I drive from San Antonio to Carrizo Springs every day now and it's interesting to see the different fields. There are feed lots on my path that have green grass right now. I'll bet their soil is/was similar to that in Castroville. You might drive south of Devine and get the number for Morales. You can't miss them as the oasis on the right side (heading south) with all breeds of cattle out grazing on the salad greens. Yesterday afternoon they were all out by the highway - beautiful
Call Morales and ask them what the cattle are eating now.
So anyway, it can be done. How do you do it? I'm going to say it's as easy as cross fencing your property with inexpensive electric strands. Simplistic but somewhat to the point. Let's say you have 1,500 acres and your neighbors and you all agree that because of the grass situation, the most you can run is 1 animal unit per 40 acres. So right now you would run 1,500/40 or 37 AU. That might be cow/calf pairs or yearling steers. I would suggest that you fence off 15 pastures of 100 acres each and provide water to each pasture. Starting with pasture number 1, put all 37 animals in there along with seed for the grass and legumes that you would like to have in there next summer. It could be you would be full of native grasses and not need any seed, but let's say you need seed. You scatter the seed and let the cattle tromp it down as they feed on the grass (or hay) in that pasture number 1. Then after 2 weeks you move them to pasture number 2 along with seed for that pasture next summer. I should probably mention that at no time do I ever mean to imply that you would use fertilizer, insecticide, herbicide, or fungicide in any of your pastures. And next year I'm going to suggest that you don't use any more seed except for winter grasses. Anyway, at this point you should get the drift that when you leave the cattle in the pastures for 2 weeks each, it will take 28 weeks before the cattle return to pasture number 1 again. Starting now, 28 weeks from now is August 27 (did I do that right?). Anyway, it's late in the summer before the cattle will return. Do you think if you leave your pastures totally alone for the next 28 weeks, they will grow any grass? The question is whether they will grow enough grass to sustain 37 AU for 2 weeks. It may not the first rotation, but that day will come. Eventually you are shooting for 100% coverage of the entire 1,500 acres with native grasses, 365 days a year. You can do that in Texas but not in North Dakota. Eventually you will find that instead of running 1 AU per 40 acres, you might be running 1 per 20 acres because your grass is growing so well and you are managing it so well.
I need to say something else. In the spring the rain will come, the grass will wake up, and will grow like a rocket. During the flush growth times, you absolutely cannot let your grass get away from you. You have to move your herd weekly instead of every 2 weeks. You might even have to move them faster. Don't worry that they cannot eat all the grass that fast, just keep them moving through the pastures so they can graze something down. An alternative, and this works well if you really get a sloppy mess during the rain, is to sacrifice one pasture to pugging for the spring, and hay your own fields instead of letting the cattle do the work.
Also be aware of seeding winter grasses 28 weeks before you rotate the animals into the winter pastures.
Here's why this works. When the cattle are herded up in small areas like your artificially fenced pastures, they work the ground in the concentrated area, they eat all the grass (not just the juicy new shoots), and they concentrate their urine and manure recycling. You can direct the sites for their recycling as you wish by placing mineral and water sources around the pastures. If you have a bad spot, move the water trough there.
This technique was tried successfully on a parcel of sterile strip mine tailings in the Arizona high desert. If it works there, it will work in Castroville.