Dynamilk: a model at farm-scale to explore the balance between forage and milk production

Leaning towards better feed and forage self-sufficiency enables farmers to improve dairy farm competitiveness and their ability to cope with climatic changes and production constraints. Finding the proper stocking rate to the potential production of grass, including effect of climate change on yields, is important to maintain milk production and secure the forage system. Building a model at farm-scale enables different dairy systems to be explored for contrasting production strategies, in order to understand which are the possible trade-offs between levels of animal production, feed and forage self-sufficiency, and sustainable grassland uses. Such a dynamic model, called Dynamilk, has been developed. A typical dairy system based on productive permanent grasslands has been simulated, with different levels of stocking rate, in order to investigate its performance (milk yield, forage self-sufficiency and herbage utilization). Two different periods have been simulated to evaluate the impacts of weather conditions. Results have shown that an adapted stocking rate can be found, allowing a high level of milk production through a better valorisation of grass during the grazing without compromising forage self-sufficiency. Current climatic conditions imply a reduction of the stocking rate compared with stocking rates considered during the 1990s