Development and application of simulation models for sustainable cattle production systems
2004
Hirooka, H. | Terada, F. | Liang, J. B.
Specialized and industrialized cattle production systems such as large scaled dairy and feedlot production have been identified as a major source of environmental pollution, it is therefore necessary to examine ways to reduce the nutrient and mineral excretions by cattle to achieve sustainable production systems. The systems analysis approach with modelling and simulation is a useful tool to integrate and quantify data on nutrient and/or mineral flows which have negative impacts on the environment through various components of the systems. The objectives of this paper were to (1) review previous modelling works which predict N excretion for cattle and (2) present a newly developed model for the prediction of N excretion in faeces and urine and examples of its application. The developed model was evaluated against validation data for Holstein lactating cows and fattening steers and Japanese Black fattening steers. The results suggested that the precision of predictions was good and this model could predict N excretions beyond breeds and sexes. Moreover, the model was used to compare biological and economic sustainability indexes (carcass weight per total N excretion and carcass price per total excretion during fattening periods) of Japanese Black and Japanese Brown cattle.
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