LiGAPS-Dairy is a generic, mechanistic model to assess potential and feed-limited milk production in different dairy production systems across the world. The model uses concepts of production ecology to simulate potential and feed-limited production, and is developed from the model LiGAPS-Beef (see https://models.pps.wur.nl/ligaps-beef). LiGAPS-Dairy consists of a thermoregulation sub-model, a feed intake and digestion sub-model, and an energy and protein utilization sub-model. Energy and protein flows are simulated. Milk production is simulated based on the defining growth factors (genotype and climate) and limiting growth factors (feed quality and feed quantity). The defining factor climate affects milk production and growth via heat stress and cold stress. The limiting factor feed quality is further split up in limitations in digestion capacity and protein deficiency. The limiting factor available feed quantity is split up in energy deficiency and protein deficiency. The model can be used to assess yield gaps in dairy production systems, to analyze yield gaps and to explore options for yield gap mitigation and improvements in resource use efficiency.
Milk production, fat- and protein-corrected milk production, average daily gain, weight of edible beef, carcass weight, feed intake, feed efficiency, and the factors defining (genotype, heat stress, cold stress) and limiting (digestion capacity, energy deficiency, protein deficiency) milk production and growth.
R 2.15.3, or a more recent version of this programming language, is required to run the model. In addition, RStudio 0.98, or a more recent version of this programming language, is recommended to run the model. The R-package ‘writexl’ is required to write model output in Excel files.
R 2.15.3, or a more recent version of this programming language, is required to run the model. In addition, RStudio 0.98, or a more recent version of this programming language, is recommended to run the model.
Files with daily weather data (.csv extension). The current version of LiGAPS-Dairy requires files with feed characteristics as well. A file with feed characteristics under potential production is available (.csv extension). Files with feed characteristics under feed quality limited production for experimental farms in the Netherlands are not available, because of IP rights on the dataset, which is property of Wageningen Livestock Research, Wageningen University & Research, the Netherlands.
Results from LiGAPS-Beef can be written to files with various extensions (.csv, .pdf, .txt, .xlsx).
The model LiGAPS-Dairy is published in Journal of Dairy Science, and can be accessed via https://doi.org/10.3168/jds.2020-19078.