Yes
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We use Ivomec (or one of its generic equivalents) on both our show calves and pasture cattle. We poured our show calves about two weeks ago. Clipped one last weekend and didn't have any scaling or other issues. I've seen scaling happen from pour ons, but very rarely (maybe one or two calves in the last ten year) at a noticeable level.
I know the pour-on works for lice as I alluded to previously. We also use it on our cow herd at the end of winter which is when they will try to get bad cases of lice.
I know the injectable says it works, I've just been taught to use the pour on. I don't like to poke any more holes in show calves than I have to so I prefer to not use injections.
There is another kind of pour-on just for lice that we sometimes use when we wean babies for show calves. I believe it is called Cylence. We've bought it as horse supply stores. It has worked great too when it is too early to use Ivomec again.