Effect of compaction, delayed sealing and aerobic exposure on maize silage quality and on formation of volatile organic compounds

Abstract

Physical and management factors, such as compaction and sealing, greatly influence the outcome of forage conservation. This study aimed to determine the effects of compaction, delayed sealing and aerobic exposure after ensiling on maize silage quality and on formation of volatile organic compounds. Whole‐crop maize (277 g/kg dry matter [DM]) in 120‐L plastic silos was compacted at either high or low density, and sealed immediately or with delay at 2 days or 4 days post‐filling (six replicates each). After ensiling for at least 175 days, the silages were exposed to air for 6‐day intervals and sampled at 2‐day intervals. A delay in sealing caused an increase in yeast counts and a decline of up to 65% in water‐soluble carbohydrates before ensiling. Sealing the silos after 4 days caused DM losses of up to 11%. Delayed sealing promoted the formation of ethyl esters at silo opening. A 4‐day delay in sealing resulted in the lowest aerobic stability. Aerobic exposure led to considerable changes in silage composition, a loss in feed value and, finally, spoilage. This study indicates that maize silage quality is adversely affected by low compaction, delayed sealing and aerobic exposure.

Effect of compaction, delayed sealing and aerobic exposure on forage choice and short‐term intake of maize silage by goats

“…Silage subsamples (50 g) were used to analyse the fermentation pattern which is described in detail in Brüning et al. (). Briefly, the following procedures and measurements were conducted: cold‐water extracts were prepared by blending the frozen samples with 200 ml distilled water and 1 ml toluene and refrigerated overnight (4°C) afterwards filtered (Minisart RC, 0.45 μm pore size, Sartorius, Göttingen, Germany).…”

“…For consideration of possible variance heterogeneity, two different approaches were evaluated as described by Brüning et al. (). ANOVA was performed with the SAS MIXED procedure using the restricted maximum‐likelihood algorithm (Schabenberger & Pierce, ).…”

“…After chopping, fresh forage is very susceptible to aerobic deterioration, if not filled in silo, packed and sealed immediately. Poor management decisions, such as leaving the chopped and filled forage unsealed, can result in prolonged air exposure up to several days, which affects both the ensiling process and the quality of silage during storage and feeding (Brüning, Gerlach, Weiss, & Südekum, ; Mills & Kung, ). Uriarte‐Archundia, Bolsen, and Brent () showed that maize silage sealed with a 48‐hr delay was 2 days less stable on air after opening than immediately sealed silage.…”

“…Recently, Brüning et al. () determined the effects of compaction, delayed sealing and aerobic exposure on maize silage quality and on formation of VOC. The three factors were selected to promote or prevent ingress of air (oxygen) into the silo to produce different silage qualities.…”

Ensiling in 2050: Some challenges and opportunities

“…In developed countries, nitrogen oxide (NO x ) emissions from fertilizer and manure accounted for 27% of GHG emissions and CO 2 from all farm sources accounted for 21% of GHG emissions. Weiss, Kroschewski, and Auerbach (2016) and Brüning, Gerlach, Weiss, and Südekum (2018) found that elevated concentrations of VOC were associated with delayed silo sealing which was accompanied by increased ethanol and yeast counts. Differences in methods of crop storage did not appear to be specifically addressed in that analysis.…”