The feed story for dairy production systems under climate change

Of all ruminant production systems, high-yielding dairy cows have the most stringent criteria onnutrition, with feed intakes up to more than three times that required for maintenance alone. Forthis reason, dairy production systems provide an interesting case study with which to explore theimplications of climate change on feed provision and utilization by the animal. Dairy productionsystems across Europe vary widely in production intensity and in nutrition strategies applied.Systems range from almost fully grazed to almost fully confined systems, and from low to highproduction intensities (per cow or per farmed hectare) of: external resource use (e.g. feedpurchased), level of farm automation and technology application, and financial investment.Irrespective of this huge variety of dairy farming systems, they have in common that home-grownroughages are an important part of the diet. Climate change will directly impact on roughageproduction and hence on: the supply and quality of roughages, the nutritional strategies adoptedand cow performance. Indirectly, through its impact on home-grown roughages climate changewill also impact on the requirements for: home-grown feed crops, purchased feed crops,supplemental by-product feeds (for example, from the food or bio-energy industries) andprocessed concentrate feeds, depending on whether production targets are to be maintained ornot. These potential consequences of climate change have been reviewed. Challenges addressedand presented here will include the need to reduce phosphorus and nitrogen surpluses and/orlosses from the system. The implications and limits to various nutritional adaptation strategies,and the alternatives available to farmers and the feed industry, will be discussed in the context ofrecent scientific insights and against the background of the models and modelling conceptscurrently in use in practice and in research