Darren,

It is tough to develop cover when cattle have access to the area.  Most new crops that would be used for cover, such as native warm season grasses (switchgrass, big bluestem, etc.,) are all very palatable to cattle, especially when they are just established.  My favorite cover is a blend of switchgrass, big bluestem, and little bluestem.  The ratio of each species I recommend in the blend somewhat depends on the geographic area and long term management goals.

Growing Deer together,

Grant