| 主权项 |
1. A pair of co-operating boluses, each of the pair of boluses being generally hemi-cylindrically shaped so as to form a cylindrical bolus, said pair of co-operating boluses being dimensioned so as to fit, simultaneously, in a side-by-side arrangement, within a conventional oral dosing gun used to administer boluses orally to cattle, wherein each of the pair of co-operating boluses comprises a bolus body comprising a matrix material and one or more biologically beneficial substances mixed with the matrix; wherein the exterior surface of the bolus body is shaped so as to have either:
at least a first groove having a first width and depth, and at least a second groove having a second width and depth, wherein the second width is less than the first width and/or the second depth is greater than the first depth; or at least one groove which differs, in terms of width and/or depth, at different locations along its length; said first and second grooves, or said variably dimensioned groove, being aligned along the long axis of the bolus; the bolus body, including said groove(s), being coated with a substantially uniform thickness of a coating material which retards or inhibits release of the beneficial substance from the matrix, such that the first and second grooves become uncoated at different rates, or the variably dimensioned groove uncoats at different rates at said different location, thereby achieving variable rates of release of the beneficial substance(s) from the matrix. |
