Chemical and microbiological changes occurring during aerobic exposure of maize silages and their influence on dry matter (DM) intake and preference by goats were evaluated. Eight maize silages differing in DM content, chopping length and compaction pressure were used for the study. After opening, silages were exposed to air for 8 days (d). In 2-d intervals, silage was stored anaerobically for use in preference trials. During the experimental phase, each possible two-way combination of the five silages (d0, d2, d4, d6 and d8) and one standard lucerne hay, was offered as free choice to six goats. Generally, a significant decline occurred in DM intake after 4 d of aerobic exposure. After 8 d, mean decrease in intake was 53% in comparison to the fresh silages. Preference when expressed as DM intake was negatively correlated to silage temperature (as difference to ambient), ethanol and ethyl lactate.

Ensiling conditions strongly influence fermentation characteristics, yeast count, and aerobic stability. Numerous volatile organic compounds including esters are produced, which may negatively affect feed intake and animal performance and air quality. In addition to a farm survey, 3 laboratory experiments were carried out to study the effects of air (by delayed sealing or by air infiltration during anaerobic storage), temperature (20 and 35°C), and various types of additives [blends of either sodium benzoate and sodium propionate (SBSP) or of sodium benzoate and potassium sorbate (SBPS); buffered mixture of formic and propionic acids (FAPA); homofermentative inoculant (LAB)]. After additive treatment, chopped whole corn plants were packed into 1.5-L glass jars and stored for several months. For treatments with air infiltration, glass jars with holes in the lid and body were used. The farm survey in 2009 revealed large variation in lactate, acetate, ethanol, n-propanol, and 1,2-propanediol concentrations. Whereas ethyl esters were detected in all silages, the mean ethyl lactate concentrations were higher than those for ethyl acetate (474 vs. 38mg/kg of dry matter). In the ensiling experiments, few unequivocal effects of the tested factors on the analyzed parameters were observed due to many interactions. Delayed ensiling without additives decreased lactic acid production but, in one trial, increased acetic acid and had no effect on ethanol. The effect of delayed sealing on yeast counts and aerobic stability differed widely among experiments. Air infiltration during fermentation tested in one trial did not alter lactic acid production, but resulted in more acetic acid in delayed and more ethanol than in promptly sealed untreated silages. Greater ethanol production was associated with increased yeast numbers. Storage at high temperature resulted in lower lactic acid and n-propanol, and a trend toward reduced ethanol production was observed. The additive FAPA consistently caused increased ethanol and reduced n-propanol levels with no effect on yeast counts and aerobic stability. When the additives SBSP and SBPS decreased n-propanol and ethanol, reduced yeast counts were also found. Ethyl ester formation was strongly correlated with those of ethanol and to a lesser degree with those of the respective acid.

The inheritance of important aroma compounds is demonstrated by the use of a model population of Fragaria · ananassa. Two cultivars were chosen for the crossing, ÔMieze SchindlerÕ and ÔElsantaÕ, which differ strongly in pedigree, phenotype, and fruit traits, including flavour. Two hundred seedlings of this cross-combination were randomly selected from a population of 438 seedlings and propagated, with three plants per seedling. Aroma analysis was performed by automated headspace solid phase micro-extraction in combination with non-targeted data analysis (pattern recognition). This method can assist breeding programmes by the preparation and analysis of hundreds of samples by a simple procedure. The method was backed up by the substance identification using gas chromatography/mass spectrometry. Data processing of 78 detectable volatile compounds by Chromstat TM in the F 1 population showed very high variability of the volatile patterns. The ester methyl anthranilate (MA) is a discriminative key compound, being present only in the mother cultivar ÔMieze SchindlerÕ, and not detectable in ÔElsantaÕ. Methyl anthranilate was detectable in one fourth of the F 1 population. This low degree of inheritance shows that this important compound is easily lost in the breeding process, which could explain why all investigated modern cultivars do not contain MA. The results are valuable for the choice of breeding partners and for selection in seedling populations.

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.

No abstract