I'm on my phone in the country side with slow internet so I cant look up a link, but if I remember correctly, you should search "Alan Savory TED Talk" on youtube for an introduction to the use of livestock to reclaim land. Essentially, the issue with most livestock grazing is that it does not mimic natural grazing, which is a seasonal, high volume, high density event where the herd moves on and allows the grazed area time to recover.