Use of mineral chelates, or organic mineral complexes, has increased performance and decreased somatic cell counts in milk compared to inorganic forms of the same mineral in some research trials. Chelates of zinc, copper, manganese, iodine, and selenium have given variable milk production responses, and their practical utility is currently undecided. Before any definitive recommendations can be made, further research is needed to better define the management conditions where positive production or health responses are likely. Dietary electrolyte balancing is a new concept being used as a tool for reducing milk fever in early lactation. Dietary electrolytes may have either a positive or negative electrical charge.
Anions are negatively charged electrolytes, and cations are positively charged.
By using different amounts of these electrolytes, a ration is formulated to be either positive or negative in charge. Feeding a slightly negative-charged ration for three to four weeks prior to calving, properly balanced for calcium, phosphorus, and magnesium, should reduce the incidence of milk fever after calving. During the three to four weeks before calving, the dry cow is usually fed more liberally to adapt her to a higher level of intake. At this time, it is critical to provide adequate amounts of coarse roughage to maintain normal rumen function and to prevent metabolic problems. These minerals should be fed only for three to four weeks prior to calving at about 200 g per head daily of a combination containing 40 to 50 percent ammonium chloride.