The marked reduction in calcium/magnesium related metabolic disorders in animals during spring as well as a steady improvement in overall animal health, as a result of a single application of dolomite, are the major reasons for the steady increase in demand for dolomite.
Regardless of the price of other magnesium fertilisers, dolomite has always provided outstanding value, which is the difference between what is paid and the monetary return.
Dolomite now has a marked price advantage when compared to magnesium oxide, in some areas. The present price of magnesium oxide supplies magnesium at approx. $1.30/kg of magnesium.
Dolomite contains approx. 115kg magnesium per tonne (11.5%) and is available in bulk ex Richmond at $90.00+GST/tonne, which equates to 78cents/kg of magnesium.
When the cost of cartage is included for truck and trailer loads delivered to Central Canterbury properties the price is $1.35/kg magnesium, and to South Canterbury properties $1.43/kg magnesium.
The effectiveness of dolomite relates to its unique composition, typically 11.5% magnesium and 24% calcium.
Metabolic disorders due to a lack of magnesium (hypomagnesaemia) often also involve calcium, if not at the time almost certainly soon after. Body reserves of magnesium are too small to meet the increased demand just prior to and after calving so sufficient needs to be ingested on a daily basis.
The ability of a single application of dolomite to markedly reduce the severity of these problems as well as help eliminate all but the worst cases is due in large part to the balance of magnesium and calcium.
Leaf analysis over years of monitoring indicates that a single application of dolomite at approx 250kg/ha (28kg/Mg) will lift magnesium leaf levels to between 0.22% and 0.25%. Animals well fed on pasture containing these levels are likely to have their magnesium intake requirements met.
To maximise milk production spring pasture needs to have calcium levels of 0.60% or higher. Pasture to which dolomite has been applied nearly always surpasses this level.
The quality of pasture is largely dictated by soil quality with well-aerated and flocculated soils usually having higher mineral content and energy levels. Dolomite being a natural deposit contains a wide range of trace elements further enhancing its performance.
Dolomite assists with physical soil structures, increasing humus content and improving tilth. Well-aerated soils drain more rapidly after heavy rain and consequently warm a little more quickly providing earlier spring growth.
Dolomite is finely ground ensuring rapid response. An improvement in animal performance can often be noticed within a fortnight of application allowing dolomite to be applied at any time with positive results.