Our customers use it with great success, Nicky. Rabon is bitter and it's hard to get the cows to eat mineral with Rabon, whereas the IGR has no taste. It's the horn flies that cause the most economic loss and the reason why cattle bunch up during the day.
You'll see added weight to your calves due to the cows not bunching up. They'll stay out grazing. When cattle bunch up, they aren't making you money. You will always see some flies on your cattle, so don't expect to
eliminate all the flies. That will never happen. The way you will know that your fly control is working, is that the cattle are grazing.
They have to eat the mineral to get the IGR, so be sure to be diligent in keeping it out. Ours is designed so that a 2 oz. intake will provide enough IGR to control the flies.
Notice I said "control", not eliminate. That will never happen.
Has anyone explained to you how the IGR works? It interrupts the life cycle of the horn fly. Put the mineral out when you get a 60 degree day, or a couple in a row and then LEAVE it out til after the first frost. One mistake ranchers make is not keeping it out long enough in the fall. If you keep it out, you won't have the over-wintering of flies and therefore, there will be less hatch in the spring.
If you have any specific questions, feel free to ask. We've worked with IGR for many years now.
You can buy Altosid by the bag and add to the mineral if you think the fly load warrants it. We have one customer who thinks his cows are too big for the 'normal' dose of IGR, so in August, after that second big hatch, he adds a little more to his mineral. FWIW
