Livestock consumption of mineral supplements is one of the most confusing aspects of ruminant nutrition. Many producers think that their animals don’t need minerals because they don’t eat it when they put it out. However, forage data shows that there is some level of mineral deficiencies every month of the year.
So why don’t livestock eat mineral more consistently? I think the answer lies in the same reason that people eat lots of fat and sugar when they don’t need the calories it brings. Animals of all kinds seem to eat the items that taste best to them.
Let’s look at the concept of taste. Humans tend to think that all animals taste foods in the same way we do. In other words, if something tastes good to us, then our livestock must like it. However, livestock tastes can be very much different than ours. So, what is taste?
At its basics, taste is a response to certain chemicals in the foods we eat. Taste is sensory reaction that we associate with the tongue. However, the smell and appearance of foods will mentally affect our taste as well. Also, what this food does in our digestive system will affect our perception of taste.
If a food corrects a deficiency that we have that has spawned a “craving”, the food will taste much better than if we have had plenty of it for a long time. This idea works somewhat for livestock. The thought is that when animals have been deficient in a mineral for a good while, they tend to eat a lot of it until they begin to correct the deficiency in the body, and then taper off on consumption. If the animals begin to build up a surplus, they may actually avoid that mineral for a while.
This concept is what begat the idea of putting out a “cafeteria” array of individual minerals for livestock to select from. However, many universities have studied this, from a metabolism view where they actually looked at the mineral levels in the body, and found that livestock won’t eat the amount they need of some of the more important mineral ingredients like phosphorus and magnesium.
This is the main reason that we combine mineral ingredients into a mineral supplement. If we can get a desired level of consumption of a mineral supplement, we should be able to provide enough of the minerals to prevent severe deficiencies or surpluses. If this works it should avert the excessive consumptions and abstentions that we see.
To make this work we have to add ingredients that will attract the livestock to eat the mineral supplement. It’s kind of like putting sugar on kid’s cereal. The sweet taste overrides the taste of something that is good for you. Only in the feed industry we use molasses and cottonseed meal to “sweeten” the mineral supplement.
However, even this doesn’t work all of the time. And the reason I think is this. Our mineral supplements are sometimes out of balance with what the mineral deficiencies are in the forages. When we get occurrences like this, the livestock won’t eat a mineral supplement because it’s too high in a certain mineral, phosphorus for example, when they don’t have a very large deficiency. That means they don’t get the magnesium, zinc, copper, and vitamins that they need because the surplus mineral doesn’t taste good to them at this time.
How do we overcome this? One way is to vary the mineral supplement you use from season to season and with changes in forage type. In the summer, phosphorus, sulfur, potassium, and magnesium all increase in the forages our livestock eat. Continuing to use mineral supplements high in these ingredients can develop surpluses in the animals, which can result in their not eating the mineral supplement.
Conversely, using supplements with lower levels of these minerals during times when the forages have lower levels and greater deficiencies develop in the animals can result in large levels of consumption of the mineral supplement with the livestock trying to correct these deficiencies.
If you graze your livestock on monocultures of forages or croplands, like kleingrass, wheat, or hybrid sudan, you also may see major differences in mineral content of the forages compared to native forages. To keep optimum mineral supplement intake, you need to have a mineral that more closely corrects the deficiencies that exist in each grazing situation.
About now you’re saying, “He’s crazy. I can’t mix my own mineral supplement every time I change pastures.” And you’re right. However, there are a multitude of mineral supplements on the market that you can choose from. Or, if you are a large enough operator, you can get mineral supplements custom made for your operation.
In either case, however, you have to know the mineral characteristics of your forages, and the mineral requirements of your livestock at any given time. To do that you need to have forage samples analyzed at key times to get a background of information to work with. Some minerals have a lot of variability from year to year, such as phosphorus, potassium, magnesium, and sulfur, while others like copper, zinc, and manganese seem to be more stable. However, taking a forage sample prior to grazing a pasture, and during the different seasons on pastures you graze all year, will give you an idea of the levels you are working with.
There as several publications that publish general guidelines for determining the mineral requirements for livestock. The National Academy Press in Washington D.C. publishes the “bible” for livestock requirements compiled by the National Research Council. They publish a book on each species of livestock. Using these resources, you can compare the percent required to the percent composition from a laboratory analysis of your forage and get an idea as to how high the mineral levels need to be in your mineral supplement.
Once you know what minerals are deficient, you can then select a mineral supplement that has those minerals in it. For instance, if you have a small phosphorus deficiency, don’t get a mineral supplement high in phosphorus. There’s nothing wrong with using a mid- to low-phosphorus supplement, if that’s all you need. Besides, it will cost less, too.
However, do make sure that it has sufficient levels of the other minerals that are deficient as well. The main reason for trying to meet the mineral needs of your livestock is to improve their production. If you correct one deficiency, but forget about three others, the improvement in production will be restrained.
Also, if you are feeding protein or energy supplements that contain a mineral such as phosphorus, livestock may not eat as much of the mineral supplement as they need to correct the other deficiencies. This is another case where a lower phosphorus mineral that contains ample amounts of other minerals can be a better choice than a high phosphorus mineral.
The main factor in all of this is the amount consumed by your livestock. You need to keep track of the mineral supplement consumption of your livestock. You don’t have to be too precise. Just keep up with how much you have fed in a week, month, etc., and divide the number of animal and the number of days into the pounds consumed (mineral consumed / [days of consumption x number of livestock]).
Keeping up with the intake will allow you to be assured that they are eating enough mineral supplement to correct their deficiencies. A normal amount of mineral intake should be about 2 to 4 ounces for cattle, 1/2 to 1.5 ounces for sheep, goats, and deer.
Monitoring consumption will also help you to know when your livestock begin to eat more, or less, than normal. When this happens, you can begin determine if something is keeping them from eating what they should, or if forage conditions have deteriorated and mineral levels have declined.
So, what happens if you have several hundred pounds of mineral supplement in the barn and all of a sudden the animals quit eating it? In this case, mixing some cottonseed meal with it will encourage them to eat the mineral supplement. Start with about 10 pounds of cottonseed meal added to 50 pounds of mineral supplement, mixed well. If they eat too much of that mixture, then cut it back to 5 pounds of cottonseed meal to 50 pounds of mineral supplement.
Sometimes all the stock needs is the meal to “jump-start” them back into eating the mineral supplement again. After they have been eating the mineral supplement – meal mix a while, take the cottonseed meal away to see if they will continue to eat the mineral. If not, add the meal back. Do not decide that the livestock have no need for the mineral unless you know that they don’t from comparing forage data to animal requirements.
Mineral supplements are a necessary part of a successful nutritional program to maintain productivity in your livestock. They can’t help if your livestock aren’t eating them. Learn more about their mineral requirements and the mineral content of your forages. Become proactive in making sure your animals are eating as much of the mineral supplement as they need.
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