The issue I have with accepting "De-Horners" as the answer is that NONE of the others shown on Google Images have attachments...they're all-in-one. There are MANY vintage, cast-iron types, of various configurations, makers and patents. Not a one of them has other parts, as this one would.
This thing would need, at minimum, a vee-shaped receiving blade, into which the horn would be forced by the pusher. And the pusher isn't well-shaped for a horn, being more flat than radiused.
Having a second, 'loose' attachment to deal with while attempting to apply the fixture to the horn of a less-than-docile bovine sounds like a non-starter...to me.