A healthy intestinal flora is the basis of a healthy mare and foal
Pregnant mares and young animals easily eat 2.5% of their body weight in dry matter in roughage per day, which is more than 3/3.5 kg of hay per 100 kg of horse. If the intestinal flora is in balance and digestion works well, a mare hardly needs any extra energy even until the end of pregnancy. And growing animals do not experience an energy shortage after their first year of life with the average roughage diet.
Problems that are regularly encountered are that the roughage is too poor, too wet (dry matter content below 70%) or even moldy. This has a negative impact on the intestinal flora. As a result, the energy from the roughage cannot be absorbed properly. In this situation, supplementary feeding of concentrates is often seen as a solution, which means double feeding is actually done.