PROBLEMS IN FEEDING FOOD-PRODUCING ANIMAL S TO MEET THE ENERGY AND NUTRIENT-REQUIREMENTS AS WELL AS TO ENABLE ANIMALS WELL-BEING

The efforts in optimizing feeding conditions of food producing animals in the past were focussed primarily on promoting performance and/or t he products' quality (MEYER 1997). In spite of great success in this d irection various risks occure due to the conflict between the increase d requirements on the one hand and the species typical demands on the other (for example: need of roughage as well as of concentrates with h igh energy and nutrient density in ruminants). Especially in feeding h igh yielding dairy cows the conflict is obvious: Even in the case, tha t high amounts of concentrates are fed it becomes more and more diffic ult to meet the energy requirement when the milk yield exceeds 40 kg m ilk per day (FLACHOWSKY a. LEBZIEN 1997). A negative energy balance is accompanied by a forced predisposition for ketosis and infertility (K RUIP 1996). Insufficient proportions of roughage in those rations pred ispose the animals for rumen acidosis and associated problems (health of claws etc.) as well as for displacement of abomasum. Thereby in fee ding high yielding dairy cows there is only the choice between differe nt risks due to the fact that the feed intake capacity did not increas e to the same extent as the milk production did. In fattening calves t he use of roughage tin Germany required by law) is on debate in this d irection (necessary to avoid disturbances in the behaviour). Further p roblems in feeding animals according to their species typical demands are related to the established conditions of housing, feeding and wate r supply (risks of mechanization and automatization due to potential d isfunction). The gene rally increased feeding intensity results - for example in poultry - in a higher frequency of skeleton diseases; the m ore and more specialized pig production (separate units for piglet pro duction, rearing units, fattening units) is accompanied by increased c hanges in diets and techniques of feed and water supply, to that the a nimals have to be accustomed. too. The science of animal nutrition get s more and more involved in questions on the species depending require ments that guarantee a physiological development of the animal, health and normal behaviour. There is an increased need to create and evalua te parameters that can be used for characterization animals' well-bein g related to different feeding strategies. Without any doubts it is a special task to veterinary nutritionists to point out risks, problems, conflicting aimes when the feeding intensity is forced continuously. The slogan,,back to nature'' is too simple and does not correspond to the complexity of efforts which are suitable and necessary to meet ani mals` energy and nutrient requirements as well as demands of animals' welfare. Eventually it is helpful to remember sometimes the limits set up by the biology and physiology when feeding intensity or techniques are on debate.