This is written for people with cow dairies, but the info on rotational grazing is good, regardless of what species you have:
Best Management Practices for Dairy Grazing
It's a slide show with narration. The man talks a little fast, but you can pause it. Otherwise, you can't read the slides as fast as he moves through them. There is also good info on here about how a cow's nutritional needs and milk production changes with the temperature. I'm sure goats have a similar pattern.