Joke about the word "Boer"

[57730]

There is a joke I don't understand in The Life and Times of Scrooge McDuck. It goes:

-My name is McDuck, from Scotland. How about you?
-Me? I'm a Boer!
-Oh, you're not so bad! I've met worse.

The joke seems to be that Scrooge misunderstands "a Boer" for something self-deprecating, but I can't figure out what. If you get the joke, could you explain it to me?

 

[5jj]

It could have been bore.

 

[Skrej]

Or even a 'boar'.