Quality of grass silage infected with spores of Clostridium tyrobutyricum

The influence of adding clostridial spores to silage was studied in 2 successive years. Direct-cut, precision-chopped herbages were infected with spores of Clostridium tyrobutyricum in doses varying from 0 to 10⁶ g^−l fresh material (FM), and ensiled in experimental silos. The material was treated with or without 4 ml formic acid (85%) kg⁻¹ FM. Silo contents were studied after 4.20 (or 50) and 100 days of ensiling.
Contents of dry matter, water-soluble carbohydrate, nitrate as well as buffering capacity of FM varied between the 2 years at harvest, whereas the numbers of clostridial spores were about the same (< 10² g⁻¹).
Infecting the crop with clostridial spores negatively affected the quality of silage in the first year. After 50 days spore numbers in the silages had increased by 40 × 10³ to 150 × 10³ times in the infected silage, compared with 5 × 10³ in the uninfected silage. No effect was seen in the second year.
Silage with high spore counts showed no residual nitrate content. Formic acid improved silage quality from a chemical point of view but had no anti-clostridial effect. Ensilability of a crop seems to be more important than the initial count of Clostridia for a successful ensiling process.     

A study of the efficacy of a bacterial inoculant and formic acid as additives for grass silage in terms of milk production

In a two-year experiment, three silages were prepared from herbage treated either with an inoculant at 1·25 × 10⁵ organisms (g fresh material (FM))⁻¹. formic acid (850 g kg⁻¹) at 4 1 (t FM)⁻¹, or no additive (untreated). In Experiment 1, unwilted and in Experiment 2, wilted silages were investigated and had mean dry matter (DM) and water soluble carbohydrate (WSC) concentrations at ensiling of 171 g kg⁻¹ and 17·6 g (kg FM)⁻¹ and 263 g kg⁻¹ and 25·1 g (kg FM)⁻¹, respectively. In Experiment 1, 45 and in Experiment 2, 54 individually fed cows were used to evaluate the silages in three-treatment, randomized-block design experiments. During weeks 4-12 of lactation the cows were offered silages ad libitum and during weeks 15-26 a constant amount of silage was fed. There were few major differences in chemical composition of the resulting silages. Formic acid had no effect on silage digestibility. Inoculant treatment increased digestibility when the grass had been wilted. The use of formic acid resulted in increased silage DM intake of 9% during weeks 4-12 of lactation in Experiment 1 but not in Experiment 2. The inoculant gave no increase in silage DM intake over the control in Experiment 1 but increased silage DM intake by 7% in Experiment 2. There was no significant response in milk yield to formic acid. In Experiment 2 the response in milk yield to inoculant treatment was significant both in weeks 4-12 of lactation (4%) and in weeks 15-26 of lactation (5%). It is concluded that the response in milk yield to the use of a specific inoculant appears to be mediated through increased intake of metabolizable energy (ME).     

Enzymes as silage additives for grass–clover mixtures

Seven laboratory-scale experiments were carried out to study the effects of cellulases/hemicellulases on silage fermentation of herbage from mixed swards of timothy ( Phleum pratense ), meadow fescue ( Festuca pratensis ) and red clover ( Trifolium pretense ). Enzyme-treated silage (approximately 3500 HEC units kg⁻¹ grass) reached a low pH sooner, had lower end pH, contained less NH₃-N and more lactic acid than did the untreated silage ( P < 0·05). Applied with an inoculant, these effects were even stronger. With easily ensiled crops (experiments 1, 2, 5 and 6) preservation was first of all improved by inoculation of lactic acid bacteria; however, for the low-sugar crops (experiments 3, 4 and 7) enzyme treatment was more significant. The enzymes derived from Aspergillus spp. gave more acetic acid than the enzymes from Trichoderma reesei. The Trichoderma enzymes liberated 4·8 g WSC kg⁻¹ FM gamma-irradiated grass during 60 d at pH 4·3 ( P < 0·05). On average, for all silages enzyme treatment increased the sum of residual sugar and fermentation products by 3·7 g kg⁻¹ FM (21 g kg⁻¹ DM) compared with the silages not treated with enzymes ( P < 0·001). Enzyme treatment increased the instantly degradable part of the feed, but total in sacco and in vitro digestibilities were not affected.     

Influences of enterobacteria on the fermentation and aerobic stability of grass silages

Grass (220 g DM kg⁻¹ was ensiled after adding 10⁶ and 10⁸ enterobacteria (90% Rahnella aquatilis , 9·9% Hafnia alvei and 0·1% Escherichia coli g⁻¹ fresh mutter. The silages were exposed to aerobic conditions alter 125 d of storage. In all treatments H. alvei rapidly superseded the initial high number of Enterobacter agglomerans (naturally present) and R. aquatilis. The maximum number of enterobacteria was detected about I d after initiation of fermentation. After 4 d of fermentation, when concentrations of undissociated lactic and acetic acids ranged from 52 to 36 mM and 41 to 51 mM respectively, no enterobacteria were detectable. Inoculating the crop with enterobacteria restilted in a temporarily retarded rate of production of lactic and acetic acids and a 50% increase in the concentration of ammonia-N. The concentration of endotoxin in the silages was 6–7 μg g⁻¹ fresh matter. There was no change in the level of endotoxin during ensiling. High numbers of enterobacteria at the beginning of the fermentation improved the aerobic stability of the silages. There was a lag in the decrease in concentrations of acids and delays in the increase in pH, respiration rate and numbers of yeast and Bacillus spores, in uninoculated silages the pH increased from 4·1 to 5·0 after 8 d of aerobic storage, whereas in inoculated silages a pH of 5·0 was not reached until after 16 d of storage.     

Determination of microbial protein in perennial ryegrass silage

The microbial matter fraction was determined in perennial ryegrass silages of different dry-matter (DM) contents, ensiled with or without Lactobacillus plantarum . ¹⁵N-Leucine and the bacterial cell wall constituent diaminopimelic acid (DAPA) were used as markers for microbial-N. Perennial ryegrass crops with DM contents of 202, 280 or 366 g kg⁻¹ fresh weight were ensiled in laboratory-scale silos and stored for 3 to 4 months. At different times after ensiling, silages were analysed and microbial fractions were isolated. Microbial-N concentration determined with ¹⁵N-leucine reached a maximum during the first week of ensilage. It remained unchanged thereafter, except in silage with a DM content of 280 g kg⁻¹ in which it decreased ( P  < 0·01) by 32% during storage. After 3 to 4 months ensilage, microbial-N concentration varied from ≈0·3 to ≈1·7 g kg⁻¹ DM. A negative relationship was observed between microbial-N concentration and silage DM content. Inoculation resulted in an approximately twofold increase ( P  < 0·001) in microbial-N concentration. Microbial-N concentrations determined with DAPA were 1·14–2·07 times higher than those determined with ¹⁵N-leucine. However, 19–35% of the DAPA in silage occurred in a soluble form, indicating that this fraction of DAPA was not associated with intact bacteria.     

Silage and milk production: studies with diets containing white clover silage

In three separate feeding experiments using a total of twenty-six individually-housed Ayrshire cows, three wilted silages made from Blanca white clover were offered ad libitum with either different supplements or different proportions of grass silage. The clover silages contained 680 g white clover kg⁻¹ on a DM basis, and had a mean DM concentration of 263 g kg⁻¹ with 231 g CP kg⁻¹ DM and 91 g ammonia-N kg⁻¹ N. The pH values averaged 4·16 and the DOMD concentrations 611 g kg⁻¹. In experiment 1 the daily intake of clover silage given alone was 15.2 kg DM per cow, i.e. 30·1 g kg⁻¹ live weight, and decreased by 0·76 kg DM kg⁻¹ barley DM and by 0·66 kg DM kg⁻¹barley plus soybean meal DM when these feeds were offered as supplements. Milk yield and fat concentration were higher on the supplement treatments than on the clover silage-only treatment. In experiments 2 and 3 the intakes of silage and total DM increased as the weight of clover in the diet increased from 0 to 700 g kg⁻¹ with parallel increases in milk yield. The effects on milk composition were small and generally non-significant. Although white clover silages with excellent fermentations were made, it is concluded that the main role of white clover in a silage system will be in mixed swards with grass to reduce the input of fertilizer N and to increase the voluntary intake of silage.     

Effects of treating lucerne with an inoculum of lactic acid bacteria or formic acid upon chemical changes during fermentation, and upon the nutritive value of the silage for lambs

A second cut of lucerne was wilted to 500 g DM kg⁻¹ and either left untreated (control) or treated with formic acid (4.5 1 fresh forage t⁻¹) or with a commercial inoculum of lactic acid bacteria (10⁵ colony forming units (cfu) g forage⁻¹). The forages were ensiled in 2-t capacity silos for 8 months, and later fed to six lambs (mean initial weight 27.7 ±1.60 kg) in a 3x3 duplicated Latin square with 27-d periods. Portions of the untreated and additive-treated forages were also ensiled in laboratory silos at 25 ° C for intervals up to 42 d. Results from the laboratory silos showed that the major increase in ammonia-N in silage occurred between 40 h and 7 d of fermentation; during this period, both formic acid and the inoculant produced a smaller increase in ammonia-N, than did the control. The pH of inoculated silage declined from 5.74 to 4.57 in 7 d, but it took 14 d for the pH of the control silage to fall below 5.0. Formic acid treatment immediately reduced the silage pH from 5.74 to 5.10 ( P < 0·01); the pH then remained unchanged until 21 d, after which it decreased slightly. When compared with control, lambs fed formic acid-treated silage consumed more ( P < 0·05) digestible organic matter; the response was associated with a trend towards decreased concentration of ammonia in plasma. Inoculation of lucerne silage did not ( P < 0·05) affect voluntary intake but increased ( P <0.05) apparent digestibility of fibre and tended to increase N retention.     

A note on ensiling safflower forage

Abstract The ensiling characteristics of safflower ( Carthamus tinctorius ) wilted to 290 and 411 g dry matter (DM) kg⁻¹ fresh material were studied in 1·5 l glass jars. The experiment included a control and the application of Lactobacillus plantarum at 3·3 × 10⁵ colony-forming units (cfu) per g of crop. After 60 days of ensiling, the pH of safflower silages was 4·6 and 4·0 in the control and inoculated silages respectively, with corresponding values for lactic acid, the major fermentation product, of 20 and 45 g kg⁻¹ DM. The silages from the anaerobic jars were stable upon aerobic exposure. It is concluded the safflower silage has potential as an alternative fodder in semiarid regions.     

The effect upon fermentation and nutritive value of silages produced after treatment by three different inoculants of lactic acid bacteria applied alone or in combination

Silages were made from the first cut of a predominantly perennial ryegrass sward. The silages were either untreated (W) or treated with formic acid (31 t⁻¹, F) or with 10⁶ lactic acid bacteria (LAB) g⁻¹ grass of each of three strains alone (A. Lactobacillus plantarum MTD1; B, Pediococcus species 6A2; C, L. plantarum 6A6) or in combination (AB. AC) to give seven treatments. The silage fermentation in 10-kg silos was followed chemically and microbiologically and the nutritive value of selected treatments evaluated using 2-t silos.
The control silage (W) fermented well. Addition of formic acid restricted fermentation and produced a silage with a high ethanol concentration. After day 4, all inoculated silages had lower pH values and higher lactic acid concentrations and a higher ratio of lactic acid to acetic acid than the control silage. Chemically there was little difference between the inoculated silages in terms of final composition. Microbiologically the LAB applied in treatments B and C dominated the LAB populations in those silages when applied alone; however, they were suppressed when applied in combination with inoculant A.
When fed to sheep, the intake of the formic acid-treated silage was significantly ( P < 0·01) lower than that of the other silages and the intake of silage treated with inoculant A significantly ( P < 0·001) higher than that of silages treated with inoculants B and C. The apparent organic matter ( P < 0·001) and nitrogen ( P < 0·01) digestibilities of the formic acid-treated silage were also significantly lower than those of the other silages.     

Silage and milk production: studies with molasses and formic acid as additives for grass silage

In two separate feeding experiments using a total of twenty-four individually housed Ayrshire cows six silages made from perennial ryegrass were offered ad libitum with supplements of concentrates. In Experiment I herbage with a dry matter (DM) concentration of 225 g kg⁻¹ received either formic acid ('Add-F') at the rate of 2·0 litres t⁻¹ or undiluted cane molasses at rates of 10, 20 and 30 litres t^−l; the mean daily silage intakes were 9·54, 908, 9·27 and 9·49 kg DM per cow and the daily milk yields, corrected to 40 g fat kg⁻¹, were 23·2, 22·3, 22·8 and 22·9 kg per cow respectively but none of the differences between the four treatments was significant. In Experiment 2 herbage with a DM concentration of 269 g kg⁻¹ received formic acid at a uniform rate of 2·6 litres t⁻¹ either with or without an additional application of molasses at 20 litres t⁻¹; the mean daily silage DM intakes were 8·70 and 9·28 kg per cow and the daily fat-corrected milk yields were 22·2 and 21·9 kg per cow respectively and were not significantly different. In both experiments the effects of the treatments on milk composition were small and not significant. It is concluded that there were no advantages in applying molasses to herbage treated with formic acid, and that the rate of application of molasses to untreated herbage which equated with the formic acid application was 20·30 litres t^−l when assessed on the basis of silage composition, intake and milk production.     

The chemical composition, digestibility and energy value of fermented and urea-treated whole crop wheat harvested at three stages of maturity

The metabolizable energy (ME) content, digestibility in vivo and chemical composition of fermented and urea-treated whole crop wheat (WCW) forage harvested were measured at different maturities. Over 2 years, twenty-four wheat forages (cv. Slepjner, Hussar and Cadenza) were harvested at 376, 516 and 632 g dry matter (DM) kg⁻¹ in Year 1 and 341, 467 and 544 g DM kg⁻¹ in Year 2 (Cuts 1, 2 and 3 respectively). Forages were conserved in 200−-ι barrels with or without a formic acid-based additive and with urea in Cuts 2 and 3 (20 or 40 g kg⁻¹ DM). Chemical compositions, digestibility in vivo and energy losses in faeces, urine and methane were measured in wethers fed 12 g DM kg⁻¹ live weight. Respective ranges in pH, crude protein, water-soluble carbohydrates, starch and neutral detergent fibre plus amylase (NDFA) contents were 3·8–8·5, 89–394, 2–43, 23–424 and 306–655 g kg⁻¹ DM. ME content, digestible organic matter content (DOMD) and digestibilities of starch and NDFA ranged between 8·4 and 15·7 MJ kg⁻¹ DM, 558 and 708 g kg⁻¹ DM, 0·901 and 0·999 and 0·362 and 0·693 respectively. Predicted methane energy losses were poorly correlated with measured values ( r ² < 0·45) in both years, but this accounted for less than 0.1 MJ ME kg⁻¹ DM. Significant ( P < 0.05) effects of maturity on the ME/DOMD ratio were observed and ascribed to differences in the extent of fermentation. Therefore, treatment application and maturity exert considerable influence on the ME content of WCW.     

Dry-matter yield and herbage quality of a perennial ryegrass/white clover sward in a rotational grazing and cutting system

The expected reduction in the use of fertilizer nitrogen (N) on grassland in the Netherlands has led to renewed interest in white clover. Therefore, the performance of a newly sown perennial ryegrass/white clover sward on clay soil was assessed during 4 consecutive years. The experiment consisted of all combinations of two defoliation systems, i.e. one or two silage cuts per year (S1, S2), spring N application rate, i.e. 0 or 50 kg ha⁻¹ year⁻¹ (N₀, N₅₀), and the management system, i.e. rotational grazing and cutting, or cutting only (RGC, CO). The overall mean white clover cover was 30%. All treatments affected white clover cover, which was 8% higher with S2 than with S1, 6% higher with N₀ than with N₅₀ and 12% higher with CO than with RGC. The overall mean annual dry-matter (DM) yield (13·1 t ha⁻¹ year⁻¹) was significantly affected only by the management system: in two relatively wetter years, the annual DM yield was 1·19 t ha⁻¹ higher with RGC than with CO, whereas there was no difference in two relatively drier years. Nitrogen application increased the DM yield in the first cut by 7·0 kg kg⁻¹ N applied, but had no significant effect on the annual DM yield. Herbage quality was not affected by the experimental treatments. The average in vitro organic matter digestibility was 0.801, and the average crude protein content was 193 g kg⁻¹ DM. With the expected reduction in the use of fertilizer N, perennial ryegrass/white clover swards should be seriously considered as an alternative option to perennial ryegrass swards on these clay soils.     

Barley/pea mixtures as cover crops for grass re-seeds

Substantial annual fluctuations in the performance of arable silage mixtures, comprising Minerva forage pea and Goldmarker barley, were observed from ten annual sowings between 1977 and 1986, Total dry matter (DM) yield varied between 2·5 and 11·5 t ha⁻¹. Dry matter content also ranged widely from 10·3% to 20·0% and there was a large variation in the proportion of peas in the DM (0·44 to 0·90). Almost 80% of this yield variation was due to the fluctuation in pea performance and over 60% of all yield variation was related to the variation in sunshine hours and air temperature.
In 1983 and 1984 differences in seed rate of between 20 and 140 kg ha⁻¹ of Minerva and 80 and 160 kg ha⁻¹ of Goldmarker influenced the forage composition at harvest, with the pea component capable of outgrowing and suppressing the other species when sown at over 80 kg ha⁻¹. Very high yields of peas were associated with increasing stress on the undersown grass re-seed and were considered undesirable.
It was concluded that sowing rates of between 120 and 160 kg ha⁻¹ for barley and a maximum of 60 kg ha⁻¹ for peas would, in most years, provide the best compromise between attaining good arable silage yields and avoiding excessive dangers of damage of undersown grass re-seeds.     

Agronomic performance and nutritive value of common and alternative grass and legume species in the Peruvian highlands

The agronomic performance and nutritive value of twelve annual and perennial grasses and legumes were analysed in order to define alternatives to local forages for dry-season feeding of ruminants in the Peruvian Andes. There were twelve species and two fertilizer treatments (no fertilizer and a N;P;K fertilizer mainly applied at sowing) in an experiment with a randomized complete block design with three replicates at each of two sites. Plant height, soil cover by forage and weed species, frost damage, dry matter (DM) yield and nutritive value of herbage were evaluated in 2005 and 2006. Among the annual species, Hordeum vulgare L. cv. UNA 80 and × Triticosecale Wittm. had the highest DM yields when fertilized (8226 and 6934 kg ha⁻¹ respectively). Without fertilizer the alternative cultivars had similar DM yields to that of the local forages. Cultivars of Avena sativa L. had lower concentrations of neutral-detergent fibre (NDF) (557 g kg⁻¹ DM) and higher concentrations of predicted net energy for lactation (5·86 MJ kg⁻¹ DM) than the other annual grass species (625 g kg⁻¹ DM and 5·01 MJ kg⁻¹ DM respectively), while the legumes were superior in concentrations of crude protein (277 g kg⁻¹ DM) and NDF (362 g kg⁻¹ DM). Considering the low agronomic performance of the perennial forages, a mixture of fertilized annual grasses and legumes appears the most appropriate approach to meeting the demand for forage of high nutritive value in the Peruvian highlands.     

An evaluation of the drop-disc technique for measurements of herbage production in ryegrass for silage

The drop-disc method of estimating herbage dry-matter production was evaluated for ryegrass from growth commencement to the silage stage; the latter typically corresponded to a maximum dry matter (DM) mass of almost 7 t ha⁻¹. A close linear relationship ( r ²= 0·829) was found between disc settlement height and DM mass up to 4–5 t ha⁻¹ for the period when growth was mainly vegetative rather than reproductive. During the latter stage, the presence of stems and the occurrence of lodging had a detrimental effect on the quality of disc calibration data. The technique was demonstrably useful in experiments as a cheap, rapid and trouble-free method for monitoring the initiation of grass production and rate of production during the vegetative stage.     

Growth performance, appetite and plasma ammonia concentrations in heifers fed inoculated lucerne prior to ensilage, then supplemented with sodium bicarbonate

A study was conducted to explore the possibility of a synergistic effect of an inoculum of lactic acid bacteria and sodium bicarbonate in improving the nutritive value of lucerne silage. Twenty Holstein heifers (live weight 183 ± 9·4 kg) were assigned to four dietary treatments consisting of: lucerne uninoculated or inoculated prior to ensilage and then either unsupplemented or supplemented with NaHCO₃ (40 g kg⁻¹ dry matter (DM)). The lucerne silage contained 320 g kg⁻¹ DM and constituted 600 kg⁻¹ diet DM. The animals were fed once daily for 90 d and samples of jugular blood were analysed for plasma ammonia and indices of blood acid-base status. Inoculation of Lucerne reduced ( P <0·01) silage pH but had no other effect on silage composition. In the absence of NaHCO₃, liveweight gain and organic matter intake were improved by inoculating lucerne prior to ensilage; however, in the presence of NaHCO₃, inoculation reduced growth rate but had no major effect on intake. Dietary treatment did not (P>0·05) affect the concentration of plasma ammonia or measures bf blood acid-base status. The results suggest that NaHCO₃ may have nullifled any potential benefit of inoculating lucerne silage to improve its nutritive value for heifers.     

Comparison of a straw/concentrate mixture with silage as a buffer feed for grazing dairy cows

Over a 24-week period during the 1986 summer, three groups of January- to March-calving dairy cows were either grazed conventionally (G) or grazed between morning and afternoon milkings and housed overnight and offered grass silage (Si) or a straw/concentrate mixture (St) ad libitum. The straw/concentrate mixture contained proportionately, 0-33 long barley straw, 0·28 ground barley, 0·12 soya bean meal, 0·25 molaferm and 0·22 minerals. The metabolizable energy (ME) and crude protein (CP) contents of the silage fed in weeks 1-8 and weeks 9-24 were 9-5 and 10⁻⁶ MJ kg MD⁻¹ and 160 and 191 g kg DM⁻¹ respectively. The straw mix had an ME content of 10⁻¹ MJ kg DM⁻¹ and CP content of 134 g kg DM⁻¹. Partial storage feeding with silage or a straw/concentrate mixture led to a decrease in estimated herbage DM intake. The feeding of the straw/concentrate mixture increased total DM intake, but the estimated total ME intake was similar for treatments G and St. The intakes (kg DM d⁻¹) for treatments G, Si and St were respectively, herbage 11·7,6·8,4·1; total l3·5,13·6,15·0; total ME intake (MJd⁻¹) 163, 155, 163.
Animal performance was, for treatments G, Si and St respectively: milk yield (kg d⁻¹) 19·2, 17·5, 19·1 (s.e.d. 0-87); milk fat content (g kg⁻¹) 36·9, 37·6, 37.1 (s.e.d. 1.22); milk protein content (g kg⁻¹) 35·3, 32·9, 33·4 (s.e.d. 0·76).     

A plate meter inadequately estimated herbage mass in a semi-arid grassland

A resting plate meter was tested in the laboratory and on a field site to determine its effectiveness for estimating peak herbage mass on semi-arid grasslands. In laboratory tests, data from the plate meter closely predicted the herbage mass of four perennial bunch grasses (thirteen of sixteen tests with r ² ≥ 0·90) but the closeness of the prediction varied with the pressure of the plate. Field tests took place on a southern Arizona, USA semi-arid grassland in 2005, 2006, 2007 and 2008. Twenty teams of two or three people sampled the site; five teams in each year measured eight to thirteen plate heights and clipped the vegetation beneath. Consistent with a need for yearly calibration, a significantly different ( P  <   0·05) linear relationship was detected between 3 of the 4 years which was associated with differences in average herbage mass of dry matter (DM) (1525 kg ha⁻¹ for 2005, 2093 kg ha⁻¹ for 2006, 1338 kg ha⁻¹ for 2007 and 1370 kg ha⁻¹ for 2008). Plate height poorly predicted herbage mass within years ( r ²  = 0·21, 0·51, 0·49 and 0·41 respectively) with plate heights explaining half or less of the variability in field herbage mass and having a mean prediction error of 466 kg DM ha⁻¹. The plate meter technique had limited potential for estimating peak herbage mass in semi-arid grasslands.     

The effect of addition of sugar and inoculation with two commercial inoculants on the fermentation of lucerne silage in laboratory silos

Lucerne (DM 236 g kg^-1, WSC 49 g (kg DM)^-1) was ensiled in test-tube silos with or without either glucose or fructose and with or without one of two commercial inoculants. The WSC content of the forage as ensiled was too low to obtain a well preserved untreated silage. By day 4 the pH values of the silages with added sugar or inoculant were significantly lower (P< 0·001) than the control silage. A satisfactory fermentation was attained only in the silages to which sugar and an inoculant had been added. These silages had a lower pH, more protein-N (P< 0·001), less ammonia-N (P<0·001), a faster increase in counts of lactic acid bacteria, and decrease in counts of coliforms than the other silages. Homo-fermentative lactic acid bacteria dominated the fermentation in the inoculated silages while leuconostocs dominated the early stages of fermentation in the control silages. The results indicate that if there is insufficient sugar in the original crop, then the bacteria in an inoculant will not be able to produce enough lactic acid to lower the pH to an acceptable level. This has important implications for the ensilage of lucerne and other highly buffered low sugar crops.     

Drying and physical characteristics of matted ryegrass

Fresh ryegrass and lucerne were macerated and compressed into thin mats over a 4-week period at two yield levels. The mats were left lo dry outside during the day. and inside overnight, and compared with unconditioned crops. Under a low swath yield of 4 t DM ha⁻¹, mats required 0·7-1·4 mm pan evaporation lo reach 70% moisture, suitable for wilted silage, compared with 1·8-3·8 mm pan evaporation for unconditioned crops. On an average non-rainy day. mats were ready to harvest as wilted silage after 2–5 h, whereas the unconditioned crop required between 6 h and 36 h of wilting. With a high swath yield of 8 t DM ha⁻¹, mats required 1·4-3·0 mm pan evaporation to reach 70% moisture compared with 2·4-5·1 mm for unconditioned windrows. Low-yield mats reached 20% moisture, suitable for hay, in 2 d of drying, after 4·5-5·3 mm of pan evaporation. The thickness and cohesion of the mats were measured to assess their sensitivity to mechanical handling. The effect of controlled rainfall on mats was also investigated. Since mat making was most effective in low-yield crops, it could become a useful complement to low-input, extensive forage production. Mat making could eliminate most silage effluent losses; it could re introduce haymaking of ryegrass as a viable system under certain circumstances.