Has anyone tried these boluses? They contain 750mg iodine, 100mg selenium, 350mg cobalt, and 400mg zinc. They are slow release and supposedly last 6 months. http://snlivestock.com/All-Guard-4-in-1-Ewe-Bolus.php I’ve heard some people use it with their goats or sheep and get great results. However, I am looking for more opinions. They have a 5 in 1 for goats, but it’s cheaper to give their copper boluses separately.