Organic Mineral Supplementation
7 November 2025There is good evidence to support the use of organic trace elements in dairy cow nutrition. While mineral supplementation makes up a very small part of a dairy ration (<1%) it is an essential component, and the majority of trace elements are deficient in forages.
What is an organic trace element?
Organic trace elements are sometimes called “protected” or “chelated” trace elements. Their key benefit is that they are more bio-available, or more easily absorbed by the animal compared to inorganic salts such as copper sulphate, zinc oxide or cobalt carbonate. An organic trace element is where the element has been bonded to a chelating agent e.g. amino acids, hydrolysed proteins, polysaccharides or yeast derivatives. Examples include zinc methionine and selenised yeast.
The most commonly used organic trace elements are copper, zinc, selenium and manganese. When supplementing with cobalt, it must be available for the rumen microbes to manufacture vitamin B12, so there is no need for this element to be chelated. Iodine is very easily absorbed in the gut from inorganic sources and is generally unaffected by antagonists and so it also has no need for chelation.
Antagonists
If forages contain high levels of heavy metals (antagonists), these can bind to certain trace elements in the gut, affecting their availability for absorption. In this case they will pass through the gut and out in the faeces without being utilised by the animal. This can lead to what is called a secondary deficiency - there may be sufficient levels of the mineral provided in the diet but if it cannot be utilised due to the presence of antagonists then deficiency symptoms can occur. The classic example is that of copper deficiency due to the antagonistic effects of sulphur, iron and especially molybdenum in the rumen. Even at low levels, molybdenum can combine with copper along with excess sulphur to produce thiomolybdates, locking up the copper and making it unavailable. This is where organic minerals are beneficial, as the trace element is protected and unaffected by antagonists in the gut, leading to greater absorption.
Benefits of organic materials
Many studies have proven the benefits of organic trace elements in dairy cow fertility, reducing days open and services per conception. There are also health benefits with both organic zinc and selenium lowering cell counts and clinical mastitis, with zinc having a key role in supporting skin integrity and the keratin lining of the teat canal. Improvements to hoof health have also been seen with zinc methionine supplementation, helping improve hoof quality/hardness with reductions in claw horn lesions.
Typically organic minerals are included as a % of the total element, and tend not to be included at 100%, due to their relative high cost. For example, a mineral may have a total zinc content of 5000mg/kg, of which 1000mg/kg comes from a chelated source (20%), with the remaining 4000mg/kg provided by the commonly used inorganic salt, zinc oxide.
Seek nutritional advice
The first step to see whether you would benefit from the use of these minerals is to analyse grass silage and any other forages fed for mineral content and have a dietary assessment of the whole diet to investigate potential deficiencies and presence of antagonists. Any perceived mineral deficiency symptoms may also be backed up through blood testing (ask your vet about this).
Mineral nutrition is a complex subject and with so many methods of supplementation and variations in product specifications and sources of trace elements, speaking to your nutritionist about reviewing current levels of supplementation. Carrying out a mineral audit on your dairy herd is worthwhile to better tailor supplementation to requirements to benefit cow health and productivity. This also applies to dry cows and youngstock.
Lorna MacPherson, SAC Consulting
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