In the UK, mineral and trace element deficiencies are on the rise. There are several contributory causes:
• More intensive use of grassland.
• High forage diets and intensive production.
• Modern grass varieties with shallow root systems less able to absorb nutrients from the soil.
• Fertilisers that produce lush grass but with low trace element content.
It follows that fodder produced from new grass varieties or heavily fertilised grass crops will also yield feeds deficient in minerals and trace elements.
Compound feeds include some minerals and trace elements, but in their absence supplements must be provided in an alternative form.
There are also seasonal requirements for specific minerals. For example:
Lactating animals need extra magnesium in times of lush grass growth (primarily spring and autumn) to help protect against grass staggers. At these times, animals can lose more magnesium in milk production than their grass diet provides.
Phosphorus is strongly linked to reproductive performance. Most forages are relatively low in phosphorus. Without supplementation this can result in poor conception rates, high returns to service and general fertility problems.
In some grasslands sodium falls below the dietary minimum needed by cattle and sheep – and even more so in summer, when livestock sweat out large quantities of water and salt. Milk yield, growth and reproductive performance can all suffer significantly without supplementary sodium
