| 摘要 |
A pellet or bolus for administration to a ruminant by deposition in its rumeno-reticular sac where it is eroded away by rumen juices and releases active agent(s) and/or components, either continuously or in pulsed doses, comprises or incorporates a magnesium-based alloy which comprised at least 40% of magnesium, at least 30% zinc and up to 20% aluminium and, optionally, copper up to 5%, and trace elements, selected from cobalt, manganese, nickel and selenium up to 1%, the percentages being by weight. A paste can be made by heating the alloy to between its solidus and liquidus points, when it can be admixed with lead shot for weighting the bolus. In the illustrated case, the bolus comprises tubular sheath (14) which contains alloy/iron shot filling (16). However, the alloy can be used for any appropriate component of the bolus. |
