I'm in upstate South Carolina, but in the part of the state with the lowest amount of rainfall and I get summer droughts most years. I have never irrigated my groves after the first year or two following transplant. I set out my transplants in the winter, and irrigate if needed during the first summer or two. I only irrigated the newly started groves if the leaves curl during the day and didn't recover by evening, but on most of my starting groves I never had to irrigate. My bamboo groves are 25 to 35 feet high and it took about 5 years to get them to a size where most of the leaves were above livestock browsing height. You'll need to keep the livestock fenced out of the developing bamboo grove until they get large and tall enough so the livestock can't reach the leaves. It would be best to start your groves on the moister parts of your property and let them spread into the dryer parts once established. Bamboo will tolerate wind once they get established as a grove, but the initial transplants would be somewhat sensitive to wind and might need a windscreen.
Of the bamboo species I am growing, Phyllostachys makinoi and Phyllostachys rubromarginata are the most drought tolerant and I read that makinoi has been growing well in the Las Vegas area. Running bamboo is the absolutely the best plant for stopping erosion on hillsides and gullies. Controlling the spread of running bamboo is not a problem in a pasture setting since the livestock will eat every shoot that they can find, so you will need to fence off the areas where you want the grove to get established during the spring shooting season. I surround my groves with a fence with gates in it and close the gates to keep them out during the shooting season.