Oooh, "lady handling" could very easily be a double entendre, couldn't it? I suppose what they're trying to say is that this is a seminar about handling a dog in the field that is not open to gentlemen. Maybe the flier was not put together by an English major. Oh well.
More generally, I've heard the "lady" modifier more or less dropped once the "lady" and her dog starts qualifying (or winning/placing if its FT's) more consistently than the "gentlemen" do.