|VIRKAJARVI, PERTTU - Natural Resources Institute Finland (LUKE)|
|KORHONEN, PANU - Natural Resources Institute Finland (LUKE)|
|BELLOCCHI, GIANNI - Institut National De La Recherche Agronomique (INRA)|
|CURNEL, YANNICK - Rothamsted Research|
|WU, LIANHAI - Rothamsted Research|
|JEGO, GUILLAUME - Agri Food - Canada|
|PERSSON, THOMAS - Norwegian Institute Of Bioeconomy Research(NIBIO)|
|HOGLIND, MATS - Norwegian Institute Of Bioeconomy Research(NIBIO)|
|VAN OIJEN, MARCEI - Centre For Ecology And Hydrology|
|GUSTAVSSON, A. - Swedish University Of Agricultural Sciences|
|KIPLING, RUDYARD - Aberystwyth University|
|Rotz, Clarence - Al|
|PALOSUO, TARU - Natural Resources Institute Finland (LUKE)|
|CALANCA, PIERLUIGI - Agroscope|
Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2017
Publication Date: 5/22/2017
Citation: Virkajarvi, P., Korhonen, P., Bellocchi, G., Curnel, Y., Wu, L., Jego, G., Persson, T., Hoglind, M., Van Oijen, M., Gustavsson, A., Kipling, R., Rotz, C.A., Palosuo, T., Calanca, P. 2017. Process-based modelling of the nutritive value of forages: a review,May 22-24,2017,Berlin,Germany. P.1.
Interpretive Summary: No Interpretive Summary is required. JLB.
Technical Abstract: Modelling sward nutritional value (NV) is of particular importance to understand the interactions between grasslands, livestock production, environment and climate-related impacts. Variables describing nutritive value vary significantly between ruminant production systems, but two types are commonly used: 1) variables related to cell wall content, digestibility and energy, and 2) variables related to protein content. This study reviews and compares alternative modelling approaches simulating forage NV. It is intended to: 1) provide model users essential information for a fit-purpose use of grassland models; 2) give model builders feedback helpful in improving the models; and 3) promote the development of state-of-the-art model assessment. The focus is on approaches applicable for European grasslands, as implemented in the grassland models, BASGRA, CATIMO, IFSM, MCPy, ModVege, PaSim, QUAL, SPACSYS, and STICS. These models cover swards cut for silage or hay, grazed swards, monocultures and mixtures, permanent grasslands and leys kept for less than five years. Six out of nine models use neutral detergent fibre (NDF) to describe content of structural carbohydrates. Digestibility of harvested dry matter (DM) is estimated as a function of NDF content and NDF digestibility in five models. Two of the models use an alternative approach that consists of estimating organic matter digestibility or in-vitro true digestibility of DM directly. Three of the models include variables to describe net energy content of DM, whereas one model use metabolizable energy. To estimate protein value of harvested DM, seven approaches use crude protein concentration calculated as a function of plant nitrogen concentration and one model uses digestible intestinal protein content.