This category  includes boles that supply minerals, trace element and vitamins to cattle and sheep.

The bolus usually sits in the animals rumen and releases its nutrients over a period of time. Some boli are fast release and some slow release , upto 12 months in some cases.

The provide a convenient and targetted delivery system for the nutrients concerned. The list of nutrients would include- Calcium, Magnesium, Phosphorus, Vaitamin D3, B Vitamins, Vitamins ADE, copper, selenium, cobalt, zinc, iodine, garlic extracts, charcoal and kaolin, 

The bolus system is becoming more important now that cattle and sheep are being kept more on grazing systems, with less bought in feed. Less minerals and viatmin coming onto the farm and so the deficiencies of each farm can become more apparent. 

Boluses containing minerals, trace elementa and vitamins can be useful in dairy cattle, beef cattle and sheep.