Similarly goats can be grown feeding them almost anything in climates where nothing of value can be farmed otherwise.
You can clearly see the lighter shade of the Egyptian land, because the goats strip it clean. That is mountainous land that has no value for farming, but the goats can roam it and eat anything that happens to grow.
Not sure how goat farming works, but AFAIK for cows they spend the first half of their lives on pasture (ie. eating grass) and the rest on feetlots (ie. eating corn).
[1]: https://www.npr.org/sections/thesalt/2019/08/13/746576239/is...
Better question...given the nutritional information on goat's milk painting it as more nutrient rich - why aren't we all drinking it?