We planted buffalo grass around the sides and front of my house many years ago. It is a great grass to hold the soil,as it spreads via rhyzomes(kind of like some bermuda grass) and is quite drought-resistant, once it is well-established. However, it is hard,and slow, to get established from seed, and the seed is expensive. I am not sure how well the horses like to graze it, as I have no buffalo grass out in the area where I can turn the horses out; it is listed in my husband's range grasses book as being one of the most important grazing grasses of the 'dry plains', though! It WILL take time to get established well enough to tolerate being grazed and/or trampled by livestock,however, so if you plant it, be prepared to water it well to get it started(once it is well-established, it is VERY drought-tolerant), and be patient until it gets a strong root system! I plan to try to reseed some of my back yard with it a bit later this fall....my well is no longer strong enough to allow for much yard-sprinkling(not that we need it here, just now....!)-I had to just 'let it go', but hope that if I can get some buffalo grass going back there, it would need almost no watering later on.
Good luck, and let us know how it does, if you decide to plant some!
Margo