The INRA 2018 feeding system for ruminants. 1. Conceptual foundations and specific features

Abstract

Feeding ruminants is a strategic issue for the farmer, combining the quest for zootechnical and economic performances, quality of products, respect for animal welfare and environment. The INRA 2018 system, based on nutritional knowledge accumulated by INRAE and in the literature, offers an approach to rationing, adapted to dairy and meat-producing cattle, sheep and goats, at barn or on pasture. The system is based on units common to both feed values, and animal needs or capacity: UF (forage units) for energy, PDI/AADI for protein and digestible amino acids, and UE (fill units) for intake. It also estimates mineral, vitamin and water intakes and requirements. Feed values depend on their chemical composition, digestibility and ruminal degradability, and on their interactions within the diet. Animal requirements take into account the different physiological functions, and intake capacity is specific to each animal category. Response laws enable performance to be simulated according to ration: milk production, growth, emissions (CH₄, nitrogen), indices of product quality and acidosis risk. INRAtion®V5 integrates these models to solve rationing problems in the field. This paper presents the basics of the system, focusing on the new features integrated in 2018. A companion paper presents examples of multi-objective resolution and multicriteria evaluation of diets for various types of ruminants and productions.