A meta‐analysis comparing standard polyethylene and oxygen barrier film in terms of losses during storage and aerobic stability of silage

A meta‐analysis was undertaken of 51 comparisons of standard polyethylene film with oxygen barrier (OB) film in covering systems for bunker silos, unwalled clamp silos and bales. Mean losses of DM or OM during storage from the top 10 to 60 cm of bunker and clamp silos were 195 g kg^?1 for standard film and 114 g kg^?1 for OB film systems (41 sets of data, P < 0·001), while mean total losses of DM from baled silage were 76·8 g kg^?1 for standard film and 45·6 g kg^?1 for OB film systems (10 sets of data, P < 0·001). Top surface silage judged subjectively to be inedible was 107 and 29·6 g kg^?1 for standard film and OB film systems respectively (5 sets of data, P = 0·02). Aerobic stability was 75 h for silage stored under standard film system and 135 h for silage stored under OB film system (11 sets of data, P = 0·001). It is concluded that the OB film system reduces losses from the outer layers of silos and from bales and increases the aerobic stability of silage in the outer layers of silos.     

Effect of type of underlay film on fermentation profile,nutritional quality and estimated loss of organic matter in the outer layer of whole‐plant maize ensiled in large bunker silos

Losses of organic matter in the outer layers of bunker silos covered with conventional polyethylene (PE) plastic can be substantial due to oxygen transmission through the plastic top‐covering film during the post‐ensiling storage period. The effect of two silo covering materials, oxygen barrier (OB) film (45 μm thickness) and clear PE film (50 μm thickness), as underlays to a white‐on‐black PE plastic top cover (120 μm thickness), was assessed in the outer layer of whole‐plant maize silage stored in three large bunker silos in the People's Republic of China. Samples of the crop at harvest and of silage from the upper 45 cm layer at 5 months post‐ensiling, prior to removal of silage for feed‐out, were analysed for DM, fermentation profile and chemical composition. Loss of OM was estimated from concentrations of ash in the crop at harvest and in the silage. Differences between underlay films in silage fermentation profile were small. Silage protected with OB underlay film had higher mean concentration of starch (p < .008) and higher mean NDF digestibility (p < .003) than silage under PE underlay film. Concentrations of ash were lower (p < .001) for silage covered with OB film than for PE film in all three trials. Mean estimated losses of OM were 170 g/kg for OB underlay film and 232 g/kg for PE underlay film (p < .001), and whole‐silo estimated net economic benefits to OB underlay film ranged from 0.17 to 0.74 US $ per tonne fresh crop ensiled.     

Effect of Lactobacillus buchneri 40788 on the fermentation,aerobic stability and nutritive value of maize silage

The effect of adding Lactobacillus buchneri 40788, a heterofermentative lactobacilli, to whole‐plant maize and its effect on fermentation and aerobic stability of the resulting silage were evaluated. Whole‐plant maize (380 g DM kg^–1 fresh weight) was ensiled in laboratory silos after the following treatments: untreated, L. buchneri 40788 at 1 × 10⁵, 2·5 × 10⁵, 5 × 10⁵, and 1 × 10⁶ colony forming units g^–1 of fresh forage or, a commercial inoculant containing homolactic acid bacteria, a single species of propionibacteria and enzymes. Addition of L. buchneri 40788 resulted in a decrease in lactic acid concentration but increased the concentration of acetic acid in silage and markedly decreased the numbers of yeasts present in the silage. All levels of L. buchneri 40788, increased the aerobic stability of silages but the effect was greatest for the two highest levels of inoculation. Treatment with the commercial inoculant had no effect on the fermentation or aerobic stability of silage. On‐farm treatment of maize silage with L. buchneri 40788, stored in a bag silo, resulted in changes in fermentation that were similar to those observed in laboratory silos. Treatment decreased the numbers of yeast in silage and increased aerobic stability (+25 h) of the silage when exposed to air. Treatment had no effect on the dry‐matter intake of silage fed to sheep. These results showed that treating silage with L. buchneri 40788 can increase the aerobic stability of maize silage in laboratory and farm silos.     

Effect of chitosan on the preservation quality of sugarcane silage

We aimed to evaluate the effects of chitosan and microbial inoculant addition to sugarcane silage fermentation, gas and effluent losses, chemical composition, in situ dry matter (DM), neutral detergent fibre (NDF) degradation and aerobic stability. A completely randomized design with four treatments (n = 40) was performed. It was arranged in a 2 × 2 factorial scheme with chitosan [0 and 6 g/kg of sugarcane DM—1.66 g/kg of natural matter (NM)] and microbial inoculant (0 and 8 mg/kg on NM). Each g of inoculant contained 3.9 × 10¹⁰ UFC/g of Pediococcus acidilactici and 3.75 × 10¹⁰ UFC/g of Propionibacterium acidicipropionici. The addition of microbial inoculant increased lactic acid concentration in silos treated with chitosan. Furthermore, chitosan increased pH and tended to increase acetic acid of silage. In contrast, the inoculant decreased pH and acetic acid, besides increasing ethanol concentration. As chitosan addition increased DM recovery, inoculant addition decreased it. Chitosan decreased NDF and acid detergent fibre (ADF) level and increased DM degradation, while inoculant decreased DM content, DM and NDF degradation. In addition, chitosan improved the aerobic stability only in non‐inoculated silos. Thus, chitosan has a positive effect on silage fermentation, reducing fermentative losses, and improving silage chemical composition and degradation. Conversely, the addition of microbial inoculant negatively affected silage DM recovery, chemical composition, and its association with chitosan decreased the aerobic stability when compared to the exclusive use of chitosan.     

Aerobic stability of sugar-cane silage inoculated with tropical strains of lactic acid bacteria

Aerobic stability is an important feature in the evaluation of silages. The aims were to investigate the chemical and microbiological changes that occur in sugar-cane (Saccharum spp.) silage after aerobic exposure, to identify the major species of yeasts associated with the aerobic deterioration process and to select lactic acid bacteria (LAB) strains that can improve the aerobic stability of this silage. Fourteen wild LAB strains belonging to Lactobacillus plantarum, L. brevis and L. hilgardii were evaluated using experimental silos. Silage samples were collected at 0, 96 and 216 h after aerobic exposure to determinate the DM, WSC, pH, products of fermentation, to evaluate the silage temperatures and to identify yeast species associated with the aerobic deterioration of silage. The strains tested were able to modify the fermentative and chemical parameters and the diversity of yeasts species of silage after aerobic exposure. There was no association between the facultative or obligatory heterofermentative fermentation patterns and the increased aerobic stability of silage. Aerobic stability of sugar-cane silages was associated with high acetic acid and 1,2-propanediol concentrations. L. hilgardii UFLA SIL51 and UFLA SIL52 strains promoted an increase in aerobic stability of silage.     

Fermentation patterns of small-bale silage and haylage produced as a feed for horses

The fermentation quality of small‐bale silage and haylage for feeding to horses in Sweden, and using a conventional high‐density hay baler, was investigated in two experiments. Treatments studied were use of additives (inoculants containing lactic acid bacteria and a chemical additive consisting of hexamethylenetetramine, sodium nitrate, sodium benzoate and sodium propionate), the influence of dry‐matter (DM) content of wilted herbage and the effect of number of stretch film layers on fermentation pattern and aerobic stability. All silages and haylages were made from predominantly Timothy swards and were well fermented as indicated by low levels of ammonia and butyric acid. Values of pH were higher and concentrations of organic acids were lower in haylages than in the silages. This was not considered to be indicative of a poor fermentation in the haylage but of a restricted fermentation due to the high DM content of the herbage. The additives enhanced aerobic storage stability because of inhibition of mould growth. The only statistically significant effect of varying the number of stretch film layers was a higher content of CO₂ inside the bales when ten layers of stretch film were applied compared with six layers.     

Effects of an indigenous and a commercial Lactobacillus buchneri strain on quality of sugar cane silage

The aim was to evaluate the effects of adding a novel Lactobacillus buchneri strain and a commercial inoculant on the fermentation and aerobic stability of sugar cane silages (Saccharum spp.). In the first experiment samples were collected from sugar cane silage at 5, 20, 40 and 80 d after ensilage in experimental silos and microorganisms belonging to the Lactobacillus genus were isolated and identified, with a wild strain of L. buchneri, UFLA SIL 72, being selected as an inoculant. In the second experiment sugar cane was inoculated with either the novel bacteria or a commercial inoculant at the moment of ensiling and compared with a control silage prepared without an inoculant. Experimental silos were opened at 0, 3, 10, 30, 60 and 90 d of ensilage and their chemical composition measured. The silages opened after 90 d were also assessed for aerobic stability. The addition of L. buchneri resulted in a higher concentration of acetic acid and reduced populations of yeasts in silage compared to the other silage treatments, and a lower ethanol concentration in the silage. The novel L. buchneri isolate and the commercial inoculant also improved aerobic stability of the sugar cane silages. It was concluded that the addition of the novel inoculants L. buchneri UFLA SIL 72 to sugar cane silage can be recommended.     

Re‐ensiling and inoculant application with Lactobacillus plantarum and Propionibacterium acidipropionici on sorghum silages

Re‐ensiling of previously ensiled forage has been a common practice in Brazil, and the use of inoculants may provide a means of reducing dry‐matter (DM) loss. This study aimed to determine the effect of re‐ensiling and the use of microbial inoculants on the quality of sorghum silage. Treatments were presence/absence of an inoculant (Lactobacillus plantarum and Propionibacterium acidipropionici) in the silage, and the re‐ensiling, or not, of the material after 24 h of exposure to air, and these were tested in a factorial 2 × 2 design. Losses due to gas, effluent and total DM were assessed, as were the fermentation characteristics, chemical composition, aerobic stability, and aerobic counts of microorganisms. Effluent loss was higher in re‐ensiled silage, and these silages had lower lactic acid content and higher levels of acetic and propionic acids. The in vitro DM digestibility was lower in the re‐ensiled sorghum silages. The re‐ensiled silage had higher aerobic stability. The inoculant only increased the acetic acid content of the silage. The re‐ensiling of sorghum silage increased effluent loss by 71·2%, and reduced DM digestibility by 5·35%. The use of inoculant did not influence the quality of sorghum silage.     

Top spoilage losses in maize silage sealed with plastic films with different permeabilities to oxygen

The quality of plastic films used for horizontal silos is important to limit losses in the upper silage layer. The aim of this work was to study the effectiveness of different plastic films in reducing the top losses in maize silage. The following treatments were evaluated: (i) coextruded polyethylene/polyamide oxygen barrier film (OB), (ii) polyethylene film (PE), (iii) polyvinyl chloride film (PVC), and (iv) coextruded PE/polyvinyl alcohol film (PVOH). These treatments differed according to oxygen permeability with values of 75, 722, 982 and 289 cm³ m^?2 per 24 hour respectively. OB and PVOH films had better temperature and fermentation profiles than the more permeable films. The OB film was effective in reducing the dry‐matter (DM) losses during storage (82 g kg^?1), and the PVOH film had an intermediate value of DM loss (101 g kg^?1). PE and PVC films had higher losses (138 and 145 g kg^?1 respectively). Oxygen permeability of the films promoted a positive correlation with DM losses (P < 0·05; r² = 0·945). The results indicate that O₂ permeability through the plastic film is a crucial factor for maintaining silage quality in the upper layer of the silo when it is perfectly sealed.     

Efficacy of adding chemical and microbial additives to silage on beef cattle performance: Systematic review and meta-analysis

The effects of different additives on farm-scale silage quality and beef cattle performance are inconsistent. This study aimed to carry out a systematic review and meta-analysis to evaluate the efficacy of chemical and microbial additives to silage on beef cattle performance. Systematic searches were performed using databases and scientific journals, and 42 articles were selected. Data for all variables were grouped into subgroups according to the additive type. For dry matter intake and average daily gain, the data were also grouped by forage type due to greater comparison numbers. The treatment mean differences and 95% confidence intervals (p < 0.05) were analysed using a random-effects model. The use of homo- and heterofermentative microbial inoculant mixtures and chemical additives (Ch) increased the average daily gain of beef cattle fed maize/sorghum silage. Homofermentative microbial inoculant (Ho), Ch, and a mixture of microbial inoculant and chemical additives also increased the average daily gain of beef cattle fed temperate grasses. Only Ch increased dry matter intake. Ch increased feed efficiency, and Ch and Ho increased carcass weight. The evaluated additives improved the silage fermentation process mainly via pH and ammonia nitrogen reduction. Overall, this meta-analysis demonstrated that silage additives improved the ensiling process and beef cattle performance, with better results with Ch use. Due to the aerobic stability and microbiological profile analyses being carried out more in laboratory-scale silos, more studies are needed to determine these silage parameters after opening the silo at the farm scale.     

Ensiling in 2050: Some challenges and opportunities

Challenges to ensiling are coming from a wide spectrum. Faster harvest rates are making it more difficult to achieve target silage densities. Larger harvest equipment is increasing soil compaction and rural road issues. Older silos are too small and are overfilled, creating safety issues, or temporary piles are placed on bare ground permitting soil contamination. Mycotoxins and other pathogens in silages are still a problem. Global warming may affect the forage crops grown and crop characteristics as well as rates of silage fermentation and aerobic deterioration. Silage as an input to bio‐refineries has an unclear future. Silage analysis is challenged by sampling and knowing what components truly predict nutritional value. The future holds many opportunities for both ensiling and silage research. Robotic harvesting will release more labour for silo packing, and there are opportunities to develop tools to estimate silage density during filling. Total mixed ration silages should allow more by‐products in rations. The development of novel silage additives to improve silage hygiene or increase nutrient availability appears promising. Predicting the onset of aerobic deterioration with quick tests for lactate‐assimilating yeasts or silage temperatures seems possible. Metabolomics and metabonomics, in addition to the microbiome tools in development, put us at the cusp of being able to see which microorganisms are active in the silo and rumen and what compounds of significance they are producing. This could lead to many advances in silage quality including reduced microbial toxins, better hygiene and improved utilization by livestock.     

The aerobic stability of silage: key findings and recent developments

When silage is exposed to air on opening the silo, or after its removal from the silo, fermentation acids and other substrates are oxidized by aerobic bacteria, yeasts and moulds. The aerobic stability of silage is a key factor in ensuring that silage provides well‐preserved nutrients to the animal with minimal amounts of mould spores and toxins. In this paper, key findings and recent developments are reviewed, and findings of recent research are integrated in terms of four themes: (i) the most significant biochemical and microbiological factors, (ii) physical and management factors, (iii) type of additive and (iv) silo sealing. The development of yeasts and moulds during plant growth, and during field wilting or storage, and the concentration of undissociated acetic acid in silage are important microbiological and biochemical factors affecting aerobic stability. Silage density and porosity are key physical factors that affect the rate of ingress of oxygen into the silage mass during the feed‐out period. A target for potential silage aerobic stability is 7 d including time in the feed trough. To achieve this target, speed of harvest should be coordinated with packing tractor weight to achieve a minimum silage density by the time of feed‐out of 210 kg DM m^?3, maximum proportional porosity of 0·4 and a rate of silage removal, which matches or exceeds the depth of air penetration into the silo. The use of additives to increase aerobic stability is advisable when there is the risk of these objectives not being met. Novel microbial approaches to solving the problem of silage aerobic deterioration are needed.     

Possibilities of increasing the residual water‐soluble carbohydrate concentration and aerobic stability of low dry‐matter perennial ryegrass silage through additive and cultivar use

Increasing the residual water‐soluble carbohydrate (WSC) concentration in silage may improve the nutritional value but impair aerobic stability. Our aim was to determine whether the residual WSC concentration and aerobic stability of low dry‐matter (<135 g kg^?1) perennial ryegrass silage could be manipulated through the judicious use of additive and cultivar. Seven additive treatments, including three innovative treatments, were compared across four consecutive harvests of the cultivars AberDart (bred to accumulate high concentrations of herbage WSC) and Fennema (control). The standard of fermentation of silage ensiled without additive (untreated) ranged from very bad to excellent. Application of ammonium tetraformate, at 3 and 6 L t^?1, or homofermentative lactic acid bacteria (LAB) alone had an inconsistent effect on the fermentation and aerobic stability, and negligible effect on residual WSC concentration. A mixture of Lactobacillus buchneri and homofermentative LAB was not an effective silage additive, producing generally poorly fermented silage. An antimicrobial mixture of sodium benzoate, sodium propionate, sodium nitrite and hexamethylenetetramine, applied at 2·5 and 5 L t^?1, frequently improved the standard of fermentation, but the effects were subject to the application rate. The high application rate was the most effective additive evaluated at improving the fermentation and increasing residual WSC concentration and consistently produced silage of excellent standard of fermentation. However, the antimicrobial mixture was not effective at protecting against aerobic instability. The effects of additive treatment were largely inconsistent across cultivars. Overall, AberDart had a negligible effect on the silage fermentation, residual WSC concentration and aerobic stability compared with Fennema.     

Effect of two additives on the fermentation,in vitro digestibility and aerobic security of Sorghum–sudangrass hybrid silages

Two additives (Silo Guard (SG) and propionic acid (PA)) were tested for their effects on the quality and aerobic security of sorghum–sudangrass hybrid silages (JC‐1 and WC‐2). Two sorghum–sudangrass hybrid varieties were harvested for ensiling without additives (CK) or after the following treatments: SG at 0·5% of fresh forage or PA at 0·5% of fresh forage, with three replicates per treatment. The addition of SG and PA both affected the fermentation quality and chemical composition of the silages by lowering pH and NH₃‐N/TN and increasing lactic acid, the LA/TA ratio, WSC and CP concentrations compared with the untreated silages. In vitro DM digestibility (IVDMD), in vitro NDF digestibility (IVNDFD) and in vitro CP digestibility (IVCPD) were increased by SG in the JC‐1 silages and WC‐2 silages. Both additives improved the aerobic stability of sorghum–sudangrass hybrid silages. Furthermore, the additives reduced the mould counts and the aflatoxin and zearalenone levels compared with the untreated silages following aerobic exposure. Therefore, ensiling two sorghum–sudangrass hybrid varieties resulted in high‐quality silages. The addition of SG and PA improved silage quality, in vitro digestibility and aerobic security.     

Effects of maize meal and limestone on the fermentation profile and aerobic stability of smooth bromegrass (Bromus inermis Leyss) silage

Chemical‐compositional characteristics of crops are crucial factors affecting the fermentation profile and aerobic stability of silages. To evaluate the effects of starch content and buffering capacity, fresh smooth bromegrass was ensiled alone (control), with 9% maize meal (MM), or with a mixture of 9% maize meal and 1.5% limestone (MX) on a fresh matter basis in sealed plastic bags. After 1, 3, 14 and 56 days of ensiling, triplicate bags of each treatment were opened for chemical and microorganism analyses, and then the samples ensiled for 56 days were placed in polyethylene containers to evaluate their aerobic stability. During the early days of ensiling, the mixtures of maize meal and limestone favoured lactic acid bacteria growth, lactic acid production and decrease in pH values. After 56 days of ensiling, the MX‐treated silages had significantly higher (p < .05) lactic acid, ammonia‐N and buffering capacity compared with the silages treated with other additives. The aerobic stability of MM‐treated silages was significantly lower (p < .05) than that of the control silages, but the MX‐treated silages showed higher (p < .05) aerobic stability than the other groups. The changes of organic acids and pH in the MX‐treated silages were also delayed, which inhibited the growth of aerobic bacteria and yeasts. These results indicate that maize meal improved the fermentation profile of smooth bromegrass silage but had a negative effect on its aerobic stability; however, limestone played important roles in both accelerating fermentation and the improvement of aerobic stability.     

Separating the effects of forage source and field microbiota on silage fermentation quality and aerobic stability

This study attempted to separate the effects of forage source and field microbiota on silage fermentation quality and aerobic stability. Single samples of grass, red clover and maize were used. Field microbiota was obtained by centrifugation of microbial suspensions of the three samples. The intact forages were dried and sterilized by heating at 60°C for 3 h + 103°C for 15 h, inoculated in a 3 (forage) × 3 (inoculum) design and reconstituted to a dry‐matter level of 400 g kg^?1 before ensiling. After ensiling for 71 d, subsamples were subjected to an 8‐d aerobic stability test, which included temperature and pH measurements. Bacterial community analysis was performed on samples before and after ensiling by 16S rRNA gene amplicon sequencing. Forage source had a marked effect on the levels of lactic acid, acetic acid, ammonia‐N and 2,3‐butanediol, but microbiota source only affected the acetic acid concentration. The forage and microbiota as well as their interactions affected silage stability variables. The maize microbiota improved silage stability, whereas silages made from the maize forage had the poorest stability. Bacterial community analysis revealed higher abundance of lactic acid bacteria on the maize forage, with Lactococcus and Leuconostoc being the dominant genera. These preliminary results suggested that fermentation quality is mainly affected by forage source, whereas the aerobic stability is affected by both forage and field microbiota.     

Effects of additives on the fermentation and aerobic stability of grass silages and total mixed rations

Mown herbage of timothy–meadow fescue (dry matter 218 (LDM) or 539 (HDM) g kg^?1) was ensiled in laboratory silos to evaluate silage additives. For LDM silage, additives including formic acid (a blend of formic acid, sodium formate, propionic acid, benzoic acid, glycerol and another blend of formic acid and ammonium formate, both applied at 5 L t^?1) were able to restrict fermentation and thereby improve intake potential of the silage. Aerobic stability (AS) of total mixed ration (TMR) was also improved. LDM grass treated with homofermentative lactic acid bacteria (_hoLAB) resulted in silage containing lactic acid at 132 g kg^?1 DM, ammonium‐N <40 g kg^?1 total N, and pH < 3·8, and the AS was poor (<36 h). The treatment including heterofermentative strain (Lactobacillus brevis) produced more acetic acid and better AS than _hoLAB. Salt treatment (sodium benzoate, potassium sorbate, sodium nitrite) reduced pH compared to the Control treatment (3·89 vs. 4·24) and improved AS of TMR. The LDM Control silage had good AS, but the TMR based on it had poor AS. All additives were able to lower pH on HDM silages also, but other benefits of using additives were minimal. The treatment including L. brevis on HDM was able to improve AS of TMR.     

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

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.     

The effect of different additives on the fermentation quality, aerobic stability and in vitro digestibility of pea/wheat bi-crop silages containing contrasting pea to wheat ratios

Studies were conducted to compare the effects of using two microbial inoculants, a sulphite salt‐based additive, formic acid and quebracho tannins, on the fermentation quality, nutritive value and aerobic stability of pea/wheat bi‐crop silages. Spring peas (Pisum sativum var. Magnus) and spring wheat (Triticum aestivum var. Axona) were drilled together at rates that gave high (HP/W; 3:1) or low (LP/W; 1:3) pea to wheat ratios. The peas and wheat were harvested at the yellow wrinkled pods and late milk/early dough maturity stage, respectively, and conserved in 1·5‐kg polyethylene bag, laboratory silos. The bi‐crops were conserved without treatment (control) or treated with either of two lactic acid bacteria‐based inoculants [Lactobacillus buchneri; applied at 10⁵ colony‐forming units (CFU) g^–1 fresh weight (FW) or Lactobacillus plantarum (applied at 10⁶ CFU g^–1 FW)], sulphite salts (applied at the rate of 1 ml sulphite solution kg^–1 FW), quebracho tannins (applied at 16 g kg^–1 FW) and formic acid (applied at 2·5 g kg^–1 FW). Six replicates were made for each treatment, and the silos were opened after 112 days of ensilage. The level of peas in the bi‐crop influenced the effectiveness of the additives. With the exception of sulphite salts, all the additives significantly reduced the soluble nitrogen (N) and ammonia‐N concentrations of all the silages. The ratio of lactic acid to acetic acid was generally lower in the LP/W silages than in the HP/W silages, and the additive treatments only increased the in vitro digestible organic matter in dry matter of the LP/W silages. Of all the additives evaluated, formic acid resulted in the least aerobic spoilage in HP/W bi‐crop silages. However, in the LP/W bi‐crops, additive treatment was not necessary for ensuring aerobic stability.     

The effect of molasses‐based pre‐fermented juice on the fermentation quality of first‐cut lucerne silage

The aim of this study was to evaluate the possible effect of pre‐fermented juice (PFJ) on the fermentation quality and nutritive value of first‐cut lucerne (Medicago sativa L.) silage. The PFJs were prepared using barley (B), wheat (W) and grass herbages (G). Both fresh (PFJ‐B, PFJ‐W and PFJ‐G) and frozen (PFJ‐B_F, PFJ‐W_F and PFJ‐G_F) PFJs were examined. Frozen PFJs were prepared by freezing fresh PFJs at ?22°C with 20% glycerol (v/v). Treatments of lucerne silage included (1) control; (2) silage treated with PFJ‐B; (3) silage treated with PFJ‐W; (4) silage treated with PFJ‐G; (5) silage treated with PFJ‐B_F; (6) silage treated with PFJ‐W_F; and (7) silage treated with PFJ‐G_F. All the treatments consisted of five replicate silos, and they were prepared in 1·0‐L glass jar silos. Results showed that silages treated with fresh and frozen PFJs, regardless of plant material, had better fermentation quality than the control silage in terms of lower pH, butyric acid (BA) and ammonia nitrogen (NH₃‐N) concentrations, as well as higher lactic acid (LA) concentration (P < 0·05) and in vitro organic matter digestibility (IVOMD), metabolizable energy (ME) content, and gas production values (P < 0·05). Results indicated that PFJ treatments enhanced the nutritive value, fermentation quality and IVOMD, ME content and gas production values of first‐cut lucerne silages.