Evaluation of a Model Laboratory Silo

Abstract

Objectives of this research were to evaluate a new type of miniature laboratory silo and describe its use in silage research. The silo unit was designed to study, separately or collectively, variables affecting the ensiling process, such as moisture, temperature, density, light, and additives. In addition, loss of wet weight and fermentation gases could be measured. The capacity of the unit was approximately 250g of forage material with a volume of 463cm3. Laboratory silos were evaluated for three forage crops (alfalfa at two moistures, whole plant corn, and corn stover) and two ensiling periods (3 and 5 wk). They also were compared with farm scale silos for whole plant corn.The laboratory silos simulated farm silos and produced high quality silages from both high moisture alfalfa and whole plant corn. The smaller amounts of substrate permitted closer control of the process and more uniformity of composition of starting material. Dry matter and pH varied least. Variation was relatively higher with carbon dioxide, acetate, and lactate. The 3-wk ensiling produced high quality silages with low pH and high content of lactic acid compared to 5-wk. Lactic acid was predicted accurately, .97 correlation, from pH, titratable acidity, and carbon dioxide output. The pH also was predicted from lactic acid and titratable acidity but with relatively less accuracy, .62 correlation.