No matter how good your forages are, they still may be deficient in one or more minerals. This is especially true for the trace minerals copper, zinc and selenium, and of course, salt. Some forages may also be deficient in calcium, phosphorus, magnesium, manganese or other minerals.
In my experience, all really good cattle production systems use a good quality mineral supplement, and make an effort to do a good job of managing the mineral program to make sure the cattle are eating the correct amount of the supplement. It is important that you start with assessing your forage mineral levels and consult with an advisor familiar with regional forage mineral deficiencies and mineral supplementation options available as you develop or improve your program. For tall fescue based systems, we generally need to supplement with salt, copper, zinc, selenium and magnesium.
There are many philosophies on supplementing minerals. When I first started 30 years ago, many cattlemen in our area used “red salt” which is either in loose or block form. Unfortunately, most of that “trace mineralized salt” contained very little copper and no selenium. It was not uncommon for me to go to a farm where the cows were in poor condition with shaggy, faded haircoats, and experiencing a wide variety of production problems. This was often blamed on fescue toxins, but I found that, in many situations, we could mix copper sulfate and sodium selenite into their base mineral (often red salt) and within a few months the cows were transformed.
When I came to work at NCSU, I met my friend and collaborator Dr. Jerry Spears. Dr. Spears is generally recognized as having a bigger impact on trace mineral nutrition for cattle (and other species as well) than any other researcher. I was fortunate to be located where he was making fundamental discoveries about selenium, copper, zinc and other important minerals. He helped me develop a program to improve minerals across our state. As we made progress with our mineral education program, many farmers started evaluating their mineral formulas and shopped around when their mineral didn’t stack up to our recommendations. This caused me some political problems, as some of the companies who needed to improve their formulas called our Dean and Department Head and complained about how I was hurting them. Fortunately, my bosses had my back and after the initial push back we helped many companies improve their formulas. Today, most farmers in our area use a complete mineral and they pay close attention to the copper and selenium levels, and most products meet or exceed our recommendations.
My recommendation these days is to find a good quality complete mineral that fits your needs, or to go together with a group to have a supplement custom mixed based on input from your local advisor. Then, put time into keeping up with the daily intake level (a cow should eat 2-4 oz per day of most products). Sometimes that is kind of hard to figure, so a good rule of thumb is that a group of 25 cows should eat about a 50 lb bag in a week or two. If cows are not eating the supplement or are eating too much, then move the feeder relative to the water and loafing areas, mix in some palatable ingredient (if intake is low) or salt (if intake is high), and eventually find a supplement that works better for you. With any product, you need to monitor intake and manage accordingly as there is normal variation in intake.
As far as mineral feeders go, make sure your feeder is inexpensive, keeps most of the rain off (none are perfect), is durable, and is easy to move. The choice of feeder is somewhat of a personal preference; make sure you choose one that is easy for you to manage so you keep up your management program. My favorite feeder is made from a plastic barrel and a truck tire. These are especially easy to move from pasture to pasture and prove to be quite durable, relative to other models I have used. We have these feeders that have been in constant use for over 10 years. If you are interested in this feeder, there is an instructional video on You Tube, and a set of plans on our website. ~ Dr. Matt Poore, NCSU professor and president of the Alliance for Grassland Renewal.
The Alliance for Grassland Renewal is a national organization focused on enhancing the appropriate adoption of novel endophyte tall fescue technology through education, incentives, self-regulation and promotion. For more resources or to learn more about the Alliance for Grassland Renewal, go to www.grasslandrenewal.org