Fermentation Of Grass Silage Research Articles

Fermentation profile and chemical composition of Mombasa grass silage treated with chitosan and microbial inoculant

Context The ensiling process presents losses that are associated with the fermentative profile, resulting in lower nutritional value, and lower aerobic stability of silages. Aims This study aimed to evaluate the effects of chitosan and microbial inoculants addition in Mombasa grass (Megathyrsus maximus) silage (MGS) fermentation profile and losses, chemical composition, in situ degradation, and aerobic stability. Methods Forty experimental silos (PVC tubing with 28-cm inner diameter and 25-cm height) were used in a randomised block (n = 5) design to evaluate the following treatments: (1) MGS without additives (control, CON); (2) MGS treated with 5.0 × 104 colony-forming units (CFU) of Lactobacillus buchneri (NCIM 40788) per gram of fresh matter (LBB); (3) MGS treated with 1.6 × 105 CFU of L. plantarum and 1.6 × 105 CFU of Pediococcus acidilactici per gram of fresh matter (LPP); and (4) MGS treated with 6 g/kg DM of chitosan (CHI). Key results The treatments did not alter the pH, ammonia-N, butyric, and lactic acid concentrations in the silage. The use of LPP reduced the ethanol content, while CHI increased propionic and branched-chain fatty acids compared with other treatments. Fermentation losses and dry-matter recovery were not affected by treatments. Chitosan reduced the organic matter of the MGS in relation to the other treatments, without having an impact on the other variables of chemical composition. The treatments did not influence the in vitro degradation, nor the pH and temperature after aerobic exposure of the silage. Conclusions Chitosan increases ethanol compared with homofermentative lactic acid bacteria inoculation and does not affect ammonia-N of Mombasa grass silage. In addition, chitosan and microbial inoculants have limited effects on Mombasa grass silage fermentation losses, nutritional value, and aerobic stability. Implications Chitosan does not reduce fermentation losses or improve the nutritional value of grass silage.

In Vitro Rumen Fermentation Characteristics, Estimated Utilizable Crude Protein and Metabolizable Energy Values of Grass Silages, Concentrate Feeds and Their Mixtures.

Four formulations of concentrate feeds, three contrasting qualities of grass silages, and mixtures of the silages (55%) and concentrates (45%, dry weight) were tested for in vitro fermentation kinetics, in vitro dry matter degradation (IVDMD), utilizable crude protein (uCP), and metabolizable energy (ME) values. The concentrates were pelleted control concentrate for dairy cows (CONT-P); pelleted alkaline concentrate with ammoniated cereal grains (ALKA-P); mash form concentrate with ALKA-P main ingredients but with feed-grade urea and barley replacing ammoniated cereal grain (UREA-M); and mash form of ALKA-P ingredients prior to alkalization (ALKA-M). The grass silages were early cut, late cut, and a mixture (1:1) of early and late cut. The objectives were to test if the feeds differed in the tested parameters within each feed category and assess the modulatory effect of concentrate feeds on the grass silage fermentation characteristics in the mixed diets. No interaction effects of the concentrate feeds by silage quality were observed for the tested parameters in the mixed diets. For concentrates, the pelleted diets were higher (p < 0.05) in IVDMD and molar proportion of propionate but lower in butyrate. The ALKA-P produced the highest estimated uCP (p < 0.01). For silages, uCP, ME, total short-chain fatty acids (VFAs), and molar proportions of propionate and branched-chain VFAs decreased (p < 0.05) with increasing stage of maturity. In conclusion, the ALKA-P could match the CONT-P in uCP and ME values and fermentation characteristics. Results for silages and their mixtures with concentrates highlight the importance of silage quality in dietary energy and protein supply for ruminants.

Lemongrass essential oil reduces Mombasa grass silage gas losses, fibre content and pH after aerobic exposure

Context Ensiling is commonly used to conserve tropical grasses, but low water-soluble carbohydrates content and high moisture content in the grass impair silage fermentation characteristics. Essential oils may be used as silage additives to decrease fermentative losses and improve the nutritional value of silage, and aerobic stability, and in vitro DM disappearance. Aims The present study aimed to evaluate the effect of including lemongrass essential oil (LEO) on the fermentative characteristics, fermentative losses, chemical composition, in vitro disappearance and aerobic stability of Mombasa grass (Megathyrsus maximum) silage. Methods Mombasa grass was ensiled for 60 days in 32 experimental silos (15-L plastic buckets, 28 cm diameter and 25 cm high), in a randomly blocked design. LEO was included at 0.00, 0.67, 1.33 and 2.00 mL per kg of silage fresh matter. Silos were weighed every 15 days, pH and temperature were measured immediately after the silos were opened, and subsamples of silage were taken to measure the fermentative profile, composition of silage effluent, chemical composition and in vitro degradation of silage. Key results Increasing the amount of LEO in Mombasa grass silage caused a linear reduction in ammonia–nitrogen, ethanol (P &lt; 0.05), acid detergent fibre of silage, gas losses and silage pH after aerobic exposure. There was no impact (P &gt; 0.05) on organic acid concentration, effluent production or DM recovery (P &gt; 0.05). Conclusions (Tilley and Terry 1963) Adding LEO to Mombasa grass silage at up to 2.00 mL per kg fresh material (almost 7.5 mL/kg DM) reduces gas losses, ammonia–nitrogen and acid-detergent fibre concentration, and silage pH after aerobic exposure. However, it is not sufficient to improve DM recovery and in vitro disappearance of silage. Implications Lemongrass essential oil shows a positive effect on Mombasa grass silage fermentation, fibre content and silage parameters after aerobic exposure, providing a useful additive in this silage.

Effect of the ionophore monensin and tannin extracts supplemented to grass silage on populations of ruminal cellulolytics and methanogens in vitro

This study examined whether the methane-decreasing effect of monensin (∼21%) and different hydrolysable tannins (24%–65%) during in vitro fermentation of grass silage was accompanied by changes in abundances of cellulolytics and methanogens. Samples of liquid (LAM) and solid (SAM) associated microbes were obtained from two rumen simulation technique experiments in which grass silage was either tested in combination with monensin (0, 2 or 4 mg d−1) or with different tannin extracts from chestnut, valonea, sumac and grape seed (0 or 1.5 g d−1). Total prokaryotes were quantified by 4′,6-diamidino-2-phenylindol (DAPI) staining of paraformaldehyde-ethanol-fixed cells and relative abundances of ruminal cellulolytic and methanogenic species were assessed by real time quantitative PCR. Results revealed no change in absolute numbers of prokaryotic cells with monensin treatment, neither in LAM nor in SAM. By contrast, supplementation of chestnut and grape seed tannins decreased total prokaryotic counts compared to control. However, relative abundances of total methanogens did not differ between tannin treatments. Thus, the decreased methane production by 65% and 24% observed for chestnut and grape seed tannins, respectively, may have been caused by a lower total number of methanogens, but methane production seemed to be also dependent on changes in the microbial community composition. While the relative abundance of F. succinogenes decreased with monensin addition, chestnut and valonea tannins inhibited R. albus. Moreover, a decline in relative abundances of Methanobrevibacter sp., especially M. ruminantium, and Methanosphaera stadtmanae was shown with supplementation of monensin or chestnut tannins. Proportions of Methanomicrobium mobile were decreased by monensin in LAM while chestnut and valonea had an increasing effect on this methanogenic species. Our results demonstrate a different impact of monensin and tannins on ruminal cellulolytics and gave indication that methane decrease by monensin and chestnut tannins was associated with decreased abundances of M. ruminantium and M. stadtmanae.

Silage preparation and fermentation quality of natural grasses treated with lactic acid bacteria and cellulase in meadow steppe and typical steppe.

ObjectiveIn order to improve fermentation quality of natural grasses, their silage preparation and fermentation quality in meadow steppe (MS) and typical steppe (TS) were studied.MethodsThe small-scale silages and round bale silages of mixed natural grasses in both steppes were prepared using the commercial lactic acid bacteria (LAB) inoculants Chikuso-1 (CH, Lactobacillus plantarum) and cellulase enzyme (AC, Acremonium cellulase) as additives.ResultsMS and TS contained 33 and 9 species of natural grasses, respectively. Stipa baicalensis in MS and Stipa grandi in TS were the dominant grasses with the highest dry matter (DM) yield. The crude protein (CP), neutral detergent fiber and water-soluble carbohydrate of the mixed natural grasses in both steppes were 8.02% to 9.03%, 66.75% to 69.47%, and 2.02% to 2.20% on a DM basis, respectively. All silages treated with LAB and cellulase were well preserved with lower pH, butyric acid and ammonia-N content, and higher lactic acid and CP content than those of control in four kinds of silages. Compared with CH- or AC-treated silages, the CH+ AC-treated silages had higher lactic acid content.ConclusionThe results confirmed that combination with LAB and cellulase may result in beneficial effects by improving the natural grass silage fermentation in both grasslands.

Biogas from grass silage – Measurements and modeling with ADM1

Mono fermentation of grass silage without the addition of manure was performed over a period of 345 days under mesophilic conditions (38 °C). A simulation study based on the IWA Anaerobic Digestion Model No. 1 (ADM1) was done in order to show its applicability to lignocellulosic biomass. Therefore, the influent was fractioned by established fodder analysis (Weender analysis and van Soest method). ADM1 was modified with a separate compound of inert decay products similar to the approach of Activated Sludge Model No. 1 (ASM1). Furthermore, a function, which described the influence of solids on the process of hydrolysis, has been integrated to reproduce reliable ammonium concentrations. The model was calibrated by using the modified Nash–Sutcliffe coefficient to evaluate simulation quality. It was possible to fit observed data by changing only hydrogen inhibition constants and the maximum acetate uptake rate. The extended ADM1 model showed good agreement with measurements and was suitable for modeling anaerobic digestion of grass silage.

Assessing the impact of various ensilage factors on the fermentation of grass silage using conventional culture and bacterial community analysis techniques

Grass silage is an important ruminant feedstuff on farms during winter. The ensilage of grass involves a natural lactic acid bacterial fermentation under anaerobic conditions, and numerous factors can influence the outcome of preservation. The aim of this study was to investigate the effect of dry matter concentration, ensiling system, compaction and air infiltration on silage bacterial community composition. The impact of these factors was examined using conventional methods of microbial analysis and culture-independent Terminal Restriction Fragment Length Polymorphism (T-RFLP). Silage fermentation was restricted in herbage with a high dry matter concentration, and this was reflected in a shift in the bacterial population present. In contrast, ensiling system had little effect on bacterial community composition. Air infiltration, in the absence of compaction, altered silage bacterial community composition and silage pH. Dry matter concentration and the absence of compaction were the main factors affecting silage microbial community composition, and this was reflected in both the conventional culture-based and T-RFLP data. T-RFLP proved a useful tool to study the factors affecting ensilage. Apart from monitoring the presence or absence of members of the population, shifts in the relative presence of members could be monitored.

Mono fermentation of grass silage by means of loop reactors

A loop reactor was operated for mono fermentation of grass silage without manure addition under mesophilic conditions (38 °C). An averaged specific biogas production of 0.50 m N 3 per kg volatile solids (VS) with a methane concentration of 52% at an organic loading rate of up to 3.5 kg VS/(m 3 d) was obtained. The retention time varied from 440 days at 1.0 kg VS/(m 3 d) to 50 days at 3.5 kg VS/(m 3 d). The degradation level was more than 60% based on VS and 75% based on COD. The first-order hydrolysis rate constant of the process was estimated to be 0.6 d −1. Despite the relative high ammonium concentration of up to 4 g/l, the system worked stable for an operation period of 310 days. In particular the TS content in the fermenter was found to be a key parameter and should not exceed 12% in order to avoid instabilities.

Interference of indirect gas produced by grass silage fermentation acids in an in vitro gas production technique

Volatile fatty acids (VFA) resulting from rumen fermentation are measured in in vitro gas production techniques (IVGPT) by including bicarbonate in the incubation medium and measuring indirect gas produced. During ensiling, anaerobic fermentation of plant organic matter also produces VFA, along with lactic acid. The aim of this study was to establish whether silage fermentation acids (SFA) affected gas production profiles and subsequent carbohydrate parameter estimations of fresh and dried grass silage. Results indicate that a substantial volume of SFA gas is produced by fermentation of both fresh and dried grass silage. SFA gas production reaches an asymptote at 30 min post-inoculation and is 81% higher in fresh versus dried grass silage ( P<0.001). Cumulative gas productions were fitted to the model: gas = A(1 − exp(− c a t)) + B(1 − exp(− c b( t − l))) × exp(5( t − l))/(1 + exp(5( t − l))), where ‘ A’ is the asymptotic gas production (ml) from fermentation of quickly degraded carbohydrate (QCHO), ‘ c a’ the fractional rate of gas production of A (fixed at >0.2 h −1), ‘ B’ the asymptotic gas production (ml) from fermentation of slowly degraded carbohydrate (SCHO), ‘ c b’ the fractional rate of gas production of B (h −1), ‘ t’ time (h) of fermentation and ‘ l’ is the discrete time lag (h) before fermentation of SCHO begins. Results indicate that failure to correct for SFA gas resulted in overestimation of A, l and total rumen degraded carbohydrate ( P<0.001), as well as underestimation of B ( P<0.001) and c b ( P<0.05). Multiple linear regression equations were developed to predict SFA gas volume produced by fresh grass silage at 30 min of incubation ( R 2 = 0.91, SEE = 0.62) and to predict the proportion of gas produced in the first 30 min of IVGPT that was derived from SFA for fresh grass silage ( R 2 = 0.95, SEE = 0.046) and dried grass silage ( R 2 = 0.71, SEE = 0.125).

Influence of grass silage fermentation and concentrate composition on the appearance and sensory characteristics of bovine M. longissimus dorsi

Satisfying consumer preferences is an important element in ensuring the sustainability of the beef industry. An array of feed ingredients are available to beef producers but the effects of pre-slaughter ration composition on determinants of consumers’ decisions to purchase beef, such as appearance and sensory characteristics, are unclear. Previous research has shown that the diet of cattle can influence fat colour, but that concentrates per se had little effect on sensory attributes of beef when compared with a grass silage or grass-based ration (French et al., 2000). The objective of the current study was to examine the effect of silage fermentation and concentrate composition on the appearance and eating quality characteristics of beef.

The effect of slurry application timing on grass silage fermentation and intake by dairy cattle

Many farmers apply slurry to grassland as a fertiliser or a means of waste disposal. There is evidence that winter slurry application leads to higher losses of nitrogen due to leaching subsequently reducing the efficiency of slurry N utilisation when compared with spring applications (Smith et al 1995). This suggests that slurry applications should be undertaken in spring, but the effect of timing on the extent of grass contamination is unknown. When grassland is used for silage production, contamination of the sward can lead to reduced silage fermentation and acceptability (Boxem and Remmelink 1987). A study was conducted to investigate the effect of timing of slurry application on fermentation and dry matter intake of first and second cut grass silage.

Effect of ethanol in feed on milk flavor and chemical composition.

A crossover study was performed using 24 dairy cows to investigate whether pure ethanol in concentrations that could be found in well-fermented silages influenced milk composition or flavor. Cows were fed a standard ration of well-fermented grass silage for ad libitum intake and high moisture barley and a protein concentrate in restricted amounts. A daily dose of ethanol (600 g) was divided into three meals/d and fed with grass silage. When cows received ethanol, milk yields decreased slightly, but milk fat and protein concentrations increased so that energy-corrected milk yield increased by 0.9 kg/d. Milk concentrations of lactose and urea decreased, concentrations of ethanol and acetone increased, concentrations of free fatty acids increased slightly, and alpha-tocopherol concentrations were unaffected. The proportion of palmitic acid in milk fat increased, and the proportion of unsaturated acids decreased. Organoleptic milk quality was reduced because of an increase in milk tainted by feed flavors. The off-flavor could not be attributed solely to the ethanol transmitted to the milk. Precautions should be taken to avoid extensive production of ethanol during fermentation of grass silage and other feeds that are to be fed to dairy cows.

Effects of Mechanical Forage Treatment and Surfactants on Fermentation of Grass Silage

Three silage experiments were conducted in Uppsala, Sweden, with the objective of determining the physical impact of different harvesting machines on the forage and on silage fermentation. Experiments were also conducted to investigate whether the application of water or a solution of surfactants to cut or long grass could compensate for the lack of released cell contents and lead to a fermentation pattern comparable to that of precision-chopped (PC) forage. Forage chopped by different machines to almost equal median particle length (23-29 mm) produced silage of very different quality, probably because of different degrees of tissue disruption. Forage chopped in a cutter head (CUT) or by a forage wagon (FW) resulted in silage with high clostridial activity and low lactic acid formation in contrast to PC forage, which produced high quality silage without butyric acid. An increase in silage density from 107 to 182 kgDM m-3

Effect of Forage Harvester on Grass Silage Fermentation, Digestibility and Animal Performance

Data from 21 experiments, conducted at ADAS Research Centres during 1971–1991, were used to compare grass silage harvested with either a flail-harvester, forage-wagon, double-chop or precision-chop harvester. In 15 of the experiments, formic acid was applied at 2·7, 3·1, 2·1 and 2·1 l/t, respectively. The silages were made from herbage with an average dry matter of 210 g/kg and water-soluble carbohydrate of 25 g/kg. Criteria have previously been established for seven chemical analyses that can be used to indicate whether or not silages are well fermented. Only two of these (pH and lactic acid) out of the seven were actually met with the precision-chop harvester and only one (acetic acid) was met by the flail-harvester and forage-wagon. None was satisfied by the double-chop machine, despite the fact that more formic acid was applied to the flail-harvester and particularly forage-wagon-made silages. The forage-wagon-made silage also suffered from soil contamination. When given to young cattle, precision-chop harvested silage resulted in the highest silage DM intake, liveweight gain and best feed conversion efficiency. Silage, made with a forage-wagon had a very low silage DM intake and liveweight gain, despite the fact that the amount of barley fed was twice as high as in the other treatments. With flail and double-chop harvested silage, both silage and total DM intake were similar. Nevertheless, liveweight gain was higher with the latter treatment. With dairy cows, the type of harvester used to make silage had no significant effect upon milk production, except that silage DM intake tended to be higher with the precision-chop harvested silage, whereas liveweight loss was significantly less with the flail harvested silage.

The Effect of Formic Acid with Formalin on Grass Silage Fermentation and the Performance of Dairy Cows

In the first experiment, perennial ryegrass with dry matter (DM) 260 g/kg and water-soluble carbohydrate (WSC) 140 g/kg DM was harvested as first-cut material on 25 May 1982. It was pre-wilted for 24 h prior to ensilage and treated with either a formic acid with formalin additive (WFF) at 4l/t or no additive (W) and ensiled in two adjoining covered 150 t bunker silos. Subsequently, both silages were satisfactorily fermented. Nevertheless, the pH, ammonia–N g/kg N and lactic-acid content were significantly lower and the residual WSC content significantly higher for WFF than W. Each silage was subsequently individually fed to ten Friesian and ten Holstein dairy cows, together with 10 kg/d of a compound feed containing 160 g/kg crude protein in a 70 d feeding trial. Additive treatment had no significant effect upon silage DM intake, milk output or composition. However, the daily liveweight losses of cows given WFF-treated silage were significantly higher than those given W. In the second experiment, perennial ryegrass (DM 180 g/kg and WSC 170–200 g/kg DM) harvested as first-cut material on 2 June 1983, was either cut and picked up within 20 min of cutting and treated with either the formic acid with formalin additive at 4l/t (NWFF) or no additive (NW); or wilted for a maximum of 24 h and treated with either the formic acid with formalin additive at 4l/t (WFF) or no additive (W). Wilting significantly increased subsequent silage DM. The pH of NW was significantly less than W, whilst the ammonia–N g/kg N of NWFF was significantly less than NW and W and that of W significantly higher than the other treatments. Additive treatment significantly increased the residual WSC content. Each silage was subsequently individually feed to 12 Friesian and 12 Holstein dairy cows together with 10 kg/d of a compound feed to 12 Friesian and 12 Holstein dairy cows together with 10 kg/d of a compound feed containing 160 g/kg protein in a 180 d feeding trial. The silage DM intake of WFF was significantly higher than NW. Silage treatment had no significant effect upon milk output or composition. The daily liveweight loss of cows given WFF-treated silage was significantly less than the other treatments, and the cows on NW had a significantly longer calving index than the other treatments. It is concluded that compared with non-additive-treated silage, formic acid with formalin applied at ensilage produced better fermented silage which, when subsequently given to lactating dairy cows, produced no significant increase in daily silage DM intake, milk output or composition, but had small significant effects upon liveweight change.

Effect of Additives on Grass Silage Fermentation and Effluent Production, and on Intake and Liveweight Change of Young Cattle

Abstract Data from 11 experiments, conducted mainly at ADAS Liscombe Research Centre during 1989–1992, were used to compare silages made with additives which included formic acid, an acid–salt-type additive, sulphuric acid, liquid inoculant and a cultured inoculant with a non-additive-treated control. The silages were made from herbage with dry matter (DM) 170 g/kg and water-soluble carbohydrate (WSC) 21 g/kg. Compared with the non-additive-treated silage, formic-acid treatment significantly reduced silage pH, ammonia–N, acetic acid, butyric acid, total short-chain fatty acid and total acid content and significantly increased the proportion of lactic acid expressed as a proportion of the total acids. The acid–salt-type additive significantly decreased pH, lactic acid, acetic acid, total short-chain fatty acids and total acid content and significantly increased WSC. Sulphuric acid significantly reduced pH and ammonia-N. The liquid inoculant had no significant effect upon any silage fermentation parameters, and the cultured inoculant significantly reduced pH and acetic acid and significantly increased the proportion of lactic acid expressed as a proportion of total acids. Effluent production was higher with acid treament, but the effect was not significant. The effluent from the acid–salt-type additive-treated silage had a significantly higher DM and WSC than the other treatments. The silage DM intakes of the formic acid (5·36 kg/d), sulphuric acid (5·29 kg/d) and the acid–salt-type additive (5·20 kg/d) were significantly higher than those of the untreated silage (4·76 kg/d), and the daily live-weight gains given by the acid–salt-type additive (0·71 kg/d) and formic acid (0·68 kg/d) treated silages were significantly higher than those of the untreated silage (0·58 kg/d). It is suggested that the improvements in silage preservation obtained from additive use at ensilage were closely reflected in terms of animal performance. The acid– salt-type additive and formic-acid treatments were most effective, the liquid inoculant and sulphuric acid inter mediate between the acid–salt-type additive or formic acid and untreated silage, whilst the cultured inoculant was similar to untreated silage.

The effect of an acid salt‐type additive on the fermentation of grass silages made in bunker silos on commercial dairy farms in Wales

AbstractThe fermentation characteristics and chemical composition of 57 first‐cut and 30 second‐cut samples of grass silages, made in bunker silos on commercial dairy farms in Wales in 1990, and treated with a nominal 61 t−1 of an acid salt‐type additive at ensilage, is described. Typical chemical composition of grass cut for ensilage was 156 g kg−1 dry matter (DM) and 28 g kg−1 water soluble carbohydrate (WSC), with 181 g (kg DM) −1 crude protein (CP) and 232 g (kg DM) −1 modified acid detergent fibre (MADF). The effect of additive use was to produce silages with DM 230 g kg−1 pH 3·93, ammonia N 70 g kg−1 total N, with residual WSC 35 g (kg DM) −1, lactic acid 83 g (kg DM) −1, total acids 118 g (kg DM) −1 and butyric acid 0·7 g (kg DM) −1. No significant differences were found between first‐ and second‐cut silages. Silage fermentation was restricted (i.e. lactic acid less than 60 g kg DM−1) in only 20% of the samples.It is suggested that on commercial farms the application rate achieved may be insufficient to produce a restricted fermentation.

Effect of herbage water‐soluble carbohydrate content and weather conditions at ensilage on the fermentation of grass silages made on commercial farms

AbstractA total of 1009 samples of silage made in bunker silos on commercial farms between 1972 and 1978 was analysed to investigate the effect of herbage water‐soluble carbohydrate content (WSC) and weather conditions at ensilage on fermentation as measured by ammonia‐N concentration and pH of first‐cut grass silages.Silage dry matter (DM) content had the major effect on fermentation. Factors influencing silage DM were rainfall and hours of sunshine during silage making, and DM content of the grass cut. WSC content of herbage ensiled also had a significant effect on subsequent fermentation. The major influences on herbage WSC were hours of sunshine and rainfall during the growing season.The effect of chemical additives, albeit at poorly defined and often inadequate rates, was small in comparison to that of silage DM.The minimum DM necessary to produce well‐fermented silage without additive was approximately 260 g kg−1. Use of formic acid significantly reduced this requirement to 240 g kg−1 and to 252 g kg−1 for sulphuric add + formalin. The results indicate that the minimum herbage WSC necessary to prevent a clostridial fermentation developing in silage with a DM content of 230 g kg−1 is approximately 37 g kg−1 without additive and 30 g kg−1 with formic acid.It is concluded that on commercial farms, weather conditions i.e. amount of rainfall and sunshine prior to and at ensilage, have a greater effect on subsequent silage fermentation than additive use.