Using models to establish the most financially optimum expansion strategy for Irish dairy farms

Determining the impact of a change of management on differing farm characteristics is a significant challenge in the evolution of dairy systems, due to the interacting components of complex biological systems. In this study the impact of increased concentrate supplementation and/or an increase in grazing intensity is simulated to determine the effect on the farm system and its economic performance. Three different grazing systems (with three different stocking rates 1.9, 2.2 and 2.5 cows per hectare, three different post-grazing heights 5.2, 4.5 and 3.8 cm, three different nitrogen fertilisation rates 160, 200 and 250 kg per ha) and four different concentrate-supplementation strategies (0.0, 0.5, 1.0 and 1.5 Mg per lactation) resulting in 12 different scenarios were simulated. Three different models (Moorepark Grass Growth Model, Pasture Base Herd Dynamic Milk model and the Moorepark Dairy Systems Model) were integrated and simulated in order to simulate the different scenarios. Overall, this study has shown that increasing concentrate supplementation generally resulted in a reduction in farm profitability, while in general increasing grazing intensity resulted in an increase in farm profitability