Modeling efficiency and robustness in ruminants, the nutritional point of view

Abstract

This synthesis reviews the modeling of nutritional aspects associated with efficiency and robustness issues in ruminants. In particular, it focuses on the role of feeding unit systems in these debates. Feeding behavior and ingestion are important first criteria to consider given their relationship to animal performance. Digestive efficiency has been measured and modeled for a long time since it is an important and largely controllable component of the overall feed efficiency. Metabolic efficiency largely depends on the level of performance given the role played by the maintenance and non-productive requirements of the animals. In addition, it depends to a large extent on the organic constituents (lipids, proteins and carbohydrates) as well as the involvement of reserves and excretion functions. Robustness is an emerging property of a complex system, it involves the many facets of the homeostasis of living things and cannot, therefore, be easily evaluated and measured. In practice, it is often tackled through short-term nutritional challenges as well as through the laws of response to feed and nutrient inputs. In all the areas mentioned in this text, the individual variations are still poorly known as well as the genetic part of these variations, this encourages dedicating more work to these topics.