A new concept of feed intake regulation in ruminants is developed starting from the idea that
feed consumption presents both costs and benefits to the animal. For a non-reproducing
animal, we consider the intake of net energy for maintenance and gain to be the benefits of
feed consumption, and the concomitant consumption of oxygen the costs, since the use of
oxygen by tissues indirectly causes an accumulation of damage to cell structures, a loss of
vitality, ageing and a limited life span. This leads to the hypothesis that feed intake …

Part I of this thesis contains a critical appraisal of the commonly accepted theory with regard
to feed intake regulation in ruminants and the presentation of a new theory. This new theory
assumes that feed consumption creates both benefits to the animal (in a non-reproducing
animal the intake of net energy for maintenance and gain) and costs (the total oxygen
consumption of the animal). It is hypothesized that, for the animal, the intake level where the
ratio between benefits and costs becomes maximal, is optimal. Predictions of this optimum …