SPRING SUMMER BONUS MAGAZINE 2026

Dynamics of mineral nutrition in dairy cows Muller Cronje – Technical Advisor: Dairy Minerals are fundamental to dairy cow health, productivity, and reproductive efficiency. Although the importance of individual macro- andmicrominerals is well established, attention has increasingly focused onmineral interactions and their effects on bioavailability andmetabolic function. This article reviews the role of key minerals in dairy nutrition, with a specific focus on antagonistic interactions and their implications for ration formulation and herd performance. Mineral nutrition is a cornerstone of dairy production systems. Minerals are involved in skeletal development, enzyme activation, osmotic balance, immune function, and milk synthesis. Unlike energy and protein, minerals do not provide caloric value, but are essential for physiological processes. Minerals are typically classified into: • Macrominerals (required in larger amounts): calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sodium (Na), sulphur (S), and chloride (Cl) • Microminerals (trace elements): zinc (Zn), copper (Cu), selenium (Se), manganese (Mn), iron (Fe), cobalt (Co), and iodine (I) The complexity of mineral nutrition arises not only from individual requirements, but also from interactions that influence absorption, transport, and metabolism. Importance of minerals in dairy cows Structural functions • Calcium and phosphorus are critical for bone formation and maintenance. • Magnesium contributes to bone integrity and neuromuscular function. Enzymatic roles • Zinc, copper, and manganese act as cofactors in enzyme systems. • Selenium is important for antioxidant defence because it is part of the enzyme glutathione peroxidase. In simple terms, this enzyme works like a clean-up system in the body by removing harmful free radicals and protecting cells from damage. Production and reproduction • Calcium is vital for muscle contraction and milk secretion. • Phosphorus plays a role in energy metabolism (ATP). • Trace minerals influence fertility, immune response, and uterine health. Mineral Interactions Mineral interactions can be synergistic (enhancing absorption/utilisation) or antagonistic (inhibiting availability). These interactions often occur at the level of: • Gastrointestinal absorption Transport proteins • Cellular uptake • Metabolic pathways Spring/Summer 2026 BONUS www.agribonus.co.za 60