Some innovative companies have developed enzymes to help digest DDGs, but there is definitely a limit on the amount of DDGs in the animal diet. Another problem is DDG quality- some of the stuff would make you puke at the sight of it. Finally there are issues with preservation/degradation during storage and transportation.
You may ask, well then were do all these DDG go to, someone must buy them... the answer is the Chinese buy them up in huge quantities.
DDG’s do not “wreak havoc” on animals. DDG’s are a valuable high protein ingredient in animal feed. Like all other feed ingredients, they have to be used in the proper proportion in a balanced ration. Feeders are looking for the lowest cost ingredients that give them optimal results. The mix can vary depending on what is available at what price. There is often a lot of substitution over the course of a year as relative prices change.
You are correct. It can be part of the ration, but not the whole thing.
One thing I find... interesting, is that there are stories of DDG going into human consupmtion in China. We can’t digest it, so it must be going for filler.