Depends on your goals. Sorghum Sudan and Pearl Millet will produce more pounds of beef per acre....but Im a polyculture guy, and like to plant mixes. Add to those some sunn hemp, crabgrass, and a little buckwheat and your have yourself some salad bar beef. The cowpea stockpiles reasonable well if you give it time (and don't graze it too hard) for the second or third grazing in the late summer, early fall. (down here in GA at least)