Effects of Different Bulk Densities on Zea mays Silage Characteristics, Temperature Profiles, CO2-and O2- Concentrations in Small Scale Silos during Aerobic Exposure

K. H. Jungbluth, G.-C. Maack, W. Büscher, L. Menghua, C. Hong, C. Qiang and Y. Sun


Full Length Research Paper  I Published December,2016


Journal of Agricultural Science and Food Technology  Vol. 2 (11), pp.180-188





In this study, effects of different bulk densities on the Maize (Zea mays) silage characteristics, temperature, CO2- and O2- gases in small silos during the aerobic exposure were investigated. The method described in Jungbluth et al. (2016) was used. For this, 8 buckets (65.3 l) were filled with 40 kg FM (218.7 kg DM m-3; n=4) or 50 kg FM (273.4 kg DM m-3; n=4) of maize silage. Temperature was measured to observe heating resulting from microbial activity. Similarly, gas samples were taken and analyzed by gas chromatography during reheating. Reheating was observed in every bucket. Temperature increases were higher (p=0.05) in the low-density treatment. Gas measurements showed CO2 flowing out and O2 diffusing into the buckets after opening. 24 h later, CO2 concentrations reached their minimum when O2 values reached their maximum. The CO2 minimum was followed by an increase in concentration, whereas O2 concentrations decreased. The reason for this change, happening immediately before reheating started, is microbial respiration, consuming O2 and producing CO2. The reheating process had no effect on the nutrient categories, crude ash, crude fibre, crude fat, neutral detergent fibre (aNDFom), and starch or on the pH value. Higher crude protein and metabolizable energy content(s) were found in the high-density treatment after reheating and dry matter losses between 0.58 and 4.38% were found and were tendentially higher in the low-density treatment. Therefore in agricultural practice it is recommended to reach high bulk densities in silage to preserve staple feed and it´s quality.

Key Words:
Maize (Zea mays) Silage, Oxygen Induced Deterioration, Density and Reheating.

Full Text-PDF