Of all the various nutrient groups we supplement for the typical cow herd, minerals and vitamins are some of the most important. They are also some of the most poorly understood. While virtually any forage or feed has a mineral content, a clear understanding of how all these sources come together in the digestive system and physiologically, once absorbed, is not common.
Building a sound mineral program is dependent on several factors. These include:
- Understand that an animal’s requirements change with different ages and stages of production. Breed types and stress periods can also come into play.
- Your forage base is a significant portion of a cow’s mineral supply. The levels and availability of these minerals can change between pastures or fields and between plant maturity and harvest methods.
- As mentioned, virtually everything you feed an animal has some mineral and vitamin content. Balancing the overall program requires a knowledge of these levels.
- Mineral supplementation is important for all aspects of performance, especially for reproduction and animal health.
- Mineral supplements are expensive. Using the correct, properly balanced mineral and vitamin supplement is critical to animal performance and economics.
So how does a producer put all these things together? It’s very common for the typical cattle producer to purchase his mineral from the local feed store. While there is nothing wrong with this, there is a high likelihood this mineral is not well matched to the conditions on the ranch.
Performing a mineral audit
Build the best mineral and vitamin program you can by performing a mineral audit on your operation. Keep in mind that this is a work in progress and will change based on numerous factors. Since this can be a fairly complicated process, it is recommended to contact an area cattle nutritionist with some background in mineral and vitamin nutrition to help wade through all the steps and information.
For now, let’s discuss this process:
1. Determine animal requirements
This can be complicated by itself. Unfortunately, we don’t have the space here to get into this exhaustively. However, you need to be able to answer the following questions:
- What is the predominant breed or breed type? Different breeds can have considerably different requirements. This is also true between frame sizes. A larger cow typically has a higher requirement than a smaller-framed animal.
- What is the average age of the herd? Younger, growing heifers and cows as well as older cows can have higher requirements compared to middle-aged cows (4 to 8 years).
- What is the typical calf size weaned? Herds weaning larger, heavier calves have a higher requirement than smaller-weaning-weight herds.
- What is the typical stress level the herd endures? Weather extremes, drought, mud – all these factors can increase mineral requirements.
Start off with base requirements as reported by the Beef National Academies of Science, Engineering and Medicine (NASEM) (formerly the Beef National Research Council [NRC]). This information is also available from your local county extension office or land-grant university. As mentioned, a nutritionist with a good mineral background can also help with this information.
2. Determine the mineral content in your forages
This will require sampling of both pastures and harvested hays or silages. Keep in mind that forage testing is one of the most valuable tools you can use, and it can make and/or save you considerable money.
Forages can vary dramatically based on the type or land area where it's grown. Some of this is related to fertilization, some to soil type and some to previous use. Developing a good mineral profile on your operation can take time and work but will benefit your performance and profitability in the long run.
To begin, it makes sense to look at the forages your cattle typically consume. Are they in a specific pasture for specific stages of production? Do you have a specific calving pasture, breeding pasture, etc.? Or are they just simply in one big pasture you run year-round? It can be useful for pastures with growing forages to take several samples of the grass throughout the year because, as mentioned, forages do change. While the core mineral content may not vary all that much in a given pasture, the digestibility will change, so the mineral availability will change. Other changes may occur as plant species change through the year. On some operations, the predominant grass might be, for instance, coastal bermudagrass, but in the late winter, there might be a significant amount of volunteer ryegrass and/or clover. Every operation is different, so look at the unique forage characteristics of yours.
Similarly, if you feed a large amount of harvested/stored forages such as hay, haylage or even silage, sampling these are important. This is actually simpler than pastures, since once these are harvested any change in nutrient content and digestibility essentially stops. The differences here are in the time of harvest and location, as well as plant species or mixture. It is recommended to sample each cutting. In some cases, if in a large field or a field with diverse soil types, more than one sample per field might be useful and improve accuracy.
3. Determine mineral content of any additional feeds or supplements provided
Any other feed or supplement will also have a mineral content. Protein supplements all contain a mineral and vitamin profile at some level. Even commodities such as whole cottonseed, dried distillers grains (DDGs) and soy hulls have a mineral content. As you decide what your protein supplementation program will be, obtain copies of the tags to begin with. In many cases, these products will only have the bare minimum mineral and vitamin information, so it may be necessary to request the full mineral profile of each product.
4. Calculate the estimated amount of each forage and feed you intend to provide in the future
If you are simply grazing pasture and providing a basic supplement, this is fairly simple. Let’s say you have two sources of minerals and are looking to feed forages and a tub. These will likely not cover all the mineral and vitamin requirements for the animal. Table 1 provides details on how the numbers would look side by side and put together. There are different ways to do this, and this is just one of those ways. This table is expressed in concentrations of each nutrient as either percentage, parts per million (ppm) or international units for the vitamins. Once you add up the levels provided and subtract these from the requirement, virtually all the minerals are deficient. Plus, in this particular case, it would be very difficult to balance a mineral supplement at a typical 0.25-pound intake under these conditions with the grazing/supplementation program as shown.
5. Consider the digestibility and bioavailability of the minerals in any of the sources
The typical rule of thumb says we consider the amount of minerals available in forage to be around 65%. This may not be entirely accurate and depends on many factors. The same is true with the supplements. Depending on the sources, the availability of each mineral has to be considered.
Performing a mineral audit and quantifying mineral supply and demand can be challenging. Taking the time and making the effort can have significant effects on animal performance and can, in many cases, help reduce the cost of overfeeding your mineral supplements.
