parts of New Zealand but historically the East Coast area hasn't dipped below the threshold. However, over the last few years we have seen the occasional case of severe selenium deficiency across sheep, cattle and more recently, horses. Selenium levels can drop in grass, hay and haylage if not rectified by fertiliser. Since forage is the main natural source of se