In Holland, new advice is that dairy farmers can better manage drier grass silage. Drier grass silage leads to less fermentation and less ammonia. This means that the dryness of the silage can be used to control the quality and usability of the protein by cows. In a dry silage the content of intestinal digester protein is higher and the unstable protein is lower than in a wetter silage. The better usability results in a lower urea number and requires less concentrate supplementation. Very wet silage can have an ammonia fraction of more than 10 percent, while very dry silage can go towards 5 percent.