Whether deer need mineral supplements or not depends on what you want the deer to do. If you are just looking for maintenance of the deer population, then they may not need mineral supplements. However, if you are looking for improved performance, increasing deer numbers, or trophy-class antlers, then yes they do need mineral supplements.
When I look at the forage data for deer that I have gathered over the last three years, it seems that a doe, in a normal productive year, could probably get by without a mineral supplement for most minerals. She would be short of some minerals at times, but most of them can be stored in bones or body organs during periods of high nutritional intake and released in times of mineral deficiencies.
However, I do think that they might be even better producers (fawn crops) if they had some of the trace minerals (zinc, copper, manganese, etc.) that do seem to be a bit deficient. So, if you were trying to increase your fawn crops, getting a mineral supplement into the deer herd could help.
Areas where I think deer do need mineral supplements are in fawn survival, body development, and better antler growth. In each of these cases, there are times each year that the diet seems to have some large mineral deficiencies. This is especially so for antler growth. The work I have done with a few high-fence type of operations, seem to show that getting a large increase in minerals into the diet of deer is part of deer growing very large antlers.
The real question is how do you get the mineral supplements into the deer? The answer is that you have to mask it with something the deer are interested in. My preference is to put the minerals into a pelleted supplement that the deer will eat. If you are trying for trophy-class antlers, a significant increase in protein and energy is also required. So it’s logical to put the minerals into a pellet with protein from cottonseed and soybean meal, and energy from grains like corn. Feeding them something they like makes getting the minerals into them much simpler.
If you are not feeding pelleted feed to deer, then the only other choice is to feed a mineral supplement. The basis is the same; you have to mask the minerals with something they like. I prefer to use a combination of soybean meal and cottonseed meal. Deer seem to need protein a lot, and cottonseed is a smell and taste deer are familiar with, from eating leftovers on livestock feeding grounds.
One final thing, all animals like salt. However, deer don’t like very much salt. Most livestock minerals have a fairly high level of salt in them to draw the livestock to them, as well as satisfy the salt requirement. However, the only way I have gotten deer to eat any feed is to either eliminate the salt completely (you can put a salt block out separately) or keep it to a very low level. In my mineral mix, I use only 25 pounds of salt per ton.
Yes, deer need mineral supplements in many cases. However, you have to approach their supplement needs different from our livestock. Keep it palatable; keep the salt low; and keep it fresh. If you can get minerals into your wild deer, you will be very pleased with the results.
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