In Holland new research shows that the effect of floors in dairy barns designed to limit ammonia emissions is often disappointing and that emissions differ little from those of traditional concrete slatted floors. The emission-limiting factors determined per floor by a government agency often turn out to be incorrect in practice. Thousands of dairy farms have each invested more than one hundred thousand euros in such floors. It is still unclear what consequences the disappointing results will have for the dairy farms concerned and perhaps also for other dairy farms.