Tracesure Selenium & Iodine Boluses For Calves & Sheep 9g - 100 or 250

Tracesure Selenium & Iodine nutritional bolus for calves and sheep. 9g Bolus containing Selenium & Iodine lasting up to 6mths. Each 9g bolus provides 100mg selenium and 400mg iodine by slow rumen release for 5-6 months. Sheep weighing over 20kg - 1 bolus. Calves weighing 75-100kg - 1 bolus. Calves weighing 100-200kg - 2 boluses