I have the best luck keeping calves sound and pretty with enough power to compete using half blood cows...herf x angus and sim x angus along with the shorty x cows..
A good stout half blood could do wonders for one, personally for cows I always like to see either some Angus, Hereford, or Shorthorn in them, to me these breeds just tend to milk better and make better mommas. As far as the clubby type genetics on them, I like any of the breeds above crossed with Who Made Who, Foreplay, or Meyer genetics.
There are alot of different post you can search that have different advice on this same topic. I would say it depends on what type of club calves you are looking produce. I use a little bit of everything. I have Angus, Simmental, Shorthorn, Maine, crosses of all these different breeds and looking to put a little Charlois in my herd next year. I like my Maine cows and my Simmental cows for breeding black show calves. My Shorthorns and Simmental cows are the best milkers in the herd. I have a Meyer 734 that was crossed with a PB Maine bull that I got a heifer out of that is now 50% Maine and 50% Simmental and I really like her. There are alot of good crosses out there, you have to take some shots and find out what works for the type of breeding you want to do.