Simulation modelling of temperate grassland based dairy calf to beef production systems

Profitable beef farming requires continuous appraisal and adaptation of production systems in response to advances in technology and evolving market and agricultural policy conditions. In this context bioeconomic models can be a useful aid to researchers seeking to understand how production systems react to these changing circumstances. A mathematical model, the Grange Dairy Beef Systems Model (GDBSM), is presented and used to simulate grassland based dairy calf to beef systems. The whole farm model consists of four interdependent components comprising farm system, animal nutrition, feed supply and financial sub models. Model applications are presented through the analysis of production scenarios concerning three cattle breed types and two finishing ages with the sensitivity of these scenarios to beef, fertiliser and concentrate price also outlined. The model results highlight the small and sometimes negative net margins (ranging from -(sic)3000 to (sic)13,000 on a per farm basis) of dairy calf to beef systems even with technically efficient management. The financial performance of all systems examined was sensitive to variation in beef price but relatively insensitive to variation in concentrate and fertiliser prices; on average the net margin per farm changed by (sic)9900, (sic)1800 and (sic)500, respectively, as the beef, concentrate and fertiliser price increased and decreased by 10%. The model presented can be used to increase understanding of the complex relationships within dairy calf to beef production systems. (C) 2012 Elsevier Ltd. All rights reserved.