I second the comment about the hallmarks being crucial to id the maker.

I've been a silversmith by trade for years though, so there are a few things I can tell you about the materials used.

This looks rather modern to me. The soldering looks made with an electric welder/electric soldering iron, as opposed to any fire/torch methods. I'm not familiar with soldering with welders so I'll leave it to others to confirm. However, if true then you can start estimating the maximum age for it. I'd be surprised if it was over a hundred years old.

Next is the decor. The patterns are made with punching tools, also called chisels sometimes. It's not a particularly elaborate or sophisticated pattern or execution of technique so whoever did this wasn't working under any big name smiths. It gives off the feel of a hobby or quickly made artisan's craft. It's neat an the result looks good but it's not sophisticated at all. Going back to the chisels used, these also feel relatively new to me. The round punches are too perfect but don't seem to have been hammered repeatedly, which means the round tool used was probably made with a bur on a drill, just like I've made mine. If it were something really old the punches would be showing more signs of imperfections especially since whoever made this only hammered once or twice each punch, not enough to cover up anything. Since the marks are too round and perfect, I take it as another sign of being relatively new.

My two cents

Edit: i see your update about the Norwegian listing from 1950 and I say 1950 sounds credible enough. Yours looks recently burnished though, making it look even newer but that could have been done just before the auction.

By a cow.

Unless you can find hallmarks on it, it's specific provenance would be difficult to determine. You would be best served if you found an appraiser that deal with this sort of item to give the best info on your drinking horn.

Looks like an elephant made the tusk.