I need some help on feed

Here is the problem that I have..  I live next to the Rockies in Utah.  It gets friggin cold.  Soon.  I need to come up with a feed and alot of the stuff listed in other threads are not available here.  There are difinate draw backs to being a Utard.  My son's calf doesn't show until August 09.  I am not sure if I should put him on more of a grower type and start a finish feed later.  When we show it's also hot.  Around 100 degrees.  So we go from -30 to 100.  It is great living in a mountain desert.  This is what I have available at local feed stores.
Oats
corn.
beet pulp pellet
soy bean meal
and milo

I would also appreciate a little explantion on what these accomplish.( feeds)  I know I sound like an idiot but not really familiar with some of these lilke milo and beat pulp

Thanks AC

Thanks for the help.  When it got warmer in the spring and closer to the show date would you add barly to the mix.

  Try not to over think it. AAOK has very good rations. Feed it consistantly for a period of time then take a look @ it and evaluate when it closer to spring. JMO. Brent