Criteria for assessing dairy farm types

In Galicia and in the rest of Spain, dairy barns are going through a transition to implement the latest technologies, improve labour efficiency, and increase size. Barns with capacity for more cows are required due to the new market demands. Such barns must be perfectly defined, so that the construction of new buildings may entail reduced investment and operating costs. A wrong decision in the design phase can lead to serious financial trouble, even to the extent of making the farm economically non-viable.This study focuses in determining the factors that most strongly affect the construction costs of dairy housing, based on the most common barn designs in Galicia. Such factors are determined by implementing different indices that analyse the shape of the building.The implemented indices concern the design of the building –mainly its shape– and consider in all cases the relation of the design to the total cost and cost per item of the different constructions. Among these indices, the ‘ratio of area to perimeter squared’ or shape index (dimensionless), and elongation (ratio between the length and the width of the building), enable the determination of the shapes that are more convenient from the economic perspective. The cost of the building envelope per square meter varies as the barn area increases. The relation between the variation in the cost of the building envelope and both indices is studied for the different design options considered.With the data obtained, some guidelines are suggested in order to help project designers find the most appropriate result for their design work.