Livestock breeding and product manufacturing, as well as the consumption of animal products based on them (such as meat, milk, and eggs), have been the subject of numerous criticisms in recent years. This is especially true for meat consumption, within which beef has become a popular target for vegans. However, without animal husbandry, the earth would almost "stand still," and our food system would collapse. Additionally, we must consider the extremely important concept that without animal husbandry, the sustainability of the earth and the circulation of nutrients would cease. Add to this the fact that certain essential amino acids and vitamins are only available through the consumption of animal products. Moreover, certain minerals can be incorporated into our diet with great efficiency through animal products, which are basically available only in the form of food supplements for those following a vegan diet. There is much criticism of animal husbandry due to the large share of agricultural land it uses, although the largest share of dry land becomes food for humans only when consumed by ruminant animals. Another accusation against livestock farming is its excessive water consumption, which again can only be considered a topic of debate with very strong reservations. Additionally, in today's animal husbandry, the amount of feed and water required to produce one kilogram of meat (and milk or eggs) is a fraction of what was needed to achieve the same results 50-60 years ago. Many people also attribute the warming process of our planet to animal husbandry, even though, globally, animal husbandry only accounts for 5-6% of greenhouse gas emissions. However, this warming greatly affects the animals we keep, and we must look for genetic characteristics that make it easier to tolerate the conditions of a warming earth. In addition to heat tolerance, these characteristics also affect the utilisation of available feed and drinking water. Animal husbandry is a very complex process, resulting in extremely important variations of foods for humans. It's important to note that on a global level, 18% of consumed energy and 37% of consumed protein come from food of animal origin. These factors are necessary to summarise the latest development results of animal husbandry and to evaluate them. This book will provide a framework for determining the place and role of animal husbandry in the cycle of nutrients.