Why Not Tower Silos?
While the choice of silage over hay is an easy one, choosing a silage storage system for 80 to 150 cows is not as simple. Well-managed tower silos experience low dry matter losses, ranging from 5 to 10 %. They require no packing or covering, therefore involve less labour at filling. Applying additives is simple; they unload in any weather, and require less space. When all factors are considered, tower silos appear well suited for herds of 80 to 100 cows. Once this herd size is exceeded the disadvantages of tower silos quickly outweigh the advantages. For storages larger than 150 tonnes dry matter (20 x 70 upright or two 8 x 20 x 65 bunkers) bunker silos are lower in capital cost, and become a feasible option in terms of feed quality. It should be pointed out that a 20-foot silo has twice the surface area exposed to oxygen as the face of an 8 x 20 bunk. If there is excessive spoilage in the bunker, it is from lack of proper management and not the size of the face. Silo gas and height of
