Effect of the stage of growth,wilting and inoculation in field pea (Pisum sativum L.) silages,III. Changes in the herbage and silage protein profiles

BACKGROUND: The effects of stage of growth, field wilting and inoculation with lactic acid bacteria (LAB) on the protein profile of herbage and silage were studied on field peas (Pisum sativum L.) harvested at four progressive morphological stages (end of flowering, I; beginning of pod filling, II; advanced pod filling, III; beginning of ripening, IV). The herbage was field wilted to a dry matter (DM) content around 330 g kg^?1, for each stage of growth. The unwilted and wilted herbages were ensiled with (I) and without (C) a LAB inoculant. RESULTS: As a result of the advancing maturity of the crop, the main protein component was Rubisco in the early stages and seed storage proteins in the more advanced stages, due to the redistribution of organic nitrogen during seed filling. Extensive degradation of Rubisco occurred in all the silages, without any effect of inoculation or wilting. A good preservation of the proteins was observed in stage IV for both unwilted and wilted silages, without further protein preservation due to LAB inoculation. CONCLUSION: Protein protection observed in the more mature pea silage was due to the protein type and its localization and not to the level of DM at ensiling or to the inoculation. Copyright © 2007 Society of Chemical Industry     

Effect of the stage of growth,wilting and inoculation in field pea (Pisum sativum L.) silages. I. Herbage composition and silage fermentation

The stage of growth, field wilting and inoculation with lactic acid bacteria (LAB) effects were studied by ensiling herbage of field pea (Pisum sativum L.) at four consecutive stages. Stands of semi‐leafless field pea, sown in spring, were harvested at four progressive morphological stages (end of flowering, I; beginning of pod filling, II; advanced pod filling, III; beginning of ripening, IV). For each stage of growth, the herbage was field wilted to a dry matter (DM) content of 318, 300, 348 and 360 g kg^?1 for stages I, II, III and IV, respectively. The unwilted and wilted herbages were ensiled in 5‐L silos, with (I) and without (C) a LAB inoculant (Lactobacillus plantarum). High levels of ethanol, lactic acid and volatile fatty acids (VFA) were observed in all silages, facilitated by the high levels of water‐soluble carbohydrates (WSC) at ensiling (from 111 to 198 g kg^?1 DM). Despite the low pH values (4.3 and 4.1 for C and I silages, respectively), all the silages showed detectable levels of butyric acid. Field peas can be successfully ensiled after a short wilting period with reduced field curing and reduce DM losses onward from advanced pod filling stage, with the aid of LAB inoculum. Copyright © 2006 Society of Chemical Industry     

Effects of wilting and mechanical conditioning on proteolysis in sainfoin (Onobrychis viciifolia Scop) wilted herbage and silage

Ensiling legumes allows conservation of high‐quality forage. However, severe protein degradation occurs during ensiling of legumes. A field study was carried out in 1999 on sainfoin (Onobrychis viciifolia Scop) to investigate the effects of wilting and mechanical conditioning on proteolysis in wilted herbage and silage. The herbage was cut with both a rubber roll conditioning machine (C) and with a mower without conditioner (U). It was wilted in the field to three dry matter (DM) levels (220, 330 and 440 g kg^?1) and ensiled in laboratory glass silos. The herbages and the silages were analysed for ensilability characteristics, fermentation quality and nitrogen fractions. During wilting the non‐protein nitrogen (NPN) values increased (p < 0.05) in both U and C treatment. The free amino acid (free AA) values increased (p < 0.05) from 2.4 to 12.9 and from 2.4 to 7.2 mol kg^?1 total nitrogen, in the U and C treatments, respectively. Low wilted silages (DM content <320 g kg^?1) underwent butyric acid fermentation and extensive proteolysis in both treatments, with lower (p < 0.05) NPN and free AA values in the C treatment. Mechanical conditioning may limit protein breakdown and catabolism of some essential amino acids by reducing the field wilting time in both sainfoin wilted herbage and silage. Copyright © 2004 Society of Chemical Industry     

Effects of harvest date, wilting and inoculation on yield and forage quality of ensiling safflower (Carthamus tinctorius L.) biomass

BACKGROUND: Safflower (Carthamus tinctorius L.), usually grown as a source of oil crop, can be used as fodder either for hay or ensiling purposes, particularly in semi‐arid regions. RESULTS: A 2‐year trial was conducted in southern Italy to evaluate the production and forage quality of safflower biomass cv. Centennial, harvested at three different stages: 1, at complete appearance of primary buds (PB); 2, at complete appearance of secondary and tertiary buds (STB); and 3, at 25% of flowering stage (FS). For each stage of growth, 50% of the biomass was ensiled in 4 L glass jars without and with inoculation (Lactobacillus plantarum, LAB), and the other 50% was field wilted for 24 h before ensiling. Dry matter (DM) content and yield (DMY), pH, buffering capacity (BC) and water soluble carbohydrates (WSC) were determined on fresh forage. On safflower silages were also evaluated ammonia‐N, crude protein (CP), fibre fractions, fat, lactic and acetic acids, Ca and P, and gas losses. DMY ranged from 4.5 t ha^?1 (PB harvesting) to 11.6 t ha^?1 (FS harvesting). DM content varied from 129 g kg^?1 (PB not wilted) to 630 g kg^?1 (FS wilted). The WSC in forage before ensiling with not wilting ranged from 128 (PB stage) to 105 and 100 g kg^?1 DM at STB and FS stages, respectively. The wilted safflower forage showed a lower WSC compared to wilted forage. The high sugar substrate allowed lactic acid fermentation and a good conservation quality in all the harvesting stages. Silages quality was strongly influenced by the treatment performed. Wilting practice increased DM, pH and NDF contents but reduced lactic acid, acetic acid and NH₃‐N values. Inoculation reduced DM, pH and NDF contents, but increased lactic and acetic acids, CP and ash. CONCLUSION: As result, wilting the forage for 1 day was very effective in the early harvesting stage because this practice significantly increased DM, reducing on the same time the intensive fermentation and proteolysis processes of silage. When harvesting is performed at the beginning of the flowering stage wilting is not necessary. Copyright © 2011 Society of Chemical Industry     

Stability of fatty acids during wilting of perennial ryegrass (Lolium perenne L.): effect of bruising and environmental conditions

BACKGROUND: Oxidation of fatty acids (FA) during field wilting of herbage could cause extensive losses of polyunsaturated FA. Recent studies showed a variable effect of wilting on the losses of FA. This suggests that environment and management conditions influence the loss of FA during wilting. The present study investigated the stability of FA in untreated and mechanically bruised perennial ryegrass, wilted under field conditions for 0, 12, 24, 36 and 48 h, or wilted under controlled climate conditions at three temperatures (15, 25 or 35 °C) and two light (dark or light) regimes to dry matter (DM) contents of 425, 525 or 625 g kg^?1. RESULTS: During 48 h of field wilting, the total FA content declined (15.2 to 11.9 g kg^?1 DM) consistently, despite an increase in herbage DM content (197 to 676 g kg^?1). Under controlled climate conditions, the herbage total FA content declined (15.1 to 11.7 g kg^?1 DM) mainly during the prolonged (56 to 62 h) initial drying to a DM content of 425 g kg^?1 and did not decline with further drying to DM contents of 525 and 625 g kg^?1. The decline in total FA was associated with a parallel decline in C18:3 content under field (9.15 to 6.36 g kg^?1 DM) and controlled (9.12 to 6.15 g kg^?1 DM) conditions. Concomitantly, the proportion of C18:3 in total FA decreased, whilst the proportion of C16:0 and C18:0 increased. Lower losses of FA (P < 0.05) were observed at 15 °C compared to 25 and 35 °C. Light did not affect the losses of FA during wilting. CONCLUSIONS: The duration of the wilting period mainly affected the changes in FA content and composition. Stability of FA in herbage could be increased by minimising the duration of wilting. Copyright © 2011 Society of Chemical Industry     

Immunoreactive fraction 1 leaf protein and dry matter content during wilting and ensiling of ryegrass and alfalfa

In four experiments with ryegrass and alfalfa, cut herbage was wilted in the field and silage made in 1- or 200-L silos. Direct-cut (mean DM, 20.3%), low wilt (mean DM, 26.0%), medium wilt (mean DM, 36.2%) and high wilt (mean DM, 47.7%) herbages were used. Fraction 1, the most abundant leaf protein, was measured by crossed immunoelectrophoresis using rabbit anti-Fraction 1 serum. In two ryegrass and one alfalfa experiments in which weather conditions allowed rapid drying to high wilt herbage in 24 h, there was no significant loss of Fraction 1 protein. In the second alfalfa experiment, in which wilting was prolonged to 3 d by adverse weather, there was a 70% loss of Fraction 1. Ensiling proceeded normally in the four experiments, with rapid fall in pH and production of VFA, lactate, and NPN; the extent and rates of production were inversely related to DM content. In alfalfa and ryegrass, pH fell below the isoelectric point of Fraction 1 within 8 d. In each ryegrass experiment, a high proportion (58 to 100%) of Fraction 1 in medium and high wilt silages survived fermentation for 28 and 68 d, with lesser amounts in other silages. With alfalfa, however, almost all Fraction 1 protein was degraded at all DM concentrations during fermentation. Fiber-associated protein increased markedly with increases in DM during wilting, and these differences were present in the mature silage of both ryegrass and alfalfa. Digestibility studies with fistulated sheep showed that appreciable amounts of immunoreactive Fraction 1 protein in ryegrass silages were undegraded in the rumen.     

Ozonated cotton stalks as a silage additive: Fermentation data on lucerne with particular reference to protein degradation

Fermentation patterns of lucerne silages were studied in laboratory silos. The treatments consisted of: (a) fresh (200 g kg>^?l DM) lucerne, ensiled without any treatment (L); (b) lucerne wilted to 525 g kg^?1 DM prior to ensilage (WL); (c) fresh lucerne + cotton stalks at a ratio of 60:40 on a dry matter (DM) basis (L + CS); and (d) fresh lucerne + ozone-treated cotton stalks at the same ratio as above (L+O₃). Silos were opened after 90 days and the silages analysed. The highest DM loss was found in the L silage (14·7%), whereas in the L+O₃ silage DM loss was practically nil. Both wilting and the addition of untreated cotton stalks proved to be effective in reducing DM losses during fermentation. The production of lactic acid and volatile organic acids in the L+ O₃ and WL silages was lower than in the L and L+CS silages. The poorest ability to preserve forage protein was found in the L silage, in which only 28 % of the protein was recovered after 90 days. The greatest ability to preserve protein was found in the L+O₃ silage, in which 78 % of the protein was maintained. Ammonia production followed generally similar patterns. Amino acids underwent extensive degradation in the L silage. Recovery of amino acids in the WL silage was in the range 69–93 %, and in the L + O₃ silage it was almost complete. Ozonated CS proved to be a good silage additive with respect to energy and protein preservation. Its future use in the field would allow direct ensilage of fresh leguminous material immediately after harvest, producing a high quality silage.     

The occurrence and prevention of ethanol fermentation in high‐dry‐matter grass silage

Ethanol is a common, usually minor fermentation product in ensiled forages, the major product being lactic acid. Occasionally, high levels of ethanol are found in silages. The aim of this study was to determine the incidence of high‐dry‐matter (DM) grass silages containing ethanol as the main fermentation product (ethanol silages), to describe the fermentation process in such silages and to determine the effect of grass maceration prior to wilting and addition of a bacterial inoculant containing Lactobacillus plantarum and Enterococcus faecium strains on fermentation. Twenty‐one laboratory silages produced between 1993 and 1995, 21 farm silages produced between 1980 and 1989 and 36 farm silages produced in 1995 (all produced without additive) were examined for pH and chemical composition. Dry matter (DM) loss during ensilage was determined for the laboratory silages only. Four laboratory silages were identified as ethanol silages. Mean concentrations of ethanol, lactic acid and acetic acid were 48.1, 15.5 and 6.0 g kg⁻¹ DM respectively. In the silages that contained lactic acid as the main fermentation product (lactic acid silages) these values were 7.7, 45.5 and 15.1 g kg⁻¹ DM. Mean DM loss and pH were 62.8 g kg⁻¹ DM and 5.32 respectively for ethanol silages and 24.4 g kg⁻¹ DM and 4.69 for lactic acid silages. There was no difference between ethanol silages and lactic acid silages in the mean concentration of ammonia‐N (94 g kg⁻¹ total N), and butyric acid was not detected (<0.2 g kg⁻¹ DM), indicating that both types of silages were well preserved. Analysis of the composition of the grass at ensiling showed a positive correlation between the concentration of soluble carbohydrates and the development into ethanol silage. Analysis of the farm silages indicated that 29% of the silages produced between 1980 and 1989 and 14% of those produced in 1995 were ethanol silages. Maceration prior to wilting and addition of silage inoculant improved lactic acid fermentation and prevented high ethanol levels. The micro‐organisms responsible for ethanol fermentation as well as the implications of feeding ethanol silages to livestock remain to be resolved. © 2000 Society of Chemical Industry     

Aerobic deterioration of lucerne (Medicago sativa) and Maize (zea mais) Silages—Effects of Yeasts

Lucerne (Medicago sativa L) silages made in test tube silos at various dry matter (DM) levels (290-537 g kg^?1) with and without addition of glucose (20 g kg^?1 herbage) at ensiling were stable during 7 days of aerobic exposure. Lucerne silages taken from seven farm silos were similarly stable while three others were unstable (average DM loss of 62 g kg^?1 DM and pH increase from 4.35 to 7.58 in 7 days). Under similar circumstances, maize (Zea mais L) silage had a high DM loss (164 g kg^?1 DM) and an increase in pH from 3.94 to 8.13. Silages were inoculated with yeast (1 × 10⁶ CFU g^?1 silage) isolated from aerobically deteriorating farm-scale lucerne and maize silages. The stable lucerne silages were not destabilised by inoculation, but the instability of unstable lucerne silages was increased. Aerobically unstable maize silage and stable lucerne silage were inoculated and studied separately or as a 50:50 mixture. There was a distinct lag in the development of aerobic instability in the mixture compared with maize silage alone. In another experiment, the growth of the inoculum in malt agar (pH 3.5) as affected by the presence of fresh and ensiled lucerne (six cultivars), birdsfoot trefoil (Lotus corniculatus L) and red clover (Trifolium pratense L) was studied. The legume herbages did not inhibit yeast growth whereas the corresponding silages did. Five aerobically stable lucerne silages inhibited yeast development in the media whereas unstable maize silage did not. It is concluded that aerobic stability was not related to silage DM, pH, yeast numbers or glucose addition at ensiling. Stability appeared to be due to the presence of an inhibitor (or inhibitors) produced during ensilage.     

Enzyme, bacterial inoculant, and formic acid effects on silage composition of orchardgrass and alfalfa

We evaluated the effects of cellulase (from Trichoderma longibrachiatum) application rates on neutral detergent fiber (NDF) concentration and fermentation products of orchardgrass (Dactylis glomerata L.) and alfalfa (Medicago sativa L.) silages harvested with decreasing dry matter (DM) digestibility. Additionally, the impacts of inoculant (Lactobacillus plantarum and Pediococcus cerevisiae), pectinase (from Aspergillus niger), or formic acid on silage composition were studied. Forages wilted to a DM content of about 320 g/kg were ensiled in laboratory silos for 60 d. Cellulase, combined with inoculant, was applied at 2, 10, and 20 ml/kg of herbage (at least 2500 IU/ml). Cellulase at 10 ml/kg was also applied alone or in combination with pectinase and inoculant or formic acid. The NDF concentration of orchardgrass silage decreased with increasing cellulase up to 20 ml/kg, at which NDF content was decreased by 30%. The NDF concentration of alfalfa silage decreased with increasing cellulase application up to 10 ml/kg, at which NDF content was decreased by 13%. Immature plants were more responsive to cellulase treatment than mature plants. Cellulase at 2 ml/kg combined with inoculant improved fermentation characteristics of the silages but generally, there was no effect on silage fermentation by higher cellulase applications, resulting in an accumulation of sugar. The improved fermentation of orchardgrass treated with cellulase and inoculant was mostly related to the effect of inoculant, whereas cellulase alone improved fermentation characteristics of alfalfa silage and this effect was enhanced by addition of inoculant. Decreased NDF and increased sugar concentrations did not improve the in vitro DM digestibility of cellulase-treated silages.     

Cellulase and Bacterial Inoculant Effects on Cocksfoot and Lucerne Ensiled at High Dry Matter Levels

Limited information exists on the response of grass and legume silage to enzyme and bacterial inoculant treatments when wilted to drier than desired conditions. This study was undertaken to evaluate the impact of cellulase (from Trichoderma longibrachiatum) application rate, when combined with a bacterial inoculant (Lactobacillus plantarum and Pediococcus cerevisiae), on the fermentation characteristics of cocksfoot (Dactylis glomerata L) and lucerne (Medicago sativa L) ensiled at high dry-matter concentrations. Forages were wilted to near 600 g dry matter kg^-1 and cellulase, combined with inoculant, was applied at 0·30 ml kg^-1 herbage and at two, four and eight times this concentration (at least 2500 IU ml^-1). Cellulase was also applied alone at 0·60 ml kg^-1. Wilted forages were ensiled in laboratory silos for 60 days. Effect of cellulase application rate on neutral detergent fibre concentrations of the silages was small and inconsistent. Averaged across species, only the intermediate cellulase concentrations decreased neutral detergent fibre concentration (P=0·082). The limited cell-wall degradation was probably related to the high silage dry-matter and lignin concentrations. Cellulase combined with inoculant increased total fermentation, when averaged across species. In cocksfoot, cellulase combined with inoculant decreased pH and NH₃-N concentration but increased the lactic: acetic acid ratio of control silage, with most of the effect caused by the inoculant. Cellulase applied alone to lucerne caused a higher lactic: acetic acid ratio than the control or when combined with the inoculant at the same cellulase rate. Thus, the effect of cellulase–inoculant mixtures on silage quality varied among plant species, with cocksfoot generally more responsive than lucerne. © 1997 SCI.     

Chemical changes and losses during the ensilage of wilted grass

Two experiments were carried out; in the first, wilted Italian ryegrass at two different dry matter (DM) levels (34% and 47%) was ensiled; in the second, fresh grass (15.9% DM) and similar herbage wilted to 30.3% DM were ensiled. Total edible DM losses from the wilted silages were low and ranged from 6.7 to 10.4%. Changes in individual sugars and organic acids were followed. The residual amounts of sugars in the wilted silages were directly related to the degree of wilting. All silages were well preserved, but little fermentation had occurred in the material wilted to 47 % DM. From a knowledge of the sugars lost and amounts of mannitol and ethanol formed it has been possible to examine quantitatively the main chemical changes during the ensilage of the wilted materials. The results confirm the efficiency with which wilted grass is anaerobically conserved.     

The effect of extended moist wilting and formic acid additive on the conservation as silage of two grasses differing in total nitrogen content

Herbage from two contiguous areas of an S.24 perennial ryegrass sward treated with differing levels of fertiliser N (LN and HN) was used to make direct cut (D) and wilted (W) formic acid silages designated LND, LNW, HND and HNW. The major nitrogenous constituents of the herbages and silages were studied and the digestibilities of the silages determined in vivo using cross-bred wethers. A 96 h wilt under poor drying conditions achieved DM of 26.3% (LNW) and 25.2% (HNW). Wilting had the effect of markedly increasing NPN to reach 37.4% TN (LNW) and 40.4% TN (HNW) after 96 h and there were concomitant increases in herbage free amino-N, amide-N and ammonia-N. However, nitrate-N decreased significantly during the wilting period and it was assumed that aerobic microbes were active on the crop. The ensiled herbages were well preserved, highest pH value being 4.01 (HNW) and, although NPN levels in wilted silage were significantly higher than unwilted, these did not exceed 50% TN. Changes noted in the free amino compounds included the accumulation of amides during wilting and their removal during ensilage, the accumulation of proline during wilting and the removal of arginine and accumulation of ornithine during the ensilage of wilted herbage. Nitrate also decreased markedly during the ensilage of wilted herbage, LNW and HNW herbages losing 58% and 57% of their nitrate-N respectively. Ammonia-N levels in LNW and HNW silages were considerably higher than in LND and HND treatments and this was tentatively linked with increased reduction of nitrate and deamination of amide and arginine during the ensilage of wilted herbages. Nitrogen digestibility coefficients were, respectively 0.672 (LND). 0.643 (LNW), 0.677 (HND) and 0.645 (HNW) and organic matter digestibility coefficients 0.698 (LNW), 0.652 (LNW), 0.666 (HND) and 0.634 (HNW). The differences in nitrogen digestibility between wilted and direct cut silages did not attain statistical significance. It was concluded that a substantial reduction in organic matter digestibility coupled with an increase in the relative proportion of low molecular weight nitrogenous compounds present were the principal effects of extended moist wilting in this experiment.     

Nutritive value of maize silage in relation to dairy cow performance and milk quality

Maize silage has become the major forage component in the ration of dairy cows over the last few decades. This review provides information on the mean content and variability in chemical composition, fatty acid (FA) profile and ensiling quality of maize silages, and discusses the major factors which cause these variations. In addition, the effect of the broad range in chemical composition of maize silages on the total tract digestibility of dietary nutrients, milk production and milk composition of dairy cows is quantified and discussed. Finally, the optimum inclusion level of maize silage in the ration of dairy cows for milk production and composition is reviewed. The data showed that the nutritive value of maize silages is highly variable and that most of this variation is caused by large differences in maturity at harvest. Maize silages ensiled at a very early stage (dry matter (DM) < 250 g kg^?1) were particularly low in starch content and starch/neutral detergent fibre (NDF) ratio, and resulted in a lower DM intake (DMI), milk yield and milk protein content. The DMI, milk yield and milk protein content increased with advancing maturity, reaching an optimum level for maize silages ensiled at DM contents of 300–350 g kg^?1, and then declined slightly at further maturity beyond 350 g kg^?1. The increases in milk (R² = 0.599) and protein (R² = 0.605) yields with maturity of maize silages were positively related to the increase in starch/NDF ratio of the maize silages. On average, the inclusion of maize silage in grass silage‐based diets improved the forage DMI by 2 kg d^?1, milk yield by 1.9 kg d^?1 and milk protein content by 1.2 g kg^?1. Further comparisons showed that, in terms of milk and milk constituent yields, the optimum grass/maize silage ratio depends on the quality of both the grass and maize silages. Replacement of grass silage with maize silage in the ration, as well as an increasing maturity of the maize silages, altered the milk FA profile of the dairy cows, notably, the concentration of the cis‐unsaturated FAs, C18:3n‐3 and n‐3/n‐6 ratio decreased in milk fat. Despite variation in nutritive value, maize silage is rich in metabolizable energy and supports higher DMI and milk yield. Harvesting maize silages at a DM content between 300 and 350 g kg^?1 and feeding in combination with grass silage results in a higher milk yield of dairy cows. © 2014 Society of Chemical Industry     

The potential of sunflower as a crop for ensilage

The chemical composition and nutritive value of sunflower, cv. Armavirec, was examined at 12 stages of growth. Maximum yield of dry matter (18.2 t ha^?1) occurred at the dough seed stage. Ether extract showed a five-fold increase with the development of the seed. This increase was reflected in the gross energy value which was maximal at 19.1 MJ kg^?1 dry matter at the dough seed stage. In-vitro organic matter digestibility was highest at the onset of flowering when the estimated metabolisable energy value was 10.5 MJ kg^?1 dry matter. Throughout the sampling period the calcium to phosphorus ratios varied from 3.9-5.9:1, an imbalance which would have to be redressed on diets based largely on sunflowers. Fresh and wilted sunflowers were successfully ensiled at the flowering stage, without the use of additives. pH values of the resulting silages were 3.86 and 4.01. The silages were each fed to six cross-bred wethers and voluntary dry matter intakes were 23.9 and 26.5 g kgW^?1 for the fresh and wilted silages respectively. For the fresh silage, intakes of digestible organic matter and digestible nitrogen were 612 and 13.6 g day^?1 compared with 684 and 16.7 g day^?1 for the wilted silage. Nitrogen retention increased with increase in silage dry matter. The optimum time of cutting for yield of nutrients is at the milky ripe stage. The composition of the crop at this stage should facilitate a satisfactory preservation by ensiling. The crop provides a high yield of dry matter over about 10 weeks in late summer and could provide a valuable standby forage crop for grass in dry areas.     

Ensiling characteristics and aerobic stability of direct‐cut and wilted grass silages inoculated with Lactobacillus casei or Lactobacillus buchneri

Two experiments were conducted to study the effects of wilting and inoculating Lactobacillus casei or Lactobacillus buchneri on the fermentation and aerobic stability of grass silages. Chopped Italian ryegrass (IR) and Festulolium (FE) were ensiled with or without wilting and added L casei (>10⁶ cfu g^?1 fresh matter (FM)) or L buchneri (>10⁶ cfu g^?1 FM). Silos were opened after 120 days and microbial counts, fermentation products and aerobic stability were determined. Addition of L casei increased lactic acid and decreased acetic acid and dry matter loss regardless of wilting and forage species. Inoculation of L buchneri decreased lactic acid and increased acetic acid and 1,2‐propanediol, while the effects appeared greater in direct‐cut than in wilted grass silages. Although 1,2‐propanediol accumulated in FE silage, the diol was degraded further to propionic acid and 1‐propanol in IR silage. The activity of 1,2‐propanediol degradation was lowered when IR was wilted prior to ensiling; 1,2‐propanediol remained and the production of propionic acid and 1‐propanol was less than one‐third of that in direct‐cut silage. Regardless of forage species, addition of L buchneri increased dry matter loss compared with the untreated control, whereas the loss was not significant in wilted silages. Ammonia production was increased by L buchneri in direct‐cut but not in wilted silages. No heating was observed with or without inoculation in direct‐cut IR silage after exposure to air. Other silages were deteriorated when L buchneri was not inoculated, while the spoilage was accelerated when L casei was added to FE. Copyright © 2005 Society of Chemical Industry     

Effects of dry matter concentration and ammonia treatment of alfalfa silage on digestion and metabolism by heifers

Alfalfa was harvested as second-cutting regrowth herbage, ensiled either at low DM (direct-cut) or high DM (wilted), untreated or treated with .82 or .66% anhydrous NH3 (percentage of DM), respectively, and offered to four Holstein heifers. Silages low in DM had more gross energy and more NDF in DM than silages high in DM. Ammonia treatment increased total, soluble, rumen-insoluble, and NH3 N fractions in treated silages compared with those fractions in untreated silages. Ammonia treatment of low DM silage reduced digestible energy intake but increased intake of high DM silage. Digestibility of DM was lower by heifers fed low than high DM silages, but hemicellulose digestibility was higher. Tissue N retention was lower by heifers fed low than high DM silage. Dry matter and cell solubles digestibilities decreased for NH3-treated silages compared with digestibilities for untreated silages. Digested DM contained more digested NDF and cellulose for NH3-treated silages compared with untreated silages. Retained N was higher for heifers fed NH3-treated alfalfa than untreated alfalfa, particularly for the low DM silages. Wilting alfalfa was more effective in improving nutrient use by heifers than treatment with NH3, which improved preservation of plant protein through ensiling.     

Effect of long-term application of animal slurries to grassland on silage quality assessed in laboratory silos

The effect on silage quality of slurry type (pig or cow), rate of application of slurry (50, 100 or 200 m³ ha^?1 year^?1) and use of a bacterial silage inoculant, was assessed on grass from a long-term slurry experiment ensiled in laboratory silos. There was no significant effect of slurry type or the quality of silage made from grass re growths. However, on the basis of ammonia-N, lactate and volatile fatty acid contents, spring (first cut) grass treated with cow slurry in both years of the study produced significantly poorer fermentation (P < 0.001) than silage from grass treated with pig slurry. The quality of silage made from slurry-treated swards compared favourably with that from swards treated with granular fertiliser. Although increasing the rate of slurry application was shown to reduce fermentation quality in most treatments, this was seen as an effect of increasing the total-N content of the herbage rather than of slurry application per se. From a study, in selected treatments, of the bacterial flora at harvest, it was also observed that slurry application had little impact on either the composition or diversity of herbage enter bacteria at harvest, and therefore probably upon subsequent fermentation. No evidence was found for the occurrence of clostridia on herbage from slurry-treated swards. Use of a bacterial inoculant (Ecosyl; ICI plc) improved fermentation quality significantly (P < 0.001) even where high rates of slurry (200 m³ ha^?1 year^?1) had been applied to swards. The high acetate and butyrate contents typical of laboratory silages untreated with additive were not seen in the inoculated silages.     

Effect of chestnut tannin on fermentation quality, proteolysis, and protein rumen degradability of alfalfa silage

Two experiments were conducted on alfalfa to investigate the effects of the addition of commercial chestnut hydrolyzable tannin at ensiling on 1) silage fermentation quality in lab-scale silos and protein degradation in the rumen, and 2) silage fermentation quality and proteolysis in bale silages. Wilted alfalfa was prepared with 4 tannin levels (0, 2, 4, and 6% on a dry matter (DM) basis; T0, T1, T2, T3, respectively) and ensiled in lab-scale silos. Silages (33% DM) were analyzed for fermentation quality, protein rumen degradability in situ, and organic matter digestibility in vitro through gas production after 120 d of conservation. Wilted alfalfa containing 0 and 4% tannin (T0 and T2) was harvested at 40% DM (wilting level I) and 53% DM (wilting level II) for bale (600 mm diameter) silage. Silages were analyzed for fermentation quality after 78 d of conservation. All the silages were well fermented with no butyric acid. Lab-scale silages showed reductions in ammonia, nonprotein nitrogen (NPN) and DM losses in T2 and T3 treatments, while the fermentation acid profiles were unaffected. In experiment 1, the untreated silage (T0) had the highest protein degradability after being incubated in the rumen. The addition of tannin reduced crude protein ruminal disappearance in a dose-dependent manner. However, the tannin reduced the organic matter digestibility by 5.1% for all of the tannin addition levels. The tannin positively affected the silage quality in the round bale silages, in particular reducing ammonia and NPN in the lowest wilting level. In both experiments, T2 treatment reduced proteolysis without any influence of DM on the binding reaction and reduced the NPN by 15% in comparison to the control.     

Effect of fermentation and bacterial inoculation on lucerne cell walls

Changes were found in the cell wall composition of lucerne after ensiling at three different dry matter (DM) contents. The amount of protein associated with cell walls was reduced during ensiling, regardless of inoculation level, by 46–68%, whereas protein associated with the lignin residue was reduced to a lesser extent (< 40%). The effect ofensiling on individual sugars of the cell wall varied. Uronics of the cell wall were decreased by 12% with wilted silages (290 g DM kg^–1) but were unchanged in a higher dry matter silage (401 g DM kg^–1) and silages with a limited pH change during ensilage. The arabinose and galactose contents, as a fraction of cell walls, decreased (15–24%), increasing glucose and xylose contents proportionally. Inoculation decreased arabinose and galactose contents early in the fermentation when the pH decline was enhanced but final values were not significantly different (P > 0.32). Removal of the sugars from the cell wall appears to be related to pH because silages with little pH change had no change in the cell wall sugars and inoculation reduced the cell wall sugars only after silage pH declined.