Introduction
Livestock management and farming are based on the valorisation of the animal physiology.
Feed is ingested, partially digested and the absorbed nutrients and energy are used for productive and non-productive functions:
Productive functions include growth, fattening, reproduction, egg and milk production but also wool production or physical activities in some animal species. Animal products (meat, egg, milk) are directly linked to one or several of these productive functions.
Non-productive functions correspond to essential physiological processes such as the maintenance of nervous system and organ functions, maintenance of body temperature, minimal physical activity and behaviour but also animal defence (behavioural adaptations and stimulation of the immune system).
