The bolus was licensed to aid the prevention of a metabolic disease called hypomagnesaemia in cows and ewes when grazing spring grass and also in the prevention of hypocalcaemia at calving time. The magnesium bolus was the first magnesium alloy composition (patented) which could successfully be used as an intraruminal device in the strategic supply of magnesium to aid in the prevention of hypomagnesaemic tetany in cattle and sheep.

Hemingway RG, Parkins JJ, Ritchie NS

"In one study the proportion of twins born to ewes given the bolus was very significantly (P<0.001) higher than for the untreated ewes".

Patent protection meant that the Glasgow device was the only such bolus on the world market for 20 years and it continues to have a large international market. The technology for the Mg/Al/Cu alloy was subsequently utilised by others in 'pulse release' anthelmintic (anti-parasitic) products.

All-Trace boluses also lie in the rumen-reticulum with 9 essential trace elements and vitamins dissolving from a constant surface area for about 8 months. This device was patented by the University of Glasgow 1980 (Hemingway, Parkins & Ritchie) and is the only bolus that supplies a sustained dietary supplement of all 7 trace elements and the 3 fat soluble vitamins required by ruminant animals.

Many millions of these products have been sold worldwide and specialised development of the trace element bolus continues.