More efficient use of resources (e.g. land, labour, feed, fertilizer, fossil fuel and water) is one of the biggest challenges to face dairy farming in Europe, directly affecting competitiveness, social acceptability, environmental sustainability and biodiversity/habitats. Feed efficiency is an important element in this. By improving feed efficiency in dairy cattle herds, dairy farmers have the opportunity to address two mains issues which they encounter. First, feed costs have a direct impact on the profitability of the dairy farm, so increasing feed efficiency contributes to a more profitable farm. Second, an improved feed efficiency can help to reduce the negative impacts of dairy production on the environment, by lowering greenhouse gas (GHG) emissions and nutrient losses to the environment associated with cattle production. This also addresses increasing societal concerns regarding this issue, thereby contributing to the improved social acceptability of the sector.