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1.
Eleven laboratory lucerne silages, ten farm-scale lucerne silages and one maize silage were analysed for fermentation products to determine if chemical composition could explain differences in aerobic stability. Three of the farm-scale lucerne silages and the maize silage heated within 4 days of exposure to air whereas the other lucerne silages were stable for longer than 7 days even after inoculation with a destabilising yeast inoculum. The silages were analysed for lactic acid, volatile fatty acids (C1 to C6), succinic acid, ethanol, and 2,3-butanediol. The concentrations of these compounds in the unstable silages were not different from levels found in stable silages on either a dry matter basis or an undissociated water basis. However, unstable silages tended to be lower in 2,3-butanediol than other silages. The time until heating in these silages was simulated using a model of aerobic fungal growth in silage. This model considered the effects of yeast and mould numbers, pH, moisture content, and lactic and acetic acid concentrations on stability. Aerobic stability in three of the four unstable silages, with and without inoculation of destabilising yeasts, was reasonably predicted by the model. Stability in the other silages was consistently underpredicted by the model. These results indicate that the stability factor found in many lucerne silages is unlikely to be one of the principal products of silage fermentation.  相似文献   

2.
A study was conducted to determine the chemical composition and in situ nutrient ruminal degradability of three lucerne products. These were dehydrated pellets, sun‐cured pellets and cubes. Results of the chemical analysis showed that sun‐cured pellets had the highest (P < 0.05) neutral and acid detergent fibre as well as total carbohydrate levels, followed by cubes and dehydrated pellets respectively. Crude protein (CP) content was highest (P < 0.05) for dehydrated pellets (204.3 g kg?1), intermediate for sun‐cured pellets (160.0 g kg?1) and lowest for cubes (153.2 g kg?1). Intermediately degradable CP (buffer‐insoluble CP minus neutral detergent‐insoluble CP) was the main protein fraction in the three products and was higher (P < 0.05) in cubes than in dehydrated and sun‐cured pellets. Estimated net energy of lactation was highest (P < 0.05) for dehydrated pellets (5.9 MJ kg?1), intermediate for cubes (5.23 MJ kg?1) and lowest (P < 0.05) for sun‐cured pellets (5.15 MJ kg?1). Results of the in situ experiment indicated that dehydrated pellets had higher (P < 0.05) ruminal protein degradability than sun‐cured pellets and cubes. The estimated ruminal escape protein values for dehydrated pellets, sun‐cured pellets and cubes were 361, 420 and 498 g kg?1 CP respectively. It was concluded that differences in chemical composition and ruminal degradability among the three lucerne products were mainly due to differences in stage of maturity. It was also concluded that the dehydration process failed to increase the ruminal escape protein value of dehydrated pellets relative to sun‐cured pellets and cubes. © 2001 Society of Chemical Industry  相似文献   

3.
Using recently developed technology, balage is often stored in large (1.2 x 1.2 m) round bales that are wrapped in plastic film with an in-line wrapper. The aerobic stability of this fermented forage is important, particularly during winter months when it is fed to livestock or sold as a cash crop. Two types of forage, orchardgrass [Dactylis glomerata L.; 54.4% dry matter (DM)] and wheat (Triticum aestivum L.; 62.4% DM), were packaged in large round bales and wrapped with an in-line wrapper during May 2002. Twenty-one bales of each balage type were unwrapped and exposed to air on Dec. 10, 2002 for 0, 2, 4, 8, 16, 24, or 32 d (ambient temperature range = 0.6 to 19.4 degrees C) to evaluate aerobic stability. For both orchardgrass and wheat balage, final bale weight, concentration of DM, and pH were not affected by exposure time. Across both balage types, DM recoveries were > or = 97% for all bales, indicating that both balage types were very stable when exposed to air. For orchardgrass balage, exposure time had no effect on concentrations of NDF, ADF, hemicellulose, cellulose, or lignin, thereby indicating that little deterioration occurred. Similarly, no contrast relating any fiber component with exposure time was significant for wheat balage. Concentrations of crude protein (CP) were not affected by exposure time for wheat balage, but there was a tendency for exposed orchardgrass bales to have greater concentrations of CP than bales sampled on d 0. Exposure time had no effect on 48-h in situ digestibility of DM for wheat balage, but there was a tendency for a linear increase with exposure time for orchardgrass balage. However, the overall range (78.2 to 80.5%) over the 32-d exposure period was very narrow, and this response is probably of limited biological significance. Generally, concentrations of fermentation acids were low, primarily because of the high concentration of DM within these balages, and only minimal changes in these acids were observed over the exposure interval. These results suggest that the balage evaluated in this trial during winter conditions was very stable after exposure to air for up to 32 d. This should allow for considerable flexibility with respect to feeding, transport, and marketing of balage during winter months without significant aerobic deterioration.  相似文献   

4.
The effects of carbon dioxide level (100% versus 20% v in nitrogen) during ensiling on microbial populations and subsequent aerobic stability were studied in whole-crop maize silage. In five trials, fresh maize was chopped and ensiled in 10-litre silos with the two different gas atmospheres. Changes in populations of lactic acid bacteria, acetic acid bacteria, enterobacteria, Bacillus spores and moulds were only slightly affected by carbon dioxide level. In four of the five trials, fermentation products and pH were unaffected by treatment. Yeast counts were altered by carbon dioxide level but not consistently. The yeast population in maize silage made from one source was inhibited by high levels of carbon dioxide whereas the opposite occurred in the silages from two other sources. Aerobic stability was inversely related to yeast population. In two other experiments, maize silage taken from a bunker silo was re-ensiled in 700-litre and 10-litre silos, respectively, and the same two gas treatments were used. Carbon dioxide level had little effect on microbial numbers except yeast counts, which tended to be higher in the 20% v carbon dioxide environment. Little effect on aerobic stability due to treatment was noted in either experiment. High carbon dioxide levels do not appear to improve aerobic stability consistently.  相似文献   

5.
The occurrence of Bacillus and Paenibacillus spores in silage is of great concern to dairy producers because their spores can survive pasteurization and some strains are capable of subsequently germinating and growing under refrigerated conditions in pasteurized milk. The objectives of this study were to verify the role of aerobic deterioration of corn silage on the proliferation of Paenibacillus spores and to evaluate the efficacy of oxygen-barrier films used to cover silage during fermentation and storage to mitigate these undesirable bacterial outbreaks. The trial was carried out on whole-crop maize (Zea mays L.) inoculated with a mixture of Lactobacillus buchneri, Lactobacillus plantarum, and Enterococcus faecium. A standard polyethylene film and a polyethylene-polyamide film with an enhanced oxygen barrier were used to produce the silage bags for this experiment. The silos were stored indoors at ambient temperature (18 to 22°C) and opened after 110 d. The silage was sampled after 0, 2, 5, 7, 9, and 14 d of aerobic exposure to quantify the growth of endospore-forming bacteria during the exposure of silages to air. Paenibacillus macerans (gram-positive, facultatively anaerobic bacteria) was able to develop during the aerobic exposure of corn silage. This species was present in the herbage at harvesting, together with clostridial spores, and survived ensiling fermentation; it constituted more than 60% of the anaerobic spore formers at silage opening. During silage spoilage, the spore concentration of P. macerans increased to values greater than 7.0 log10 cfu/g of silage. The use of different plastic films to seal silages affected the growth of P. macerans and the number of spores during aerobic exposure of silages. These results indicate that the number of Paenibacillus spores could greatly increase in silage after exposure to air, and that oxygen-barrier films could help to reduce the potential for silage contamination of this important group of milk spoilage microorganisms by delaying the onset of aerobic deterioration.  相似文献   

6.
Effects of 8 chemical and bacterial additives on the quality of corn silage   总被引:2,自引:0,他引:2  
This project aimed to evaluate the effects 8 additives on the fermentation, dry matter (DM) losses, nutritive value, and aerobic stability of corn silage. Corn forage harvested at 31% DM was chopped (10 mm) and treated with (1) deionized water (control); (2) Buchneri 500 (BUC; 1 × 105 cfu/g of Pediococcus pentosaceus 12455 and 4 × 105 cfu/g of Lactobacillus buchneri 40788; Lallemand Animal Nutrition, Milwaukee, WI); (3) sodium benzoate (BEN; 0.1% of fresh forage); (4) Silage Savor acid mixture (SAV: 0.1% of fresh forage; Kemin Industries Inc., Des Moines, IA); (5) 1 × 106 cfu/g of Acetobacter pasteurianus-ATCC 9323; (6) 1 × 106 cfu/g of Gluconobacter oxydans-ATCC 621; (7) Ecosyl 200T (1 × 105 cfu/g of Lactobacillus plantarum MTD/1; Ecosyl Products Inc., Byron, IL); (8) Silo-King WS (1.5 × 105 cfu/g of L. plantarum, P. pentosaceus and Enterococcus faecium; Agri-King, Fulton, IL); and (9) Biomax 5 (BIO; 1 × 105 cfu/g of L. plantarum PA-28 and K-270; Chr. Hansen Animal Health and Nutrition, Milwaukee, WI). Treated forage was ensiled in quadruplicate in mini silos at a density of 172 kg of DM/m3 for 3 and 120 d. After 3 d of ensiling, the pH of all silages was below 4 but ethanol concentrations were least in BEN silage (2.03 vs. 3.24% DM) and lactic acid was greatest in SAV silage (2.97 vs. 2.51% DM). Among 120-d silages, additives did not affect DM recovery (mean = 89.8% ± 2.27) or in vitro DM digestibility (mean = 71.5% ± 0.63). The SAV silage had greater ammonia-N (0.85 g/kg of DM) and butyric acid (0.22 vs. 0.0% DM) than other treatments. In contrast, BEN and Silo-King silages had the least ammonia-N concentration and had no butyric acid. The BEN and A. pasteurianus silages had the lowest pH (3.69) and BEN silage had the least ethanol (1.04% DM) and ammonia nitrogen (0.64 g/kg DM) concentrations, suggesting that fermentation was more extensive and protein degradation was less in BEN silages. The BUC and BIO silages had greater acetic acid concentrations than control silages (3.19 and 3.19 vs. 2.78% DM), but yeast counts did not differ. Aerobic stability was increased by 64% by BUC (44.30 h) and by 35% by BEN (36.49 h), but other silages had similar values (27.0 ± 1.13 h).  相似文献   

7.
The incorporation of (a) sorbic acid (0.18 and 0.90 g kg?1, fresh weight basis) and potassium sorbate (0.90 g kg?1) with chopped lucerne, and (b) sorbic acid (0.90 g kg?1) and potassium sorbate (0.90 g kg?1) with chopped maize (whole-plant) at the time of ensiling, led to a reduction in the surface spoilage associated with the ensilage of these two forages. Use of sorbic acid (0.90 g kg?1) and potassium sorbate (0.90 g kg?1) led to (a) a reduction of volatile nitrogen (VN), higher levels of residual water-soluble carbohydrates (WSC) in lucerne silage and more aerobically stable lucerne silage and (b) a reduction in weight loss, population of yeasts and moulds, and VN, higher levels of WSC in maize silage and more aerobically stable maize silage when compared to the untreated forages or forages treated with sorbic acid and potssium sorbate at 0.045 and 0.18 g kg?1 (fresh weight basis), respectively.  相似文献   

8.
The economic damage that results from aerobic deterioration of silage is a significant problem for farm profitability and feed quality. This paper quantifies the dry matter (DM) and nutritional losses that occur during the exposure of corn and sorghum silages to air over 14 d and assesses the possibility of enhancing the aerobic stability of silages through inoculation with lactic acid bacteria (LAB). The trial was carried out in Northern Italy on corn (50% milk line) and grain sorghum (early dough stage) silages. The crops were ensiled in 30-L jars, without a LAB inoculant (C), with a Lactobacillus plantarum inoculum (LP), and with a Lactobacillus buchneri inoculum (LB; theoretical rate of 1 × 106 cfu/g of fresh forage). The pre-ensiled material, the silage at silo opening, and the aerobically exposed silage were analyzed for DM content, fermentative profiles, yeast and mold count, starch, crude protein, ash, fiber components, 24-h and 48-h DM digestibility and neutral detergent fiber (NDF) degradability. The yield and nutrient analysis data of the corn and sorghum silages were used as input for Milk2006 to estimate the total digestible nutrients, net energy of lactation, and milk production per Mg of DM. The DM fermentation and respiration losses were also calculated. The inocula influenced the in vitro NDF digestibility at 24 h, the net energy for lactation (NEL), and the predicted milk yield per megagram of DM, whereas the length of time of air exposure influenced DM digestibility at 24 and 48 h, the NEL, and the predicted milk yield per megagram of DM in the corn silages. The inocula only influenced the milk yield per megagram of DM and the air exposure affected the DM digestibility at 24 h, the NEL, and the milk yield per megagram of DM in the sorghum silages. The milk yield, after 14 d of air exposure, decreased to 1,442, 1,418, and 1,277 kg/Mg of DM for C, LB, and LP corn silages, respectively, compared with an average value of 1,568 kg of silage at opening. In the sorghum silages, the milk yield, after 14 d of air exposure, decreased to 1,226, 1,278, and 1,250 kg/Mg of DM for C, LB, and LP, respectively. When the estimated milk yield per megagram of harvested DM of corn and sorghum silage were related to mold count, it was shown that the loss of potential milk production occurred when the mold count exceeded 4 log cfu/g of silage, and it was almost halved when the mold count reached values greater than 8 log cfu/g of silage. Inoculation with L. buchneri, at a rate of 1 × 106 cfu/g of fresh forage, enhanced the stability of the silage after exposure to air, and, consequently, contributed to maintaining the nutritional value of the harvested forage over time, for air exposure up to 7 d.  相似文献   

9.
We evaluated the effectiveness of an additive comprising sodium benzoate, potassium sorbate, and sodium nitrite (SSL) as active ingredients for its ability to improve the aerobic stability of corn silages made in North America. In experiment 1, treatment with SSL (1.5 and 2.0 L/t) on whole-plant corn (WPC) was compared with treatment with an additive containing buffered propionic acid and citric acid (BPA; 2 L/t) on corn harvested at 32 and 38% dry matter and ensiled for 120 d. Silage treated with BPA was higher in ammonia-N and propionic acid relative to other treatments. Treatments with all of the additives had numerically, but not statistically, fewer yeasts compared with untreated silage. Both application rates of SSL resulted in lower concentrations of ethanol compared with untreated and BPA silages. Treatment with BPA improved the aerobic stability of silages compared with untreated silage, but the effect from SSL was markedly greater. In experiment 2, WPC was untreated or treated with 2 or 3 L of SSL/t or a microbial inoculant containing Enterococcus faecium M74, Lactobacillus plantarum CH6072, and Lactobacillus buchneri LN1819 (final total lactic acid bacteria application rate of 150,000 cfu/g of fresh forage). Silages were air stressed for 24 h at 28 and 42 d of storage and ensiled for 49 d before opening. Inoculation had no effect on acid end products, ethanol, number of yeasts, or aerobic stability compared with other treatments. Treatment with SSL decreased the amount of ethanol, had no effect on number of yeasts, and improved aerobic stability in a dose-dependent manner compared with other treatments. In experiment 3, WPC was untreated or treated with 2 L of SSL/t and ensiled for 5, 15, and 30 d. Treatment with SSL resulted in silage with fewer yeasts and lower concentrations of ethanol after all times of ensiling compared with untreated silage. In addition, SSL improved aerobic stability after each period of ensiling, but the effect was more at 15 and 30 d compared with 5 d of storage. Treating WPC with SSL can improve the aerobic stability of corn silage made in North America, and the effect can be observed as soon as 5 d after ensiling.  相似文献   

10.
Germination and growth of spores of butyric acid bacteria (BAB) may cause severe defects in semihard cheeses. Silage is the main source of BAB spores in cheese milk. The objectives of the study were to determine the significance of grass silages and corn silages as sources of BAB spores and to investigate the relationships between high concentrations of BAB spores in corn silage and aerobic deterioration. In the first survey, samples were taken from various locations in silos containing grass and corn silages and from mixed silages in the ration offered to the cows on 21 farms. We demonstrated that the quantity of BAB spores consumed by cows was determined by a small fraction of silage with a high concentration of spores (above 5 log10 BAB/g). High concentrations were most often found in corn silage within areas with visible molds (69% of the samples). Areas with visible molds in grass silage and surface layers of corn silage contained, respectively, 21 and 19% of the cases of concentrations above 5 log10 BAB spores/g. Based on these results, we concluded that currently in the Netherlands, corn silage is a more important source of BAB than is grass silage. In a second survey, 8 corn silages were divided into 16 sections and each section was studied in detail. High concentrations of BAB spores were found in only the top 50 cm of these 8 silages. Elevated concentrations of BAB spores were associated with different signs of aerobic deterioration. In 13% of the sections in corn silage with more than 5 log10 yeasts and molds/g, more than 5 log10 BAB spores/g were found. Sections with a temperature of more than 5°C above ambient temperature contained, in 21% of the cases, more than 5 log10 BAB spores/g. Concentrations above 5 log10 BAB spores/g were measured in 50% of the sections with a pH above 4.4. All sections with a pH above 4.4 also showed a temperature that was more than 5°C above ambient temperature and a concentration of yeasts and molds above 5 log10 cfu/g. Based on these results, we postulated that high concentrations of BAB spores in corn silage are the result of oxygen penetration into the silage, resulting in aerobic deterioration and the formation of anaerobic niches with an increased pH just below the surface. Growth of BAB in these anaerobic niches with an increased pH caused the locally high concentrations of BAB in corn silage.  相似文献   

11.
Whole-plant corn was harvested at 33 (normal) and 41% (moderately high) dry matter (DM) and ensiled in quadruplicate 20-L laboratory silos to investigate the effects of Lactobacillus buchneri 40788 (LB) or L. plantarum MTD-1 (LP) alone, or in combination, on the fermentation and aerobic stability of the resulting silage. Aerobic stability was defined as the amount of time after exposure to air for the silage temperature to reach 2°C above ambient temperature. The chopped forage was used in a 2 × 2 × 2 factorial arrangement of treatments: normal and moderately high DM contents, LB at 0 (untreated) or 4 × 105 cfu/g of fresh forage, and LP at 0 or 1 × 105 cfu/g. After 240 d of ensiling, corn silage harvested at the moderately high DM had higher pH, higher concentrations of ethanol, and more yeasts compared with the silage ensiled at the normal DM content. Inoculation with LB did not affect the concentration of lactic acid in silages with a moderately high DM, but decreased the concentration of lactic acid in the silage with normal DM. Higher concentrations of acetic acid were found in the silage treated with LB compared with those not treated with this organism. Inoculation with LP increased the concentration of lactic acid only in the silage with the normal DM content. The concentration of acetic acid was lower in silage treated with LP with a moderately high DM content, but greater in the silage treated with LP with the normal DM content when compared with silages without this inoculant. Appreciable amounts of 1,2-propanediol (average 1.65%, DM basis) were found in all silages treated with LB regardless of the DM content. The addition of L. buchneri increased the concentration of NH3-N in silages but the addition of L. plantarum decreased it. Aerobic stability was improved in all silages treated with LB, with greater aerobic stability occurring in the silage with moderately high DM compared with silage with normal DM content. Inoculation with LP had no effect on aerobic stability. There were no interactions between L. buchneri and L. plantarum for most fermentation products or aerobic stability of the silages. This study showed that inoculating whole-plant corn with L. buchneri 40788 or L. plantarum MTD-1 has different beneficial effects on the resulting silage. There appear to be no major interactions between these organisms when added together to forage. Thus, there is potential to add both organisms simultaneously to improve the fermentation and aerobic stability of corn silage.  相似文献   

12.
Chopped barley forage was ensiled untreated or treated with several doses (1 x 10(5) to 1 x 10(6) cfu/g of fresh forage) of Lactobacillus buchneri 40788 in laboratory silos and untreated or treated (4 x 10(5) cfu/g) in a farm silo. Silage from the farm silos was fed to lactating cows. In the laboratory silo, the effects of inoculation on fermentation and aerobic stability were also compared to silage treated with a commercial inoculant and a buffered propionic acid additive. Inoculation with L. buchneri 40788 decreased the final concentrations of lactic acid but increased concentrations of acetic acid and ethanol in silage from laboratory and farm silos. Silages stored in laboratory silos did not heat after exposure to air for 7 d and were then mixed with alfalfa silage and a concentrate to form total mixed rations (TMR) that were further exposed to air. The TMR containing silages treated with L. buchneri 40788 or a buffered propionic-acid-based additive took longer to heat and spoil than the TMR containing untreated silage or silagetreated with the commercial inoculant. Silage stored in a farm silo and treated with L. buchneri 40788 had fewer yeasts and molds than did untreated silage. Aerobic stability was greater in treated silage alone and in a TMR containing treated silage. Dry matter intake (18.6 kg/d), milk production (25.7 kg/d), and milk composition did not differ between cows fed a TMR containinguntreated or treated silage. These findings show that L. buchneri can improve the aerobic stability of barley silage in laboratory and farm silos and that feeding treated silage had no negative effect on intake or performance.  相似文献   

13.
Two experiments were conducted to determine the rumen fluid disappearance rates (kd) of β‐carotene, lutein, total carotene and total xanthophyll from lucerne (Medicago sativa) hay, in two ruminant species: Brahman steers (fat‐pigmenting) and Granadine goats (non‐pigmenting). Within species, the in vitro and the in situ methods were compared. The concentration of carotenoid compounds was determined by spectrophotometry and high performance liquid chromatography. The in vitro disappearance trends were linear for all compounds (P<0.01). β‐carotene kd were 0.13 and 0.37; lutein, 0.20 and 0.25; total carotene, 0.20 and 0.62 and total xanthophyll, 0.30 and 0.77 h −1 for steers and goats, respectively. The in situ disappearance trends were quadratic (P<0.01). Dry matter kd were 1.9 and 1.5% h−1; cellular content, 2.0 and 2.3; β‐carotene, 2.5 and 1.2; lutein, 2.5 and 1.5; total carotene, 2.2 and 1.0 and total xanthophyll, 2.1 and 1.1% h−1 for steers and goats, respectively. The large disappearance rates of carotenoids observed in the in situ method vs the virtual absence of disappearance in the in vitro method in both species, can be related to the dry matter and cellular content kd. These results suggest that carotenoids disappear probably by joining the cellular content and not by their direct destruction or by attack from the ruminal microorganisms, and the ruminal disappearance is independent of the species studied. © 1999 Society of Chemical Industry  相似文献   

14.
The objective of this study was to evaluate the effects of an additive comprising sodium benzoate, potassium sorbate, and sodium nitrite on the quality of silages fermented from various forage crops. Thirteen crops in 3 groups (differing in dry matter concentration and degree of ensilability) were treated with the additive mixture and compared with untreated control silages. The main focus was on yeast and Clostridia spp. activity in the silages, although other silage quality criteria also were measured. Treated silages from difficult-to-ensile crops at low dry matter were found to have significantly lower silage pH, fewer clostridial spores, and reduced concentrations of ammonia N, butyric acid, and ethanol. In addition, dry matter losses were reduced in treated silages compared with those receiving no additive. Similar results were observed in silages from easy or intermediate ensilable crops when the dry matter concentration was <300 g/kg. When the dry matter concentration was >350 g/kg, the treated silages contained less ammonia N, ethanol, and yeast for 3 out of 4 forages. All treated silages from all crops were aerobically stable during the examination time. The application of the tested additive mixture reduced the growth of undesirable microflora and thereby reduced silage losses and prolonged the aerobic stability of the silages.  相似文献   

15.
总结了我国50多年来对不同酒类酵母筛选也应用的研究成果,并通过大量翔实的数据详尽地阐释了酒类酵母不同的特性与作用,推出优良菌种,以达到优质高产、节约粮食之目的。酒类酵母分为酒精酵母、生香酵母、威士忌酵母。酒精酵母又分为小曲酒酵母、大曲酒酵母、小麦酒精酵母、甘蔗酒精酵母。四川小曲酒酵母以纳溪109号酵母较优良,黄酒126号酵母次之;大曲酒酵母以1308号较优,AS2.399次之;小麦酒精酵母以1308号酒精酵母较优;甘蔗酒精酵母则以川102号较优。(陶然)  相似文献   

16.
The objective of this study was to investigate whether higher lucerne (Medicago sativa; alfalfa) silage inclusion rate and longer lucerne chop length improves rumen function through increased provision of physically effective fiber, when included in a maize and lucerne silage-based total mixed ration. Diets were formulated to contain a 50:50 forage:concentrate ratio [dry matter (DM) basis] and be isonitrogenous and contain equal levels of neutral detergent fiber (320 g/kg). The forage portion of the offered diets was composed of maize and lucerne silage DM in proportions (wt/wt) of either 25:75 (high lucerne; HL) or 75:25 (low lucerne; LL). Second-cut lucerne was harvested and conserved as silage at either a long (L) or a short (S) chop length (geometric mean particle lengths of 9.0 and 14.3 mm, respectively). These variables were combined in a 2 × 2 factorial arrangement to give 4 treatments (HLL, HLS, LLL, LLS), which were fed in a 4 × 4 Latin square design study to 4 rumen-cannulated, multiparous, Holstein dairy cows in mid lactation. Effects on DM intake, chewing behavior, rumen volatile fatty acid concentration, rumen pH, rumen and fecal particle size, milk production, and milk fatty acid profile were measured. Longer chop length increased rumination times per kilogram of DM intake (+2.8 min/kg) relative to the S chop length, with HLL diets resulting in the most rumination chews. Rumen concentrations of total volatile fatty acids, acetate, and n-valerate were higher for the HLS diet than the other 3 diets, whereas rumen propionate concentration was lowest for the HLL diet. Physically effective fiber (particles >4 mm) percentage in the rumen mat was increased when L chop length was fed regardless of lucerne inclusion rate. No effect of treatment was observed for milk yield, although milk protein concentration was increased by L for the LL diet (+1.6 g/kg) and decreased by L for the HLL diet (?1.4 g/kg). Milk fat concentrations of total cis-18:1 (+3.7 g/100 g of fatty acids) and 18:3 n-3 (+0.2 g/100 g of fatty acids) were greater with HL. In conclusion, longer lucerne silage chop length increased time spent ruminating per kilogram of DM intake, but had no effect on rumen pH in the present study. Increasing dietary lucerne inclusion rate had no effects on rumination activity or rumen pH, but decreased the ratio of n-6:n-3 polyunsaturated fatty acid concentrations in milk fat.  相似文献   

17.
Three experiments were conducted to evaluate the effects of inoculation, maturity, and mechanical processing of corn silage on aerobic stability and pack density. Corn silage was stored in 20-L mini silos for the three aerobic stability experiments. Corn silage was stored in 80-L mini silos for the three pack-density experiments. The wet pack density of corn silage tended to decrease as maturity advanced in all of the pack-density experiments, and processed corn silage had a greater wet pack density compared with unprocessed corn silage in two of the three 20-L mini silo experiments. Aerobic stability, measured as the number of hours to reach 1.7 degrees C above ambient, was greater for processed corn silage in two of the three 20-L mini silo experiments, and was greater for inoculated corn silage across the three 20-L mini silo experiments. Inoculation of corn silage with lactic acid producing bacteria tended to improve aerobic stability of corn silage more than maturity and mechanical processing.  相似文献   

18.
An enzyme preparation containing cellulolytic, hemicellulolytic and amylolytic activities was added to whole crop maize before ensiling in laboratory or pilot-scale silos. In the enzyme-treated silages, 5–28% of the cell wall components were degraded. The reduction in starch contents relative to the control, ranged from 40 to 75%. Higher enzyme dosages and longer incubation periods increased the degradation. The enzyme-treated silages contained high concentrations of ethanol (2–3 mol kg–1 DM) and higher yeast counts. Counts of enterobacteria and lactic acid bacteria did not differ. Levels of lactic acid were increased in the enzyme-treated silages while acetic acid concentrations were similar. The starch in maize silage was degraded relatively easily by the amylase activity present in the enzyme preparation in comparison to the degradation of cell wall constituents. The liberated sugars were fermented to ethanol by yeasts. Probably the increased yeast count explains the observed lower aerobic stability of the enzyme-treated silages.  相似文献   

19.
Whole crop corn (DM 29.2%) and a total mixed ration (TMR, DM 56.8%) containing wet brewers grains, alfalfa hay, dried beet pulp, cracked corn, soybean meal, and molasses at a ratio of 5:1:1:1:1:1 on fresh weight basis, were ensiled with and without Lactobacillus casei or Lactobacillus buchneri in laboratory silos. The effects of inoculation on microbial counts, fermentation products, and aerobic stability were determined after 10 and 60 d. Untreated corn silage was well preserved with high lactic acid content, whereas large numbers of remaining yeasts resulted in low stability on exposure to air. Inoculation with L. casei suppressed heterolactic fermentation, but no improvements were found in aerobic stability. The addition of L. buchneri markedly enhanced the aerobic stability, while not affecting the DM loss and NH3-N production. Large amounts of ethanol were found when the TMR was ensiled, and the content of ethanol overwhelmed that of lactic acid in untreated silage. This fermentation was related to high yeast populations and accounted for a large loss of DM found in the initial 10 d. The ethanol production decreased when inoculated with L. casei and L. buchneri, but the effects diminished at 60 d of ensiling. Inoculation with L. buchneri lowered the yeasts in TMR silage from the beginning of storage; however, the populations decreased to undetectable levels when stored for 60 d, regardless of inoculation. No heating was observed in TMR silage during aerobic deterioration test for 7 d. This stability was achieved even when a high population of yeasts remained and was not affected by either inoculation or ensiling period. The results indicate that inoculation with L. buchneri can inhibit yeast growth and improve aerobic stability of corn and TMR silage; however, high stability of TMR silage can be obtained even when no treatments were made and high population (>10(5) cfu/g) of yeasts were detected.  相似文献   

20.
玉米胚芽超氧化物歧化酶提取及对酒精发酵的影响   总被引:1,自引:1,他引:1  
赵华  陶静 《酿酒科技》2005,(6):54-57
从玉米胚芽提取SOD的最佳工艺条件为:100g玉米中加入200mL0.05mol/L磷酸缓冲液,40℃浸泡玉米36h,淋干后分离胚芽与胚乳,再加入胚芽质量2倍的0.05mol/L磷酸缓冲液破碎后浸提1h,离心得SOD提取液,总酶活为22549.0u;然后添加硫酸铵依次达到饱和度40%和90%,进行除杂蛋白和盐析,离心后将沉淀冷冻干燥即得到SOD粗酶制剂,其比活为334.6u/mg蛋白。将分离后的胚乳和提取SOD后的胚芽残渣混合进行酒精发酵,淀粉出酒率达到53.16%,证明胚芽SOD提取不影响酒精发酵,且可降低酒精的生产成本。  相似文献   

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