| The objectives of this project were to evaluate the effects of confinement (0 grazing) vs. pasture based (160 days grazing) dairying, 4 milk yield goals (5500 to 11,000 kg cow-1 yr-1), and high vs. low input cropping on 7 measures of sustainability on a standardized Atlantic Canadian dairy farm. These objectives were addressed through the development and application of the ADSM, a dynamic, deterministic model constructed as a system of differential equations describing flows of C and N within a dairy farm and to/from the surrounding environment. The ADSM also models fossil energy use and economic factors. The ADSM is based on empirical data and mechanistic principles obtained from a farm survey, local data, and literature sources. It is parameterized to reflect typical Maritime conditions, and is sensitive to a number of management parameters. The ADSM models a sole dairy enterprise, including replacement stock, and a land base seeded to grass-legume forage for hay/silage, grass-legume pasture, and barley. (Abstract shortened by UMI.). |
