Don't know the economics, but there are people online who seem to be going, a winter annual cold season, and Sudan sorghum summer, and yielding far far more pounds of fodder than a traditional perennial grass. Of coarse, with added cost of seed, drilling, and with added pounds taken off, the need for added pounds put back on, in fertilizer. I'm sure this method is Highly dependent on your local rain fall, soil type, moisture holding, ect. I also don't know the nutrition, other than Sudan can be dangerous to horses in large quantity, or atleast pregnant horses.