Dynamic computer models to identify the optimal system and management of population structure for self-contained meat sheep crossbreeding enterprises

Abstract

Two deterministic computer models for the choice of the crossing system possessing optimum design flock structures, for self-contained meat sheep crossbreeding enterprises were developed, using Microsoft Excel's Solver software. Both of the models use a dynamic strategy for optimization of the flock structures for a time period of 10 years. There are two breeds of sheep and up to three flocks considered in each model. Also, the initial total number of the ewes in the flocks to commence the crossing system with, is an optional input parameter which should be determined by the breeder. At any time for a given set of the input data, the computer models search all options to determine the optimal structure of the flocks under a detailed year-by-year scheme. The models predict the relevant parameters while applying the standard cash flow discounting method (optional), and propose either a rotational crossing, a terminal-rotation crossing, a single two way crossing, or a combination of these systems. Meanwhile, the flock structures, and most of the important phenotypic, genotypic and economic parameters are displayed diagrammatically for a clear understanding of the simulation modeling. ... Finally, the models allowed little variations in the flock structures from optimality. e.g., small proportions of the female lambs and/or hogget ewes could be sold with negligible effect on the optimal profitability of the proposed crossing system.