We all know that cows are ruminants. However, a newborn calf (pre-ruminant) acts like a monogastric animal. The milk bypasses the rumen and flows directly into the abomasum by the esophageal groove reflex. So if you want your calves to become strong and high milk producing heifers, it is of high importance that the rumen starts developing as soon as possible, without limiting the energy intake in the first weeks of life! This is the challenge!