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GrazeIn: a model of herbage intake and milk production for grazing dairy cows. 3. Simulations and external validation of the model

Abstract : GrazeIn is a model for predicting herbage intake and milk production of grazing dairy cows. The objectives of this paper are to test its robustness according to a planned arrangement of grazing and feeding scenarios using a simulation procedure, and to investigate the precision of the predictions from an external validation procedure with independent data. Simulations show that the predicted effects of herbage allowance, herbage mass, herbage digestibility, concentrate supplementation, forage supplementation and daily time at pasture are consistent with current knowledge. The external validation of GrazeIn is investigated from a large dataset of twenty experiments representing 206 grazing herds, from five research centres within Western Europe. On average, mean actual and predicted values are 14 center dot 4 and 14 center dot 2 kg DM d-1 for herbage intake and 22 center dot 7 and 24 center dot 7 kg d-1 for milk production, respectively. The overall precision of the predictions, estimated by the mean prediction error, are 16% (i.e. 2 center dot 3 kg DM d-1) and 14% (i.e. 3 center dot 1 kg d-1) for herbage intake and milk production, respectively. It is concluded that the GrazeIn model is able to predict variations in herbage intake and milk production of grazing dairy cows in a realistic manner over a wide range of grazing management practices, rendering it suitable as a basis for decision support systems.
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https://hal.inrae.fr/hal-02652404
Contributor : Migration Prodinra <>
Submitted on : Friday, May 29, 2020 - 7:10:35 PM
Last modification on : Friday, April 23, 2021 - 10:44:01 AM

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Remy Delagarde, H Valk, C.S. Mayne, A.J. Rook, A. González-Rodríguez, et al.. GrazeIn: a model of herbage intake and milk production for grazing dairy cows. 3. Simulations and external validation of the model. Grass and Forage Science, Wiley, 2011, 66 (1), pp.61-77. ⟨10.1111/j.1365-2494.2010.00769.x⟩. ⟨hal-02652404⟩

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