Outliers are a major concern in data quality as it limits the reliability of any data. The objective of our investigation was to examine the presence and cause of outliers in the system for controlling and recording the feed intake of dairy cows in Lovsta farm, Uppsala Sweden. The analyses were made on data recorded as a timestamp of each visit of the cows to the feeding troughs from the period of August 2015 to January 2016. A three step methodology was applied to this data. The first step was fitting a mixed model to the data then the resulting residuals was used in the second step to fit a model based clustering for Gaussian mixture distribution which resulted in clusters of which 2.5% of the observations were in the outlier cluster. Finally, as the third step, a logistic regression was then fit modelling the presence of outliers versus the non-outlier clusters. It appeared that on early hours of the morning between 6am to 11.59am, there is a high possibility of recorded values to be outliers with odds ratio of 1.1227 and this is also the same time frame noted to have the least activity in feed consumption of the cows with a decrease of 0.027 kilograms as compared to the other timeframes. These findings provide a basis for further investigation to more specifically narrow down the causes of the outliers.

Ensiling is one of the most common processes used as a conservation method for forages on farms and plays an important role in farm economics. Therefore, with the aim to improve the conservation and the nutritive value of silage, the utilization of silage additives such as fibrolytic enzymes (FE) and lactic acid bacteria (LAB) inoculants has been a common on-farm practice. FE are enzymes capable of breaking down complex polysaccharides such as cellulose and hemicellulose. The latter results in an increased substrate availability for epiphytic and inoculated LAB during silage fermentation, thus promoting a higher production of organic acids such as lactic acid and volatile fatty acids such as acetic acid, which are key acids to improve the conservation of the forage by reducing dry matter losses and improving aerobic stability. The degradation of cellulose and hemicellulose results in a partial degradation of fiber measured by the neutral detergent fiber (NDF) and acid detergent fiber (ADF) extraction technique. Therefore, FE could have the potential to improve ruminal fiber digestibility of treated forages. Alternatively, LAB inoculants are used as silage additives with the primary objective to dominate over the epiphytic bacteria present in silage, to accelerate the fermentation process, and to reinforce aerobic stability of the forage at feed out. Additionally, recent research has shown that certain strains of LAB might have the potential to partially degrade NDF and ADF during ensiling, therefore improving fiber digestibility. The first objective of this research project was to evaluate the effects of different mixtures of FE (a mixture of cellulase and xylanase (C+X); xylanase (X); ß-glucanase (G); a mixture of ß-glucanase and xylanase (G+X); and a negative control) on alfalfa harvested at early and late maturity, and stored for 40 or 120 d of ensiling. Alfalfa harvested at early maturity, treated with FE and ensiled for 40 d did not show significant improvements during ensiling in fiber degradability, fermentation characteristics or fiber digestibility in vitro assessed by the Tilley and Terry methodology. However, when harvested at late maturity and treated with a mixture of C+X; X and G+X, the NDF and ADF content at 40 d of ensiling tended to decrease. FE improved total volatile fatty acid production at 40 and 120 d of ensiling. Improvements in fiber digestibility were observed in vitro at 24 h for the C+X treatments. The results of this study suggest that the effects of FE are more pronounced in silages higher in fiber concentration, such as in the late-maturity alfalfa cut. The second objective of this research was to evaluate the effects of two homofermentative LAB (hoLAB) strains, and two heterofermentative LAB (htLAB) strains on alfalfa harvested at late maturity and stored for 40 or 120 d of ensiling. At 40 d of ensiling, hoLAB-treated silages had the greatest DM recovery and the lowest ADF concentration. Lactic acid production was greater for hoLAB-treated silages. At 120 d of ensiling, hoLAB-treated silages had the highest concentration in lactic acid whereas htLAB had the highest concentration in acetic acid and hoLAB-treated silages had the lowest ADF and NDF concentrations while htLAB tended to have higher NDF concentrations. Overall, it appears that the fiber degradation promoted during ensiling influenced digestibility depending upon hoLAB or htLAB inoculation, with hoLAB showing improved digestibility levels. The presented work suggests that certain FE can have the potential as a management resource on farms aiming to improve the nutritive value of forages with a high fiber concentration. As expected, hoLAB and htLAB inoculants improved the fermentation characteristics of alfalfa silage, but it was shown that LAB may exert a differential effect on fiber digestibility depending on their specific metabolism.

Deoxynivalenol (DON) contamination of grain destined for animal feeds is a major toxicological risk to monogastrics and is suspected of restricting productivity in ruminants. Whereas bacterial additives have been developed that can detoxify DON in the rumen and lower intestine, there are currently no commercial inoculants able to perform this task in crimped grain (CG) silage, a regionally important method of moist grain preservation based on homo- and heterofermentative lactic acid bacteria or chemical additives. Determining whether this ensiling process alongside the action of detoxifying bacteria has the potential to remove DON in CG prior to ingestion, was explored in mini-silo ensiling experiments. CG was heat treated (100 °C, 60 min) or ensiled fresh in triplicate 50 g silos, spiked with 5 mg/kg DON and inoculated with lactic acid bacteria derived from wild birds, natural epiphytic inoculants and commercially sourced silage additives (21 d). DON recovery was only significantly reduced (31.2 ± 14.4% recovery, p < 0.001, n= 30) by heat treatment, as determined by IAC-RP-HPLC-UV. Bacterial assemblage analysis by 16S rRNA PCR-DGGE-SEQ identified Weissella cibaria, Pantoea agglomerans, Bacillus subtilis, B. licheniformis and Hafnia alvei as candidate detoxification agents, of which W. cibaria and H. alvei decreased DON recovery in vitro (11.3 and 6.2% recovery respectively, p < 0.05, n = 18), which translated to inoculated W. cibaria yielding a decrease in DON recovery (67.2± 14.4%, 28 d) in naturally contaminated crimped wheat (13.5 ± 1.0 mg/kg, 35-40% moisture, p < 0.05, n =15). As W. cibaria is a lactic acid bacteria already associated with fermented CG by default it has promise as a novel DON detoxification agent in CG silage. DON is however just one of many hepatotoxic co-contaminants. Retrorsine, a DNA-crosslinking pyrrolizidine alkaloid derived from Ragwort (Senecio sp.) was investigated for interactive toxicity with DON in an in vitro co-exposure experiment. HepG2 cells were exposed to Log10 multifactorial binary exposures for 48 h followed by a suite of assays to elucidate mechanisms of interactive cytotoxicity, genotoxicity and modulation of the proteome. Retrorsine was tentatively confirmed to form DNA/protein crosslinks in the comet, micronucleus and crosslinking assays, whilst DON was found to potently induce cytotoxicity and apoptosis. Co-exposure yielded a complex toxicity response, with low doses yielding antagonistic effects and high doses trending towards additive effects, although DON dose was generally the principle component. The difficulties associated with undertaking an interactive toxicity study where both toxins have multiple metabolic and cellular targets are highlighted.

There are concerns that genetic modification of maize with Bacillus thuringiensis may influence its structural and chemical composition which, together with the Cry1Ab proteins, may affect agro-ecosystem processes and feed quality. This study was aimed at investigating the expression of Cry1Ab protein in leaves, stems and roots of Bt maize and the effect of genetic modification (MON810) on activity of earthworms, silage quality and decomposition of residues in the field. In 2009/10 four maize cultivars; DKC61-25B, DKC61-24, PAN6Q-321B and PAN6777 were planted. Expression of Cry1Ab in leaves, stems and roots was analyzed at 6, 8, 10 and 12 weeks after planting (WAP). Earthworms were also sampled from the same treatments at 6, 9 and 18 WAP. Two silage experiments were conducted using maize cultivars, DKC80-12B and DKC80-10 produced in the 2008/09 season and DKC61-25B, DKC61-24, PAN6Q-321B and PAN6777, produced in 2009/10. The silage was sampled at 0, 2, 4, 8, 15 and 42 days in 2008/09 and 0, 8 and 42 days in 2009/10 and analyzed for Ash Free Dry Matter, Crude Fiber, Neutral Detergent Fiber, Acid Detergent Fiber, Acid Detergent Lignin, Crude Protein and Total Digestible Nutrients. Two litter-bag decomposition studies were also carried out (i) in 2008 (surface applied) using maize cultivars DKC80-12B, DKC80-10 and DKC6-125 residues and (ii) in 2009 (soil incorporated) using DKC75-15B, CRN3505, PAN6Q-321B v and PAN6Q-121. Ash-free dry matter and Cry1Ab protein were measured throughout the incubation time. There were no differences between DKC61-25B and PAN6Q-321B in terms of expression of Cry1Ab in leaves, stems and roots over time. The Cry1Ab expression levels were in decreasing order: leaves > stems > roots. No effects of Bt maize on earthworm numbers and biomass were observed. There were no differences in all silages parameters except NDF and ADF, which were higher in the Bt maize silage than that of the non-Bt maize from the 2008/09 season. The Cry1Ab levels were essentially not reduced during ensiling. The maize residues (both Bt and non-Bt maize) degraded to similar levels, either when surface-applied or incorporated into soil but soil-incorporated residues decomposed faster than surface-applied ones. Cry1Ab degraded as the plant matrix decomposed. The findings suggested that maize genetically modified with the Bt MON810 event can be grown in the Central Eastern Cape without affecting earthworm numbers and biomass, silage quality and decomposition of maize residues.

Made available in DSpace on 2016-05-02T13:55:26Z (GMT). No. of bitstreams: 1 Rodrigo de Oliveira Cesarino.pdf: 260466 bytes, checksum: 275938861302541a4ebf1c00bb87b762 (MD5) Previous issue date: 2006-05-11 / Coordenacao de Aperfeicoamento de Pessoal de Nïvel Superior / Corn silage is an alternative forage to feed cattle of good energy value and if it goes well prepared it can present equivalent nutritious value to that existed in original green material This research was led with the objective of evaluating agronomic characteristics and bromatological in corn for silage fertilized in covering with liquid dejections of swine (LDS) The experiment was installed in a private property in the municipal district of Alfenas - MG Double hybrid corn was used Geneze 2005 and corn variety (Al-Band) The experimental disign was of blocks casualized with five treatments and four blocks The treatments were T1-witness without covering manuring T2-Nitrogen and Potassium at 30-00-20 350 kg/ha T3-50 m3 LSD/ha T4-100 m3 LSD/ha and T5-150 m3 LSD/ha The obtained results were submitted to the variance analysis with test Scott-Knott at the level of significance of 5% It was evaluated the heights of plants and of ears of corn fallen ill plants or broken percentage of dry matter and production of dry matter pH rude protein (PB) fiber in neutral detergent (FDN) fiber in acid detergent (FDA) digestibility in vitro of the matter evaporates (DIVMS) lignine and ashes The largest averages of plants height were observed in treatments that received manure covering and chemical fertilizer The largest averages of corn ear height happened in the treatments that received chemical fertilizer and 100 m3 LSD/ha The largest percentage of fallen ill plants and broken it was verified in variety Al-Band (4,0%) For the cultivate Geneze 2005 the production of dry matter was 15,5% superior than the variety Al-Band The largest production of dry matter was observed in the chemical treatment (14.913 Kg MS/ha) followed by the treatment of 150 m3 LSD/ha (13.719 kg MS/ha) The medium values of dry matter were influenced by the treatments presenting variations of 30,93% (witness) and 33,83% (chemical) The pH values presented a width of 3,72 (Al-Band) to 3,75 (Geneze 2005) differentiating statistically to each other It was observed in cultivating Geneze 2005 a larger value of PB in the chemical treatment (5,98%) followed by the other treatments In the treatments witness and 150 m3 DLS/ha the largest values of FDN were observed compared with the smallest value observed in the chemical fertilizer (53,87%) The largest percentage of FDA was observed in cultivating Geneze 2005 in relation to variety Al-Band It was observed that the treatment that received the chemical fertilizer in covering presented a larger coefficient of DIVMS (54,44%) The largest values of DIVMS were observed for to cultivate Geneze 2005 in the chemical treatment suggesting relation to the largest participation of grains however the values observed for to cultivate Al-Band didn't show statistical difference Chemical fertilizer treatment showed lower statistic level for lignin in both cultivates of corn In Ash percentage the witness treatment for both corn cultivates were higher than the treatments with LDS The manure covering with liquid dejections of swine above 100 m3/ha provided satisfactory productivities and of good nutritional value in corn growing for silage This way the liquid dejections of swine can be an alternative in the manuring in covering in the culture of the corn The hybrid Geneze 2005 presented the largest productivities when compared to variety Al-Band / Esta pesquisa foi conduzida em propriedade rural particular localizada no município de Alfenas - MG, no período experimental de novembro de 2004 a março de 2005 Objetivou-se obter informações sobre a influência da adubação com dejetos líquidos de suínos em cobertura sobre características agronômicas composição bromatológica e valor nutritivo de cultivares de milho utilizados para ensilagem O delineamento experimental foi em blocos casualizados com cinco tratamentos e quatro repetições Foram utilizados duas cultivares de milho comerciais Geneze 2005 e AL-Band Os tratamentos foram T1- testemunha sem adubação de cobertura T2-NK na fórmula 30-00-20, 350 kg/ha T3- 50 m3 DLS/ha T4-100 m3 DLS/ha e T5-150 m3 DLS/ha Os resultados obtidos foram submetidos à análise de variância e as médias separadas pelo teste Scott-Knott a 5% Avaliou-se os dados agronomicos altura de plantas e de espigas plantas acamadas ou quebradas porcentagem de matéria seca e produção de matéria seca Na silagem avaliou-se o pH proteína bruta (PB) fibra em detergente neutro (FDN) fibra em detregente ácido (FDA) digestibilidade in vitro da matéria seca (DIVMS) lignina e cinzas As maiores médias de altura de plantas foram observadas nos tratamentos que receberam tanto a adubação química quanto os que receberam cobertura com DLS As maiores médias de altura de espiga ocorreram nos tratamentos que receberam adubação química e 100 m3 DLS/ha A maior porcentagem de plantas acamadas e quebradas foi verificada para a cultivar AL-Band (4,0 %) Para a cultivar Geneze 2005 observou-se uma produção média de MS 15,5% superior a encontrada para a cultivar AL-Band A maior produtividade de matéria seca foi observada no tratamento químico (14.913 kg MS /ha) seguida do tratamento 150 m3 DLS/ha (13.719 kg MS/ha) Os teores médios de matéria seca foram influenciados pelos tratamentos apresentando variações de 30,93% (testemunha) e 33,83% (químico) Os valores de pH apresentaram uma amplitude de 3,72 (AL-Band) a 3,75 (Geneze 2005) diferenciando estatisticamente entre si Observou-se na cultivar Geneze 2005 um maior teor de PB no tratamento químico (5,98%) seguido dos demais tratamentos Nos tratamentos testemunha e 150 m3 DLS/ha foram observados os maiores valores de FDN comparado com o menor valor observado no químico (53,87%) A maior porcentagem de FDA foi observado na cultivar Geneze 2005 em relação a cultivar AL-Band Observou-se que o tratamento que recebeu a adubação química em cobertura apresentou um maior coeficiente de DIVMS (54,44%) Os maiores valores de DIVMS foram observados para a cultivar Geneze 2005 no tratamento químico podendo ser em função da maior participação de grãos porém os valores observado para a cultivar Al-Band não apresentaram diferenças estatísticas Com a adubação química observou-se menores valores médios de lignina em relação às adubações em cobertura com DLS para ambas as cultivares Os valores médios da porcentagem de cinzas foram estatisticamente superiores para ambas cultivares no tratamento testemunha A adubação em cobertura com dejetos líquidos de suínos acima de 100 m3/ha proporcionou produtividades satisfatórias e de bom valor nutritivo em milho para silagem Desta forma os dejetos líquidos de suínos podem ser uma alternativa na adubação em cobertura na cultura do milho

O presente estudo teve por objetivo a avaliação do efeito de estádios de maturidade de cultivares de milho (Zea mays L.) para produção de silagem sobre os parâmetros agronômicos e qualitativos da planta e das frações que a compõem. Foram avaliados seis híbridos de milho para silagem, colhidos em oito estádios de maturidade, em dois anos agrícolas, safra de 2002 e 2003. As plantas atingiram o teor de matéria seca (MS) recomendado para ensilagem (32 a 35% MS) entre 92 e 112 dias após a semeadura (DAS). O híbrido CO 32 apresentou os maiores (P<0,05) teores de MS da planta e do colmo, e as menores (P<0,05) produções MS do colmo ao longo do período de avaliação, enquanto o híbrido P 3041 obteve os menores (P<0,05) teores de MS da planta e do colmo. Os híbridos DKB 333B e AG 1051, de ciclo normal, apresentaram as maiores (P<0,05) produções de colmo no 1&#186;, 3&#186;, 4&#186;, 5&#186; e 8&#186; corte. O avanço da maturidade resultou em aumentos (P<0,05) no teor de MS da planta (de 14,5 para 46%) e do colmo (de 16,9 para 28%), produção de MS da planta (de 9,6 para 20,9 t MS/ha) e produção de grãos (de 0 para 9,3 t MS/ha). Aumentos (P<0,05) nos teores de MS das frações folha (de 23,2 para 48,8%), sabugo (de 10,0 para 55,5%) e grãos (de 50,4 para 70,9%) também foram observados ao longo do tempo. Além disso, observou-se aumentos (P<0,05) nas porcentagens de sabugo (de 1,6 para 9,2%) e grãos (de 0 para 43,4%), e redução (P<0,05) na porcentagem de colmo (de 63,4 para 29,5%) e folhas (de 27,5 para 10,8%). Com o avanço da maturidade foram observados aumentos (P<0,05) nos teores médios de amido da planta (1,8 a 26,1%) e do grão (60,2 a 91,9%); e na produção de matéria seca digestível (PMSD) da planta (7,2 a 16,3 t/ha) e do grão (3,3 a 8,9 t/ha). Em contrapartida, verificou-se redução (P<0,05) nos teores de fibra em detergente neutro (FDN) da planta (71,9 para 52,8%); FDN digestível da planta (64,7 para 54,4%) e do colmo (55,2 para 39,6%); proteína bruta (PB) da planta (12,5 para 7,0%) e do colmo (7,0 para 4,2%); e na digestibilidade verdadeira in vitro da MS (DVIVMS) do colmo (66 para 53,7%) e do grão (99,1 para 96,4%). No ponto de ensilagem, os híbridos P 3041, AG 1051 e Z 8550 foram os materiais que apresentaram as características mais desejáveis na confecção de silagem de qualidade. Para a fração colmo, o híbrido Z 8550 apresentou os menores (P<0,05) teores de PB e FDN, e os maiores (P<0,05) teores de FDN digestível, DVIVMS e PMSD. Os híbridos P 3041, DKB 333B e AG 1051, de endosperma duro, apresentaram juntamente com o híbrido Z 8550, as maiores (P<0,05) PMSD do colmo. No ponto de ensilagem, o maior (P<0,05) teor de amido do grão foi observado para os híbridos de endosperma duro (P 3041 e DKB 333B), enquanto que a maior (P<0,05) DVIVMS do grão foi verificada para os materiais de endosperma dentado (AG 5011 e AG 1051). A avaliação detalhada da planta, levando em consideração a produtividade, a participação percentual dos seus componentes, além da composição química intrínseca dos mesmos é fundamental para a adequação do processo de ensilagem e êxito dos sistemas de produção. / The objective of this experiment was to evaluate the effect of the maturity stage of corn (Zea mays L.) cultivars for silage production on agronomic and qualitative parameters of plant and its compounds. Six corn silage cultivars were evaluated in eight maturity stages, and two harvesting seasons (2002 and 2003). The plants reached the recommended dry matter (DM) content for silage production (32 to 35% DM) between 92 and 112 days after sowing (DAS). The cultivar CO 32 showed the highest (P<0.05) plant and stem DM content, and the lowest (P<0.05) stem DM production along the evaluation period, while P 3041 cultivar achieved the lowest (P<0,05) plant and stem DM content. The normal maturity cycle cultivars DKB 333B and AG 1051, showed the highest (P<0.05) stem production at 1st, 3rd, 4th, 5th and 8th harvesting age. As maturity advance there were increases (P<0.05) of plant DM content, (from 14.5 to 46%), stem DM content (from 16.9 to 28%), plant DM production (from 9.6 to 20.9 t DM/ha) and grain production (from 0 to 9.3 t DM/ha). Increases (P<0.05) of leaves DM content (from 23.2 to 48.8%), cob DM content (from 10 to 55.5%), and grains DM content (from 50.4 to 70.9%) were observed according to the maturity stage. Furthermore, resulted in increases (P<0.05) in cob percentage (from 1.6 to 9.2%) and grain percentage (from 0 to 43.4%), and decreases (P<0.05) in stem percentage (from 63.4 to 29.5%) and leaves percentage (from 27.5 to 10.8%) as plants matured. Plant maturing resulted in increases in plant (1.8 to 26.1%) and grain (60.2 to 91.9%) starch content, and in the plant (7.2 to 16.3 t/ha) and grain (3.3 to 8.9 t/ha) digestible DM production. However there were verified decreases (P<0.05) in plant (71.9 to 52.8%) neutral detergent fiber (NDF), plant (64.7 to 54.4%) and stem (55.2 to 39.6%) digestible NDF, plant (12.5 to 7.0%) and stem (7.0 to 4.2%) crude protein (CP), and stem (66 to 53.7%) and grain (99.1 to 96.4%) in vitro true dry matter digestibility (IVTDMD) content. At the ensilage moment, P 3041, AG 1051 and Z 8550 cultivars showed the most desirable characteristics for silage production with quality. For the stem fraction, Z 8550 cultivar showed the lowest (P<0.05) CP and NDF content, and the highest values (P<0.05) for stem digestible NDF, IVTDMD, and digestible DM productions. The cultivars P 3041, DKB 333B and AG 1051, with hard endosperm, showed together with Z 8550 cultivar, the highest (P<0.05) stem DDMP. For the grain, it was observed that at the ensilage moment, the highest (P<0.05) starch content was verified for the hard endosperm cultivars (P 3041 and DKB 333B), while the highest (P<0.05) IVTDMD was observed for the soft endosperm cultivars (AG 5011 e AG 1051). Grain DDMP was similar (P>0.05) for the evaluated cultivars.

O objetivo do presente trabalho foi avaliar o efeito de aditivos químicos e microbianos sobre as perdas de matéria seca, perfil fermentativo, valor nutritivo e estabilidade aeróbia da silagem de cana-de-açúcar. A variedade utilizada para confeccionar os silos laboratoriais foi RB-72454 com 12 meses de idade fisiológica. O experimento foi desenvolvido em delineamento inteiramente casualizado, sendo seis tratamentos, com quatro repetições cada. Além da silagem de cana-de-açúcar controle, foram utilizados dois aditivos microbianos: Lactobacillus plantarum e o conjunto de bactérias L. plantarum + Streptococcus faecium + Pediocccus acidilactici (BAL). Esses dois aditivos microbianos também foram aplicados associados a duas doses de benzoato de sódio, 0,01 e 0,05% da massa verde (MV). Os aditivos microbianos foram aplicados à contagem de 5 x 104 ufc/g de forragem. As variáveis analisadas foram: perdas totais e gasosas, produção de efluente, recuperação de matéria seca, perfil fermentativo, estabilidade aeróbia e valor nutritivo no momento da abertura dos silos e durante o ensaio de estabilidade aeróbia. As maiores perdas fermentativas e gasosas foram observadas para o tratamento da associação de L. plantarum com benzoato de sódio na dosagem de 0,05% da MV. No entanto, não houve diferença entre os tratamentos para as variáveis do perfil fermentativo. Com relação ao valor nutritivo, as silagens que foram tratadas com associação de L. plantarum com benzoato de sódio na dosagem de 0,05% da MV, apresentaram no momento da abertura maior concentração de componentes fibrosos e menores coeficientes de digestibilidade da matéria seca. A maioria dos tratamentos apresentou desempenho semelhante ao tratamento controle no valor nutritivo no momento da abertura dos silos. Com relação ao ensaio de estabilidade aeróbia na associação de L. plantarum com benzoato de sódio na dosagem de 0,05% da MV, foi observado o menor acúmulo de temperatura nos primeiros cinco dias após abertura (ADITE-5) e menor pico de temperatura da massa exposta ao ar. Da mesma forma, as silagens tratadas com esses aditivos mantiveram estável o valor de pH e apresentaram maior recuperação de matéria seca das silagens nos primeiros cinco dias pós-abertura. Todavia, não houve diferenças significativas entres os tratamentos para as outras variáveis analisadas na fase aeróbia. Com relação ao valor nutritivo das silagens no momento da abertura, associação de L. plantarum com benzoato de sódio na dosagem de 0,05% da MV apresentou menores valores da fração fibrosa e maior digestibilidade da matéria seca nos primeiros cinco dias da fase aeróbia. Para a avaliação químico-bromatológicas, não foram encontradas diferença nos teores de carboidratos solúveis e proteína bruta entre os tratamentos. De forma geral, a analise conjunta dos experimentos mostra que as silagens tratadas com associação de L. plantarum com benzoato de sódio na dosagem de 0,05% da MV, apresentaram melhor desempenho na fase aeróbia que na fase fermentativa. / The objective of this study was to evaluate the effect of chemical and microbial additives on dry matter losses, fermentative profile, nutritive value and aerobic stability of sugarcane silages. The variety used to ensiling was RB-72454, harvested with 12 months of regrowth. It was analyzed as a completely randomized model, with six treatments and four replications for each treatment. Besides the control sugarcane silage, were tested two types of microbial additives: Lactobacillus plantarum and the association of L. plantarum and Streptococcus faecium and Pediocccus acidilactici (BAL). Moreover these two microbial additives were associated with two levels of sodium benzoate, 0.01 or 0.05% of fresh matter. The microbial additives were applied trying to reach 5 x 104 UFC/g of forage. The variables analyzed were: total dry matter losses, gases losses, effluent yield, dry matter recovery rate, fermentative profile, aerobic stability and nutritive value when the silos were opened and during the aerobic stability trial. The greatest fermentative and gaseous losses were observed in silages treated with L. plantarum associated with 0.05% of sodium benzoate. However, there is no difference among treatments regarding the fermentative profile. The silages added with L. plantarum associated to 0.05% of sodium benzoate showed highest cell wall content and lowest in vitro dry matter digestibility. Most of the treatments showed similar nutritive value as control silages. Regarding the aerobic stability assay, L. plantarum associated to 0.05% of sodium benzoate had highest accumulated temperature in the first five days (ADITE-5) and the lowest temperature pick. Similarly, these silages remained the pH stable and showed highest dry matter recovery rate in the first five days during aerobic trial. Although, there were no differences in the other variables in aerobic assay. In terms of nutritive value, the treatment of L. plantarum associated 0.05% of sodium benzoate, showed lowest fiber content and highest in vitro dry matter digestibility during the first five days of aerobic stability trial. There were no differences in the water soluble carbohydrates and crude protein content among treatments. In general, considering the whole trial, the treatment with L. platarum associated with 0.05% of sodium benzoate had better performance during the aerobic phase than the fermentative one.

La sélection génomique offre de nouvelles perspectives en amélioration des plantes pour la sélection de caractères complexes. Le travail proposé porte sur l’évaluation de son intérêt dans le cadre d’un programme de sélection réciproque pour la valeur d’hybrides entre deux groupes génétiques de maïs complémentaires. Il s’appuie sur un dispositif expérimental original constitué de 900 hybrides produits dans un plan factoriel entre deux dispositifs multiparentaux connectés. L’objectif de la sélection est d’améliorer le rendement ensilage des hybrides tout en améliorant leur digestibilité. Une réflexion sur les modèles permettant de prédire la valeur hybride sera conduite et testée sur les données expérimentales et par simulations. Ce travail, conduit en collaboration avec sept sociétés de sélection (au sein de PROMAÏS) devrait permettre d’améliorer les dispositifs de sélection classiques et de produire des hybrides d’intérêt agronomique. Il s’inscrit dans le cadre plus général de l’amélioration pour la valeur en croisement commune à de nombreuses espèces végétales allogames et à certaines espèces animales. / Genomic selection opens new prospects in plant breeding for the selection of complex traits. The proposed study aims to evaluate its efficiency in the context of a reciprocal selection schemes for the hybrid value between two complementary maize groups. The work will rely on an original experimental design including 900 hybrids produced from a factorial between two multiparental connected designs. The selection objective is to increase the hybrids silage yield as well as their digestibility. Several models for the hybrid value prediction will be proposed and tested on the experimental data and by simulations. This study, carried out in close connection with seven plant breeding companies (members of PROMAÏS) will contribute to the improvement of breeding designs and will produce new interesting hybrids. It falls within the general context of the selection for hybrid value which is common to numerous plant allogamous species and animal species.

Le maïs (Zea mays L.) est la plante la plus cultivée au monde. Pour valoriser le fort effet d’hétérosis pour les caractères liés à la biomasse, la diversité génétique du maïs est structurée en groupes hétérotiques et les variétés cultivées sont majoritairement des hybrides F1 entre lignées de groupes complémentaires. La valeur hybride se décompose comme la somme de l’Aptitude Générale à la Combinaison (AGC) de chacune des lignées parentales et de l’Aptitude Spécifique à la Combinaison (ASC) du couple. En Europe du Nord, le maïs est souvent utilisé en ensilage destiné à l'alimentation animale. L’objectif de sélection est d’améliorer la productivité et d'assurer une bonne digestibilité du maïs ensilage. Les objectifs de cette thèse étaient : (i) d’estimer l’importance de l’AGC et de l’ASC dans la variance génétique hybride pour les caractères de qualité de l’ensilage, (ii) d’identifier les locus (QTL) impliqués dans ces caractères et d’étudier leur colocalisation avec des QTL de productivité, (iii) d’évaluer l’intérêt de la sélection génomique pour la prédiction des performances hybrides et (iv) de comparer l’efficacité de deux dispositifs de calibration des prédictions basés sur un factoriel ou l’utilisation classique de testeurs du groupe complémentaire. Dans le cadre du projet SAM-MCR, 6 familles biparentales connectées ont été créés dans les groupes « corné » et « denté » à partir de 4 lignées fondatrices. Dans une première phase, 822 lignées cornées et 802 dentées ont été génotypées pour 20k SNP et croisées selon un factoriel incomplet pour produire 951 hybrides, phénotypés pour des caractères de qualité et de productivité (étudiés par H. Giraud pendant sa thèse). L’analyse des caractères de qualité a montré une prédominance de l’AGC par rapport à l’ASC ainsi qu’une corrélation négative entre les caractères de qualité et le rendement. De nombreux QTLs multi-alléliques ont été détectés, la plupart spécifiques d’un groupe et dont certains colocalisent avec des QTL de rendement. Par validation croisée, la qualité de prédictions basées sur les QTL détectés s’est avérée plus faible que celle obtenue par prédiction génomique. La prise en compte de l’ASC n‘a pas permis d’améliorer sensiblement la qualité de prédictions des modèles. Dans une seconde phase, 90 lignées ont été choisies par groupe : 30 sélectionnées sur la base de leurs prédictions génomiques pour la productivité et la valeur énergétique et 60 choisies aléatoirement parmi les 6 familles. Ces lignées ont été croisées selon un factoriel incomplet pour produire 360 nouveaux hybrides : 120 issus des lignées sélectionnées et 240 issus des lignées choisies au hasard. Les 90 lignées de chaque groupe ont aussi été croisées à deux lignées fondatrices du groupe complémentaire (testeurs). Les hybrides issus des lignées sélectionnées se sont avérés plus productifs mais de moins bonne qualité. Nous avons confirmé la bonne qualité des prédictions génomiques obtenus dans le factoriel initial sur les nouveaux hybrides évalués dans d’autres environnements et après sélection et observé une bonne corrélation entre les AGC estimées dans le factoriel et dans le dispositif testeurs. Des dispositifs factoriels et testeurs ont été simulés en faisant varier la part d’ASC, le nombre d’hybrides et la contribution de chaque lignée dans le jeu de calibration. A moyens expérimentaux égaux, le dispositif factoriel s’est avéré plus efficace en termes de capacité prédictive et de gain génétique cumulé que le dispositif testeur (jusqu’à +50%) pour un caractère présentant de l’ASC et équivalent pour un caractère purement additif. Les résultats de cette thèse ouvrent de nouvelles perspectives pour revisiter les schémas de sélection hybrides en remplaçant l’évaluation des lignées candidates, classiquement faite sur testeur, par l’évaluation directe d’hybrides issus d’un factoriel incomplet. La mise en œuvre de tels dispositifs nécessitera de réorganiser la logistique des programmes de sélection. / Maize (Zea mays L.) is the most cultivated crop in the world. To exploit the strong heterosis for traits related to biomass, the genetic diversity of maize is structured into heterotic groups and cultivated varieties are mainly F1 hybrids obtained by crossing lines from complementary groups. The hybrid value can be decomposed as the sum of the General Combining Ability (GCA) of each parental line and the Specific Combining Ability (ASC) of the cross. In northern Europe, maize is often used as silage for animal feed and the breeding objective is to improve productivity while ensuring a good energetic value and digestibility of the silage. The objectives of this thesis were: (i) to estimate the importance of GCA and SCA in hybrid genetic variance for silage quality traits, (ii) to identify loci (QTL) involved in these traits and to study their colocalization with QTL for productivity traits, (iii) to evaluate the interest of genomic selection for the prediction of hybrid performances and (iv) to compare the prediction accuracies of two calibration designs either based on a factorial or on the conventional use of testers from the complementary group. As part of the SAM-MCR project, 6 biparental connected families were created in the "flint" and "dent" groups from 4 founder lines. In a first phase, 822 flint and 802 dent lines were genotyped for 20k SNPs and crossed according to an incomplete factorial to produce 951 hybrids which were phenotyped for quality traits and for productivity traits (studied by H. Giraud during her phD). Quality trait analysis showed a predominance of GCA over SCA and a negative correlation between digestibility traits and silage yield. Several multi-allelic QTLs were detected, most of them being specific to one group. Several colocalizations were found with yield QTL. Using cross-validation, we observed that the predictive ability of models based on detected QTLs was lower than that obtained by genomic predictions. Considering the SCA did not improve model predictive abilities for most of the traits. In a second phase, 90 lines were chosen per group: 30 were selected based on their genomic predictions for productivity and the energetic value and 60 were randomly sampled from the 6 families. These lines were crossed according to an incomplete factorial to produce 360 new hybrids: 120 from selected lines and 240 from randomly chosen lines. The 90 lines of each group were also crossed to two lines of the complementary group (testers). Hybrids from the selected lines were more productive but had a lower silage quality. We confirmed the good accuracy of the genomic predictions obtained in the initial factorial on the new hybrids evaluated in other environments and after selection. We also observed good correlations between GCA estimated in the factorial and in the testcross design. Different factorial and testcross designs were simulated by varying the proportion of dominance/SCA, the number of hybrids and the contribution of each line to the calibration set. Considering the same number of hybrids in the calibration set, the factorial was more efficient in terms of predictive ability and cumulative genetic gain (up to + 50%) than the testcross design for traits showing SCA and was similar for purely additive traits. The results of this thesis open new perspectives to revisit hybrid breeding schemes by replacing the evaluation of candidate lines, classically made on testcross, by the direct evaluation of hybrids resulting from an incomplete factorial. The implementation of such designs will require reorganizing the logistics of selection programs.

In zwei Berichten werden der Einfluss von Saattermin und Gülledüngung sowie unterschiedliche Maßnahmen zur Unkrautregulierung auf Ertrag und Qualität von Silomais im ökologischen Landbau dokumentiert. Ein früher Saattermin erhöht die TM-Erträge. Alle geprüften Ausbringungsverfahren an Rindergülle (vor Saat breitflächig, Unterfußdüngung, 2-Blattstadium Injektion, 6-8-Blattstadium Schleppschlauch) sind praxistauglich und führen zu höheren Erträgen und besseren Qualitäten. Die Feldversuche zeigen, dass je nach vorhandener Technik verschiedene Strategien der Unkrautregulierung erfolgreich umgesetzt werden können.