An animal marking and treatment apparatus, comprising, an animal treatment apparatus to apply an animal treatment to a surface or subcutaneous layer at a treatment location of an animal via an operative end of the animal treatment apparatus ; and a marking cassette attached to the animal treatment apparatus at the operative end , comprising, - a housing that has a holding portion at one end, and a mounting portion engaged directly or indirectly, to the animal treatment apparatus at an opposing end, and - a marking portion located in the holding portion, the marking portion adapted to mark the surface of the animal when applied thereto and leave at least a portion of a circular mark on the surface, the marking portion having an absorbent pad that contains a marking medium, wherein the marking cassette is adapted to mark the surface of the animal to leave the at least a portion of the circular mark from the marking portion on the animal indicating the treatment has been applied, and the location of the treatment by marking at the same time as the treatment, wherein the animal treatment is applied through a hollow centre of the marking portion , characterized in that the marking cassette further comprises a removable replaceable cover to cover the marking portion , and that the the removable replaceable cover includes a hollow centre and the hollow centre of the marking portion corresponds with the hollow centre of the removable replaceable cover . an animal treatment apparatus to apply an animal treatment to a surface or subcutaneous layer at a treatment location of an animal via an operative end of the animal treatment apparatus ; and a marking cassette attached to the animal treatment apparatus at the operative end , comprising, - a housing that has a holding portion at one end, and a mounting portion engaged directly or indirectly, to the animal treatment apparatus at an opposing end, and - a marking portion located in the holding portion, the marking portion adapted to mark the surface of the animal when applied thereto and leave at least a portion of a circular mark on the surface, the marking portion having an absorbent pad that contains a marking medium, - a housing that has a holding portion at one end, and a mounting portion engaged directly or indirectly, to the animal treatment apparatus at an opposing end, and - a marking portion located in the holding portion, the marking portion adapted to mark the surface of the animal when applied thereto and leave at least a portion of a circular mark on the surface, the marking portion having an absorbent pad that contains a marking medium, wherein the marking cassette is adapted to mark the surface of the animal to leave the at least a portion of the circular mark from the marking portion on the animal indicating the treatment has been applied, and the location of the treatment by marking at the same time as the treatment, wherein the animal treatment is applied through a hollow centre of the marking portion , characterized in that the marking cassette further comprises a removable replaceable cover to cover the marking portion , and that the the removable replaceable cover includes a hollow centre and the hollow centre of the marking portion corresponds with the hollow centre of the removable replaceable cover . <EOS>