Input substitutability in the EC compound feed industry
利用对偶理论和超越对数成本函数，估计比利时和荷兰配合饲料行业三种投入（谷物、谷物替代品、高蛋白饲料）的需求弹性，发现投入间存在替代与互补关系，对饲料企业决策有参考价值。
Duality theory allows for the multiple-output, multiple-input technology typical of compound feed production, to be characterized by a joint cost function. For estimation purposes, a translog cost function with three inputs (cereals, cereal substitutes, and high protein feeds) and three compound feed outputs (for cattle, for hogs, and for poultry) are specified. Constraints typical of the technology being modelled, such as linear homogeneity in feed inputs and zero net substitution effects between feed and non-feed inputs, are imposed. The model is estimated with data of the Belgian and Dutch compound feed industry in a time-series, cross-section framework. The results show that all three inputs considered have inelastic demand, that there is substitutability between cereals and the other two inputs, and complementarity between high-protein feeds and cereal substitutes.