Some form of trace mineral supplementation is conducted on nearly every dairy farm in New Zealand. It is estimated that farmers spend at least $60 million dollars on trace mineral supplements for dairy cows every year. That is a lot of money compared to some other animal health requirements.
The animal health budget is often a first candidate for cost-cutting measures, especially where the cost-benefit ratio is not well defined. Compared to countries like the US with ad lib supplemental feeding, the return on investment from any trace mineral programme is difficult to ascertain under NZ's predominantly pasture-grazing feeding regime.
To cut out all trace mineral supplementation would obviously be poor economy. Compared to a decade or so ago, many farms now supplement with trace minerals The problem with many unmonitored trace supplementation regimes is that the minerals may be overdosed (wasteful and potentially dangerous), or underdosed (reduced benefit).
Apart from excess or too little trace mineral supplementation being either wasteful or inefficient, the form of mineral being given may not be cost-effective. In the face of high levels of antagonists like molybdenum, iron and sulphur, copper uptake from copper sulphate can be very minimal. It may be more cost-effective to use an organic form of copper which is less affected by antagonists, than to increase the copper sulphate level or use copper injections.
Topdressed selenium prills are an effective way to supply a herd's selenium needs, but there is a cost. However, adding selenium to a customised trace mineral mix for delivery via the water system can be done for virtually no additional cost.
Your veterinarian is the best person to advise you on a trace mineral programme that most cost-effectively meets the needs of your farm. Please contact Totally Vets at either Feilding or Palmerston North for our recommendation on customised trace mineral mixes for your property.