Importance of Mineral Supplementation in the Dairy Herd

The inclusion of minerals in dairy and beef diets is extremely important under any production system to ensure optimal daily gain, efficient milk production and overall health.

The major elements include Calcium, Phosphorus, Magnesium, Potassium, Sulphur, Sodium and Chloride – but it is important to know the role that each of these elements play.

Calcium and Phosphorus is very important for bone formation, and a ratio of 2:1 is best suited for beef and dairy animals. To prevent milk fever, calcium must be included for post parturition cows -together with vitamin D and Magnesium.

The inclusion of Magnesium is very important for dairy cows in the prevention of grass tetany during periods of stress or inclement weather conditions – such as spring and autumn. A general rule of thumb is to provide dairy cows at grass with 56 grams of calcined magnesite per head per day.

For electrolyte balance and cellular metabolism, the inclusion of Potassium and Chloride is very important to prevent metabolic disorders such as ketosis, metritis or displaced abomasums.

Trace elements such as Copper, Zinc, Manganese, Iodine, Cobalt, Selenium and Iron are also important, as a deficiency in any of these will have severe consequences in terms of reduced live weight gain, infertility, delayed oestrus, retained placenta and higher incidence of metabolic disorders.

Copper is particularly important for hair coat colour, while Selenium and Iodine are important for optimum fertility. To have a good hard hoof for beef and dairy animals, the inclusion of bioplex zinc will help – together with biotin – to strengthen and reduce lameness.

It is important to note that energy and protein metabolism will be compromised if a mineral deficiency is prominent. Vitamins also play an important role in calcium absorption, strength of bones, immune function and foetal development.

The most important vitamins include A, D, E and C. In particular, vitamin E has been shown to have positive effects on fertility and is a great antioxidant vitamin in boosting immune function.

With regard to high molybdenum areas across Ireland, it is important to match minerals to the animal’s requirements, as minerals will be locked up and not made available in such areas. Soil testing will be required to find the range of minerals contained in the soil and quantify the level of molybdenum in such areas.

The form of minerals in these situations will be important as different forms of minerals can be supplied for these specific areas i.e. protected bioplexes. Chelated minerals and boluses can be administrated – which can be slow release or pulse release – which will allow the animal to have a store of these minerals.

In general, most minerals are incorporated in the finished feed of either coarse rations or concentrates; special attention must be directed to know feeding rates for optimal mineral intake of minerals to avoid any such deficiencies or problems.

Inclusion of minerals may also be incorporated through dusting of paddocks – or minerals can be included in water troughs. Other ways to include minerals in the diet of beef and dairy animals include the inclusion of loose minerals on top of grass silage or placing molassed mineral buckets at pasture or in housing facilities.

It is important to check the specification of each source of mineral for inclusion into the diet of both dairy and beef systems, and to know the feeding rate of such minerals to avoid problems with toxicity.  For pre-parturition cows, it is important that supplementation of minerals is given at least 8 weeks prior to parturition.