First, don't confuse best with most. Also, you must have well-drained land to grow better hay grasses.
Bahiagrass grows all over south Mississippi, but it might not make the highest quality hay. Dallisgrass grows better than bahiagrass and bermudagrass on moist bottom soils, but ergot in the seed heads may be a problem in hay. Hybrid and improved vegetative bermudagrasses will produce a large quantity of high quality hay, but it usually requires more management than do other summer grasses.
Horse owners usually prefer a weed free, high quality bermudagrass hay, whereas cattlemen may settle for less at a lower price.
Source : msstate.edu