They may be adequate for the animals that you may be hunting and then again the guide service that you are going to use may not allow them. The best thing to do is to contact the guide service that you plan on using and ask them about it.
I know that here in North America there are guides for moose and bear in Alaska that require a minimum of a .30 caliber and up.
They would be adequate for the smaller of the plains game, but if you're planning on getting into the kudu and eland size animals, you will want to move up to at least a good 30 caliber or better rifle with a good bonded bullet. As critter mentioned, when you pick out a PH to go with, it would be a good idea to get their recommendation to make sure when you get there that they don't say your rifle is too light for the task and make you use an unfamiliar one of theirs,
Bring them in on a string. I love this term, if you want to be successful on calling in Elk, try not to just sound like the other caller. We all laugh at each other when we are practicing Elk calling at home or while camping. When I first started calling in Elk, I had no idea what i was doing and it's funny how many I could call in. The biggest Bull that I have called in to date was actually my first. I was making cow calls and screwing it up big time. But it's obvious I didn't screw up...