Are you saying the deer will not eat it?  I find that strange.

I talked with a guy recently who is an intensive grazier.  He said he wishes he could find some johnsongrass seed to buy and plant.  He used to have a johnsongrass problem, but now that he is "intensive grazing", he can't seem to keep it on his farm.

(No such luck - johnsongrass is a noxious weed in this state, and buying or transporting the seed is not an option.)

To answer your question, nrw1717, I don't know if there is anything that will choke out johnsongrass.  If you can spray the area, planting any legume would allow you to use post-grass herbicides;  but beyond that, intensive grazing is probably the only way I know to "choke it out".