When fed free-choice selenium can be added at a level not to exceed 120 rng of selenium per kilogram of TM salt. When fed free-choice selenium can be added at a level not to exceed 30 mg of selenium per kilogram of mineral. The benefits of trace mineral supplementation outweigh the relatively small cost. The most common and convenient way to overcome these problems is by feeding a mineral supplement that contains adequate levels of these elements. Caution Trace element nutrition of livestock is extremely complicated.
Many interactions occur between the trace elements and between trace elements and other nutrients.
These interactions can be very complex and many are not well understood. In addition, the quantities of trace elements needed is very small. All trace elements are toxic if fed in excessive quantities. For these reasons, trace element nutrition is best left to knowledgeable professionals. Such minerals could be fed with red or blue salt.