The important trace elements in pasture systems are cobalt, copper, iodine, selenium and zinc.
Required for the production of Vitamin B12, energy metabolism in the rumen and in the cow, fibre digestion and immunity. High manganese in soil reduces cobalt uptake by the plant. Therefore, as pasture is generally high in manganese it is usually low in cobalt.
Required for growth and production, animal health and immunity, reproduction and calf viability. High intake of molybdenum, sulphur and iron, which often occurs in pasture-based diets, especially in winter and spring, reduces copper uptake by the animal.
Warning: Some feeds (e.g. PKE) contain copper, hence caution must be had if providing additional copper supplementation.
Required for intake, energy metabolism and milk production, protein synthesis, reproduction and heat detection. uptake of iodine by pasture can be low. Additionally, iodine is easily leached during wet weather in winter and spring. requirements for iodine increase during cold, wet weather.
Required for disease resistance (e.g. mastitis), placental shedding (post-calving cleaning), milk production, reproduction, calf viability and immunity. There are regions that will have high selenium levels in pasture, particularly if they have been fertilised with selenium fertiliser. In such areas supplementation should be avoided. If in doubt, consult with your vet or farm consultant.
Required for growth and production, reproduction, hoof strength and immune system. The need for zinc supplementation will vary from farm to farm. Farms using zinc in summer for facial eczema may still require zinc supplementation in the spring. Pasture analysis should determine the need for supplementation. Excess zinc intake will increase the risk of milk fever and copper deficiency and may depress appetite.
Trace element requirements
|Cobalt||8-10||0.8-1.0||Cobalt sulphate orally
Commercial cobalt sources, cobalt sulphate fertiliser, strategic use of B12 injections. Can be added to spring fertiliser.
|Copper||250-400||25-40||Copper sulphate orally, copper bullet, copper capsule (needles), copper injection (not recommended for cows during the breeding season), commercial copper sources, copper sulphate fertiliser (not recommended in secondary deficiencies).|
|Iodine||50-60||5-6||"Stock iodine" (3ml of 2% or 0.5 ml of 10% per cow orally), 8ml of 5% teat spray on flank weekly, commercial iodine sources, oil-based slow-release injections.|
Oral or injection products, commercial selenium sources, and slow-release injections. Can be added to fertiliser.
* for other than facial eczema
|750||75||Zinc sulphate, zinc oxide, and commercial zinc sources.|
For further information refer to DairyNZ Farmfact: Trace element supplementation (3-4)