Le taro (Colocasia esculenta L SCHOTT) est un tubercule d’une grande importance alimentaire au Tchad pour la consommation humaine et animale. La littérature sur les pratiques culturales et les technologies traditionnelles post-récolte des variétés tchadiennes demeure presque inexistante. Une enquête a donc été menée dans la région du Mayo-Kebbi (Tchad) où le taro est très cultivé. Il résulte qu’il existe principalement deux variétés de taro au Tchad : la variété « Gouning souol» ou variété locale qui est caractérisée par une âcreté importante et un temps de cuisson prolongé (6 à 8 h). Ces propriétés ont entraîné l’abandon de la culture de cette variété au profit de la variété « Gouning sosso » qui présente une âcreté moindre et un temps de cuisson plus court (45 à 60 minutes). Une technique traditionnelle pour réduire l’âcreté et diminuer le temps de cuisson consiste à tremper les tranches de taro frais soit dans l’eau, soit dans une solution de trempage de maïs ou soit dans une infusion de tamarin pendant 24 à 48 h selon l'intensité de l'âcreté. Après séchage au soleil, les cossettes sèches sont transformées en farine. Ces produits de transformation servent à la préparation de boules de pâtes, de bouillie, de soupes ou de beignets. Des analyses ont été effectuées sur une gamme d’échantillon de farine de taro produite conformément à la recette artisanale dans l’optique de comprendre l’effet de cette technologie traditionnelle. Des cossettes fraîches de taro ont été trempées pendant 0, 1 h, 3 h, 6 h, 12 h et 24 h dans de l’eau, ou dans une solution de trempage de maïs ou dans une infusion de tamarin. Chaque échantillon a ensuite été séché au soleil pendant 48 h puis broyé en farine. La matière sèche, les protéines brutes, les cendres, les fibres brutes, les macroéléments minéraux et oligoéléments ont été évalués dans le but de déterminer les effets du trempage traditionnel sur le profil nutritionnel du taro. La digestibilité in vitro de l’amidon sous l’action de l’α-amylase et la teneur en oxalates de différentes farines de taro ont été également déterminées. Il ressort de ces analyses que seul le trempage dans une infusion de tamarin a induit une baisse significative (P < 0,001) de la teneur en protéines brutes (de 3,26 % pour T0 à 2,68 % pour le traitement au tamarin à T24). L’infusion de tamarin n’a pas modifié la teneur en fibres brutes alors que les autres traitements l’ont assez significativement diminuée (P < 0,001). Toutes les méthodes de trempage ont entraîné une diminution significative des teneurs en minéraux, à l’exception d’une augmentation des teneurs en sodium (due à la qualité de l’eau des préparations) et en phosphore (probablement due à l’hydrolyse des phytates du maïs). Une perte significative en fer a été constatée passant de 144 mg/kg de MS (témoin) à 78 mg/kg de MS (échantillon traité à l’eau pendant 12 h), soit une perte de 45,83 %. La plus faible diminution de taux de fer est observée dans le cas de l'échantillon trempé dans l'infusion de tamarin avec une perte maximale de 31,25 % après 24 h. La teneur en zinc ne varie pas. Les procédés de trempage entraînent globalement une amélioration de la digestibilité du taro après une simple cuisson (95°C pendant 30 minutes) qui passe de 39,30 % (échantillon témoin non trempé) à 78,67 % pour le taro trempé dans l’eau. Après 3 h de trempage, la farine de taro traitée par la solution de maïs est significativement plus digestible (77,12 %) que les échantillons résultant de deux autres traitements [tamarin (60,86 %), eau (60,45 %)] qui sont statistiquement similaires. (...) / Colocasia esculenta L SCHOTT is a valuable tuber widely consumed in Chad by humans and livestock. There is very little available literature about the cultivation and the post-harvest traditional technologies of the Chadian varieties of taro. A survey was carried out in the Mayo-Kebbi region ( Chad) where taro is a widely cultivated. There are two main varieties of taro in Chad : the " Gouning souol " variety, a local variety characterized by an important level of acridity and the prolonged cooking time (6 to 8 hours). The presence of these properties led to the replacement of the cultivation of this variety by the " Gouning sosso " variety which presents a lower level of acridity and a shorter cooking time (45 to 60 minutes). A traditional process to reduce the acridity and decrease the cooking time consists in dipping the slices of fresh taro in the water, or in a corn solution or in a tamarind infusion for a period of 24 to 48 hours according to the intensity of the acridity. After drying in the sun, the dried chips are ground into flour. This flour is then used to prepare mixtures of porridge, soups and cakes. Analyses were carried out on samples of taro flour produced in accordance with the traditional methods of soaking to determine the effects of this traditional process. Fresh taro chips were dipped over a period of 0, 1, 3, 6, 12 and 24 hours in the water, or in the corn infusion or in the tamarind infusion. Each sample was then dried in the sun for 48 hours and ground into flour. Dry matter, crude protein, ash, crude fiber, minerals and various trace elements were assessed. The in vitro digestibility of taro starch using α-amylase enzyme and the amount of total oxalates in the different taro flour were also determined. The soaking in the tamarind infusion induced a significant (P < 0.001) decrease in protein content (from 3.26 % for the control sample to 2.68 % for the treatment with the tamarind infusion at T24). The other treatments (corn solution and water) reduced also the protein level of taro but not significantly. The crude fibre content was not affected by the tamarind infusion but decreased significantly in the other treatments at the threshold level of 5 %. All methods of soaking led to a significant decrease of the mineral contents, except for an increase in sodium (due to the quality of the water used to prepare solutions) and in phosphorus (probably due to the hydrolysis of phytates by the corn infusion). A significant loss in trace element (Iron) was observed, decreasing from 144 mg / kg of DM (control sample) to 78 mg / kg of DM (after 12 hours of water soaking) corresponding to a loss of 45.83 %. The lowest decrease in iron level was observed after the treatment by the tamarind infusion (31.25 % after 24 hours). All the soaking processes were seen to have improved the digestibility of taro flour. By simply cooking (at a temperature of 95°C for 30 minutes), the in vitro digestibility increased from 39.30 % for the control sample to 78.67 % for the water treated samples of taro. After three hours of soaking, the taro flour treated by the solution of corn becomes significantly more digestible (77.12 %) than by the two other treatments [tamarind (60.86 %), water (60.45 %)] that are statistically similar. (...)

<p style="text-align: justify; ">Hladno presovano ulje semena uljane tikve je&nbsp;proizvod specifičan za Srbiju, za razliku od zemalja u regionu koje imaju dugu tradiciju proizvodnje&nbsp;devičanskog tikvinog ulja.&nbsp;Tokom postupka hladnog presovanja sirovogosu&scaron;enog&nbsp;semena uljane tikve na pužnoj presi&nbsp;temperatura izdvojenog ulja ne prelazi 50 ^oC, &scaron;to se&nbsp;odražava na fizičko-hemijske, nutritivne i senzorne&nbsp;karakteristike kao i na oksidativnu stabilnost i&nbsp;antioksidativni potencijal ovog ulja.&nbsp;U cilju &scaron;to bolje karakterizacije ovog proizvoda na&nbsp;na&scaron;em trži&scaron;tu, ispitan je kvalitet hladno presovanog&nbsp;tikvinog ulja poreklom iz semena vi&scaron;e različitih&nbsp;slobodnooplodnih sorti i F1 hibrida, golosemenih i&nbsp;uljanih tikvi sa ljuskom, koje uspevaju u na&scaron;oj&nbsp;zemlji.&nbsp;Hladno presovano ulje semena tikve odlikuju&nbsp;specifične senzorne karakteristike: pored izuzetno&nbsp;blage arome, mirisa na sirovo seme tikve i ukusa&nbsp;koji podseća na meso tikve, ovo ulje se posebno&nbsp;izdvaja po boji koja je kod ispitivanog ulja bila&nbsp;svetlo-smedja do crvenkasta. Prema senzornim&nbsp;karakteristikama (naročito boji) izdvojili su se uzorci ulja poreklom iz semena austrijskih hibrida. Na&nbsp;osnovu sastava masnih kiselina ovo ulje pripada olinsko-linolnom tipu, &scaron;to ga svrstava u nutritivno&nbsp;veoma vredna biljna ulja, čemu doprinosi i visok&nbsp;sadržaj gama-tokoferola, koji je dominantan u&nbsp;tikvinom ulju. Određivanje sastava i sadržaja sterola je posebno bilo značajno kada je u pitanju hladno&nbsp;presovano tikvino ulje s obzirom da nema&nbsp;literaturnih podataka na tu temu. U ispitivanim&nbsp;uzorcima su bili dominantni delta-7 steroli, a određen je i izuzetno visok sadržaj skvalena, koji&nbsp;ima veoma važnu biolo&scaron;ku funkciju. Ispitivano ulje je posedovalo dobar antiradikalski potencijal, koji je&nbsp;bio u snažnoj linearnoj zavisnosti sa sadržajem fenolnih materija. Ulje dobijeno ekstrakcijom iz&nbsp;pogače, koja je zaostala nakon hladnog presovanja&nbsp;semena, posedovalo je veći antiradikalski potencijal&nbsp;u odnosu na hladno presovano &scaron;to je rezultat&nbsp;sadržaja fenolnih materija u većem procentu i ne&scaron;to&nbsp;nižeg sadržaja tokoferola u odnosu na hladno<br />presovano ulje.</p> / <p> Cold-pressed pumpkin oil is a product specific<br /> to Serbia, given that other countries in the<br /> region traditionally produce virgin pumpkin oil.<br /> In the process of cold pressing raw-dried<br /> pumpkin seeds by screw press, the<br /> temperature of extracted oil does not exceed<br /> 50oC, which affects physical, chemical,<br /> nutritional and sensory characteristics of this<br /> oil, as well as its oxidative stability and<br /> antiradical capacity.<br /> For the purpose of more precise<br /> characterization of this product in the domestic<br /> market, the quality of cold pressed oil from<br /> seeds of many free breeding varieties and F1<br /> hybrids &ndash; of both naked and husk seed<br /> pumpkins being grown in our country &ndash; was<br /> examined.<br /> Specific sensorial properties: light brown to<br /> reddish color, mild aroma, a smell similar to<br /> that of raw pumpkin seeds and a taste<br /> resembling that of pumpkin pulp are<br /> characteristic for this oil. As for sensory<br /> characteristics, the samples of oil from<br /> Austrian hybrid seeds, stood out. On the basis<br /> of fatty acid content, this oil belongs to the<br /> oleic-linoleic type, meaning it is a highly<br /> nutritional vegetable oil, which is also due to<br /> high levels of dominant gamma-tocopherol. Determination of the types and content of</p> <p> sterols was particularly important, given that<br /> there are no data specific to cold-pressed<br /> pumpkin oil in the literature. Delta-7 sterols are<br /> the most dominant sterols in examined oil<br /> samples and also very high content of<br /> squalene was found, which a compound with<br /> an important biological function is. The oil has<br /> an excellent antiradical capacity, showing a<br /> strong linear correlation with the amounts of<br /> phenolic compounds. Oil extracted from the<br /> cake, left over after the cold pressing of<br /> pumpkin seeds, had greater antiradical<br /> capacity than the samples of cold pressed oil,<br /> due to higher percentage of phenolic<br /> compounds and a slightly lower content of<br /> tocopherols compared to cold pressed oil.</p>

O objetivo deste estudo foi caracterizar o perfil de fermentação anaeróbia de colostro e determinar seu valor nutritivo, assim como avaliar o desempenho de bezerros leiteiros alimentados com silagem de colostro como dieta líquida. No primeiro experimento, colostro bovino de segunda e terceira ordenhas foi fermentado em garrafas plásticas tipo PET que foram cheias e ligeiramente pressionadas antes do seu fechamento, criando assim uma condição anaeróbia. As garrafas foram armazenadas em sala escura à temperatura ambiente e cinco garrafas foram abertas 0,1, 2, 3, 4, 5, 6, 7, 14, 21, 28 e 56 dias após, para determinação de pH, acidez titulável, temperatura, ácido lático, nitrogênio total, nitrogênio não-protéico (NNP), caseína, lactose, glicose, gordura e contagem de microorganismos. Os valores de pH, acidez titulável e concentração de ácido lático apresentaram variação durante o armazenamento (P<0,0001). A fração NNP apresentou aumento (P<0,0001), enquanto que os valores de caseína e lactose diminuíram (P<0,0001) e apresentaram baixos valores após 56 dias. O desenvolvimento de bactérias ácido-láticas (BAL) foi intenso durante o processo fermentativo, enquanto que enterobactérias e leveduras apresentaram declínio. No segundo experimento, colostro bovino de segunda e terceira ordenhas foi fermentado da mesma forma que no primeiro experimento, mas em diferentes condições de temperaturas ambientais. As garrafas foram armazenadas em incubadora BOD com temperatura controlada (32,5±1°C ou 22,5±1°C) ou em sala escura à temperatura ambiente, sendo abertas três garrafas após 0, 1, 7, 14, 21, 28 e 35 dias para avaliação dos mesmos parâmetros avaliados no primeiro estudo. A maioria dos parâmetros apresentou comportamento semelhante ao observado no primeiro experimento. O desenvolvimento de BAL foi intenso, principalmente quando o colostro foi armazenado em temperatura mais elevada. A temperatura também afetou os parâmetros nutricionais (P<0,0001) com acréscimos nos valores de NNP e redução da concentração de caseína e lactose. No terceiro experimento, dezoito bezerros Holandês foram alocados em abrigos individuais até a oitava semana de vida, com livre acesso à água e concentrado inicial, e passaram a receber 4L da dieta líquida, sucedâneo lácteo ou colostro fermentado sob condições anaeróbicas (silagem de colostro), diluído na razão de 1:1. Os animais alimentados com silagem de colostro apresentaram menor consumo de concentrado, ganho de peso diário e peso vivo (P<0,07) durante o período experimental, em comparação aos animais consumindo sucedâneo lácteo. As avaliações quanto à altura na cernelha, perímetro torácico e largura da garupa não apresentaram diferenças (P>0,07). Todos os parâmetros sanguíneos avaliados (glicose, N-uréico, ácidos graxos livres e -hidroxibutirato) foram afetados pelos tratamentos (P<0,07), exceto a concentração plasmática de proteínas totais (P>0,07). O escore fecal foi afetado pelos tratamentos durante a segunda semana de vida (P<0,07), com animais alimentados com silagem de colostro apresentando fezes anormais e muito secas. A dinâmica fermentativa observada mostra que o colostro pode ser conservado através de fermentação anaeróbia de forma eficiente. Entretanto, o fornecimento de silagem de 12 colostro como dieta líquida exclusiva durante o período de aleitamento não resulta em desempenho animal adequado, não sendo uma boa alternativa de substituto de leite. / The objective of this study was to characterize the fermentative dynamic of bovine colostrum, under anaerobic condition, and determine the nutritional value, as well as evaluate dairy calves´ performance receiving colostrum silage as liquid diet. In the first experiment, bovine colostrum from second and third milking was fermented at room temperature in PET plastic bottles that were filled and lightly pressed before its closure, thereby creating an anaerobic condition. The bottles were stored in the dark at room temperature and five bottles were opened on days 0,1, 2, 3, 4, 5, 6, 7, 14, 21, 28 and 56 after for determination of pH, titratable acidity, temperature, lactic acid, total nitrogen, non-protein nitrogen (NPN), casein, lactose, glucose, fat and counts of microorganisms. The pH, titratable acidity and concentration of lactic acid showed large variation during storage (P<0.0001). The NPN fraction increased (P<0.0001), whereas the values of casein and lactose decreased (P<0.0001) and showed very low values after 56d. The development of lactic-acid bacteria (LAB) was intense during the fermentation process, while enterobacteria and yeasts declined. In the second experiment, bovine colostrum from second and third milking was collected, mixed and stored in PET plastic bottles, in the same manner as it was for the first study. However, the bottles were stored in a dark room with temperature controlled by a BOD incubator (32.5±1°C or 22.5±1°C) or at room temperature. Three bottles were opened after 0, 1, 7, 14, 21, 28 and 35 days for evaluation of the same parameters done during the first study. Most parameters presented similar patterns as observed in the first trial. The development of LAB was intense, especially when colostrum was stored at higher temperature. Temperature also influenced the results of nutritional parameters (P<0.0001) with increases in NPN values and reduction of casein and lactose concentration. In the third experiment, eighteen Holstein calves were allocated to individual hutches until the eighth week of life, with free access to water and starter feed, and fed 4 liters of liquid diet: milk replacer or colostrum fermented under anaerobic condition (colostrum silage), diluted at a 1:1 ratio. Animals fed colostrum silage had lower intake of starter, average daily gain and body weight (P<0.07) during the experimental period, compared to animals consuming milk replacer. The values of withers height, heart girth and hip width showed no differences (P>0.07). All blood parameters measured (glucose, urea-N, free fatty acids and -hydroxybutyric acid) were affected by treatments (P<0.07), except the total protein plasma concentration (P>0.07). The fecal score was affected by treatments during the second week of life (P<0.07), with animals fed colostrum silage presenting abnormal and very dry feces. The dynamics of fermentation show that colostrum can be efficiently stored under anaerobic conditions. However, feeding colostrum silage as an exclusive liquid diet, during the whole milk-feeding period, results in poor animal performance, being considered as an inadequate alternative as milk replacer.

Grünland mit hoher Produktivität und Futterqualität bildet die Grundlage der Wiederkäuerernährung. In Grünlandbeständen mit ausbleibender oder geringer Stickstoffdüngung sind Leguminosen unerlässlich für Produktivität und Futterqualität, was auf die Fähigkeit von Leguminosen Luftstickstoff zu binden zurückzuführen ist. Gegenwärtig ist Trifolium repens L. eine der wichtigsten Futterleguminosen im Grünland der gemäßigten Zonen Europas. Es ist allerdings bekannt, dass T. repens eine gute Wasserversorgung benötigt, um einen hohen Ertrag zu erzielen. Verringerte Niederschlagsmengen in der Vegetationsperiode, die unter Klimawandelbedingungen vorausgesagt werden, könnten somit die Ertragsleistung von T. repens verringern. In Zukunft steigt dadurch möglicherweise auch die Bedeutung anderer Futterleguminosen, die besser an trockenere Bedingungen angepasst sind und somit als Alternative für T. repens dienen könnten. Da die Kenntnisse über das agronomische Potenzial solcher möglichen alternativen Leguminosen begrenzt sind, haben wir in dieser Studie fünf vielversprechende und wahrscheinlich besser an Trockenheit angepasste Leguminosen untersucht. Für unsere Versuche haben wir Lotus corniculatus L., L. uliginosus Schkuhr, Medicago lupulina L., M. falcate L. und Onobrychis viciifolia Scop. ausgewählt. In einem ersten Schritt wurde das agronomische Potenzial der Leguminosen im Hinblick auf Etablierung und frühe Ertragsentwicklung mit nicht limitierter Wasserversorgung getestet. Weiterhin wurden der Ertrag und die Ertragsstabilität sowie die Wassernutzung der alternativen Leguminosen bei temporärer Trockenheit untersucht und mit der von T. repens verglichen. Der Einfluss von Trockenstress auf wichtige Futterwert bestimmende Inhaltsstoffe der Leguminosen (Rohprotein, neutrale Detergenzienfasern, saure Detergenzienfasen und wasserlösliche Kohlenhydrate) war überdies Gegenstand der Betrachtungen. Um die oben genannten Parameter zu untersuchen, wurde von 2009 (Einsaatjahr) bis 2011 ein Experiment in Großgefäßen in einer Vegetationshalle durchgeführt. In diesem Versuch wurden alle Leguminosen sowohl in Monokultur als auch in einer praxisüblichen Mischung mit Lolium perenne L. angesät. Im Versuchszeitraum folgten die klimatischen Bedingungen in der Vegetationshalle einem normalen jahreszeitlichen Verlauf, der Frost im Winter und höhere Temperaturen im Sommer umfasste. Der für den Versuch notwendige Trockenstress wurde in drei Aufwüchsen innerhalb von zwei Jahren durch temporären Bewässerungsstopp erzeugt. Dabei wurde im Frühjahr 2010 (April/Mai) ein moderater und im Sommer 2010 (Juli/August) sowie im Frühjahr 2011 (April/Mai) je ein starker Trockenstress induziert. Mit Ausnahme von M. falcata, welches eine verzögerte Anfangsentwicklung zeigte, waren die Keimung und die Etablierung von allen alternativen Leguminosen vergleichbar mit der von T. repens. Die Ertragsleistung von M. lupulina und L. corniculatus in Monokultur war ähnlich hoch wie die von T. repens. In Mischung zeigten beide alternativen Leguminosen zwar Potenzial, aber die Ertragsleistungen waren dennoch geringer als die der T. repens/L. perenne Mischung. In unserem Versuch führte Trockenstress zu verringertem Ertrag und er beeinflusste auch die agronomische Wassernutzungseffizienz (Verhältnis von Ertrag zu Wasserverbrauch). Ausschlaggebend waren dabei die Stärke und die Dauer des Trockenstresses. Besonders starker, aber auch bereits moderater Trockenstress führten bei T. repens zu erheblichen Ertragsverlusten von bis zu 56%. Demgegenüber zeigten vor allem M. lupulina, aber auch L. corniculatus und M. falcata lediglich marginale Ertragsverluste bei moderatem Trockenstress und meist geringere Ertragsverluste als T. repens bei starkem Stress. Die agronomische Wassernutzungseffizienz war bei moderatem Stress verhältnismäßig stabil, wohingegen starker Stress im Vergleich zur Kontrolle meist zu einer geringeren agronomischen Wassernutzungseffizienz führte. Sowohl unter Kontroll- als auch unter Stressbedingungen zeigte speziell M. lupulina in Monokultur eine ähnliche oder sogar eine höhere agronomische Wassernutzugseffizienz als T. repens. Zudem war die agronomische Wassernutzungseffizienz der Mischungen mit M. lupulina, L. corniculatus und M. falcata weniger negativ von starkem Trockenstress betroffen als die Mischung mit T. repens. Dies bestätigte zum einen die Trockenheitsempfindlichkeit von T. repens und zum anderen die bessere Anpassung der alternativen Leguminosen an trockenere Bedingungen. Wir beobachteten, dass eine Änderung in der Stickstofffixierungsleistung der Leguminosen eine gute Erklärungsgröße für Änderungen des Ertrags und der agronomischen Wassernutzungseffizienz darstellt. Hohe Stickstofffixierungsleistung geht dabei meist mit höherem Ertrag und höherer agronomischer Wassernutzungseffizienz einher. Die intrinsische Wassernutzungseffizienz (Verhältnis von assimiliertem CO2 und stomatärer Leitfähigkeit), gemessen als 13C, war ein schlechterer Indikator für die agronomische Wassernutzungseffizienz: Obwohl die intrinsische Wassernutzungseffizienz unter starkem Trockenstress zunahm, sank die agronomische Wassernutzungseffizienz meist ab. Dennoch besitzt die Erhöhung der intrinsischen Wassernutzungseffizienz ein gewisses Potenzial als Anpassung an trockenere Bedingungen Der Trockenstresseffekt auf die Futterqualität war in unserer Studie generell deutlich geringer als der Effekt auf den Ertrag. Besonders moderater Stress hatte wenig Einfluss auf die Futterqualität, während sich die Effekte bei starkem Stress verstärkten. Starker Trockenstress führte meist zu einer Verringerung des Rohprotein- und Fasergehalts (neutrale und saure Detergenzienfasern), wohingegen sich der Gehalt an wasserlöslichen Kohlenhydraten erhöhte. Dies könnte ein Hinweis darauf sein, dass sich die Futterqualität bei Trockenstress sogar verbessert. Nichtsdestotrotz hatten in unserem Versuch die Leguminosenart und die Einsaat als Monokultur oder Mischung einen größeren Einfluss auf die Futterqualität als der Trockenstress. Der Einfluss von Trockenstress auf die Futterqualität ist deshalb bei der Wahl einer geeigneten Futterleguminose weniger von Bedeutung als andere agronomische Eigenschaften. Zusammenfassend ist zu sagen, dass besonders M. lupulina und in geringerem Maße auch L. corniculatus und M. falcata Potenzial als Alternative für T. repens bei Trockenstress zeigen. Nach ausreichender Etablierungszeit entwickeln sich besonders M. lupulina aber auch L. corniculatus und M. falcata stabiler und können sogar höhere Erträge als T. repens bei Trockenstress produzieren. Bezüglich der Futterqualität sind oben genannte alternative Leguminosen ebenfalls vergleichbar mit T. repens.

Résumé indisponible

Plicatula is a taxonomic group within of the genus Paspalum that contains interesting species considering their phenotypic diversity for forage traits, and some of these species have been improved through artificial interspecific hybridization. Nitrogen (N) is an important limiting factor to produce biomass. Forage legumes contribute with symbiotic N2 fixation and can increase biomass yield and the nutritive value of the pastures. The objectives of this thesis were: (i) evaluate dry matter yield (DMY), N use efficiency (NUE), nutritive value, cold tolerance and plant persistence in hybrids of Paspalum plicatulum x P. guenoarum subjected to N application rates, (ii) compare biomass yield and nutritive value of the grass–legume system to a grass–N fertilizer system, and (iii) select the best hybrids for new steps within the breeding program. The study was conducted from September 2015 to May 2017. The experimental design was a randomized complete block in split-plot arrangement with three replicates. Treatments were five N rates (0, 60, 120, 240, and 480 kg N ha-1 N), and one grass-legumes mixture (Trifolium repens + Lotus corniculatus) as whole plots, and six genotypes (1020133, 102069, 103084, 103061, P. guenoarum ecotype Azulão and Megathyrsus maximus cv. Aruana used as a control) as subplots. Nitrogen rates of 240 and 480 kg N ha-1 increased Total-DMY, Leaf-DMY, cold tolerance and persistence but decreased NUE. Higher NUE was obtained with N rates between 60 and 120 kg N ha-1. Total-DMY for grass-legume mixture was similar to the N rates of 60 and 120 kg N ha-1. Hybrid 1020133 had Total-DMY similar to Azulão and Aruana, as well as Leaf-DMY greater than Aruana. Hybrid 1020133 showed greater cold tolerance and exhibited greater NUE at 60 kg N ha-1 than the other genotypes. At the N rate of 480 kg N ha-1 increased crude protein (27%) and digestibility (4%) and decreased neutral (6%) and acid (7%) detergent fiber compared to the 0 kg N ha-1. Grass-legume mixture showed greater nutritive value compared to N-fertilized grass. Hybrid 103061 had greater crude protein and digestibility and lower neutral and acid detergent fiber than Azulão and Aruana. Therefore, there is opportunity to increase DMY, NUE, cold tolerance and plant persistence, and improve the nutritive value through genotype selection and N management. In addition, grass-legume mixture showed greater nutritive value than N-fertilized grass and can be an alternative practice to replace to the application of N fertilizer up to the rate of 120 kg N ha-1. Hybrids 1020133 and 103061 should be indicated for new studies, such as seed production and animal performance.

Made available in DSpace on 2014-12-17T15:34:43Z (GMT). No. of bitstreams: 1 JoaoVEN_DISSERT.pdf: 2633777 bytes, checksum: a59b41665f97067cdafb895c7d67745c (MD5) Previous issue date: 2012-02-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / He aim of this study was to evaluate the structural characters, herbage accumulation, nutritive value and performance of sheep in different tropical pastures. The treatments were two cultivars and two of the genera Panicum Brachiaria pastures under intermittent stocking and variable stocking rate, in the rainy season. We evaluated the masses and the components of herbage pre grazing in two layers, and after grazing. Chemical analyzes were made of the stems and leaf blades pre grazing in two layers. We used 48 male sheep and whole for the assessment of individual weight gain and area, and anestrous females to adjust the stocking rate. In the cv. Massai showed the highest herbage mass, leaf blades and dead material, and the largest volume density and leaf blade: stem pre grazing. There was no difference among cultivars for the percentage of leaf blade (PLB) in both strata, but the higher the PLB was higher than the bottom. The highest percentage of dead material (PDM) was observed in cvs. Massai and Marandu in the two strata. In cvs. Massai and Piat? were observed lower levels of crude protein in stem and leaf. In stratum 0-25 cm lower nutritional value was observed in the stem in the leaf blades did not grant the nutritional value among the strata. Herbage mass, leaf blade, PLB and proportion of stem in the residue of the Massai pastures were higher than cv. Aruana. There was no difference for efficiencies in harvest leaf and stem between the cultivars. The cv. Massai got the higher accumulation of leaf per cycle per day. Animals kept in grass swards Aruana had the highest average daily gain. The higher stocking rates and earnings per area were observed in grass swards and Marandu Massai. The cultivars are suitable for sheep meat production in the rainy season / O objetivo deste estudo foi avaliar os caracteres estruturais, o ac?mulo de forragem, o valor nutritivo e o desempenho de ovinos em diferentes pastagens tropicais. Os tratamentos constitu?ram em duas cultivares dos g?neros Panicum e duas de Brachiaria, manejadas sob lota??o intermitente e taxa de lota??o vari?vel, na ?poca das ?guas. Foram avaliadas as massas e os componentes da forragem no pr? pastejo em dois estratos, e no p?s pastejo. Foram feitas an?lises bromatol?gicas dos colmos e das l?minas foliares no pr? pastejo em dois estratos. Utilizou-se 48 ovinos machos e inteiros para a avalia??o do ganho de peso individual e por ?rea, al?m de f?meas em anestro para ajuste na taxa de lota??o. Na cv. Massai foram observadas as maiores massa de forragem, de l?minas foliares e de material morto, al?m da maior densidade volum?trica e rela??o l?mina foliar:colmo no pr? pastejo. N?o houve diferen?a entre as cultivares para o percentual de l?minas foliares (PLF) em ambos os estratos, por?m o PLF no superior foi maior que no inferior. O maior percentual de material morto (PMM) foi observado nas cvs. Massai e Marandu nos dois estratos. Nas cvs. Massai e Piat? foram observados os menores teores de prote?na bruta no colmo e na l?mina foliar. No estrato de 0 25 cm foi observado menor valor nutritivo no colmo, nas l?minas foliares o valor nutritivo n?o deferiu entre os estratos. A massa de forragem, de l?mina foliar, PLF e propor??o de colmo no res?duo dos pastos de Massai foram superiores aos da cv. Aruana. N?o houve diferen?a para as efici?ncias na colheita de l?mina foliar e colmo entre as cultivares estudadas. A cv. Massai obteve os maiores ac?mulos de l?mina foliar por ciclo e por dia. Os animais mantidos em pastos de capim Aruana obtiveram os maiores ganhos m?dios di?rios. As maiores taxas de lota??o e ganhos por ?rea foram observadas nos pastos de capim Massai e Marandu. As cultivares testadas s?o adequadas a produ??o de carne ovina na ?poca das ?guas

Made available in DSpace on 2014-12-17T15:34:49Z (GMT). No. of bitstreams: 1 ItaniaMMA_DISSERT.pdf: 824423 bytes, checksum: afea5ac43f7f8530cfb948b922808ef4 (MD5) Previous issue date: 2014-02-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The objective of this work was to evaluate the effect of supplements feeding on growth of calves grazing a Panicum maximum cv. Momba?a pasture during the dry season. The experimental design was a randomized blocks with three treatments and three replications. The treatments were: mineral salt ad libidum; multiple mixture (MM) fed at 0.2% of live weight (PV); and, concentrate feed (SC) fed at 0.7% of PV. Thirty six weaned calves averaging eight months and 192 kg of initial live weight were utilized. The masses and pasture components, nutritive value and rate of forage growth were evaluated. Animal performance was measured as average daily gain (ADG) and live weight gain (LWG). The supplemental feeding was adjusted after weighing. There was no difference between periods for forage mass and leaf: stem ratio. The highest values for forage green mass, leaf blades mass and stem percentage were observed in the first trial period. The canopy height and the available forage on offer did not differ among treatments. The percentage of dead was higher for the last periods of evaluation. The leaf: stem ratio and the leaf percentage were greater in the second period. There was significant difference (p<0,05) among treatments for the ADG and were 250, 460 and 770 g/day for salt, MM and SC, respectively. The biggest LWG was observed in the treatment SC. contents of PB, DIVMO, NDF and LDA on leaf blades, thatched roofs and dead material dead not differ among treatments. The highest GPV was observed in the SC treatment. The contents of PB, DIVMO, NDF and LDA for leaf blades stem and dead material did not differ among treatments. Independent of the use supplements , it is possible to keep steers gaining weight, during dry season, since the stocking rate is appropriately adjusted / O objetivo deste trabalho foi avaliar o efeito de suplementos na recria de bovinos em pastos de Panicum maximum cv. Momba?a na ?poca seca. Utilizou-se o delineamento experimental de blocos ao acaso, com tr?s tratamentos e tr?s repeti??es. Os tratamentos constitu?ram-se de: sal mineral ? vontade; mistura m?ltipla (MM), fornecida a 0,2% do peso vivo (PV); e, suplemento concentrado (SC), fornecido a 0,7% do PV. Foram utilizados 36 bezerros desmamados, com idade m?dia de oito meses e peso m?dio inicial de 192 kg. Mensalmente, os pastos foram amostrados para as estimativas de altura, massa de forragem (MF), massa de forragem verde (MFV), massa de l?mina foliar (MLF), porcentagens de folha (PF), colmo (PC) e morto (PM), rela??o folha:colmo (RFC) e folha:n?o folha, oferta de forragem e taxa de ac?mulo de forragem (TAF), sendo os dados agrupados em quatro per?odos. Os animais foram pesados a cada 28 dias e a produ??o animal foi avaliada quanto ao ganho m?dio di?rio (GMD) e ganho de peso vivo por ?rea (GPV). A quantidade de suplemento foi ajustada a cada pesagem. N?o houve diferen?a entre per?odos para a massa de forragem e rela??o folha:colmo. Os maiores valores para massa de forragem verde, massa de l?mina foliar e porcentagem de colmo foram observados no primeiro per?odo de avalia??o. A altura do dossel e a oferta de forragem n?o diferiram entre os tratamentos. A porcentagem de material morto foi maior nos ?ltimos per?odos de avalia??o. A rela??o folha:n?o folha e a porcentagem de l?mina foliar foram maiores no segundo per?odo. O GMD foi de 250, 460 e 770 g/animal/dia, respectivamente, para sal, MM e SC. O maior GPV foi observado no tratamento SC. Os teores de PB, DIVMO, FDN e LDA nas l?minas foliares, colmo e material morto n?o diferiram entre os tratamentos. Independente do uso de suplementos, ? poss?vel manter o ganho de peso dos animais durante a esta??o seca, desde que a taxa de lota??o seja ajustada de forma adequada

Plicatula is a taxonomic group within of the genus Paspalum that contains interesting species considering their phenotypic diversity for forage traits, and some of these species have been improved through artificial interspecific hybridization. Nitrogen (N) is an important limiting factor to produce biomass. Forage legumes contribute with symbiotic N2 fixation and can increase biomass yield and the nutritive value of the pastures. The objectives of this thesis were: (i) evaluate dry matter yield (DMY), N use efficiency (NUE), nutritive value, cold tolerance and plant persistence in hybrids of Paspalum plicatulum x P. guenoarum subjected to N application rates, (ii) compare biomass yield and nutritive value of the grass–legume system to a grass–N fertilizer system, and (iii) select the best hybrids for new steps within the breeding program. The study was conducted from September 2015 to May 2017. The experimental design was a randomized complete block in split-plot arrangement with three replicates. Treatments were five N rates (0, 60, 120, 240, and 480 kg N ha-1 N), and one grass-legumes mixture (Trifolium repens + Lotus corniculatus) as whole plots, and six genotypes (1020133, 102069, 103084, 103061, P. guenoarum ecotype Azulão and Megathyrsus maximus cv. Aruana used as a control) as subplots. Nitrogen rates of 240 and 480 kg N ha-1 increased Total-DMY, Leaf-DMY, cold tolerance and persistence but decreased NUE. Higher NUE was obtained with N rates between 60 and 120 kg N ha-1. Total-DMY for grass-legume mixture was similar to the N rates of 60 and 120 kg N ha-1. Hybrid 1020133 had Total-DMY similar to Azulão and Aruana, as well as Leaf-DMY greater than Aruana. Hybrid 1020133 showed greater cold tolerance and exhibited greater NUE at 60 kg N ha-1 than the other genotypes. At the N rate of 480 kg N ha-1 increased crude protein (27%) and digestibility (4%) and decreased neutral (6%) and acid (7%) detergent fiber compared to the 0 kg N ha-1. Grass-legume mixture showed greater nutritive value compared to N-fertilized grass. Hybrid 103061 had greater crude protein and digestibility and lower neutral and acid detergent fiber than Azulão and Aruana. Therefore, there is opportunity to increase DMY, NUE, cold tolerance and plant persistence, and improve the nutritive value through genotype selection and N management. In addition, grass-legume mixture showed greater nutritive value than N-fertilized grass and can be an alternative practice to replace to the application of N fertilizer up to the rate of 120 kg N ha-1. Hybrids 1020133 and 103061 should be indicated for new studies, such as seed production and animal performance.

The aim of this study is to assess the effect of different management practises on submontane meadow plant diversity, species richness and biomass production. The experiment was carried out in the submontane region Šumava (Kaplicko, Velký Chuchelec, Údolí Velenovského potoka). There were applied four types of management {--} continual grazing, mulching, fallow (Velký Chuchelec) and mowing (Údolí Velenovského potoka). Plant diverzity and hay production has been observing for three years. Obtained data were used for calculation Simpson and Hill index diverzity, value of fodder quality and nutritive and water regime (condition) of site. Values were used for statistical computing (ANOVA, Fischer LSD test). The plant species diverzity and biomass production are significantly affected by grassland management (treatment). Mulching and fallow lead to lower species richness and increases the coverage of grasses. Hay production is higher on mulching and fallow stands and on mowed stands than on continuously grazed stands. Mowing leads to higher species richness. Is necessary to conserve this status by mowing or the better way is to intesify contemporary management.