The capacity of silage inoculant bacteria to bind aflatoxin B1 in vitro and in artificially contaminated corn silage

The objectives were to examine the aflatoxin B₁ (AFB₁)-binding capacity of silage bacteria and factors affecting the responses. Experiments 1 and 2 examined the effects of bacterial strain and population on the AFB₁-binding capacity of 10 bacteria. When applied at 10⁶ cfu/mL to an in vitro medium, only Lactobacillus plantarum PT5B bound the AFB₁ and the binding capacity was low (4%). When applied at 10⁹ cfu/mL, all 10 bacteria bound AFB₁, but L. plantarum R2014 (Lp) and EQ12, Lactobacillus buchneri R1102 (Lb), and Pediococcus acidilactici R2142 and EQ01 (Pa) had the greatest capacity (23.9 to 33%). Experiment 3 examined the AFB₁-binding capacity of viable and nonviable (HCl-treated) forms of Lp, Lb, and Pa at different pH. Nonviable Lb and Lp, but not Pa, increased AFB₁ binding. Binding of AFB₁ was greatest at pH 2.5 and least at pH 8. As the nonviable Lb and Lp that bound AFB₁ in experiment 3 would not be effective silage inoculants, experiment 4 examined effects of benign versus severe treatments (85 vs. 100°C; pH 2.5 vs. <1) on the viability of Lp, Lb, and Pa. The population of bacteria was reduced from 9 to 4 log cfu/mL by treatment with HCl at pH 2.5 and to 2 log cfu/mL by 85 or 100°C, whereas acidification at pH <1 eliminated the bacteria. Experiment 5 determined the effect of the ensiling duration and benign treatment methods [37 (viable cells) or 85°C (heated cells) or acidification with HCl at pH 2.5 (acid-treated cells)] on binding of AFB₁ and silage quality during the fermentation of corn forage. Corn forage was ensiled after treatment with only deionized water (control), AFB₁ (30 µg/kg of fresh forage), or a mixture of AFB₁ and 10⁹ cfu/g of each of the treated bacteria. Adding AFB₁ alone to corn forage reduced the pH decline during the first 3 d of ensiling and increased or tended to increase butyric acid concentration and final pH after ensiling for 21 d. Bacterial inoculation inhibited these negative effects. The fermentation profile of silage treated with Lb and Pa did not differ from those of the control silage. In all silages treated with the toxin, the AFB₁ concentration decreased linearly (from 30 to ≤0.35 µg/kg) within 3 d of ensiling. Certain silage bacteria can bind AFB₁ but the efficacy depends on several factors.     

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 dry matter content on the microbial community and on the effectiveness of a microbial inoculant to improve the aerobic stability of corn silage

Silage inoculants are commonly used as a tool to improve the fermentation and aerobic stability of corn silage fed to dairy cows. However, their effectiveness can be inconsistent. Our objective was to determine the effect of the dry matter (DM) content of freshly chopped whole-plant corn on its microbial community as affected by an inoculant containing Lentilactobacillus hilgardii, Lentilactobacillus buchneri, and Pediococcus pentosaceus on improving the aerobic stability of silage. Whole-plant corn was harvested at low (31.80%, LDM), medium (33.32%, MDM), or high (39.44%, HDM) DM content and treated with nothing (CTR) or an inoculant (INO) containing L. hilgardii CNCM I-4785 at 150,000 cfu/g fresh forage, L. buchneri NCIMB 40788 at 150,000 cfu/g fresh forage, P. pentosaceus NCIMB12455 at 100,000 cfu/g of fresh forage, β-glucanase (5,750 IU/g), and xylanase (30,000 IU/g) and ensiled for 20 and 60 d. Data were analyzed as a completely randomized design in a 3-by-2 factorial arrangement of treatments. Fresh LDM forage had a higher concentration of reducing sugars, a less rich, diverse, and even bacterial community, and greater relative abundance of Saccharomycetales than MDM and HDM forages. Silages at 20 and 60 d, inoculated LDM had a more modest proliferation of culturable lactic acid bacteria than inoculated MDM. At 20 d, regardless of treatment, LDM had greater concentrations of lactic and acetic acids. Also at 20 d, LDM had lower numbers of culturable yeasts but greater relative abundance of Enterobacteriaceae than MDM and HDM. For silage at 20 d, HDM silage was more aerobically stable than LDM and MDM and inoculation improved aerobic stability 1.8-fold compared with CTR. For silage at 60 d, there was an interaction between DM content and inoculation. The improvements in stability by inoculation, compared with CTR, were greater in MDM (261 vs. 41 h) and HDM (320 vs. 66 h) silages than in LDM (85 vs. 46 h). The lower DM content and possible slower pH decline in LDM might have facilitated the development of undesirable bacteria and coupled with its greater concentration of reducing sugars and lactic and acetic acids, which are substrates for aerobic microorganisms, might explain the more modest improvements in aerobic stability from inoculation in LDM compared with MDM and HDM. Our findings suggest that the DM content of whole-plant corn affected its epiphytic microbial community and the effectiveness of the inoculant, which improved aerobic stability at all DM but to a greater extent in HDM and MDM than in LDM, especially after 60 d of ensiling.     

Effect of replacing alfalfa silage with high moisture corn on nutrient utilization and milk production

Twenty-four multiparous lactating Holstein cows were blocked by days in milk and assigned to treatment sequences in a replicated 4x4 Latin square with 21-d periods. The four diets, formulated from alfalfa silage plus a concentrate mix based on ground high moisture ear corn, contained [dry matter (DM) basis]: 1) 20% concentrate, 80% alfalfa silage (24% nonfiber carbohydrates; NFC), 2) 35% concentrate, 65% alfalfa silage (30% NFC), 3) 50% concentrate, 50% alfalfa silage (37% NFC), or 4) 65% concentrate, 35% alfalfa silage (43% NFC). Soybean meal and urea were added to make diets isonitrogenous with equal nonprotein N (43% of total N). Intake of DM and milk yield indicated that adaptation was complete within 7 d of changing the diets within the Latin square. There were linear increases in apparent digestibility of DM and organic matter, and a linear decrease in neutral detergent fiber (NDF) digestibility with increasing dietary NFC. Solutions of significant quadratic equations yielded estimated maxima for intake of DM, organic matter, digestible organic matter, and NDF at, respectively, 37, 38, 43, and 27% dietary NFC. There were linear increases in yields of milk, protein, lactose, and solids not fat with increasing dietary NFC. Feed efficiency (milk/DM intake) yielded a quadratic response with a minimum at 27% dietary NFC. Maxima for milk fat content, fat yield, and fat-corrected milk yield were estimated to occur at, respectively, 30, 34 and 38% dietary NFC. In this short-term trial, maximal DM intake and fat-corrected milk yield indicated that the optimum concentrate for cows fed high moisture ear corn plus alfalfa silage as the only forage was equivalent to 37 to 38% dietary NFC; however, yields of milk, protein and solids not fat were still increasing at 65% dietary concentrate (43% NFC).     

Improving corn silage quality in the top layer of farm bunker silos through the use of a next-generation barrier film with high impermeability to oxygen

This study examined the effect on the fermentation, chemical, and microbiological quality of corn silage covered with a new-generation high oxygen barrier film (HOB) made with a special grade of ethylene-vinyl alcohol (EVOH) compared with a standard polyethylene film (PE). Two bunkers (farms 1 and 2) were divided into 2 parts lengthwise so that half of the silo would be covered with PE film and the other with HOB film. Plastic net bags with fresh chopped corn were buried in the upper layer (close to and far from the wall) and in the central part of the bunkers. During spring-summer consumption, the bags were unloaded, weighed, and subsampled to analyze the dry matter (DM) content, neutral detergent fiber and starch contents, pH, lactic and monocarboxylic acids, yeast and mold counts, aerobic and anaerobic spore-former counts, and aerobic stability. We also determined the economic benefit of applying the novel covering. The top layer of silage conserved under the HOB film had a higher lactic acid content and lower pH; lower counts of yeasts, molds, and aerobic and anaerobic spore-formers; higher aerobic stability; and lower DM losses than the silage conserved under the PE film. The use of the HOB film prevented almost all of the silage in the upper layer from spoiling; only 2 out of 32 samples had a mold count > 6 log₁₀ cfu/g. This led to a net economic gain when the HOB film was used on both farms due to the increased DM recovery and reduced labor time required to clean the upper layer, even though the HOB film cost about 2.3 times more than the PE film. Furthermore, use of the HOB film, which ensures a longer shelf life of silage during consumption, reduced the detrimental effect of yeasts, molds, and aerobic and anaerobic spore-formers on the nutritional and microbiological quality of the unloaded silage.     

不同微生物青贮剂对全株玉米青贮饲料的影响

选用两种不同的青贮发酵剂对全株玉米进行发酵,观察发酵8 d、10 d、20 d、40 d两种青贮发酵剂对全株玉米微生物消长及营养品质的影响。结果表明,经两种青贮发酵剂处理后,全株玉米青贮饲料均有酒香味;发酵前期（8 d、10 d）乳酸菌生长迅速,酵母菌生长相对缓慢。两种发酵剂对全株玉米青贮饲料的pH值、水分、粗蛋白、粗脂肪、粗灰分和粗纤维含量的影响差异不大,但对总酸、中性洗涤纤维和酸性洗涤纤维含量影响差异较大,青贮发酵剂B适合短期发酵使用,而青贮发酵剂A适合长期发酵保藏使用。两种青贮发酵剂处理的全株玉米青贮饲料中的限制因子（挥发性盐基氮、霉菌、黄曲霉毒素B1、玉米赤霉烯酮、呕吐毒素）均符合相关标准要求。     

Evaluation of two biodegradable coatings on corn silage quality

This experiment was performed to assess two different biodegradable coating formulations for the preservation of corn silage quality. Soy‐ and casein‐based biodegradable coatings were evaluated for their ability to exclude oxygen and preserve corn silage. Experiments were conducted under natural conditions outdoors. The effect of the coating composition on silage quality was compared with the quality of silage covered with a plastic (0.15 mm) (positive control) and uncovered (negative control) after 4 and 8 week periods. The results showed that the two biodegradable coatings offered the same level of silage protection during the overall experiment (8 weeks). As compared with the negative control, the two formulations prevented deterioration associated with air infiltration (heating, mold growth and dry matter losses) and limited the decrease in nutritive value. Also, the pH of the coated silage was significantly lower (P ≤ 0.05) than the negative control after 4 weeks of storage. Silage coated with the biodegradable coatings was able to maintain the pH below 4.5 during the first 4 weeks of storage. The decline in lactic acid concentration seems to have been initiated by the lactate‐utilizing yeasts, responsible for the increase in the silage pH. No visual growth of mold was observed in silage sealed with biodegradable coatings. This study showed that biodegradable coatings were able to protect the quality of silage during 4 weeks but the biodegradable coatings were not as good as plastic at preserving silage after 8 weeks of storage. Copyright © 2005 Society of Chemical Industry     

Effect of replacing corn silage with annual ryegrass silage on nutrient digestibility,intake, and milk yield for lactating dairy cows

Twenty Holstein cows were used in an 8-wk randomized block design study to determine the effects of replacing corn silage with ryegrass silage on nutrient intake, apparent digestion, milk yield, and milk composition. The 8-wk trial consisted of a 2-wk preliminary period followed by a 6-wk collection period. Experimental diets were formulated to provide 55.5% of the total dry matter (DM) as forage. Ryegrass silage was substituted for 0, 35, 65, and 100% of DM provided by corn silage. Dietary concentrations of neutral detergent fiber (NDF) and acid detergent fiber (ADF) increased as ryegrass silage replaced corn silage. Intake of DM and crude protein (CP) was similar for all treatments, but intake of NDF and ADF increased linearly as ryegrass silage replaced corn silage. Apparent digestibility of DM declined linearly, whereas digestibility of CP increased linearly as ryegrass silage replaced corn silage. Apparent digestibility of NDF and ADF was highest for the diets in which ryegrass or corn silages provided all of the forage, resulting in a quadratic response. Dry matter intake was not different among treatments. Yield of milk, fat, and protein increased as ryegrass silage replaced corn silage. No differences were observed for body weight change, body condition score, and serum urea nitrogen concentration, but serum glucose concentration increased with increasing dietary proportion of ryegrass silage. These results indicate that substituting ryegrass silage for a portion or all of the corn silage in diets fed to lactating dairy cows can improve yield of milk and components.     

Effects of an esterase-producing inoculant on fermentation, aerobic stability, and neutral detergent fiber digestibility of corn silage

This experiment evaluated effects of an inoculant containing esterase-producing bacteria on fermentation, aerobic stability, in situ dry matter digestibility (DMD), and neutral detergent fiber (NDF) digestibility (NDFD) of corn silage. Two corn hybrids grown on adjacent fields [Croplan Genetics 851RR2 (CS1) and Vigoro 61R36 (CS2)] were harvested at approximately 39% dry matter. Each forage was conserved in quadruplicate in 20-L mini silos with or without application of an inoculant at a level to achieve 1.0 × 10⁴ cfu/g of Lactobacillus casei and 1.0 × 10⁵ cfu/g of Lactobacillus buchneri. After 110 d of ensiling, silos were opened and silages were analyzed for chemical composition, fermentation indices, microbial counts, and aerobic stability. In situ DMD, 24-h and 48-h DMD, and NDFD were measured by incubating ground (6-mm) samples in triplicate in each of 2 lactating, fistulated dairy cows fed a corn silage-based diet. Inoculation decreased concentrations of total fermentation acids and lactate, as well as lactate to acetate ratio, and increased propionate concentration compared with the uninoculated control in CS1 but not CS2. Inoculation tended to decrease yeast counts of CS1 but increased yeast counts and tended to increase the mold counts of CS2. Consequently, inoculation improved the aerobic stability of CS1 by 57.3 h (98%) but decreased that of CS2 by 20.5 h (20%). Inoculation also increased the potentially degradable fraction of CS1 and the total degradable fraction, 24-h and 48-h DMD, and 48-h NDFD of CS2. Inoculation of CS1 modified the fermentation, improved the aerobic stability, and increased the potentially degradable DM fraction. Inoculation of CS2 did not affect fermentation, but decreased the aerobic stability and increased the total degradable DM fraction, 24-h and 48-h DMD, and 48-h NDFD.     

Effects of 8 chemical and bacterial additives on the quality of corn silage

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).     

Effects of tallow in diets based on corn silage or alfalfa silage on digestion and nutrient use by lactating dairy cows

Six multiparous Holstein cows (average 31 days in milk; 36.3 kg/d of milk) fitted with ruminal cannulas were used in a 6 x 6 Latin square with 21-d periods to investigate the effects of diets that varied in forage source and amount of supplemental tallow. Isonitrogenous diets in a 2 x 3 factorial arrangement were based on either high corn silage (40:10 corn silage to alfalfa silage, % of dry matter) or high alfalfa silage (10:40 corn silage to alfalfa silage, % of dry matter) and contained 0, 2, or 4% tallow. Intakes of dry matter and total fatty acids were lower when cows were fed the high corn silage diet. Tallow supplementation linearly decreased dry matter intake. Milk yield was unaffected by diet; yields of milk fat and 3.5% fat-corrected milk were higher for the high alfalfa silage diet but were unaffected by tallow. Milk fat percentage was higher for the high alfalfa silage and tended to decrease when tallow was added to the high corn silage diet. Contents of trans-C18:1 isomers in milk fat were increased by high corn silage and tallow, and tended to be increased more when tallow was fed in the high corn silage diet. Ruminal pH and acetate:propionate were lower when high corn silage was fed. Ruminal acetate:propionate decreased linearly as tallow increased; the molar proportion of acetate was decreased more when tallow was added to the high corn silage diet. Ruminal liquid dilution rates were higher for the alfalfa silage diet; ruminal volume and solid passage rates were similar among diets. Total tract apparent digestibilities of dry matter, organic matter, crude protein, starch, energy, and total fatty acids were unaffected by diet. Digestibilities of neutral detergent fiber, acid detergent fiber, hemicellulose, and cellulose were lower when high corn silage was fed. The high alfalfa silage diet increased intakes of metabolizable energy and N, and increased milk energy and productive N. Tallow decreased the amount of N absorbed but had few other effects on utilization of energy or N. Tallow linearly increased concentrations of nonesterified fatty acids and cholesterol in plasma; cholesterol was increased by high alfalfa silage. Overall, forage source had more pronounced effects on production and metabolism than did tallow supplementation. Few interactions between forage source and tallow supplementation were detected except that ruminal fermentation and milk fat content were affected more negatively when tallow was fed in the high corn silage diet.     

Effect of arachis oil on the conservation of heavily wilted herbage ensiled in plastic containers. I. Effect on silage fermentation quality, nutritive value, nutrient losses and intake by sheep

Arachis oil was added to heavily wilted herbage of approximately 40% dry matter, before ensiling in polyethylene containers. The oil was added at a mean level of 4·16% of the total dry matter ensiled. The mean dry matter loss from the two control and the two oil-treated silages teas approximately 13%. There was a lower loss as inedible waste in the oil-treated silages and mould growth appeared to be inhibited by the oil. There was a lower percentage of butyric acid and propioiuc acid in the oil-treated silages than in the control silages, this effect being statistically significant. Ensiling resulted in a greater fall in digestibility of the control material than in the oil-treated material. The oil-treated silages had higher metabolisable energy contents than the control silages but the dry matter intakes of both silages by sheep were low.     

Effect of applying inoculants with heterolactic or homolactic and heterolactic bacteria on the fermentation and quality of corn silage

This study examined the effect of applying different bacterial inoculants on the fermentation and quality of corn silage. Corn plants were harvested at 35% DM, chopped, and ensiled in 20-L mini silos after application of (1) deionized water (CON) or inoculants containing (2) 1 × 10⁵ cfu/g of Pediococcus pentosaceus 12455 and Propionibacteria freudenreichii (B2); (3) 4 × 10⁵ cfu/g of Lactobacillus buchneri 40788 (BUC); or (4) 1 × 10⁵ cfu/g of Pediococcus pentosaceus 12455 and 4 × 10⁵ cfu/g of L. buchneri 40788 (B500). Four replicates of each treatment were weighed into polyethylene bags within 20-L mini silos. Silos were stored for 575 d at ambient temperature (25°C) in a covered barn. After silos were opened, aerobic stability, chemical composition, and yeast and mold counts were determined. The DNA in treated and untreated silages was extracted using lysozyme/sodium dodecyl sulfate lysis and phenol/chloroform and used as a template for a conventional PCR with primers designed on the 16S rRNA gene to detect the presence of L. buchneri in all silage samples. Acetic acid concentration was greater in B2 silages versus others (6.46 vs. 4.23% DM). Silages treated with BUC and B500 had lower pH and propionic acid concentration and greater lactic acid concentration than others. The B500 silage had the greatest lactic:acetic acid ratio (1.54 vs. 0.41), and only treatment with BUC reduced DM losses (5.0 vs. 14.3%). Yeast and mold counts were less than the threshold (10⁵) typically associated with silage spoilage and did not differ among treatments. Consequently, all silages were very stable (>250 h). Aerobic stability was not improved by any inoculant but was lower in B500 silages versus others (276 vs. 386 h). The conventional PCR confirmed the presence of similar populations of L. buchneri in all silages. This may have contributed to the prolonged aerobic stability of all silages.     

Effects of lactic acid bacteria in a silage inoculant on ruminal nutrient digestibility,nitrogen metabolism,and lactation performance of high-producing dairy cows

Silage treated with lactic acid bacteria inoculants has been reported to increase ruminal microbial biomass when tested in vitro. Therefore, we tested if alfalfa silage inoculated with Lactobacillus plantarum MTD-1 would improve ruminal N metabolism and increase milk production in high-producing dairy cows. Twenty-eight early lactation Holstein cows (8 ruminally cannulated) were blocked by DIM and milk production; animals were used in a double crossover design consisting of four 28-d periods. Animals in each block were randomly assigned to 2 treatments: a diet containing uninoculated alfalfa silage (control) and a diet containing alfalfa silage inoculated with L. plantarum MTD-1 (LP). Diets were formulated to contain 50% of alfalfa silage, 16% crude protein, and 25% neutral detergent fiber (dry matter basis). Milk production and dry matter intake were recorded in the last 14 d of each period. Milk samples were collected twice at both daily milkings on d 20, 21, 27, and 28 of each period. On d 22, omasal samples were collected from the cannulated animals over a period of 3 d to quantify ruminal digestibility and nutrient flows. Data were analyzed using mixed models of SAS 9.4 (SAS Institute). Compared to the control, cows receiving the LP treatment had greater milk production (40.4 vs. 39.6 kg/d) and lower milk urea nitrogen concentration (11.6 vs. 12.7 mg/dL), despite minor changes in energy-corrected milk. Milk lactose concentration was greater in the milk produced by cows fed the LP treatment, which reflected a tendency for increased milk lactose yield. Although milk true protein concentration was lower for cows in the LP treatment, milk true protein yield was the same on both control and LP treatments. Improvements in milk production of animals under the LP treatment were associated with greater organic matter truly digested in the rumen, especially ruminal neutral detergent fiber digestion. Minor changes were observed in total omasal microbial nonammonia N flow in cows receiving the LP treatment. Therefore, alfalfa silage treated with L. plantarum MTD-1 may improve ruminal fermentation and milk production; however, because of a lack of response in ruminal N metabolism, these changes did not result in greater energy-corrected milk in high-producing dairy cows.     

Feeding value and nutrient preservation of high moisture corn ensiled in conventional silos forlactating dairy cows.

Sixty-one Holstein cows were used at varying stages of lactation to evaluate the feeding value of high moisture shelled corn ensiled in conventional silos. Control rations consisted of comparable amounts of conventional shelled corn dried in commercial drying facilities. Cows fed high moisture corn produced milk of higher fat content (3.09 versus 2.64%) and greater quantities of fat (.73 versus .64 kg) while they consumed less concentrate (9.28 versus 9.84 kg), resulting in the crude fiber content of the dry matter being 14.60% compared to 13.82% for control cows. Covariate adjustment of treatment means to equal intake of crude fiber eliminated differences above. Milk, 4% fat corrected milk, silage, total dry matter intake, and rumen volatile fatty acids were not significantly different between groups. Dry matter recovery following the ensiling process was 96.0 plus or minus 1.9% with 3.0 plus or minus 1.1% classified as spoiled corn, resulting in a total of 7% loss. Recoveries of all proximate constituents were similar to dry matter with the exception of ash (82.4%). Costs of the two systems were evaluated for varying corn prices and moisture.     

Short communication: Effect of corn planting population on phosphorus concentration and uptake in corn silage

Greater utilization of nutrients reduces the potential runoff of nutrients to bodies of water. The objective of this study was to determine the concentration of P in corn biomass to estimate the removal of P from the soil when planting corn at different population levels. Whole-plant corn samples were collected during an on-farm research project conducted previously. The study included 7 different growing and harvesting conditions. In each cornfield, corn was planted in plots at a theoretical seeding rate of 55,000, 70,000, 85,000, and 100,000 seeds/ha. Each seeding rate had 4 replicates within each field. At harvesting time, 5 consecutive plants from the 2 center rows and at 2 randomly selected spots within each plot were cut by hand at 15 cm above ground. Whole plants were weighed and chopped. After mixing thoroughly, a sample of the chopped material was placed in a bag, immediately placed in a cooler with dry ice, and transferred to the laboratory for storage. After thawing and drying, samples were ground and analyzed for P concentration. Single plant biomass and the number of standing plants at harvesting were used to determine dry matter yield. Total extraction of P was estimated as the product between plant biomass and P concentration. All variables were analyzed using a statistical model that included the effects of field, planting population, planting population nested within field, and random residual error. The concentration of P in the corn plant was greatest for 55,000 and 70,000 plants/ha (0.250% dry matter) and least for 85,000 and 100,000 plants/ha (0.235% dry matter), whereas the uptake of P through the harvested biomass increased when corn planting population increased. In conclusion, increasing the planting population of corn for silage can increase P uptake from the soil, therefore reducing the potential runoff of P to bodies of water.     

复合菌剂和酸化剂组合对玉米秸秆青贮的影响

以玉米秸秆为原料,设置对照组（CK）和5个试验组（分别添加布氏乳杆菌（L1）、植物乳杆菌（L2）、戊糖片球菌（L3）、复合菌剂（L4）、复合菌剂及酸化剂（L5））。选取不同发酵时间（0 d、15 d、30 d、45 d、60 d、90 d）取样,测定玉米秸秆中乳酸菌数、酵母菌数以及pH随时间的变化规律,并在青贮饲料发酵90 d结束后检测青贮发酵产物及有氧稳定性。结果表明,与对照组相比,乳酸菌剂的添加均能提高青贮饲料品质,但戊糖片球菌提升效果较差;复合菌剂与单独添加布氏乳杆菌或植物乳杆菌之间无明显差异（P＞0.05）;酸化剂的添加显著提高了青贮饲料有氧稳定性（P＜0.05）。     

Effect of re-ensiling on the quality of sorghum silage

The commercialization of silage in many countries, including Brazil, has increased in recent years. Re-ensiling of previously ensiled forage occurs when silage is relocated from one farm to another, where it will be compacted and sealed again. During this process, silage is exposed to oxygen before being ensiled, which may affect its quality. We exposed sorghum silage to air during the anaerobic storage phase to simulate the transportation of silages between farms. Experimental treatments included silage exposed to air for 0 or 12 h, with or without the use of an inoculant containing a mixture of Lactobacillus plantarum and the propionic bacteria Propionibacterium acidipropionici (1 × 10⁶ cfu/g of forage; Biomax corn, Lallemand, Saint-Simon, France), totaling 4 treatments: conventional silage, conventional silage with inoculant use, re-ensilage after exposure to air, and re-ensilage after exposure to air with use of an inoculant. The sorghum was stored in experimental silos containing about 9.0 kg of fresh forage per replicate. Treatments were tested in a factorial 2 × 2 design with 5 replicates each. Chemical composition, in vitro dry matter digestibility, fermentative characteristics, losses (due to gas, effluents, and total dry matter), microorganism counts, and aerobic stability of sorghum silage were evaluated. Dry matter content of sorghum before ensiling was 273.12 g/kg. The 12-h re-ensiling process increased the effluent loss of the silage when compared with conventional silage (456.42 vs. 201.19 g/kg of FM, respectively). In addition, re-ensiled silages presented lower concentrations of lactic acid and higher concentrations of propionic acid than the silages that had not been opened during storage. The aerobic stability of silage was not affected by the re-ensiling process and the use of inoculant. The use of inoculant increased the pH and loss of dry matter of the silages (4.23 vs. 3.98 and 14.05 vs. 7.82%, respectively) and therefore did not provide any benefits in this study.     

The effect of silage cutting height on the nutritive value of a normal corn silage hybrid compared with brown midrib corn silage fed to lactating cows

A brown midrib (BMR) hybrid and a silage-specific non-BMR (7511FQ) hybrid were harvested at a normal cut height leaving 10 to 15 cm of stalk in the field. The non-BMR hybrid was also cut at a greater height leaving 45 to 50 cm of stalk. Cutting high increased the concentrations of dry matter (+4%), crude protein (+5%), net energy for lactation (+3%), and starch (+7%), but decreased the concentrations of acid detergent fiber (−9%), neutral detergent fiber (−8%), and acid detergent lignin (−13%) for 7511FQ. As expected, the BMR corn silage was 30% lower in lignin concentration than 7511FQ. After 30 h of in vitro ruminal fermentation, the digestibility of neutral detergent fiber for normal cut 7511FQ, the same hybrid cut high, and the normal cut BMR hybrid were 51.7, 51.4, and 63.5%, respectively. Twenty-seven multiparous lactating cows were fed a total mixed ration composed of the respective silages (45% of dry matter) with alfalfa haylage (5%), alfalfa hay (5%), and concentrate (45%) (to make the TMR isocaloric and isonitrogenous) in a study with a 3 × 3 Latin square design with 21-d periods. Milk production was greater for cows fed the BMR hybrid (48.8 kg/d) compared with those fed the normal cut 7511FQ (46.8 kg/d) or cut high (47.7 kg/d). Dry matter intake was not affected by treatment. Feed efficiency for cows fed the BMR silage (1.83) was greater than for those fed high-cut 7511FQ (1.75), but was not different from cows fed the normal cut 7511FQ (1.77). Cows fed the BMR silage had milk with greater concentrations of lactose but lower milk urea nitrogen than cows on other treatments. Harvesting a silage-specific, non-BMR corn hybrid at a high harvest height improved its nutritive content, but the improvement in feeding value was not equivalent to that found when cows were fed BMR corn silage.     

Comparison of brown midrib sorghum-sudangrass with corn silage on lactational performance and nutrient digestibility in Holstein dairy cows

Total mixed rations containing brown midrib sorghum-sudangrass silage (bmrSS) or corn silage (CS) at either 35 or 45% of dietary dry matter were fed to Holstein dairy cows to determine the effect on lactational performance and nutrient digestibility. Twelve cows were assigned to 1 of 4 diets in replicated 4 × 4 Latin squares with 21-d periods. In vitro 30-h neutral detergent fiber digestion, measured before the start of the trial, was 46.0% for CS and 58.3% for bmrSS. Dry matter intake was greatest when cows were fed the 35% CS (23.4 kg/d) and 45% CS (23.2 kg/d) diets, was least when cows were fed the 45% bmrSS diet (17.6 kg/d), and was intermediate when cows were fed the 35% bmrSS diet (20.1 kg/d). The bmrSS diets resulted in greater body weight gain per 21-d period but similar body condition scores compared with the CS diets. Yield of solids-corrected milk (SCM) was similar among the diets. Efficiency (SCM:dry matter intake) was 28% greater for cows fed the bmrSS than those fed the CS diets. In vivo digestibilities of organic matter and crude protein were greater for the CS diets than the bmrSS diets, but total tract digestibilities of neutral detergent fiber and starch were similar among diets. Ruminal pH was greater when cows were fed the 45% bmrSS diet (6.58), was least when cows were fed the 35% CS (6.10) and 45% CS diets (6.13), and was intermediate when cows were fed the 35% bmrSS diet (6.42). The ratio of acetate to propionate was greater for the bmrSS diets (2.77) than for the CS diets (2.41), with no difference among diets in total volatile fatty acid concentrations (122 mM). In conclusion, cows fed bmrSS had greater efficiency of SCM production, higher ruminal pH, and greater acetate to propionate ratios than cows fed CS. With these diets fed in a short-term study, bmrSS appeared to be an effective alternative to the CS hybrid when fed at either 35 or 45% of dietary dry matter.