This article from researchers from Ohio State University describes an experiment conducted to identify the factors that cause reduced production of cows fed a diet with high content of corn distillers grain with solubles (DDGS).

Successful colostrum management requires careful attention to cleanliness. Colostrum, while it is still in a healthy cow, should have a bacteria count of essentially zero. However, by the time it gets into the calf, bacteria counts are often very high.