Dynamics of gas formation during ensilage

The formation of a whole spectrum of gasses, which is undesirable occurs during ensiling process. The formation of gasses is undesirable, because it is often a sign of undesirable processes in silages, and causes concern about the impact on the global environment. Formation of CO2 is the most abundant. Besides CO2, the formation of toxic N oxides also occurs during ensiling. Since silage additive addition affects the fermentation pattern, the aim of the study was to monitor the formation of various gasses from silages treated with different silage additives. A grass ley (70% timothy) was harvested on August 24th 2013, nearby Helsingborg. Bacterial inoculant (E. faecium, L. plantarum, L. buchneri) at the rate of 250000 cfu/g FF, and silage additive Safesil at the rate of 3 L/ton FF were compared with untreated control. Gasses collected in bags were analysed for N2, H2, O2, CO, CH4 by gas chromatographaphy. CO2, NO, and NO2 were absorbed in water and analysed using ion chromatography. Standard analyses to determine silage quality were performed after ensiling period. Silages treated with bacterial inoculant had significantly higher pH, propionic acid, acetic acid, and ethanol contents but lower concentration of lactic acid than other silage treatments. Control and bacterially inoculated silages produced more gas than Safesil treated silages, mainly due to an increased proportion of CO2. The formation of NOx gases displayed no significant differences among other treatments

The effect of nitrate content in forage on quality of silage fermentation

Nitrate content in fresh herbage is one of the factors affecting fermentation in silage. Hein (1970) observed that ensiling of forages with low nitrate content often results in silages with high butyric acid contents. Butyric acid is an undesirable product of clostridia in silages indicating low silage nutritional quality (Pahlow et al., 2003). The effect of nitrate on butyric acid formation is derived from its degradation products. Nitrate undergoes reduction to nitrite which can be further converted to nitric oxide which is considered to be toxic for clostridia (Spoelstra, 1983). Therefore, crops high in nitrate decreases clostridial activity and, hence, butyric acid formation. The effect of nitrate content in fresh crops on butyric acid formation was summarized by Weissbach (1996). The summary shows high occurrence (78%) of butyric acid in silages made from crops low (1 g NO3 per kg DM was only 26%. Since it is common to use silage additives to improve or secure a proper ensiling process, it is interesting to study how different nitrate contents in fresh crops influence efficiency of silage additives. The objective of the study was, therefore, to study the effect of nitrite containing silage additives on silage quality with crops differing in nitrate content

Leys from a Nordic perspective

The project involved creating a popular scientific review of the cultivation and use of leys for livestock. Target groups are the agricultural sector and industry. The project had four work packages (WP): crop production, harvest and conservation, feed value for different animals, and economy. Within each work package, search strings were developed and inclusion criteria defined, and a database for each WP developed through searching in online databases. Each selected article was assessed first on the title (include or exclude), second based on reading the abstract, and third based on reading the article. The review provides an extensive list of literature related to ley production and use, a description of the most important findings, and suggestions for future research

Possibilities to improve silage conservation

The objective of this thesis was to investigate factors to improve the silage quality of different types of forage crops. The focus was on the influence of crop maturity, silage additives and laceration on the quality of whole-crop cereals silages. The ensilability of whole-crop cereals was highly dependent upon the stage of maturity. An important factor related to the stage of maturity and influencing the ensilability of whole-crop cereals seems to be the concentration of WSC in the fresh forage. Ensiling at the milk stage was found to be a more suitable time to harvest whole-crop cereals since there is a sufficient concentration of water soluble carbohydrates (WSC) that provides the conditions for lactic acid bacteria (LAB) to rapidly dominate the silage microflora and produce enough acids to reduce pH thereby giving a better protection of the silage against the spoilage microflora. The low WSC concentration of whole-crop cereals at dough stage seems to restrain good fermentation. However, silages harvested at the milk stage still appear to have a low aerobic stability. Precision chopping had variable affects on silage fermentation and showed that laceration is not a guarantee of a good silage quality of whole-crop cereals. At the milk stage, precision chopping improved the silage fermentation, whereas the dough-stage silages tended to give clostridial fermentation resulting in poor quality and high DM losses. Precision chopping promoted a higher silage density at the milk stage and resulted in reduced DM losses at the dough stage. Application of silage additives was the most important factor in improving silage quality. A mixture of sodium benzoate, sodium propionate, hexamine and sodium nitrite seems to be the most suitable additive to secure the silage quality and improve the aerobic stability in whole-crop cereals as well as in moderate and highly -wilted clover-grass forages. No remaining toxic residues of the nitrite concentration were found in the silages. A similar influence on the ensiling process is found when using the combination of sodium benzoate, sodium propionate and propionic acid. The results of mixtures of formic acid and propionic acid were closely related to the chop length of the forage. These additive combinations seem to improve the silage quality and storage stability in precision-chopped silages at both maturities, while the quality of long-cut treated silages often appeared to be low. The variable efficiency of inoculation of whole crop cereals with LAB seems to be associated with types and numbers of epiphytic bacteria in the herbage. The inoculation of homofermentative LAB successfully reduced pH of both precision-chopped and long cut-silages but abundant production of lactic acid did not secure the aerobic stability of thes

Ensilering i slang

Slutsatser · Trots en låg TS-halt (23-28%), avsaknaden av ensileringsmedel och flera uppehåll under inläggningen var gräsensilaget av bra hygienisk kvalitet både i Winlin- och i AgBag-slangen: Inga spår av klostridieaktivitet (dvs. lågt A-tal och låg smörsyrahalt) och inga kvalitetsskillnader mellan slangarna. · Snitt- och hackvagnen producerade trots olika hackelselängd och mekanisk bearbetningsgrad ensilage av lika hög kvalitet (inga skillnader). Det berodde troligtvis på att rotorn i packarna utövar en kraftig krossningseffekt på växtmaterialet. Det gynnar en snabb mjölksyrajäsning och maskerar hack- och snittvagnarnas svagare krossningseffekt. De flesta praktiker föredrar dock exakthackat framför snittat foder. · Den genomsnittliga densiteten i slangarna var något högre i Winlin- än i AgBag-slangen (169 kgTS/m3 resp. 153 kgTS/m3). Variationen inom slangarna var stor (SD = 60 resp. 52 kgTS/m3). Den högre densiteten i Winlin-slangen berodde på endast en slangsektion med hög densitet. Att dessa densitetsskillnader inte påverkade ensilagekvaliteten mer kan bero på att slangar (utan hål) troligtvis är mer gastäta än andra typer av silor. · Vi hittade inget bra samband mellan packarens vajerspänning och ensilagets densitet. Sannolikt kan man inte förvänta sig att få olika densiteter inom en och samma slang. Det är troligt att innehållet i slangen kan glida inom plasthöljet när man varierar vajerspänningen. Därmed utjämnas eventuella densitetsskillnader mellan olika slangsektioner. · Under de testade förhållanden hade Pöttingers Jumbo snittvagn en kapacitet som var 1,6 gånger Taarups hackvagn

Different experimental designs in testing of silage additives

Quality of silage fermentation and consequent aerobic stability of silages is still a common problem of many types of silage. Experimental testing of silage additives is commonly conducted under routine ensiling condition with properly consolidated forages and airtight silos. Consequently, it is not surprising that results of these trials do often not display a potential of a product in the agricultural practice. Punctures and other damages of silo cover as well as uneven forage consolidation in a silo are common. These defects make ensiling conditions more difficult and challenge a silage additive to fulfil its purpose. It has been observed that silos which were not tight under the fermentation process are more prone to be aerobically unstable (Jonsson & Pahlow, 1984). Based on this observation, a German system for evaluation effects of silage additives (DLG, 2009) applies a design where silage additives are tested under difficult ensiling condition by two times of air ingress into a mini-silo for 8-12 hours combined with a very low packing density. This condition, however, does not properly reflect silo un-tightness. It is more common that a silo is exposed to a weak but constant air ingress. This condition is more closely reflected by a design with a 2-hours weekly air ingress used by Pauly and Hjelm (2015) in testing efficiency of silage additives on conservation of crimped maize. Therefore, the objective of this study was to compare the impact of ensiling challenged by weekly aeration in a silage additive test to improve forage conservation

A note on sample preparation in the analysis of nitrate and nitrite in forage

Nitrate content in forage is of interest as it pose a risk of poisoning for ruminants at levels above 1000 mg NO3-N per kg DM (Strickland et al, 1995; Undersander et al, 1999). Analysing nitrate in forages by colorimetric methods have been questioned during decades due to interference of coloured substances in the forage (Wiseman & Jacobson, 1962; Wegner, 1972; Anderson & Case, 1999). Nevertheless, the colorimetric method using flow injection analysis (FIA) with a Cu-Cd reduction column has become a standard method in analysing nitrite and nitrate after reduction to nitrite (MacKown & Weik, 2004). The problem of diverging results in nitrate analysis has often appeared as a result of different nitrate extraction techniques, as opposed to differences due to detection methods after extraction (Anderson & Case, 1999). The sample preparation and analytical method in use at the departments of Soil and Environment, Crop Production Ecology and Animal Nutrition and Management at the Swedish University of Agricultural Science has been water extraction of dried samples followed by the nitrite and nitrate analysis according to the ISO method 13395;1996. As nitrate, and in particular nitrite, are unstable compounds, doubts have been raised concerning the influence of the sample preparation step. The present study was made with the aim to compare result of nitrite and nitrate analyses of dried or un-dried samples and extraction with boiling water or room tempered water