Academic literature on the topic 'Silage Clostridium'

ABSTRACT A PCR-denaturing gradient gel electrophoresis (DGGE) method was used to examine on-farm sources of Clostridium cluster I strains in four dairy farms over 2 years. Conventional microbiological analysis was used in parallel to monitor size of clostridial populations present in various components of the milk production chain (soil, forage, grass silage, maize silage, dry hay, and raw milk). PCR amplification with Clostridium cluster I-specific 16S rRNA gene primers followed by DGGE separation yielded a total of 47 operational taxonomic units (OTUs), which varied greatly with respect to frequency of occurrence. Some OTUs were found only in forage, and forage profiles differed according to farm location (southern or northern Québec). More clostridial contamination was found in maize silage than in grass silage. Milk represented a potential environment for certain OTUs. No OTU was milk specific, indicating that OTUs originated from other environments. Most (83%) of the OTUs detected in raw milk were also found in grass or maize silage. Milk DGGE profiles differed according to farm and sampling year and fit into two distinct categories. One milk profile category was characterized by the presence of a few dominant OTUs, the presence of which appeared to be more related to farm management than to feed contamination. OTUs were more varied in the second profile category. The identities of certain OTUs frequently found in milk were resolved by cloning and sequencing. Clostridium disporicum was identified as an important member of clostridial populations transmitted to milk. Clostridium tyrobutyricum was consistently found in milk and was widespread in the other farm environments examined.

AbstractIntroductionSilage quality deteriorates with Clostridium spp. contamination, and if consumed, such silage jeopardises herd health and productivity. Minimising its occurrence reduces economic and animal welfare risks. The study investigated the influence of environmental and technological determinants on the Clostridium genus’ occurrence in silage.Material and MethodsAnalyses were conducted on 305 silage samples directly collected from farms located in all Polish provinces. Cultures and isolates were evaluated phenotypically and examined for occurrence of Clostridium spp., particularly C. perfringens and C. botulinum using PCR techniques. The results were statistically analysed using the ᵡ2 test for continuous and Student’s t-test for non-continuous values.ResultsThe most influential effect on Clostridium spp. occurrence is exerted by factors potentially associated with primary production, like the type of fertilisation and the contamination level of the ensiled feed material. Clostridium spp. was detected in 232 (76%) samples, and C. perfringens strains, predominantly toxinotype A, in 79 (26%). C. botulinum occurrence was not detected.ConclusionsDeterioration of silage by clostridia could be prevented by a properly conducted ensiling process with the addition of starter cultures, but the presence of spores mainly depends on primary production and the extent of contamination of the feed material.

AbstractThe successful ensiling of lucerne (Medicago sativa L.) depends on a rapid acidification in the silo and consequently relies on a sufficient proliferation of, particularly homofermentative, lactic acid bacteria. Similarly, growth of spoilage bacteria, such as enterobacteria and clostridia, must be suppressed and silage additives are therefore frequently applied to promote favourable conditions during ensiling. Three silage additives or soil were applied during lucerne ensiling and investigated for their effects on silage quality characteristics and abundances of total bacteria as well as the bacterial key players Lactobacillus spp., homofermentative Lact. plantarum, heterofermentative Lact. buchneri, Clostridium spp. and Enterobacteriaceae after 30 days of storage. Inoculation with viable Lact. plantarum resulted in highest concentration of this species and excellent silage quality, i.e. high lactic acid concentration coupled with low acetic acid and ammonia-nitrogen concentrations. A sodium nitrite and hexamine-based additive did not support growth of lactic acid bacteria, which was also apparent by higher pH and low lactic acid concentration. No effect of treatments was found on spoilage-related enterobacteria and clostridia, even not when adding soil to lucerne to increase initial clostridial contamination. However, soil treatment resulted in increased ammonia-nitrogen and acetic acid concentrations. Consequently, among the bacterial key players, lactic acid bacteria concentrations were related to silage quality. Regarding spoilage bacteria, however, alterations in silage quality characteristics were not reflected in the abundances of enterobacteria and clostridia. Future investigations should underpin the present findings and help to understand how silage additives affect microbial key players and silage fermentation.

Clostridia are anaerobic spore-forming bacteria, which degrade carbohydrates to butyric acid, carbon dioxide, hydrogen and other compounds. These bacteria are commonly found in feces of ruminants, from where they can enter to udders and milk via manure or fodder. This study was done to find a sustainable sanitation method to control the resistant clostridial spores as they are difficult to control in the food processing industry. Clostridia spoil cheeses and other dairy products, and thereby increase the carbon footprint of products and cause economical losses in the dairy industry. The efficacy of two organic peroxides; peracetic acid (PAA) and performic acid (PFA) was tested against 30 clostridia strains isolated from cattle slurry, silage, or spoiled cheeses. PAA, at a concentration of 220 mg L−1, only eliminated 6/30 clostridia strains, whereas PFA totally eliminated 26/30 clostridia strains at a concentration of 120 mg L−1. PFA therefore seems to be a more potent disinfectant than the more commonly used PAA. PFA is an effective disinfectant against Clostridium tyrobutyricum and other resistant clostridia at 120 mg L−1 for 5–10 min contact time at room temperature.

Abstract Fresh forage crops have traditionally been preserved by fermentation, either based on the spontaneous fermentation by epiphytic lactic acid bacterial populations or driven by the addition of lactic acid bacteria inoculant cultures. Although this method of preservation is effective at retarding the spoilage and pathogenic bacteria it does not eliminate these organisms from the forage. Spore-forming and other bacteria are often able to survive the low pH and organic acid levels in the fermented forages and outgrow during feed-out and in the animal. The purpose of this research was to understand the levels and diversity of pathogens in silage systems as an important prerequisite to develop effective ways to control them. From February 2016 to December of 2019, 866 corn silage samples and 577 haylage samples were collected from 457 US dairy farms across 27 states to assess the pathogenic levels in silage. Results indicate the clostridia levels in the haylage samples averaged 9.4 x 103 cfu/g with a range of less than 10 cfu/g to 4.1 x 106 cfu/g. Corn silage had a significantly lower level of clostridia (p<0.05) averaging 2.3 x 103 cfu/g. Clostridium perfringens was the dominant species identified in both haylage and corn silage and accounted for more than 60% of all the clostridia isolates. The other major clostridia species identified were C. beijerinckii, Paraclostridium bifermentens and C. butyricum. E. coli levels were also determined in the haylage and corn silage samples. In haylage, the average E. coli level was 2.1 x 104 cfu/g and ranged from less than 10 cfu/g to 2.5 x 106 cfu/g and were significantly higher (p<0.05) than levels detected in corn silage (average of 5.4 x 101 cfu/g). Further work is underway to determine the source of these pathogens and methods of controlling through the fermentation process.

Recycling broiler litter (BL) nutrients is an important strategy for sustainable forage production. However, BL can contain Clostridia bacteria that can contaminate forages at harvest, resulting in poor ensilage quality and botulism-related animal health risks. A better understanding of the effects of BL amendment on alfalfa (Medicago sativa L.) production and ensiling is beneficial for promoting manure-based alfalfa production. This 2-year study examined the effects of high-level BL (HBL) at 112 kg N ha−1 and low-level (LBL) at 56 kg N ha−1 on alfalfa forage production, fermentation characteristics, and Clostridium botulinum concentrations in silage and haylage produced from 350 g dry matter (DM) kg−1 forage and 500 g DM kg−1 forage respectively, and soil characteristics compared to a control treatment (CT). Results showed that the application of BL did not affect forage production (12.8–13.1 MG ha−1) and nutritive value. The alfalfa produced high forage yield with superior ensilabilty in the second year. The BL application increased soil NH4-N, Ca, Fe, and B, but did not affect fermentation characteristics or Clostridium botulinum concentrations in ensilage. Silage had superior fermentation quality, and Clostridium botulinum concentration was found to be higher than in haylage. Broiler litter fertilization for alfalfa is environmentally safe and has forge production, ensilage fermentation quality, and botulism risks similar to CT.

A novel anaerobic, mesophilic, hydrogen-producing bacterium, designated strain M2/40T, was isolated from a mesophilic, two-phase, laboratory-scale biogas reactor fed continuously with maize silage supplemented with 5 % wheat straw. 16S rRNA gene sequence comparison revealed an affiliation to the genus Clostridium sensu stricto (cluster I of the clostridia), with Clostridium cellulovorans as the closest characterized species, showing 93.8 % sequence similarity to the type strain. Cells of strain M2/40T were rods to elongated filamentous rods that showed variable Gram staining. Optimal growth occurred at 35 °C and at pH 7. Grown on glucose, the main fermentation products were H2, CO2, formate, lactate and propionate. The DNA G+C content was 29.6 mol%. The major fatty acids (>10 %) were C16 : 0, summed feature 10 (C18 : 1ω11c/ω9t/ω6t and/or unknown ECL 17.834) and C18 : 1ω11c dimethylacetal. Based on phenotypic, chemotaxonomic and phylogenetic differences, strain M2/40T represents a novel species within the genus Clostridium , for which we propose the name Clostridium bornimense sp. nov. The type strain is M2/40T ( = DSM 25664T = CECT 8097T).

Silage contains a number of potential hazards to the safety and quality of milk and dairy products. This paper reviews the present knowledge about silage as a source of (1) spores of anaerobic spore-formers (Clostridium species) and aerobic spore-formers (mainly Bacillus and Paenibacillus species), (2) the zoonotic pathogenic bacteria Listeria monocytogenes and Escherichia coli, and (3) mycotoxins. A distinction is made between field-derived mycotoxins, i.e. mycotoxins that are formed during growth of crops in the field, and ensilage-derived mycotoxins, i.e. mycotoxins that are formed after ensiling. The routes of transmission of these hazards from feed to milk, the effect of pasteurization of milk, and reduction strategies are discussed. Aerobic deterioration of silages is a major factor influencing levels of spores of both aerobic and anaerobic spore-formers, L. monocytogenes, and certain mycotoxins.

Bacteria produce hydrogen during anaerobic dark digestion of carbon rich natural resources including renewable cellulosic materials. The purpose of this work was to study the impact of maize silage pretreatment with Trichoderma fungi, bioaugmentation with defined bacterial inocula and/ or biostimulation with humic acids and an additional inorganic nitrogen source on the fermentative hydrogen production in laboratory batch assay. Experiments were carried out with and without Trichoderma asperellum pretreated silage. The selected bacterial inocula consisted of Clostridium, Enterobacter and Tissierella species, with or without Bacillus mycoides. Headspace gas composition, the amount of dry particulate matter, chemical oxygen demand and concentration of volatile fatty acids in liquid were determined. Bacterial communities were studied with fluorescence in situ hibridization. The predominant cultivable microbial species were isolated and identified. The study demonstrated a significant increase of hydrogen production from maize silage by indigenous bacteria after pretreatment with Trichoderma in comparison with silage untreated with Trichoderma. From tested factors, pretreatment, biostimulation with additional nutrients (ammonium nitrate and/ or humic acids) and bioaugmentation with defined bacterial inocula, pretreatment demonstrated significant improvement of hydrogen production from maize silage. Thereby, aerobic treatment with Trichoderma could be recommended for the pretreatment of silage for the purpose of fermentative production of hydrogen.

One of the most serious and economically important defects caused by clostridia in milk products is the late blowing of semi-hard cheeses.

Clostridia occur naturally in soil and can contaminate milk through crops contaminated by dung and soil followed by a less successful silage process, that give them opportunity to grow unaerobically. When anaerobic conditions occur, such as storage of semi-hard cheese, they ferment lactic acid to butyric acid and the gases CO₂ and H₂.

At the fusion of Arla and MD Foods, a series of changes were conducted on the MPN method for lactic acid fermentation for clostridia in milk. These changes resulted in an increased accuracy due to an increased number of test tubes and the change of media from MRCM to BBB, Bryant & Burkey Broth, that was thought to be more selective for Cl. tyrobutyricum, the organism mostly found in hard cheese. When the number of dairy farmers that were given quality reduction fines increased, the new method was suspected and a validation was conducted.

The validation included inoculation of different clostridia and bacillus strains into BBB substrate and enzymatic testing of positive samples with Rapid ID 32A. The inoculation result showed that almost all tested different clostridia strains could grow in BBB substrate.

Test on BBB positive tubes with Rapid ID 32A resulted in 95% clostridia of which 70% was Cl. tyrobutyricum. These results correlated well with earlier studies on MRCM substrate and the increase in quality reduction fines probably depended on the larger number of test tubes used in the new method rather than the change of substrate.

Clostridier eller främst Cl. tyrobutyricum är den art som i de flesta fall orsakar feljästa ellersönderjästa ostar, vilket är ett välkänt problem inom mejeriindustrin. Clostridiesporer finns naturligt i jord och hamnar i mjölkråvaran via gröda som kontaminerats med gödsel och jord och som tillsammans med en mindre lyckad ensileringsprocess gör att clostridierna växer till. När anaeroba förhållanden uppstår, såsom vid lagring av hårdost, förjäser clostridierna laktat och smörsyra varvid vätgas och koldioxid bildas.

I samband med fusionen av Arla/MD Foods, genomfördes metodförändringar för MPN-metoden för laktatjäsande clostridier i mjölk, som används inom mjölkbedömningen. Dessa förändringar innebar en skärpning i noggrannheten genom att man ökade antal rör, samt ett substratbyte från MRCM till BBB, Bryant & Burkey Broth, som ansågs mer gynnsamt för Cl. tyrobutyricum.

Då antalet mjölkproducenter som fick kvalitetsavdrag ökade, riktades misstankar mot den nya metoden och en validering genomfördes.

Resultatet av valideringen, som innebar ympning av renkulturer, utodling av positiva rör med efterföljande typning, visade att de flesta av de tillsatta stammarna av clostridier hade förmågan att ge ett positivt utslag vid tillsats av renkulturer. Utodling och typning av positiva rör visade att ca 70 % av de positiva utslagen innehöll Cl. tyrobutyricum och hela 95 % någon clostridieart. Dessa resultat korrelerar med tidigare studier på MRCM-substrat och ökningen av positiva utslag berodde troligtvis på det ökade antalet rör som den nya metoden innebar.

Ziel der vorliegenden Arbeit war zum einen die Ermittlung des im Grünfutter notwen-digen Mindest-Nitratgehaltes zur Erzielung buttersäurefreier Silagen, wobei TS-Gehalt und Z/PK-Quotient des Ausgangsmaterials sowie dessen Belastungsgrad mit Clostridiensporen berücksichtigt wurden. Dazu wurden zwei mehrfaktorielle Laborsi-lierversuche durchgeführt, bei denen eine Variationsreihe des Nitratgehaltes (0,01...0,3 % NO3-N in TS) mit Variationsreihen des TS-Gehaltes (ca. 14...40 %) und des Z/PK-Quotienten (1,5...3,1) systematisch kombiniert wurden. Jede Wertekombi-nation wurde sowohl mit sauber geerntetem Grünfutter als auch mit Clostridienspo-ren kontaminiertem Grünfutter geprüft. Die Silagen wurden nach 180 Tagen Lage-rungsdauer untersucht. Zum anderen wurde die Dynamik der Clostridienentwicklung im Gärungsverlauf in Abhängigkeit von TS-Gehalt, Säuerungsintensität und Nitratge-halt geprüft. Jede Stufe des TS-Gehaltes (20, 30, 40 und 50 %) wurde mit Zusätzen von Nitrat, Milchsäurebakterien (MSB) bzw. MSB + Glucose und MSB + Nitrat ange-setzt. Das Ausgangsmaterial (Dac. glomerata, nitratfrei) war durchgehend mit Clostridiensporen kontaminiert. Die Untersuchung der Silagen erfolgte 3, 7, 14, 28, 56 und 180 Tage nach dem Ansatz. Der Konservierungserfolg bei der Silierung hängt nicht nur vom TS-Gehalt und Z/PK-Quotienten sondern auch vom Nitratgehalt und Clostridiensporenbesatz des Aus-gangsmaterials ab. Bei sehr niedrigem Nitratgehalt des Grünfutters liegt ein erhöhtes Risiko für die Entstehung von Buttersäure in der Silage vor, auch bei dem als leicht vergärbar geltendem Grünfutter (VK > 45) und auch dann, wenn es im sauber geern-tetem Zustand einsiliert worden ist. Bei weiter erhöhten VK-Werten, > 45 (durch Er-höhung des TS-Gehaltes und/oder Z/PK-Quotienten), wird die Höhe der Buttersäure-gehalte zwar eingeschränkt. Zur sicheren Ausschaltung von Buttersäuregärung ist jedoch auch hier ein gewisser Nitratgehalt notwendig. Bei der Silierung nitratfrei-en/nitratarmen Grünfutters nimmt das Fehlgärungsrisiko mit dem Belastungsgrad an Clostridiensporen zu. Der notwendige Mindest-Nitratgehalt (MNG) hängt sowohl vom VK-Wert als auch vom Kontaminationsgrad des Grünfutters mit Clostridiensporen ab. Er ist um so niedriger, je höher der VK-Wert und geringer der Kontaminationsgrad ist, und umgekehrt. (MNG (% NO3-N in TS) für sporenarmes Grünfutter = 0,24 - 0,0035 . VK MNG (% NO3-N in TS) für sporenreiches Grünfutter = 0,20 - 0,0021 . VK) Hohe Clostridiensporengehalte lagen vor allem in buttersäurehaltigen Silagen vor und insbesondere dann, wenn das Grünfutter sehr geringe Nitratgehalte aufwies. Zwischen der Höhe der Buttersäuregehalte und dem Clostridiensporengehalt besteht jedoch kein direkter Zusammenhang. Erhöhung des TS-Gehaltes bewirkt eine Ein-schränkung der Clostridienentwicklung. Ein Rückgang des Sporengehaltes im Ver-gleich zum Ausgangsmaterial (nitratfrei) lag aber erst bei einem TS-Gehalt von etwa 50 % vor. Durch Zusätze von MSB sowie MSB + Glucose konnte die Milchsäuregä-rung deutlich intensiviert werden. Ein sehr geringer pH-Wert war schon am 3. oder 7. Lagerungstag erreicht. Buttersäuregärung war aber erst bei TS-Gehalten > 40 % ausgeschaltet. Eine Einschränkung der Sporenbildung lag ebenfalls erst bei TS-Gehalten über 40 % vor. Bei Nitratzusatz blieben die Silagen aller TS-Stufen bis zur Auslagerung buttersäurefrei. Die Sporengehalte gingen in allen TS-Stufen während des Gärungsverlaufes kontinuierlich zurück. Bei steigenden TS-Gehalten war der Rückgang der Sporengehalte verlangsamt. Durch die Kombination von MSB und Nit-rat konnte nicht nur ein sicherer Erfolg bei der Unterbindung von Buttersäurebildung und Laktatabbau sondern auch eine starke Verminderung der Sporengehalte erreicht werden.
The first aim of this work was to determine the minimum content of nitrate (MCN) which is required to get silage free of butyric acid. For it, two multi-factorial experi-ments with orchardgrass were carried out under laboratory condition. In this experi-ments, nitrate content (0.01 ... 0.3 % N in DM) was systematically combined with staggered levels of the dry matter (DM) content (14 ... 40 %) and of the ratio of water-soluble carbohydrate to buffering capacity (WSC/BC: 1.5 ... 3.1). All variants were tested with forage without or with addition of clostridial spores. The silages were ana-lysed after 180 days of incubation. The second aim of this study was to explain the dynamic of clostridial development during ensilage, depending on DM content, intensity of lactic acid formation, and ni-trate content. orchardgrass (free of nitrate) with 4 levels of DM (20, 30, 40, and 50 %) was firstly contaminated with clostridial spores about 104 / g FM. Then it was ensi-laged with following treatments: without additives, with inoculation of lactic acid bac-teria (LAB) alone or in combination with 2 % Glucose in FM (LAB+G), with nitrate addition (0.1 and 0.15 % N in DM), and with LAB plus nitrate 0.1 % N in DM. The si-lages were analysed 3, 7, 14, 28, 56, and 180 days after ensiling. Results showed that silage quality not only depends on DM content and ratio of WSC to BC, but also depends on nitrate content and extent of clostridial spores in forage. With an extremely low content of nitrate a high risk of butyric acid formation is given in silages, even if the ensiling material had a high ensilability (FC ³ 45) and a very low content of clostridial spores. The butyric acid concentration decreased with in-creasing DM content from 14 to 40 % or with increasing WSC/BC-ratio. But to get the silages free of butyric acid, a certain amount of nitrate was required. By adding clos-tridial spores in fodder the risk of butyric acid formation was increased, especially in case of material lacking in nitrate. The value of MCN depends on ensilability of the forage, as measured by DM-content and WSC/BC-ratio or by fermentability coefficient (FC) = DM+8WCS/BC, as well as depends on content of clostridial spores in the material used. The higher the FC-value and the lower the spores content is, the less nitrate is required to get silage free of butyric acid. MNC (% N in DM) for very low contaminated forage = 0.24 - 0.0035.FC MNC (% N in DM) for high contaminated forage = 0.20 - 0.021.FC High content of clostridial spores was especially found in silages containing butyric acid, which were made from forage with very low nitrate content (£ 0.02 % N in DM). But a strong relationship was not found between butyric acid and spores content. By increasing DM content the development of clostridia during ensiling was limited. A continuous decrease of spores content, in comparison with the forage before ensiled, was observed at first by increasing DM content to 50 %. By inoculation with LAB or LAB+G the lactic acid formation was strongly stimulated. A very low pH was reached 3 or 7 days after ensiling. But the butyric acid formation could be firstly prevented by increasing DM content to over 40 %. For all levels of DM, by nitrate addition the silages remained no butyric acid during the whole period of incubation. The concentration of clostridial spores decreased continuously during ensilage. This decrease was slower with increasing DM content . By combination of LAB with nitrate a reliable prevention of butyric acid formation and a fast decrease in spores concentration were reached.

Ziel der Arbeit war es, die Besonderheiten des Gärungsverlaufes bei der Silierung von nitratarmem Grünfutter aufzuklären. Dazu wurden sechs Silierversuche zur Untersuchung des Gärungsverlaufes mit unterschiedlichem Clostridiensporenbesatz durchgeführt. Dabei wurde auch die Wirkung eines Zusatzes von 0,05 bzw. 0,1 % N / TS als Nitrat und Nitrit sowie Zusätze von Inoculantien und Ameisensäure geprüft. Weiterhin wurde untersucht, ob die unter Laborbedingungen gefundenen Auswirkungen des Fehlens von Nitrat ebenso bei Grünfutter, das unter praxisnahen Bedingungen geerntet wurde, auftreten. Zur Fragestellung, welche Siliermittel bei nitratarmem Grünfutter eingesetzt werden können, wurde auch hier der Zusatz von zwei MSB-Präparaten und Ameisensäure, sowie eines nitrithaltigen Siliermittels bei geringem und erhöhtem Clostridiensporengehalt des Siliergutes geprüft. Als Ergebnis dieser mehrjährigen, umfangreichen Untersuchungen mit verschiedenen Futterpflanzen und unterschiedlicher Clostridiensporenbelastung hatte sich gezeigt, daß der Verlauf der Stoffumsetzungen und das Gärproduktmuster am Ende der Gärung in Abhängigkeit vom Nitratgehalt wesentlich unterschiedlich ist. In Silagen aus nitratarmem Grünfutter trat Buttersäure bereits von Gärbeginn und parallel zur Milchsäuregärung auf. Die Essigsäuregehalte waren stets sehr niedrig. Anaerob stabile und instabile Silagen aus nitratarmem Grünfutter weisen in allen Stadien des Gärungsprozesses ein völlig anderes Verhältnis zwischen Buttersäure und den übrigen Merkmalen des unerwünschten Stoffabbaus - Essigsäure, Ammoniak, pH - auf als Silagen aus nitrathaltigem Grünfutter. Für die Einschätzung der Vergärbarkeit sind außer TS und Z/PK auch der Nitratgehalt sowie epiphytischer Keimbesatz und Clostridiensporengehalt des AM zu berücksichtigen. Bei Fehlen von Nitrat besteht, unabhängig von der nach TS und Z/PK vorhergesagten Vergärbarkeit, ein besonderes Risiko für das Auftreten von Buttersäure. In Abhängigkeit vom Aufwuchs war die Einschätzung der Vergärbarkeit des Grünfutters verschieden und es trat eine unterschiedliche Gärqualität der Silagen auf. Bei nitratarmem Grünfutter ist der strategische Einsatz von MSB-Präparaten zu empfehlen. Das nitrithaltige Siliermittel hatte sich insbesondere bei erhöhter Clostridiensporenbelastung und/oder niedrigem TS-Gehalt des Grünfutters als sehr wirksam erwiesen. Bei Anwendung des derzeit gültigen, für Silagen aus nitratreichem Grünfutter entwickelten DLG-Beurteilungsschlüssels auf Silagen aus nitratarmem Ausgangsmaterial ist mit einer Fehlbewertung zu rechnen.
The object of this work is to explain the distinctive feature of ensilage of green forage low in nitrate. The fermentation process of ensiling green forage low in nitrate was proved in 6 experiments with different content of spores of clostridia. In all experiments the green forage was ensiled with following treatments: without additives (control), with 0,05 and 0,1% N / DM as nitrate or nitrite, with lactic acid bacteria and formic acid. Furthermore the effects of absence of nitrate, proved under laboratory conditions, has been investigated in experiments with green forage produced under practical conditions. The treatments were the same as mentional above. As a result of this several years and extensive investigations with different green fodder and different content of spores of clostridia it was shown that metabolism during fermentation process and pattern of fermentation products in the end of fermentation are significant different depending on content of nitrate in green forage. In ensiling material low in nitrate butyric acid was formed already at the beginning of the fermentation process, parallel to the lactic acid fermentation. The content of acetic acid was always extremely low. In comparison with silages from green forage high in nitrate anaerobe stable or unstable silages show a different ratio between butyric acid and other characteristics of undesirable decomposition during fermentation - acetic acid, ammonia, pH - in equal fermentation stages. In summary, one can say that epiphytic lactic acid bacteria, content of clostridia spores and nitrate of herbage take into account to judge the fermentability more than previous, together with DM and WSC/BC. Furthermore the judgement of herbage fermentability and the fermentation quality of silages were different depending on number of growth. In silages low in nitrate is an especially risk for occurrence of butyric acid, independing on judgement of fermentability on the basis of DM and ratio of watersoluble carbohydrates to buffering capacity. It`s advisable to use lactic acid bacteria additives (inoculants) always for ensiling green forage low in nitrate. The additive with nitrite has proved as most effectively especially for green forage high in clostridia spores and/ or low content of dry matter of green forage. It is very probably, that the use of current DLG- evaluation system to estimate the fermentation quality, developed for silages from green forage high in nitrate, is not correct and leads to error of judgement of silages from green forage low in nitrate.

O objetivo desse trabalho foi descobrir melhores estratégias de controle de perdas em silagens de cana-de-açúcar, utilizando combinações de aditivos químicos e microbianos ou estratégias de vedações. No primeiro experimento o intuito foi estudar estratégias de controle de clostrídios em silagens de cana-de-açúcar aditivadas com cal virgem. Os tratamentos foram: 1) controle; 2) 1,5% cal virgem (Cal); 3) 1,5% cal virgem + 5×105 ufc/g Lactobacillus plantarum Ma 18/5U (Cal+LP); 4) 1.5% cal virgem + 5×105 ufc/g Lactobacillus buchneri 40788 (Cal+LB); 5) 1,5% cal virgem + 0,07% nitrito de sódio (Cal+Nitrito); 6) 1,5% cal virgem + 0,15% benzoato de sódio (Cal+Benzoato). Como silos experimentais foram utilizados baldes plásticos com capacidade de 20 L. A cal não foi eficiente em diminuir perdas em relação ao controle (20,6% e 19,1%, respectivamente) já as combinações cal+Benzoato, cal+Nitrito, cal+LB e cal+LP, diminuíram perdas, apresentando os valores de 11,2%, 14,1%, 14,1% e 13,9%, respectivamente. A estabilidade aeróbia das silagens tratadas com cal (172 h), cal+Benzoato (155 h) e cal+Nitrito (223 h), foram maiores em comparação às tratadas com cal+LB (49 h), cal+LP (48,4 h) e controle (51,9 h). A silagem controle apresentou menores contagens de clostrídios (3,26 log ufc/g) e os tratamentos Cal e Cal+LB apresentaram as contagens mais altas (6,74 log ufc/g e 5,96 log ufc/g, respectivamente), enquanto Cal+nitrito (5,24 log ufc/g), Cal+LP (4,63 log ufc/g) e Cal+benzoato (4,41 log ufc/g) apresentaram contagens intermediárias. Nenhum tratamento imposto foi capaz de controlar o crescimento de clostrídios estimulado pela cal virgem. No segundo ensaio o objetivo foi comparar filmes plásticos na vedação de silagens de cana-de-açúcar. Os tratamentos impostos foram: 1) filme de poliamida 45?m, recoberta com manta de polietileno para proteção contra raios ultravioleta e danos físicos (PA45+M); 2) filme de polietileno coextrusado com poliamida, dupla face, 125?m (PA125); 3) filme de polietileno, dupla face, 200?m (DF). Três silos tipo trincheira foram preenchidos simultaneamente e durante o abastecimento a cana-de-açúcar picada foi tratada com benzoato de sódio na dose 0,15% da matéria natural. Decorridos 90 dias de armazenamento, os silos foram abertos e as silagens utilizadas como ingredientes para alimentação de vacas em lactação. Quinze vacas Holandesas (615 kg PV) foram alocadas aleatoriamente em três Quadrados Latinos 3x3, com períodos de 18 dias. O consumo de matéria seca (CMS). Amostras de leite foram coletadas para análises de proteína, gordura, lactose, caseína, ácidos graxos livres, sólidos totais, Nuréico e contagem de células somáticas. O óxido de cromo foi utilizado como marcador externo para estimar a produção fecal. As diferentes estratégias de vedação não influenciaram a qualidade das silagens e, consequentemente, não afetaram o CMS 19,9 kg/dia, a produção 25,1 kg/dia e a composição do leite (gordura 3,5%, proteína 3,3%, lactose 4,4%), das vacas. As diferentes estratégias de vedação utilizadas não influenciam a qualidade das silagens de cana-de-açúcar e o desempenho de vacas leiteiras e se mostraram efetivas para vedação de silos horizontais. No presente estudo, tanto a utilização de aditivos como a adoção de estratégias de vedação não foram efetivas em controlar perdas em silagens de cana-de-açúcar.
The aim of this study was to discover the best strategies to control losses in sugarcane silages, using combinations of chemical and microbial additives or covering strategies. In the first trial the aim was to compare strategies to prevent clostridium grow in sugarcane silages added with lime. Treatments were Control: no additives; L: 1.5% lime; L + LP: 1.5% lime + Lactobacillus plantarum Ma 18/5U (5×105 cfu/g fresh forage); L + LB: 1.5% lime + Lactobacillus buchneri 40788 (5×105 cfu/g fresh forage); L + N: 1.5% lime + 0.07% sodium nitrite; L + B: 1.5% lime + 0.15% sodium benzoate. As experimental silos were used plastic buckets with a capacity of 20 L. Mini bags were prepared with the following treatments 1) control, 2) 1.5 % of lime and 3) 1.5 % of lime + 5 × 105 cfu/g of L. plantarum, in order to analyze the pH drop at the onset of fermentation. The lime was not effective in decreasing losses compared to control silages (20.6% and 19.1%, respectively) however the treatments lime+Benzoate, lime+nitrite, lime+LP and lime+LB, decreased losses, showing lower values: 11.2%, 14.1%, 14.1% and 13.9%, respectively. The aerobic stability of silages treated with lime (172 h), lime+Benzoate (155 h) and lime+Nitrite (223 h) were higher compared to those treated with lime+LB (49 h), lime+LP (48.4 h) and control (51.9 h). The control treatment showed the lowest counts of clostridia (3.26 log cfu/g) and treatment with lime and lime+LB had the highest counts (6.74 log cfu/g and 5.96 log cfu/g, respectively), while lime+nitrite (5.24 log cfu/g), lime+LP (4.63 log cfu/g) and lime+benzoate (4.41 log cfu/g) showed intermediate counts of clostridia. None of additives combined with lime were able to provide butyric acid free silages. In the second trial the aim was to compare plastic films for sealing sugarcane silages. Treatments were: 1) polyamide film 45?m plus a protection against physical damage and ultraviolet light (PA45 + P), 2) polyethylene film coextruded with polyamide, black-on--white, 125?m (PA125), 3) polyethylene film, blackon- white 200?m (BW). Three trench silos were filled out simultaneously with chopped sugarcane treated with 0.15% of sodium benzoate (as fed basis). After 90 days of storage, the silos were opened and silages fed to lactating cows as total mixed rations. . Fifteen Holstein cows (615 kg BW) were randomly allocated into 3x3 Latin square with periods of 18 days. Dry matter intake, diet apparent digestibility, milk yield and milk composition were evaluated on days 14 to 18 in each period. Chromium oxide was used as external marker to estimate fecal excretion. Sealing strategies had no influence on silage quality and cows performance. Dry matter intake (19.9 kg /day), milk yield (25.1 kg/day), and milk composition (fat 3.5%, 3.3% protein, and 4.4% lactose) were quite similar across treatments. The different sealing strategies do not affect sugarcane silage quality and dairy cows performance and proven effective for sealing horizontal silos. In the present study, neither additives nor covering strategies were effective in reducing losses in sugarcane silages.

Os surtos de botulismo em bovinos geram grande impacto na economia brasileira, uma vez que a bovinocultura é considerada uma das principais atividades econômicas do país, sendo atuante no cenário mundial do agronegócio. No presente trabalho são descritos os aspectos epidemiológicos, clínico-patológicos e laboratoriais do surto de intoxicação botulínica em bovinos de corte, alimentados com silagem de milho, ocorrido no Estado de Minas Gerais no período de 2 a 5 de agosto de 2017. A doença acarretou a morte de 1.100 bovinos precoces e preparados para o abate, consistindo uma alta taxa de letalidade e gerando ume perda econômica estimada em 2 milhões de reais para o pecuarista. Os animais apresentaram sinais e sintomas da doença, contribuindo para a resolução do diagnóstico clínico. Foram identificados dificuldade de deambulação, sinais clínicos de paralisia progressiva dos membros posteriores para os inferiores, hipotonia e sialorreia. Ausência de alterações neurológicas. Os animais permaneciam em decúbito lateral, paralisia cardiorrespiratória seguida de morte. O diagnóstico laboratorial constatou presença de toxina botulínica C e D em amostras de alimento servido ao gado e no soro bovino. Foram investigadas ainda presença de toxina em fragmentos do fígado, conteúdo ruminal e intestinal bovino que atestaram negativo. Além de amostras de água, ração e grãos de soja, que não continham a toxina. A existência de toxina na alimentação revela a importância da armazenagem e conservação corretas da silagem, de modo que não propicie um ambiente favorável para o desenvolvimento da bactéria Clostridium botulinum sendo fator de risco para a ocorrência de surtos.
The outbreaks of botulism in cattle have a great impact on the Brazilian economy, since cattle farming is considered one of the main economic activities in the country, being active in the global agribusiness scenario. This paper describes the epidemiological, clinical-pathological and laboratory aspects of the outbreak of botulinum intoxication in beef cattle, fed with corn silage, which occurred in the State of Minas Gerais from August 2 to 5, 2017. The disease caused the death of 1,100 precocious and prepared cattle for slaughter, consisting of a high lethality rate and generating an economic loss estimated at 2 million reais for the rancher. The animals showed signs and symptoms of the disease, contributing to the resolution of the clinical diagnosis. Deambulation difficulties, clinical signs of progressive paralysis from the posterior to the lower limbs, hypotonia and sialorrhea were identified. Absence of neurological changes. The animals remained in lateral decubitus, cardiorespiratory paralysis followed by death. The laboratory diagnosis found the presence of botulinum toxin C and D in samples of food served to cattle and in bovine serum. The presence of toxin in liver fragments, ruminal and bovine intestinal contents were also investigated and confirmed negative. In addition to samples of water, feed and soy beans, which did not contain the toxin. The existence of toxins in the diet reveals the importance of correct silage storage and conservation, so that it does not provide a favorable environment for the development of the bacterium Clostridium botulinum, which is a risk factor for the occurrence of outbreaks.