It is important to know the energy content of the feed we give our horses. If a horse takes in more energy than it expends, it will grow fat. Too little energy coming in and the horse will lose weight. Most countries have adopted units for energy in feeds but, because of differing traditions, the official units vary between countries. This often creates problems when concentrate mixtures from England or Germany are marketed, for example, in Scandinavia or France, since the latter may use other energy units than those used in the country of origin.