Grass growth models for estimating digestibility and dry matter yield of forage grasses in Finland

摘要

Grass growth models that describe the development of grass digestibility (D-value, g kg~(-1) DM) at the first silage cut are widely used in Finland for optimal timing of harvests, due to the rapid decline in D-value prior to the optimal harvest stage.However, the models need to be improved in order to provide estimates of D-value and DM yield for all harvests (first, second and third cuts) taken during the growing season. Our aim is to publish statistical growth models that predict digestibility andDM yield (kg DM ha~(-1)) in all three cuts for Timothy (Pblen npratense L.) and Meadow fescue (Festucapratensis Huds.) swards. The models are based on data collected around Finland from 1996 to 2016. The updated models are regression or random regression models where the explanatory variables are the temperature sum or growing time Other parameters, such as geographical location and the date of the previous cut, are also used.