Iron Oxide. If you see iron oxide on a label, that is what makes a mineral or product appear red. There is 0% bioavailability in iron oxide. That means a deer gets no use out of it.
Zinc Oxide, Manganese oxide. They are only ½ as bioavailable as zinc sulfate and manganese sulfate. I don’t use zinc oxide, manganese oxide nor iron oxide. That is because they are the poorest nutritionally of the micro nutrients.
Annual Ryegrass. So many cheap wildlife seeds contain annual ryegrass. Sure, they grow fast but the deer tend to not eat them unless there is not much else available to graze. Ground cover uneaten does not equal nutrition. You also only have 25-33% of the calcium as clovers and only 65-75% as much protein. Why annual rye? Because it only costs $.60 per lb. versus $2-3 per lb.
Oats, wheat, rye, triticale and barley. Yes, they grow fast. Yes, the deer will eat them. They contain decent levels of digestible fibers. What they aren’t though is sources of protein nor calcium. Just like annual ryegrass, you see only 12-18% crude protein and calcium levels much lower than clovers and brassicas. I am not saying to not plant grains but do not rely on grains as your sole source of forage. Yes, you will attract deer but aren’t we trying to pack in the best available nutrition that we can to help get these deer conditioned before winter?
B Vitamins. I saw on a bigger name wildlife companies’ deer mineral tag, b-vitamins. You rarely if ever see that on livestock minerals anymore. People are educated. Ruminants, which include deer will not get effective use out of b-vitamins unless they are rumen protected. Rumen protected b vitamins are very costly and mainly are used by high performance dairy farms. Unless your feeding swine, horses or chickens, why would you feed anything with b vitamins on the tag?