Dissertations / Theses on the topic 'Organic dairy'

Thesis (B.S.)--California Polytechnic State University, 2009.
Project advisor: Leanne Berning. Title from PDF title page; viewed on Jan. 21, 2010. Includes bibliographical references. Also available on microfiche.

Améliorer la santé des vaches laitières en élevage agrobiologiques (AB) est bien souvent nécessaire, pour ces élevages ne répondant pas toujours aux principes de l’AB et aux attentes des consommateurs d’avoir un niveau de santé et bien-être animal élevé. Cette thèse explore des voies d’amélioration du conseil sanitaire en vue d'améliorer la santé animale dans ces élevages. Les résultats de nos travaux montrent que les vétérinaires ont le plus souvent un rôle de thérapeute dans les élevages laitiers AB. L'obtention d'un rôle de conseiller a été entravée par des spécificités liées à l’AB, telles que les différences entre éleveurs et vétérinaires dans les objectifs de gestion de la santé des animaux et les pratiques sanitaires. Une étude d'intervention a été effectuée pour tester un dispositif de conseil dans des élevages AB en France et en Suède, basé sur l’utilisation d’outils de surveillance et prévention de maladies de production. Le dispositif a été réalisé en utilisant une approche participative, impliquant l’éleveur et le conseiller ; la flexibilité de l’outil a permis de produire un protocole de surveillance adaptée à chaque élevage. Bien qu’aucun effet sur la santé du troupeau n’a été prouvé, le dispositif a été perçu pour contribuer à la santé du troupeau par ses utilisateurs. Il a rempli la plupart de ses fonctions prévues de surveillance et de prévention des maladies et a stimulé le dialogue entre éleveurs et conseillers. Des outils qui stimulent le dialogue et qui sont adaptables à chaque élevage sont une voie à suivre pour le développement du conseil en santé animale
Improving herd health on organic dairy farms is often needed, since organic dairy farms do not consistently meet the organic principles and consumers’ expectations of high animal health and welfare. This thesis explores ways to improve the pertinence of herd health advisory services in order to improve animal health on organic dairy farms. The results of our studies show that veterinarians mostoften have a role of therapist on organic dairy farms. Obtaining a more advisory role was hampered due to specificities of the organic sector, such as differences between farmers and veterinarians in animal health management objectives and practices. An intervention study was performed testing a Herd Health and Production Management (HHPM) program on organic dairy farms in France and Sweden, based on herd health monitoring and disease prevention activities. The program was built using a participatory approach, making farmer and advisor work together ; the adaptability of the program allowed to design farm specific herd health monitoring tools. Although no effecton herd health measured, the program was perceived to contribute to herd health by its users. The program fulfilled most of its intended functions in herd healthmonitoring and disease prevention and stimulated dialogue between farmers and their advisors. We consider that dialogue promoting and tools adaptable to farm specific situations are a possible way forward for the development of advisory services in animal health

Thesis (Ph. D.)--Washington State University, December 2009.
Title from PDF title page (viewed on Feb. 19, 2010). "Department of Biological Systems Engineering." Includes bibliographical references.

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Fundação de Amparo à Pesquisa do Estado de Minas Gerais
O mercado de trigo (Triticum aestivum L.) orgânico para produção de pão cresceu em grande magnitude na região da Nova Inglaterra, nos Estados Unidos. Este nicho de mercado representa uma alternativa de renda para os produtores de leite orgânico abastecerem este mercado através do cultivo e colheita de grãos em rotação de cultura na própria fazenda. Objetivou-se com este estudo determinar a sustentabilidade de oito sequências de rotação de cultura (três anos de rotação) durante o período de 25 anos em uma propriedade produtora de leite orgânica bem manejada. Uma fazenda média foi simulada utilizando o modelo computacional Integrated Farm System Model (versão 3.6) para avaliar o efeito da rotação de cultura no desempenho da cultura, impacto ambiental e rentabilidade. As estratégias de rotação incluíram pasto contínuo (azevém e trigo), milho (Zea mays L.) colhido cedo seguido de trigo de inverno (milho-trigo de inverno- pasto), milho seguido de trigo de primavera (milho-trigo de primavera-pasto), pasto em rotação com trigo de inverno (azevém/trigo - trigo de inverno - azevém/trigo), pasto em rotação com trigo de primavera (azevém/trigo - trigo de primavera - azevém/trigo), soja [Glycine max (L.) Merr.] em rotação por trigo de inverno (soja - trigo de inverno - azevém/trigo) e primavera (soja - trigo de primavera - azevém/trigo), milho em cultivo consecutivo (milho - milho - azevém/trigo) e soja seguida de milho (soja - milho - azevém/trigo). O trigo foi colhido em grão e comercializado a preço premium em todos os anos simulados. Em todas as simulações foram cultivados azevém e trigo (Lolium perenne / Trifolium pratense) consorciados no terceiro ano. Em geral, não houve benefício econômico e ambiental na rotação de cultura em comparação o pasto contínuo (monocultivo). Entretanto, entre as rotações de cultura, o cultivo de trigo de inverno deve ser incentivado, particularmente em rotação com a soja, para reduzir o impacto ambiental e aumentar rentabilidade da fazenda.
The market for high-quality organic bread wheat (Triticum aestivum L.) is increasing in New England. This economic niche represents one alternative income for organic dairy producers (if they include wheat in their crop rotation) to supply this market by raising wheat as a cash crop. Our objective was to determine the sustainability to eight crop rotation sequences of 3-yr rotations in a long-term (25-yr) well-managed organic dairy farm. A medium-sized organic dairy farm was simulated with the Integrated Farm System Model (IFSM, version 3.6) to evaluate crop rotation (management) effects on crop performance, environmental impacts and profitability. The cropping strategies included continuous ryegrass/red clover (continuous grass), corn (Zea mays L.) harvested early followed by winter wheat (corn-wwheat-grass), corn followed by spring wheat (corn-swheat-grass), ryegrass/red clover rotated with winter wheat (grass-wwheat-grass), ryegrass/red clover in rotation with spring wheat (grass-swheat-grass), soybean [Glycine max (L.) Merr.] rotated by both winter wheat (soybean-wwheat-grass) and spring wheat (soybean- swheat-grass), corn double cropped (corn-corn-grass) and soybean followed by corn (soybean- corn-grass). Wheat was harvested as a cash crop in all simulated years and sold at a premium price. All rotations were in long rotation with perennial ryegrass/red clover (Lolium perenne / Trifolium pratense) over the 3-yr. In general, there was no economic and environmental benefit to shifting land from continues grass-based production to specified cropping rotations. However, under crop rotation, use of winter wheat should be encouraged, particularly soybean replaced with cash crop wheat, to reduce environmental impact and improve farm profitability.

This thesis focused on the conversion period from conventional to organic agriculture for a Quebec dairy farm. The crucial problem resided in developing an economic framework to evaluate alternative crop rotations that would provide farmers in transition an optimal rotation plan compatible with organic farming practices.
Two multi-period linear programming models were developed for that purpose, both models having different assumptions concerning effects that the transition might have on crop yield.
In both transitional models, two crop rotations were selected in the optimal solution. In addition, the establishment of crop rotations was comparable for both models, and this showed that the assumed drop in yield did not have a large impact on the selection of crop rotation. Also, the results support the notion that conversion to organic agriculture had a relatively less negative effect on farm profit if the transition was done gradually.

Production of dairy and associated products is a source of millions of gallons of wastewater every year. Water used in cleaning feeding stalls as well as the liquid component of the animal waste are two of the major volumetric components of this wastewater. This water is nutrient rich, often limiting the viability as a land applied fertilizer. However, these same nutrients could be used as an inexpensive feedstock for the cultivation of algae, which can then be used to produce downstream products including animal feed and aquaculture. As part of this study, algal biomass was cultivated on dairy wastewater from the Utah State University Caine Dairy. A Rotating Algal Biofilm Reactor (RABR) system was used to grow the biomass. The RABR is a biofilm technology designed and developed at Utah State University and has been applied to the treatment of municipal wastewater. In this study, the RABR was adapted for use in a dairy wastewater stream. The RABR was operated at temperatures ranging from 7-27 °C, and organic carbon levels in the wastewater ranged from 300-1200 mg/L of Total Organic Carbon (TOC). Areal algal biofilm growth rates were calculated, and statistical analysis showed that both increasing temperature and levels of organic carbon contributed to an increase in biomass growth and an increase in nutrient removal. Equations were then developed using a linearization method and corresponding constants and equations were generated that can be used to evaluate algal biomass productivity and nutrient removal rates in future experiments and designs for dairy wastewater.

The total number of operating dairy farms in the US has decreased by 74.1% over the past 25 years, dropping from 155,339 in 1992 to just 40,219 in 2017. As milk prices have fallen and become more volatile, profit margins have tightened, causing farmers to leave the business due to low profitability. Some Vermont farmers are currently looking for new economic strategies. One approach has been to transition from conventional to organic production in order to take advantage of better prices and new market opportunities. In order to make production decisions, farmers need accurate financial information on the costs and benefits of the various options available. Since 2004, UVM Extension has collected panel data on organic dairy farms in Vermont to help meet this growing need. As a part of UVM’s long-term organic dairy profitability research, this study analyzed 10 years of financial panel data (2006-2017) from an unbalanced panel of approximately 40 organic dairy farms in Vermont. For article 1, a multivariate fixed effects regression model was used to identify key factors influencing farm profitability and estimate their effects on Return on Assets. Variables related to feeding management, farm management, farm characteristics, input costs, and year were shown to be significant. For article 2, industry wide milk price trends were compared with descriptive statistics on Vermont organic dairy profitability outcomes across a 3-year period (2015-2017) in order to test the hypothesis that recent price shifts have a had a noticeable effect on farm profitability. Despite limited data for 2017, results indicated a study-wide reduction in ROA in line with national market trends. In identifying management and market factors associated with profitability, this thesis provides valuable decision-making information for farmers interested in switching to organic. Results suggest that feeding management and milk quality improvements can improve profitability outcomes on Vermont farms. Vermont farmers will also benefit from the updated cost of production and financial performance data presented here. Evidence from this thesis also supports a need for new supply management policies and a more nuanced approach to organic dairy profitability research.

Pasture-based dairies have become more prevalent in recent years due to a higher proportion of organic milk demand and production. Organic certification requires that animals must graze at least 120 days in each growing season. However, dry matter intake is often limited when dairy animals receive most of their herbage from pasture, resulting in lower animal performance and milk production. The purpose of this study was to analyze the complimentary effect of high energy grasses with birdsfoot trefoil (BFT) tannins to improve intake of dairy heifers. Jersey heifers were rotationally grazed for 105 days in 2017 and 2018 on eight different pasture treatments, which included monocultures of perennial ryegrass (PR), orchardgrass (OG), meadow bromegrass (MB), and tall fescue (TF), with each respective grass also planted in mixture with BFT. Intake was measured by sampling herbage before and after each seven-day grazing period and was from greatest to least as follows: MB+BFT, OG+BFT, OG, MB, PR+BFT, TF+BFT, PR, TF. Physical characteristics such as pasture bulk density, herbage height, herbage allowance, leaf pubescence, leaf softness, and birdsfoot trefoil content as well as nutritional properties such as fat, non-fibrous carbohydrates, fiber, and energy were all associated with intake. Crude protein and ash were also associated with intake. While PR+BFT did not have the greatest overall intake, it was the only treatment that consistently had greater intake than its respective grass monoculture (PR). Since it had more energy and tannins than all other grasses, a complimentary effect between energy and tannins to increase intake was likely. The fact that both physical and chemical herbage characteristics were associated with intake shows the importance of planting the right species in pasture as well as making proper management decisions to maximize nutritive value and herbage intake.

This thesis explores the details and profitability of two distinct operational strategies utilized by dairy operations as alternatives to expanding milk production. It features farms that have either transitioned to organic production or installed a farm-scale anaerobic digester, motivated in part by the opportunity for market specialization or income diversification to increase the viability of their dairy farm businesses. The first analysis examines the demographics and production characteristics impacting the profitability of organic dairy farmers in Vermont and Maine. This provides policymakers, educators, lenders, and suppliers with a profile of this sector that accounts for 23% of dairy farms in Vermont and 20% of dairy farms in Maine, annually shipping, on average, 787,600 lbs. milk per farm. The study was conducted through a longitudinal survey of 83 organic farmers in Vermont and Maine from 2004 to 2012. A multiple linear regression analysis of the sample demonstrated six significant variables that affect farm profitability measured by return on assets (ROA). Having at least 80% Holstein herd composition, increasing the daily pounds of grain fed to cows during the winter months, a primary farm operator having grown-up on dairy farm, and the use of feed mixing machinery all positively impacted ROA. Farm profitability was negatively affected on farms with a high rate of annual cow morbidity and also tended to decrease over the course of the survey as organic prices leveled. While the model developed here has some explanatory power (R2 = 0.387), variability in farm profitability is affected by complex economic pressures. The second analysis reports the predicted and actual annual maintenance figures collected from anaerobic digester systems in Vermont. Within Vermont, 16 farms operate methane-generating ADS. All of these farms have received some form of public funds and/or a voluntary consumer premium. The analysis compares costs by creating a ratio of actual maintenance, repair, oil, and labor costs over these same predicted costs. This ratio is used to assess whether the suggested industry operating cost estimator tends to over or under predict annual maintenance costs. The ratio was evaluated with a one-way Student's t-test (p = 0.046) finding that maintenance costs tend to be under-predicted compared to the actual costs. One-way ANOVA was used to determine a statistically significant effect of herd size (F = 6.453, p = 0.052), showing that the maintenance ratio varies significantly between groups, This analysis indicates that predicting annual maintenance, repairs, and labor costs as a function of 3.5% of total kWh production is an acceptable method for digesters on farms with more than 500 cows, but under predicts maintenance costs for smaller farms. For smaller farms, the actual costs were on average 2.5 times higher.

Organic dairying is growing in popularity in New Zealand and the demand for knowledge is ever increasing. Many more farmers are considering organics as an alternative to their current conventional system. However, limited information is available on organic dairying in a New Zealand pastoral situation particularly in relation to its effect on fertility. The New Zealand dairy industry requires the dairy cow to become pregnant every year at the same time to maximise milk production and utilise the high pasture production in spring. A cow requires 40 to 60 days for uterine involution to occur and for resumption of oestrous cycles. It is critical that the cow becomes pregnant within the six to eight week mating period, however, this can be difficult for late calvers or those cows that had or still have a uterine infection, to undergo uterine involution and be successfully mated. These cows will often not become pregnant and as a consequence be culled for infertility. During the first few weeks postpartum, the bacterial composition of the uterus fluctuates as a result of spontaneous contamination, elimination and recontamination. Most cows are able to eliminate these bacteria, however, 10 to 17% of cows are unable to do this. In these cows, the bacteria persist, cause infection and inflammation, and delay uterine involution. The main objective of this present study was to investigate the effect of different management systems (Organic and Conventional) on productivity and reproduction, particularly the process of uterine involution and its relationship with reproductive outcomes. Uterine involution will be studied through the following measurements: cervical diameter as assessed by measurement per rectum, plasma concentrations of glucocorticoids and bacteriology of the uterus. Lactation characteristics: milk yield, cumulative milk yield, milksolids production and somatic cell count will also be investigated. From the results, it can be concluded that Organic cows have reduced milk yield (P=0.05) and milksolids production (P<0.01) through there were no major differences at peak lactation or in the rate of decline after. However, overall somatic cell count was not affected by management system though the Conventional cows had high somatic cell counts in early lactation (P=0.925). Cervical diameter was affected by the management system with the difference between Organic and Conventional cows almost significant (P=0.06). Cortisol concentrations were significantly higher in Organic cows (0.68 ± 0.08 ng/ml) when compared to Conventional cows (0.95 ± 0.06 ng/ml) (P=0.01). Cortisol concentrations decreased over time postpartum (P<0.01). Additionally Organic cows had a shorter interval from calving to AI (P=0.017). However, none of the other reproductive outcomes were affected by management system. Simple correlations established that reproductive outcomes and bacterial counts, reproductive outcomes and cortisol at Day seven, and cortisol and milk production characteristics, were not independent of each other. Aerobic bacterial counts on Day 28 and the interval from calving to AI were found to be significantly correlated (r= 0.615). Stepwise partial regression analysis, plus analysis of variance calculated on the relationships between uterine involution parameters and reproductive outcomes found multiple weak correlations. It found that cervical diameter, and aerobic and anaerobic bacterial counts on Day 28 were significantly correlated with the interval from calving to first AI (P=0.018). The differences in lactation characteristics are related to the lower pasture production on the organic farmlet reducing the maximal potential milk production and the possibly earlier calving dates of the Conventional cows. The differences in bacterial counts and almost significant difference in cervical diameter may be related to the lower cortisol levels and thus suggest that the Organic cows may be less stressed. As stress suppresses the immune system, it may be possible that the higher bacterial counts are indicitative of a less efficient or slightly weakened immune system which takes longer to eliminate bacteria in the uterus; however this is open to conjecture. The shorter interval from calving to AI suggests that Organic cows may be exhibiting oestrus behaviour earlier postpartum or the Conventional cows are having “silent heats” but this difference is possibly related to human factors. The correlation between parameters of uterine involution and interval from calving to AI, and the lower values for uterine involution parameters in Organic cows suggest the possibility of faster uterine involution and this may result in better fertility in the Organic cows. More research needs to be carried out to further investigate the effect of organic dairying on uterine involution and reproduction outcomes but organic dairying at the very least does not negatively impact on uterine involution and fertility.

The thesis presented consists of two essays that analyze input substitution and decision making in crop and livestock production systems. The first essay consists of a whole-farm analysis that sought to optimize feed mixes and enterprise combinations for an organic dairy operation in the Southeastern United States. This was accomplished through mathematical programming where whole-farm net returns were maximized, and total feed costs were minimized simultaneously for four milk production level cases. Additionally, the sensitivity of the system and break-even milk price were explored. Results suggest substitutability in ration components where an increase in supplemental feeds is justified by additional milk output and sales. The second essay utilizes econometric methods and hedonic modeling to explore factors that drive the price of row crop planters on the used machinery market. Factors relating to make, age, condition, planter specifications, sale type, spatial aspects, seasonality, and year of the sale were analyzed. Results suggest non-linear relationships for row number and age relative to price and interactions between variables make and age that imply varying depreciation depending on the manufacturer. An additional break-even analysis relating to pasture yields and planter purchase price was conducted to explore these primary concepts in further detail.

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The aim of this study were: I) to characterize the organic dairy farms in Santa Catarina, identify the motivations and evaluation of producers on the particular production system, in comparison to conventional farms and; II) to compare indicators of health and animal welfare (AW) of dairy herds, management systems and milk quality in both systems. We selected 17 organic dairy farms or in the conversion process and 17 conventional farms. All producers were visited twice: once in March, once in September/2010, which were open interviews about the historic and farmer s opinions on organic production and an evaluation on the structuring of production farms, discussed the differences between the systems. The technologies and management practices adopted were analyzed in the light of current legislation in order to estimate the contribution needed to ensure the permanence of these families in the organic system. One question in the interviews was examined the farmers' perceptions about animal welfare. Data on environment, food and health management, clinical examination of animals and bulk tank milk samples were collected. Notes on diseases and treatments done in animals were evaluated within the period. Our results indicate that the reduction in production costs and benefits to health and environment are factors that motivate the organic, while the lack of technical support and logistics market are cited as major barriers. It is also evident that farmers know little about the recent regulations, which limits its suitability standards. Organic farmers make production less intensive than conventional ones, where the composition of the herd and feed management are key differences. Both systems kept similar level of animal health, despite greatest difficulty of organic in controlling ectoparasites in summer. We found a lower incidence of disease in animals in the organic, and were reduced use of antimicrobials than in conventional, which is an important indicator of welfare animal and food safety. The levels of animal welfare in some way correspond with the farmers' perceptions on the subject, so improvements could occur via changes in attitudes of the producers.
Os objetivos desse trabalho foram: I) caracterizar os produtores de leite orgânico da região oeste de Santa Catarina, identificar suas motivações e sua avaliação particular sobre o sistema de produção em comparação aos produtores convencionais e, II) comparar indicadores de saúde e bem-estar animal (BEA) dos rebanhos leiteiros, manejos e qualidade do leite nos dois sistemas. Foram selecionadas 17 unidades leiteiras orgânicas ou em fase de conversão e 17 unidades convencionais similares, de agricultores familiares. Foram feitas duas visitas à cada propriedade, em março e setembro de 2010, onde foram feitas entrevistas abertas sobre o histórico e opiniões sobre a produção orgânica e, na avaliação sobre a estruturação das unidades produtivas, foram discutidas as diferenças entre os sistemas. As tecnologias e manejos adotados foram analisados à luz da legislação vigente a fim de se estimar o aporte necessário para garantir a permanência dessas famílias no sistema orgânico. A percepção dos produtores sobre bem-estar animal foi analisada por intermédio de uma questão pontual dentro das entrevistas. Também foram feitas observações do ambiente, manejo sanitário e alimentar, exame clínico dos animais, avaliação do leite total e anotações sobre doenças e tratamentos feitos nos animais dentro do período. Os resultados indicam que a redução nos custos de produção e benefícios a saúde e ambiente são fatores que motivam os produtores orgânicos, enquanto a falta de suporte técnico e logística de mercado são apontadas como entraves importantes. Percebe-se também que os produtores conhecem pouco sobre as recentes normativas, o que limita sua adequação aos padrões. Os produtores orgânicos desenvolvem uma produção menos intensiva do que os convencionais, onde a composição do rebanho e manejo alimentar são as principais diferenças. Os sistemas mantêm níveis similares de saúde animal, porém, o sistema orgânico enfrenta uma dificuldade maior em controlar os ectoparasitas no verão. Foi encontrada uma incidência menor de doenças nos animais no sistema orgânico e, consequentemente, um menor uso de antibióticos sintéticos do que no convencional, o que é importante para o bem-estar animal e segurança alimentar. Os níveis de bem-estar animal foram relacionados ao sistema e correspondem de certa forma, com a percepção dos produtores sobre o tema, portanto, melhorias poderiam ocorrer via mudança de atitudes dos produtores.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conhecer as formas e as transformações do fósforo (P) aplicado via fertilizantes orgânicos e minerais é importante para melhorar o manejo e otimizar o uso do P. Os objetivos com o presente trabalho foram avaliar formas orgânicas e inorgânicas de P em solos adubados com esterco bovino, torta de filtro e superfosfato triplo em função do tempo de contato solo-adubo, e estabelecer relações entre as formas de P e a disponibilidade. As formas de P orgânico (Po) e inorgânico (Pi) foram determinadas em amostras de Latossolo Vermelho argiloso (LV) e de Argissolo Vermelho Amarelo arenoso (PVA), adubadas ou não com 100 mg dm-3 de P nas formas de esterco bovino, torta de filtro e superfosfato triplo, e mantidas em incubação por 15, 45, 90 e 180 dias. O Pi foi fracionado em P solúvel e fracamente retido, P ligado ao Al ou Fe, P ocluso e P ligado ao Ca. O P orgânico foi fracionado em Po lábil, Po da biomassa microbiana, Po moderadamente lábil, Po dos ácidos fúlvicos, Po dos ácidos húmicos e Po residual. Com as amostras de solo também foi conduzido experimento com plantas de milho para determinar a produção de matéria seca e a absorção de P. No latossolo foi observado maior teor de Pi ocluso e Po residual e a adubação também aumentou os teores dessas frações, indicando que o P dos adubos é incorporado às frações menos disponíveis, o que torna os teores de P disponível menores neste solo. No argissolo predominaram Pi ligado ao Fe e Po associado aos ácidos húmicos, e o P adicionado foi incorporado às formas ligadas ao Al e ao Fe, que contribuíram para maior disponibilidade de P neste solo. As frações mais estáveis tanto do Pi quanto do Po não se correlacionaram com o P disponível, e as frações menos estáveis se correlacionaram com a matéria seca acumulada e o P absorvido pelas plantas, indicando que mesmo estando em maior teor, as frações mais estáveis contribuem de forma mais limitada para a absorção de P pelas plantas. No solo latossolo, o acúmulo de P nas formas ligadas ao Al e ao Fe, no tratamento com superfosfato triplo, foi determinante para maior disponibilidade. No solo argissolo, o aumento das formas de P ligado ao Al e ao Fe, junto ao menor acúmulo de P ocluído no tratamento com esterco bovino, resultou na maior disponibilidade. A interação entre tipo de solo e adubo definiu o destino do P aplicado, bem como a disponibilidade
Evaluating the forms and transformations of phosphorus (P) applied via organic and mineral fertilizers is important to improve the management and optimize the use of P. The objectives of the present study were to evaluate organic and inorganic forms of P in two soil types, fertilized with dairy manure, filter cake and triple superphosphate, as a function of the incubation time, and to establish relationships between soil P forms and P available, plant uptake P and growth. The organic (Po) and inorganic (P) forms of P were determined on samples of typic Hapludox clayey and arenic Hapludult sand, fertilized or not with 100 mg dm-3 of P as dairy manure, filter cake and triple superphosphate, and incubated for 15, 45, 90 and 180 days. Pi was fractionated into soluble and weakly bound P, Al or Fe bound P, occluded P and Ca bound P. The organic Po was fractionated into labile Po, microbial Po, moderately labile Po, fulvic acids associate Po, humic acids associate Po and residual Po. In the soil samples, an experiment with maize plants was also carried out to determine the plant dry matter production and the absorption of P. It was observed higher levels of occluded Pi and residual Po in the Hapludox. The fertilization also increased the contents of these fractions indicating that P is incorporated to the less available fractions. Therefore, the available P contents were smaller in this soil. In the Hapludult, Fe bound Pi and humic acids associated Po were the predominant P forms. The added P was incorporated into the Al and Fe bound P forms, which contributed to higher P availability in this soil. The more stable fractions of both Pi and Po did not correlate with available P, and the less stable fractions correlated with accumulated dry matter and P uptook by plants, indicating that even having a higher P content, the more stable fractions contribute in a more limited way to the P uptake by plants. In the Hapludox, the increase of Al, Fe bound P in the triple superphosphate treatment was crucial for greater availability. In the Hapludult, the increase of Al, Fe bound P, with lower occlusion of P in cattle manure treatment, resulted in higher availability. The interaction between the soil and fertilizer type defined the fate of the applied P, as well as the availability
FAPESP 2014/11466-3

The fate of the carbon and nitrogen in dairy farm effluent (DFE) applied onto soil was investigated through laboratory experiments and field lysimeter studies. They resulted in the development and testing of a complex carbon (C) and nitrogen (N) simulation model (CaNS-Eff) of the soil-plant-microbial system. To minimise the risk of contamination of surface waters, regulatory authorities in New Zealand promote irrigation onto land as the preferred treatment method for DFE. The allowable annual loading rates for DFE, as defined in statutory regional plans are based on annual N balance calculations, comparing N inputs to outputs from the farming system. Little information is available, however, to assess the effects that these loading rates have on the receiving environment. It is this need, to understand the fate of land-applied DFE and develop a tool to describe the process, that is addressed in this research. The microbially mediated net N mineralisation from DFE takes a central role in the turnover of DFE, as the total N in DFE is dominated by organic N. In a laboratory experiment, where DFE was applied at the standard farm loading rate of 68 kg N ha⁻¹, the net C mineralisation from the DFE was finished 13 days after application and represented 30% of the applied C, with no net N mineralisation being measured by Day 113. The soluble fraction of DFE appeared to have a microbial availability similar to that of glucose. The low and gradually changing respiration rate measured from DFE indicated a semi-continuous substrate supply to the microbial biomass, reflecting the complex nature and broad range of C compounds in DFE. The repeated application of DFE will gradually enhance the mineralisable fraction of the total soil organic N and in the long term increase net N mineralisation. To address the lack of data on the fate of faecal-N in DFE, a ¹⁵N-labelled faecal component of DFE was applied under two different water treatments onto intact soil cores with pasture growing on them. At the end of 255 days, approximately 2% of the applied faecal ¹⁵N had been leached, 11 % was in plant material, 11 % was still as effluent on the surface, and 40% remained in the soil (39% as organic N). Unmeasured gaseous losses and physical losses from the soil surface of the cores supposedly account for the remaining ¹⁵N (approximately 36%). Separate analysis of the total and ammonium nitrogen contents and ¹⁵N enrichments of the DFE and filtered sub-samples (0.5 mm, 0.2µm) showed that the faecal-N fraction was not labelled homogeneously. Due to this heterogeneity, which was exacerbated by the filtration of DFE on the soil surface, it was difficult to calculate the turnover of the total faecal-N fraction based on ¹⁵N results. By making a simplifying assumption about the enrichment of the ¹⁵N in the DFE that infiltrated the soil, the contribution from DFE-N to all plant available N fractions including soil inorganic N was estimated to have been approximately 11 % of the applied DFE-N. An initial two-year study investigating the feasibility of manipulating soil water conditions through controlled drainage to enhance denitrification from irrigated DFE was extended a further two years for this thesis project. The resulting four-year data set provided the opportunity to evaluate the sustainability of DFE application onto land, an extended data set against which to test the adequacy of CaNS-Eff, and to identify the key processes in the fate of DFE irrigated onto soil under field conditions. In the final year of DFE irrigation, 1554 kg N ha⁻¹ of DFE-N was applied onto the lysimeters, with the main removal mechanism being pasture uptake (700 kg N ha⁻¹ yr⁻¹ removed). An average of 193 kg N ha⁻¹ yr⁻¹ was leached, with 80% of this being organic N. The nitrate leaching decreased with increasing soil moisture conditions through controlled drainage. At the high DFE loading rate used, the total soil C and N, pH and the microbial biomass increased at different rates over the four years. The long-term sustainability of the application of DFE can only be maintained when the supply of inorganic N is matched by the demand of the pasture. The complex simulation model (CaNS-Eff) of the soil-plant-microbial system was developed to describe the transport and transformations of C and N components in effluents applied onto the soil. The model addresses the shortcomings in existing models and simulates the transport, adsorption and filtration of both dissolved and particulate components of an effluent. The soil matrix is divided into mobile and immobile flow domains with convective flow of solutes occurring in the mobile fraction only. Diffusion is considered to occur between the micropore and mesopore domains both between and within a soil layer, allowing dissolved material to move into the immobile zone. To select an appropriate sub-model to simulate the water fluxes within CaNS-Eff, the measured drainage volumes and water table heights from the lysimeters were compared to simulated values over four years. Two different modelling approaches were compared, a simpler water balance model, DRAINMOD, and a solution to Richards' equation, SWIM. Both models provided excellent estimation of the total amount of drainage and water table height. The greatest errors in drainage volume were associated with rain events over the summer and autumn, when antecedent soil conditions were driest. When soil water and interlayer fluxes are required at small time steps such as during infiltration under DFE-irrigation, SWIM's more mechanistic approach offered more flexibility and consequently was the sub-model selected to use within CaNS-Eff. Measured bromide leaching from the lysimeters showed that on average 18% of the bromide from an irrigation event bypassed the soil matrix and was leached in the initial drainage event. This bypass mechanism accounted for the high amount of organic N leached under DFE-irrigation onto these soils and a description of this bypass process needed to be included in CaNS-Eff. Between 80 and 90% of the N and C leached from the lysimeters was particulate (> 0.2 µm in size), demonstrating the need to describe transport of particulate material in CaNS-Eff. The filtration behaviour of four soil horizons was measured by characterising the size of C material in a DFE, applying this DFE onto intact soil cores, and collecting and analyzing the resulting leachate using the same size characterisation. After two water flushes, an average of 34% of the applied DFE-C was leached through the top 0-50 mm soil cores, with a corresponding amount of 27% being leached from the 50-150 mm soil cores. Most of the C leaching occurred during the initial DFE application onto the soil. To simulate the transport and leaching of particulate C, a sub-model was developed and parameterised that describes the movement of the effluent in terms of filtering and trapping the C within a soil horizon and then washing it out with subsequent flow events. The microbial availability of the various organic fractions within the soil system are described in CaNS-Eff by availability spectra of multiple first-order decay functions. The simulation of microbial dynamics is based on actual consumption of available C for three microbial biomass populations: heterotrophs, nitrifiers and denitrifiers. The respiration level of a population is controlled by the amount of C that is available to that population. This respiration rate can vary between low level maintenance requirements, when very little substrate is available, and higher levels when excess substrate is available to an actively growing population. The plant component is described as both above and below-ground fractions of a rye grass-clover pasture. The parameter set used in CaNS-Eff to simulate the fate of DFE irrigated onto the conventionally drained lysimeter treatments over three years with a subsequent 10 months non-irrigation period was derived from own laboratory studies, field measurements, experimental literature data and published model studies. As no systematic calibration exercise was undertaken to optimise these parameters, the parameter set should be considered as "initial best estimates" and not as a calibrated data set on which a full validation of CaNS-Eff could be based. Over the 42 months of simulation, the cumulative drainage from CaNS-Eff for the conventionally drained DFE lysimeter was always within the 95% CI of the measured value. On the basis of individual drainage bulking periods, CaNS-Eff was able to explain 92% of the variation in the measured drainage volumes. On an event basis the accuracy of the simulated water filled pore space (WFPS) was better than that of the drainage volume, with an average of 70% of the simulated WFPS values being within the 95% CI for the soil layers investigated, compared to 44% for the drainage volumes. Overall the hydrological component of CaNS-Eff, which is based on the SWIM model, could be considered as satisfactory for the purposes of predicting the soil water status and drainage volume from the conventionally drained lysimeter treatment for this study. The simulated cumulative nitrate leaching of 4.7 g NO₃-N m⁻² over the 42 months of lysimeter operation was in good agreement to the measured amount of 3.0 (± 2.7) g NO₃-N m⁻². Similarly, the total simulated ammonium leaching of 2.7g NH₄- N m⁻² was very close to the measured amount of 2.5 (± 1.35) g NH₄- N m⁻² , however the dynamics were not as close to the measured values as with the nitrate leaching. The simulated amount of organic N leached was approximately double that measured, and most of the difference originated from the simulated de-adsorption of the dissolved fraction of organic N during the l0-month period after the final DFE irrigation. The 305 g C m⁻² of simulated particulate C leached was close to the measured amount of 224 g C m⁻² over the 31 months of simulation. The dissolved C fraction was substantially over-predicted. There was good agreement in the non-adsorbed and particulate fractions of the leached C and N in DFE. However, the isothermic behaviour of the adsorbed pools indicated that a non-reversible component needed to be introduced or that the dynamics of the de-adsorption needed to be improved. Taking into account that the parameters were not calibrated but only "initial best estimates", the agreement in the dynamics and the absolute amounts between the measured and simulated values of leached C and N demonstrated that CaNS-Eff contains an adequate description of the leaching processes following DFE irrigation onto the soil. The simulated pasture N production was in reasonable agreement with the measured data. The simulated dynamics and amounts of microbial biomass in the topsoil layers were in good agreement with the measured data. This is an important result as the soil microbial biomass is the key transformation station for organic materials. Excepting the topsoil layer, the simulated total C and N dynamics were close to the measured values. The model predicted an accumulation of C and N in the topsoil layer as expected, but not measured. Although no measurements were available to compare the dynamics and amounts of the soil NO₃-N and NH₄-N, the simulated values appear realistic for an effluent treatment site and are consistent with measured pasture data. Considering the large amount of total N and C applied onto the lysimeters over the 42 months of operation (4 t ha⁻¹ of N and 42 t ha⁻¹0f C), the various forms of C and N in dissolved and particulate DFE as well as in returned pasture, and that the parameters used in the test have not been calibrated, the simulated values from CaNS-Eff compared satisfactorily to the measured data.

Dans une situation de forte vulnérabilité induite par les crises laitières de 2009 et 2014-2016, de nombreux éleveurs laitiers se convertissent à l’AB qui semble une alternative prometteuse. Mais la conversion à l’AB est une période de changements de pratiques agricoles, d'interlocuteurs de conseil, etc. sources d’incertitudes sans valorisation immédiate du lait au prix du lait AB avant 1 an ½ à 2 ans. Ce choix de conversion pose la question de la vulnérabilité des exploitations laitières, c’est à dire de leur capacité à faire face, à s’adapter ou à se remettre des effets de divers aléas avant, pendant et à l’issue de la conversion à l’AB. Ma thèse visait à évaluer si la conversion à l’AB est un moyen de réduire la vulnérabilité des exploitations laitières. Pour ce faire, je me suis appuyée sur trois dispositifs de suivis d’éleveurs laitiers à différents moments de leur conversion à l’AB. Au plan de la production de connaissances, ce travail montre que la conversion à l’AB peut être un levier important pour la réduction de la vulnérabilité des exploitations agricoles à condition de s’orienter vers un système à dominante herbagère. Au plan méthodologique, la principale originalité de mon travail réside dans le développement d’une méthode d’évaluation intégrée et dynamique de la vulnérabilité
In a situation of high vulnerability induced by the 2009 and 2014-2016 milk crises, many dairy farmers convert to organic farming, which seems a promising alternative. But the conversion to organic farming is a period of changes in farming practices, farm consultants, etc. sources of uncertainties without immediate valuation of the milk at the organic price before 1 ½ to 2 years. This conversion decision raises the question of the vulnerability of dairy farms, i.e. their ability to cope with, adapt to or recover from the effects of various hazards before, during and after the conversion. My PhD project aimed to assess whether the conversion to organic farming is a way to reduce the vulnerability of dairy farms. To that end, my work relied on three research set-ups based on surveys with dairy farmers at different stages of their conversion to organic farming. In terms of knowledge production, this work shows that conversion to organic farming can be an important lever to reduce farms vulnerability, as long as they move towards pasture-based system. In terms of methodological production, the main originality of my work lies in the development of an integrated and dynamic method for vulnerability assessment

Mit Ökobilanzen werden Umwelteigenschaften von Produkten und Dienstleistungen analysiert und zunehmend bei der Bewertung von Milchproduktionssystemen eingesetzt. Um konsistente Berichterstattung und Vergleichbarkeit von produktbezogenen Treibhausgasemissionen im Milchsektor zu gewährleisten hat die International Dairy Federation (IDF) Berechnungsgrundlagen publiziert. Allerdings werden die Effekte von Variabilität betrieblicher Kennzahlen und Unsicherheit von Emissionsfaktoren unzureichend betrachtet. Diese Arbeit hat es zum Ziel diese Lücke zu schließen. In der ersten Studie wurden verschiedene Definitions- und Berechnungsmöglichkeiten des Referenzflusses und der funktionellen Einheit für die Klimabilanz von Milchproduktion verglichen. Eine hohe Bandbreite an möglichen Ergebnissen – bei gleichen Eingangsdaten – ermöglicht eine große Ergebnisunsicherheit. Die Voraussetzungen für zeitliche Repräsentativität wurden in der zweiten Studie untersucht. Über 6 aufeinanderfolgende Jahre wurde auf einem ökologischen Milchviehbetrieb in Norddeutschland die Klimabilanz mit einem detaillierten Stoffflussmodel analysiert. Dabei zeigte es sich, dass für den untersuchten Betrieb mindestens 4 aufeinanderfolgende Jahre untersucht werden müssen um belastbare Ergebnisse zu erzielen. Die dritte Studie befasst sich mit der Forderung mindestens ein Stufe 2 Verfahren der Methodik des IPCC zu verwenden. Mit Daten von 20 norwegischen Milchviehbetrieben wurde die Unsicherheit der Klimabilanz auf Basis von Tier 1 Berechnungen bei bodenbürtigen Emissionen mit dem FARM Modell ermittelt. Von allen 190 direkten Vergleichen von zwei Betrieben miteinander waren 78 % signifikant unterschiedlich Aus den drei Studien wird geschlossen, dass die existierenden Regeln zur Erstellung von Klimabilanzen von Milchproduktion teilweise zu unpräzise und teilweise zu streng sind, und damit sowohl Erstellung als auch Interpretation von betrieblichen Klimabilanzen in der Milchproduktion erschwert werden.
Life cycle assessment (LCA) analyses the environmental performance of products and services and has become increasingly important also for the environmental assessment of dairy systems. In order to create consistent results for communication, declaration and comparison, the International Dairy Federation (IDF) provides a guideline for the calculation of product-related greenhouse gas (GHG) emissions in the dairy sector. However, the effects of farm data variability and emission factor uncertainty on the comparability of GHG assessments on the farming level are seldom considered. This thesis aims to fill this gap. In the first study, different settings in the definition of energy corrected milk (ECM) and the reference flows were compared in a calculation example based on average farming data. A high bandwidth of the carbon footprint result indicated a severe uncertainty when calculation procedures are not well documented. The second case study examined the production data from six consecutive milk years in an organic dairy farm in northern Germany and its effect on the estimation of product-related GHG emissions. It was shown that data from at least four years is needed to provide reliable results for that farm. The third study dealt with the demand of the IDF guidelines to use at least Tier 2 in the methodology of the Intergovernmental Panel on Climate Change (IPCC). Using data from 20 Norwegian dairy farms, the uncertainty of the carbon footprint using Tier 1 of the IPCC guidelines within the FARM model was assessed. From all 190 direct comparisons of two farms in the study, 78 % of the comparisons were significantly different with a relative difference of 8.7 % being enough to establish significance of the difference. From the three studies it was concluded that existing rules may partly not be precise enough to allow for comparison of farms or farming systems, or partly too strict and thereby hindering the execution of carbon footprint studies.

Avaliou-se o desempenho do reator anaeróbio em batelada seqüencial com biomassa imobilizada (ASBBR) no tratamento de soro de queijo quanto submetido a diferentes estratégias de alimentação e cargas orgânicas volumétricas (COV). O reator operou com agitação mecânica através de impelidor do tipo hélice na rotação de 500 rpm. Um volume de 2 litros foi alimentado por ciclo com 1 litro de volume residual, totalizando 3 litros. O substrato utilizado foi soro de queijo desidratado reconstituído. Suplementou-se o sistema com NaHCO3 na razão de 50% NaHCO3/DQO. Foram testadas as seguintes COVs: 2, 4, 8 e 12 gDQO/l.d. Para ciclos de 8 horas e em cada COV, três estratégias de alimentação foram testadas: (a) operação em batelada com ciclo de 8 horas, (b) batelada alimentada de 2 horas (c) batelada alimentada de 4 horas. Na COV de 2 gDQO/l.d, a conversão de matéria orgânica como DQO em amostras filtradas foi de 92, 96 e 91% para as estratégias de alimentação (a), (b) e (c), respectivamente. Para a COV de 4 gDQO/l.d, o desempenho foi de 94, 97 e 93%, respectivamente. Para a COV de 8 gDQO/l.d houve redução nas eficiências de conversão a 83, 85 e 86%, respectivamente. O aumento da COV para 12 gDQO/l.d, resultou na redução em eficiências de 72, 73 e 81%, respectivamente. Os perfis durante os ciclos da concentração de ácidos voláteis totais mostraram que, apesar do aumento gradual com o tempo de enchimento aumentando, nenhuma diferença significativa foi detectada em termos dos seus valores máximos. Foi observada a redução de ácido propiônico como conseqüência do aumento do tempo de enchimento. Assim, para COV de 2 e 4 gDQO/l.d, a estratégia de alimentação (b) proporcionou maiores eficiências de conversão e estabilidade operacional, enquanto que este comportamento foi observado na estratégia de alimentação (c) para os valores de COV de 8 e 12 gDQO/l.d.
The performance of an anaerobic sequencing batch biofilm reactor (ASBBR) treating cheese whey was evaluated when subjected to different feeding strategies and volumetric organic loads (VOL). The reactor operated under mechanical stirring provided by helix impellers at rotor speed of 500 rpm. A volume of 2 l was fed per cycle with 1 l of residual volume, totalizing 3 l. Reconstituted dehydrated cheese whey was used as substrate. NaHCO3 was supplemented at a ratio of 50% NaHCO3/COD. The following VOLs were tested: 2, 4, 8 and 12 gCOD/l.d. For 8-h cycles and each value of VOL three feed strategies were tested: (a) batch operation with 8-h cycle; (b) 2-h fed-batch operation; and (c) 4-h fed-batch. In the VOL of 2 gCOD/l.d, organic matter conversions as COD were 92, 96 and 91%, for feeding strategies (a), (b) and (c), respectively. For the VOL of 4 gCOD/l.d, performance values were 94, 97 and 93%, respectively. For the VOL of 8 gCOD/l.d there was a reduction in conversion efficiency to 84, 85 and 86%, respectively. The increase of VOL to 12 gCOD/l.d resulted in the reduction in efficiency of 78, 73 and 81%, respectively. The profiles of total volatile acids concentration obtained during the cycles showed that despite its gradual increase with the increasingly filling time, no significant differences were detected in terms of maximum values. Reduction in proprionic acid concentration along the cycle were observed as consequence of the increase of the filling time. Thus, for VOL of 2 and 4 gCOD/l.d feeding strategy (b) provided higher conversion efficiency and operation stability. This behavior was similar to that observed for the feeding strategy (c) at the VOL of 8 and 12 gCOD/l.d.

Urea kao deo neproteinske frakcije azota mleka, predstavlja krajnji produkt metabolizma proteina u predželucima preživara. Portalnim krvotokom toksični amonijak, nastao mikrobiološkom razgradnjom proteina u rumenu dolazi do jetre gde se transformiše u ureu, koja kasnije krvotokom dospeva u mleko. Ishrana, odnosno sadržaj sirovih proteina u obroku ima najveći uticaj na sadržaj uree u mleku. Sadržaj uree sve više se koristi kao parametar pomoću kojeg je moguće pratiti unos sirovih proteina i energije obrokom kod mlečnih krava. Pored ishrane na sadržaj uree u mleku utiču i drugi faktori, kao što su sezona, prinos mleka, stadijum laktacije, paritet i dr.Plodnost krava je veoma važna osobina mlečnih goveda na koju utiče veliki broj faktora. Dosadašnja istraživanja u ovoj oblasti ukazuju na moguću vezu između plodnosti krava i sadržaja uree u mleku.Određivanje sadržaja uree u mleku primenom infracrvene spektrofotometrije u analizi mleka prilikom redovne mesečne kontrole mlečnosti krava pružilo je nove mogućnosti u praćenju kvaliteta mleka.Cilj ovog istraživanja bio je da se utvrdi:1. variranje sadržaja uree u mleku unutar stada,2. uticaj paragenetskih faktora (farma, sistem proizvodnje, sistem držanja, sezona, redni broj laktacije i stadijum laktacije) na sadržaj uree u mleku,3. korelacija sadržaja uree sa parametrima mlečnosti krava i brojem somatskih ćelija i4. korelacija između sadržaja uree u mleku i dužine servis perioda.U okviru ovog istraživanja analizirano je 46.315 uzoraka mleka, u okviru redovne kontrole mlečnosti, sa 11 farmi sa područija Vojvodine. Od kojih je jedna sa organskom, a 10 farmi sa konvencionalnom proizvodnjom. Određivanje sadržaja uree u mleku vršeno je na aparatu MilcoScan.Prosečan sadržaj uree u mleku (25,18 mg/dl) bio je u okviru optimalnih vrednosti sadržaja uree u mleku. Koeficijent varijacije za sadržaj uree (34,15%) bio je znatno veći od koeficijenta varijacije za ostale sastojke mleka.Dobijeni rezultati u okviru ove doktorske disertacije ukazuju da najveći uticaj na sadržaj uree u mleku ima menadžment farme. Utvrđen je i statitički značajan uticaj ostalih ispitivanih paragenetskih faktora.Sistem držanja statistički značajno utiče na sadržaj uree u mleku. Niži sadržaj uree u mleku bio je kod krava u slobodnom sistemu držanja.Kao posledica specifičnosti organske proizvodnje konstatovane su statistički značajne razlike između organske i konvencionalne proizvodnje mleka. Razlike se ogledaju u smanjenom sadržaju uree u mleku i prinosu mleka, a povećanom sadržaju mlečne masti i proteina. Broj somatskih ćelija u mleku iz organske proizvodnje je znatno manji u odnosu na broj istih u mleku iz konvencionalne proizvodnje mleka, dok je servis period u posmatranom periodu bio duži kod krava u organskoj proizvodnji u odnosu na krave u konvencionalnoj proizvodnji mleka.Posmatrano po sezonama kontrole najniži sadržaj uree u mleku bio je u jesenjem periodu (22,19 mg/dl), a najveći u letnjem period (27,11 mg/dl). Razlike u sadržaju uree po laktacijama su male, ali statistčki značajne.Konstatovan je statistički značajan uticaj stadijuma laktacije na sadržaj uree u mleku. Najniži sadržaj bio je na početku laktacije (23,05 mg/dl), a maksimalan sadržaj uree u mleku od 26,40 mg/dl, bio je od 121 do 180 dana laktacije.Utvrđene su pozitivne, statistički visoko značajne, korelacije između sadržaja uree i pojedinih sastojaka mleka, kao i između sadržaja uree i prinosa mleka. Korelacija između sadržaja uree i broja somatskih ćelija u mleku je negativna i visoko statistički značajna.U okviru ovog istraživanja utvrđena je pozitivna i statistički visoko značajna korelacija između sadržaja uree u mleku i dužine servis perioda.Dobijeni rezultati, tumačeni u kontekstu drugih istraživanja na ovu temu ukazuju na veliki značaj praćenja sadržaja uree u mleku, koji može doprineti poboljšanju menadžmenta ishrane i reprodukcije na farmama mlečnih krava, a sve u cilju smanjenja troškova na farmama, kroz smanjenje troškova ishrane i troškova veterinarskih usluga.
Urea as a part of non-protein fraction of nitrogen in milk represents the final product of protein metabolism in the rumen of ruminants. By portal bloodstream toxic ammonia comes into liver where it is transformed into urea, which comes later into milk by bloodstream. Nutrition and contents of crude proteins in the diet have the greatest influence on the milk urea content. The content of milk urea has been increasingly used as a parameter by which it is possible to monitor balance of energy and crude proteins in the feed of dairy cows.Apart from feeding, milk urea content can be influenced by some other factors as season, milk yield, stage of lactation, parity etc.A great number of factors influence cow’s fertility. Previous research in this field has indicated a possible relationship between the fertility of cows and urea content in milk.Determination of urea content in milk, by infrared spectrophotometric, on monthly bases, for milk recording porpoises, offers new opportunities for milk quality monitor.The aim of this study was to determine:1. Variations of milk urea content within the herd,2. The influence of paragenetic factors (a farm, production and housing system, season, parity and stage of lactation) on the milk urea content,3. The correlation with milk urea content and parameters of milk yield as well as the somatic cells count,4. The correlation between the milk urea content and the length of open days.This research includes 46,315 samples of milk which were analysed as regular milk recording samples from 11 farms in Vojvodina. There are 10 farms withconventional and only one farm with organic production.Determination of the milk urea contents was carried out by MilkoScan FT+.In the analyzed milk samples the average milk urea content (25.18 mg / dl) was within the optimum values. The coefficient of variation for the milk urea content (34.15%) was significantly higher than the coefficient of variation for the other ingredients in milk.The obtained results in this PhD thesis indicate that the management of a farm has the greatest influence on the content of milk urea. Statistically some significant influence of other examined paragenetic factors was found.According to statistics the housing system significantly influences the milk urea content. Lower milk urea content was found in cow's milk in free-stall system.As the result of specific organic production some statistically significant differences between organic and conventional milk production were found. The differences shows lower milk urea content and milk yield, as well as higher milk fat and protein content. The somatic cells count in organic milk production is significantly lower than their number in milk from conventional milk production. The open days during observation period were longer in cows from an organic dairy farm then the cows from conventional dairy farms.According to season and stage of lactation an important influence on milk urea was found. The seasonal observation shows the lowest milk urea content in autumn period (22.19 mg / dl) and the highest in summer period (27.11 mg / dl). The lowest content was at the beginning of lactation (23.05 mg / dl) and the maximum milk urea content (26.40 mg /dl) was from 121 to 180 days of lactation. Differences in the milk urea content between lactation were small, but statistically significant.There are positive and statistically significant, correlations between the milk urea content and some ingredients of milk, as well as between milk urea content and milk yield. The correlation between the milk urea content and somatic cells count in milk is negative and high statistically significant.It is shown in this research that high milk urea content has negative impact on the length of open days.Obtained results, interpreted in the context of other studies on the same subject indicate the great importance of the observation of the milk urea content. It can contribute to improving the feeding and reproduction on dairy farms, and lead to reduction of both feeding and veterinary costs.

I Poliidrossialcanoati (PHA) sono poliesteri completamente biodegradabili, prodotti da microrganismi come fonte di energia e di carbonio per la sintesi di nuovo materiale cellulare, utilizzando come substrato materie prime rinnovabili. Questi poliesteri sono considerati potenziali candidati per la sostituzione delle materie plastiche convenzionali. Tuttavia, i più alti costi di produzione dei PHA in confronto a quelli delle materie plastiche derivanti dal petrolio, rappresentano il principale ostacolo per la parziale sostituzione di questi ultimi con i biopolimeri. Gli alti costi sono principalmente dovuti all'utilizzo di colture microbiche pure (in cui sia presente un solo ceppo batterico) e substrati puri e costosi. Nell'ultimo decennio è stato sviluppato un processo di produzione a tre stadi alternativo e potenzialmente a minor costo, basato sull'utilizzo di colture microbiche miste (Mixed Microbials Culture, MMC) e una varietà di substrati organici a costo contenuto o nullo, quali alcuni rifiuti dell’industria agro-alimentare. Il presente studio si è concentrato sulla prima fase del processo di produzione dei PHA da colture miste, la fermentazione acidogenica, utilizzando siero di latte come fonte di carbonio per produrre acidi organici. In particolare questo lavoro ha avuto come obiettivo quello di studiare come diverse condizioni operative utilizzate nella fase di fermentazione acidogenica possono influenzare la concentrazione e il profilo degli acidi organici prodotti. Sono stati valutati anche gli effetti dei diversi profili degli acidi organici sulla fase di selezione della coltura microbica, in termini di capacità di stoccaggio di PHA e composizione polimerica.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The objective of this research was to evaluate of three grazing systems (GS) with Elephant grass (EG) + Italian ryegrass (IR) + spontaneous growing species (SGS); EG + IR + SGS + Forage peanut (FP); and EG + IR + SGS + Red clover (RC), in order to use the area in rotational grazing during all agricultural year. EG was planted in rows with a distance of 4 m each one of them. In the cool-season, IR was sowed between rows of EG; RC was sowed and the FP who has found established since 2006 was preserved on respectively GS. Experimental design was completely randomized with three treatments (GS), two replicates (paddocks) and independent evaluations (grazing cycles). For evaluation, were used lactating Holstein cows receiving 1% of BW day-1 feed supplement concentrate. The pre and post forage mass parameters, botanical and structural composition, forage production and stocking rate were evaluated. Samples were collected by the handplucking method to analyze the organic matter, mineral matter, crude protein (CP), neutral detergent fiber (NDF), in situ organic matter digestibility (ISOMD), in situ dry matter digestibility (ISDMD) of forage. Eight grazing cycle were performed during the experimental period (357 days). The values of forage production and stocking rate were 15.03, 16.33, 17.03 t ha-1 and 3.57, 3.52 and 3.65 animal unit ha-1, respectively grazing systems. Grazing systems involving grasses and forage legumes in different cycles provide use of the area during the agricultural year in rotational grazing with dairy cattle. SGS increased significantly (P≤0.05) over in GS without forage legume. Higher value of CP, ISOMD and lower of NDF for GS mixed with forage legumes. Considering the herbage mass, stocking rate and nutritive value, the pastures mixed to forage legumes showed better performance.
O objetivo desta pesquisa foi avaliar três sistemas forrageiros (SF) com capim elefante (CE) + azevém (AZ) + espécies de crescimento espontâneo (ECE); CE + AZ + ECE + amendoim forrageiro (AM); e CE + AZ + ECE + trevo vermelho (TV), com o intuito de utilização da área em pastejo rotativo durante todo o ano agrícola. O CE foi estabelecido em linhas afastadas a cada 4 m. No período hibernal fez-se o estabelecimento do AZ entre as linhas do CE; o TV foi semeado e o AM que já se encontrava estabelecido desde 2006, foi preservado, considerando os respectivos tratamentos. O delineamento experimental foi o inteiramente casualizado, com três tratamentos (SF), duas repetições (piquetes) e avaliações independentes (ciclos de pastejo). Para avaliação foram utilizadas vacas da raça Holandesa em lactação, que receberam suplementação alimentar com concentrado à razão de 1% do peso corporal dia-1. Foram avaliados parâmetros de massa de forragem pré e pós pastejo, composições botânica e estrutural, produção de forragem e taxa de lotação. Para analisar a matéria orgânica, matéria mineral, a fibra em detergente neutro (FDN), a proteína bruta (PB), a digestibilidade in situ da matéria seca (DISMS) e a digestibilidade in situ da matéria orgânica (DISMO) da forragem, foram coletadas amostras de pastejo simulado. Durante o período experimental (357 dias) foram efetuados oito ciclos de pastejo. Os valores de produção de forragem e de taxa de lotação foram de 15,03; 16,33; 17,03 t ha-1 e 3,57; 3,52 e 3,65 UA ha-1, respectivamente para os sistemas forrageiros. Sistemas forrageiros, envolvendo gramíneas e leguminosas de diferentes ciclos, proporcionam a utilização da área durante todo o ano agrícola em pastejo rotativo com bovinos leiteiros. Houve aumento significativo (P≤0,05) para ECE na pastagem sem leguminosa. Foram observados maiores valores de PB, DISMO e menores de FDN para os SF consorciados com leguminosas. Considerando a massa de forragem, a taxa de lotação e o valor nutritivo, as pastagens consorciadas com leguminosas forrageiras apresentaram melhor desempenho.

Organics recycling is increasing in New England as multiple states have enacted laws to divert organic materials, including food scraps and food processing residuals, away from landfills. Anaerobic digesters on dairy farms represent an attractive approach to food waste recycling because existing infrastructure is in place and co-digestion of dairy manure with food waste can increase renewable biogas production. In addition, anaerobic digestion results in effluents that can be separated into solid and liquid residual materials, or 'digestates'. Screw-press separated solids consist of lignocellulosic biomass resistant to microbial degradation during anaerobic digestion. These separated solids are typically recycled on farms as animal bedding before returning to the digester, whereas remaining liquid digestates are typically spread as fertilizer for nearby feed crops or pasture fields. Within this model, anaerobic digestion is not a nutrient management solution and repeated land application of digestate nutrients can create eutrophication risk over time. Alternative models are needed where digestate materials are converted into valuable products to be sold off-farm, enabling the removal of nutrients to help meet nutrient management goals. In this thesis, I address two research questions related to the pursuit of such alternative models. First, how do physicochemical characteristics of digestate materials vary across full-scale systems in the region, including systems with and without food waste as a substantial proportion of feedstock, and how do these variations affect the potential for conversion of digestates into valuable products (e.g., soil amendments)? Second, can separated digestate solids be used for commercial cultivation of gourmet oyster mushrooms (Pleurotus ostreatus) to produce food for human consumption, providing synchronous nutrient recovery and food production? Results from my first research chapter indicate that increasing food waste inputs (and thus diversification of feedstock recipes) will likely increase the variability of some solid and liquid digestate characteristics and can result in greater contamination with synthetic particles, with implications for nutrient recovery efforts and associated products. My second research chapter shows that screw-press separated digestate solids can offset non-local substrate ingredients to a degree while achieving oyster mushroom yields comparable to commercial recipes. Furthermore, this strategy could divert nutrients away from land adjacent to digesters and directly into safe, nutritious, protein-rich food for humans, while also producing a useful spent mushroom substrate product.

Le radical hydroxyle OH est le principal oxydant dans la troposphère, mais ses puits restent encore difficiles à quantifier. L’un de ses principaux puits, est l’oxydation des Composés Organiques Volatils (COVs), composés provenant principalement de sources naturelles, à l’échelle du globe. Ils comprennent une grande variété d’espèces chimiques avec des réactivités très variables vis-à-vis des radicaux OH. Mesurer la réactivité OH totale, permet d’évaluer la charge en espèces réactives et d’estimer l’importance des espèces non mesurées/ non connues. Dans ce contexte, ce travail de thèse a d’abord visé d’optimiser la CRM ou « Comparative Reactivity Method », pour la mesure de la réactivité OH. Une fois les performances vérifiées, la CRM a été déployée dans deux écosystèmes : forestier et agricole. Les mesures de réactivité OH dans une forêt de pins maritimes ont montré des maximas de nuit arrivant jusqu’à 99 s-1 dans la canopée ; des niveaux se situant dans la limite supérieure de ce qui a été précédemment vu en sites forestiers. Des réactivités plus faibles, ne dépassant pas les 20- 30 s-1 en milieu de journée, ont été observées dans un champ agricole, en sortie d’une chambre dynamique de colza, en milieu de floraison. Dans ces deux écosystèmes, une différence a été trouvée entre la réactivité mesurée et celle calculée à partir des composés gazeux mesurés individuellement. Elle indique la présence d’une fraction manquante de composés primaires et secondaires non mesurés/ non identifiés. Ces travaux ont également mis en évidence l’importance de déterminer la spéciation des monoterpènes. Ceci nous a motivé à, optimiser et déployer un système de FastGC/ PTR-MS dans une forêt de chênes verts, ce qui nous a permis de suivre avec une haute résolution temporelle le cycle diurne des principaux monoterpènes, dont l’émission dépend du type de chêne ainsi que de la lumière
The hydroxyl radical OH is the most powerful oxidant in the troposphere, however, characterizing its sinks remains a challenge. One important OH sink, is the oxidation of volatile organic compounds (VOCs), mainly released from biogenic sources, on the global scale. VOCs include a wide variety of chemical species with different lifetimes towards OH. Measuring OH reactivity is a useful tool to evaluate the loading in reactive species and to estimate the amplitude of unmeasured/unidentified compounds. In this context, this PhD work aimed to build and optimize a CRM or Comparative Reactivity method instrument for OH reactivity measurements. Afterwards, the CRM was deployed in a forest and an agricultural ecosystem. OH reactivity in a maritime pine forest showed maxima during night, reaching 99 s-1 inside the canopy, among the highest in forest environments. Relatively lower levels (max 20-30 s-1 at mid-day), were recorded from a dynamic chamber, during the blooming season of a rapeseed field. In these ecosystems, a difference was obtained between measured and calculated OH reactivity from measured compounds. It highlights the presence of a missing fraction of unmeasured primary and secondary compounds. These experiments demonstrate the importance of a detailed information on monoterpenes chemical speciation. In this perspective, a FastGC/PTR-MS system was optimized and deployed in a green oak forest. It allowed to monitor, with a fine time resolution, diurnal cyles of the main monoterpenes, which emissions are dependent on the tree type and on solar radiation

AD is regarded as a sustainable technology that could assist the UK Government meet internationally agreed GHG emission targets by 2050. However, the mature status of the technology is based on expensive systems that rely on high energy feedstock to be profitable. Meanwhile, the natural biodegradation of cow slurry is a recognised contributor to climate change despite having a relatively low CH4 potential because of the large volumes produced. Economic mixing is essential to the cost-effectiveness of farm AD but techniques applied are not always appropriate as slurry is a shear thinning thixotropic Herschel-Bulkley fluid and therefore challenging to mix. The apparent viscosity of slurry and the shear stress induced was most influenced by solids content (exponential change) followed by temperature (linear). Most shear thinning occurred before a rising shear rate of 20s-1 was achieved with the fluid acting near-Newtonian above. Thixotropic recovery occurred within 1 hour of resting. Rheological values were also much higher than previously reported. Highest CH4 production occurred in the first 10 days of the batch process using a range of mixing regimes with different shear rates and rest periods. During fed-batch operations, changing shear rate had a minimal effect on CH4 production using a 30-day HRT whereas shorter rest periods increased production. Specific CH4 production rate was highest when feeding and mixing coincided. However, when HRT was reduced (OLR increased) the CH4 produced by all mixed regimes significantly increased with highest values being achieved using high intensity mixing rested for short periods. Lower HRTs also requires smaller digesters. Parasitic mixing energy invariably had the most influence on net energy production. Signs of instability were evident after 20 days using the low HRT. Significant microbial adaptation was also observed as the experiments progressed. The research outcomes demonstrate that mixing regime and HRT can be managed to maximise net energy production whilst reducing capital expenditure.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
The contradictions and potentialities concerning the social and productive organization of land reform rural settlements are recurrent themes in studies of several areas of knowledge. The discussions about the centrality of the rural social movements, about the work organization in this context and the possibility of the families remaining in the land, among other themes, have contributed to concretize the counter-hegemonic experiences in the rural setting. Thus, aiming at understanding the relation between the collective articulation processes and the productive organization in a land reform rural settlement, this paper wishes to contribute with the debate on the contradictions and potentialities of the social struggles for land, work and housing rights. For this purpose we carried out an analysis about the centrality of the local social organization processes and its implications for the productive organization in the context of a rural settlement. According to the research aims, this study was conducted by the ethnographic method. This methodology allows us not only to understand the aspects related to the potentialities and contradictions of the collective articulation process in this context, but also to reflect on the way each settled rural worker is affected by this phenomenon. The field research was carried out in a land reform settlement located in the city called Araras, in the state of S?o Paulo. This settlement is made of four areas, composing an assembly permeated by different characteristics. The research participants were the actors/actresses in some way involved with the settlement, such as the settlers and the supporters who eventually took part in meetings held during the fieldwork. Besides the entries in the field diary brought forth by participant observations, we conducted three interviews with the settlers from a same settlement area. The discussion on the contradictions and potentialities identified in the research context are grounded on the Community Psychology theoretical assumptions. With its praxis directed to social change and by adhering to its principle of not enhancing deficiencies, but individuals and community potentialities, Community Psychology is concerned with the perspective of daily resistance, with the breaking down of oppression mechanisms, as well as with its commitment of lending visibility to small groups? confrontations and micro resistances. The research results indicate that collective articulation processes are central for the productive organization as it is the main element to keep the settlers in the land. Therefore, the strengthening of these two spheres, productive organization and social organization, is determinant for the settlement prosperity and for maintaining this collective of settlers in their plots of land.
As contradi??es e as potencialidades inerentes ? organiza??o social e produtiva dos assentamentos rurais de reforma agr?ria s?o tem?ticas recorrentes em pesquisas de diversas ?reas do conhecimento. A discuss?o sobre a centralidade dos movimentos sociais do campo, a organiza??o do trabalho neste contexto e a possibilidade de perman?ncia das fam?lias na terra, entre outros temas, tem contribu?do com a concretiza??o de experi?ncias contra hegem?nicas no contexto rural. Desta forma, com o objetivo de compreender a rela??o entre os processos de articula??o coletiva e a organiza??o produtiva no contexto de um assentamento rural de reforma agr?ria, este trabalho pretende contribuir com o debate sobre as contradi??es e as potencialidades das lutas sociais pelo direito ? terra, ao trabalho e ? moradia. Para tanto, realizamos uma an?lise sobre a centralidade dos processos de organiza??o social local e suas implica??es para a organiza??o produtiva no contexto de um assentamento rural. Em conson?ncia com os objetivos da pesquisa, utilizamos o m?todo etnogr?fico para o desenvolvimento deste estudo. A utiliza??o do m?todo etnogr?fico nos permitiu n?o apenas compreender os aspectos relativos ?s potencialidades e contradi??es do processo de articula??o coletiva neste contexto, mas tamb?m refletir sobre o modo como cada trabalhador/a rural assentado/a ? afetado/a por esse fen?meno. A pesquisa de campo foi realizada em um assentamento de reforma agr?ria localizado na cidade de Araras ? SP. Este assentamento ? formado por quatro ?reas, compondo um conjunto permeado por diferentes caracter?sticas. Foram participantes da pesquisa os atores/atrizes de alguma forma envolvidos/as com o assentamento, ou seja, os/as assentados/as e apoiadores/as que eventualmente participaram dos encontros realizados durante o trabalho de campo. Al?m dos registros em di?rio de campo gerados pelas observa??es participantes, tamb?m foram realizadas tr?s entrevistas com assentados de uma mesma ?rea do assentamento. As contradi??es e potencialidades identificadas no contexto pesquisado s?o discutidas com base nos pressupostos te?ricos da Psicologia Comunit?ria. Com sua pr?xis voltada para a mudan?a social e partindo do princ?pio de n?o destacar defici?ncias, mas sim as potencialidades dos indiv?duos e da comunidade, a Psicologia Comunit?ria tem uma rela??o com a perspectiva de resist?ncia cotidiana, com o rompimento dos mecanismos de opress?o, bem como o compromisso de dar visibilidade aos enfrentamentos e microrresist?ncias de pequenos grupos. Os resultados da pesquisa indicam que os processos de articula??o coletiva s?o centrais para a organiza??o produtiva enquanto principal elemento que sustenta a perman?ncia dos/as assentados/as na terra. Portanto, o fortalecimento destas duas esferas, quais sejam, a organiza??o produtiva e tamb?m a organiza??o social, ? determinante para a prosperidade do assentamento e para a perman?ncia desse coletivo de assentados/as em seus lotes de terra.

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This study concerns a contemporary reading of experiences carved within the Landless Workers` Movement (LWM) formation process analyzing how agroecology is thought, while a political practice of collective confrontation, suggesting a contraposition to transgenic food as well as to the agri-business. Concomitantly, it is highlighted how the agroecology engenders a production and social organizational modal in the Landless` campsites upholding respect to the environment with the objective of generating income for the rural workers. These central issues will be approached from diverse experience lived by the individuals that struggle for the land and Agricultural Reform. For this research the Antônio Companheiro Tavares campsite, located in the city of São Miguel do Iguaçu and comprised of 79 families, was chosen. This site is held as reference in agroecology by the LWM. From contradictions evidenced in the organization processes of different forms of work and farming, as well as the way they were lived by the members utilizing daily life experiences, we analyzed how, in the process of struggling for land and agriculture reform, a movement political culture aimed to protected practices and environmental recuperation was engendered based on the cultural references of the way of life of landless workers embroidered in their life experiences and in their relation with other social entities when outlining the LWM. Thus, the research focus mainly on the social experience of the rural workers questioning how this experience processes itself in the set of relations, how it is established in the lively process by the historical subjects and their functions that engraft feelings and movement to organizing their own work and in relation to the LWM itself
Este estudo trata de uma leitura contemporânea das experiências tecidas no interior do processo de formação do MST, analisando como a agroecologia passa a ser pensada enquanto uma prática política de enfrentamento coletivo, oferecendo uma contraposição aos trangênicos, bem como ao agronegócio. Concomitantemente, procuramos evidenciar como a agroecologia engendra um modelo de organização social e da produção nos assentamentos, primando pelo respeito ao meio-ambiente e tendo por objetivo a geração de renda aos trabalhadores rurais. Estas questões centrais serão abordadas a partir da diversidade de experiências vividas pelos sujeitos que lutam pela terra e pela Reforma Agrária. Para a pesquisa optou-se pela escolha do Assentamento Antônio Companheiro Tavares, no município de São Miguel do Iguaçu, que possui 79 famílias assentadas na área e é tido pelo MST enquanto referência em Agroecologia. A partir das contradições evidenciadas nos processos de organização das diferentes formas de trabalho e cultivo, bem como do modo que foram vividas pelos assentados, no fazer-se das experiências da vida cotidiana, analisamos como, no processo de luta pela terra e pela reforma agrária, se engendrou uma cultura política de movimento que se volta para práticas de proteção e recuperação do meio-ambiente, a partir das referências culturais do modo de vida dos trabalhadores sem-terra, tecidas em suas experiências de vida e nas relações com outros sujeitos sociais e entidades, no fazer-se do MST. Assim, a pesquisa tem por principal enfoque a experiência social dos trabalhadores rurais, problematizando como essa experiência se processa no conjunto das relações, como se constitui no processo vivido pelos sujeitos históricos e suas ações, que imprimem sentidos e movimentos à organização do seu próprio trabalho e também em relação ao próprio MST

碩士
國立宜蘭大學
動物科技學系碩士班
100
Abstract Rice crop is the major organic crop in Taiwan. When the organic rice grain is harvested so is organic rice straw, which could be used for organic feeding. However, rice crop production is seasonal. Organic rice straw would not be available for feed on a daily basis. Proper preservation is deemed necessary for a constant feed supply. Comparing hay production, making silage is less proned to weather changes and may improve forage quality. Inoculating lactic acid bacteria at ensiling has been used to ensure fermentation quality. However, heat produced during the intial days may inhibit lactic acid bacteria. Streptococcus thermophilus (ST) can survive at high temperature and may be a better silage lactic acid bacteria. Experiment 1 evaluated effect of inoculating conventional and organic rice straw with ST at ensiling on chemical composition and fermentation quality. In comparison to conventional rice straw, organic rice straw had higher crude protein (CP) and acid detergent fiber concentration before ensiling and lower pH, neutral detergent fiber and ammonia concentration. Inoculating ST did not affect lactic acid and volatile fatty acid (VFA) concentration, but decreased pH faster during early days after ensiling. Experiment 2 compared chemical composition and fermentation quality of organic rice straw silage made from the same rice paddy over 4 years. Rice straw pH and dry matter were 5.9-6.5 and 34-38% before ensiling. These data changed by year. After ensiling, all silage pH fell below 4.8. Treatment with ST decreased initial silage pH. Silage chemical composition was affected by year, but not ST. Lactic acid and VFA concentration were not affected by treatment. Experiment 3 investigated effect of feeding organic rice straw silage to wether dairy goats with low (200 g/d) or high (300 g/d) concentrate supply on feed intake, growth, and plasma characteristics. Goats in both concentrate treatments had weight gain. Forage intake of low concentrate treatment (64.3%) reached the organic farming standard (60%), but not high concentrate (55.9%). Organic feed intake of both treatments were below 85%. Experiment 4 evaluated effect of partial replacement of concentrate with organic rice bran on nutrient utilization in weather dairy goats fed organic rice straw silage. Quantity of forage and organic feed supply was based on data from experiment 3. The results obtained show that both forage (low rice bran: 77.4%; high rice bran: 79.3%) and organic feed (low rice bran: 87.4%; high rice bran: 91.6%) intake fulfilled constraints for organic feeding. High rice bran inclusion decreased CP intake by goats. In conclusions, the chemical composition and fermentation quality of organic rice straw silage was better than those of conventional. Inoculating ST could decrease silage pH faster but not for conventional rice straw. Feeding more rice bran could help to reach organic feeding standard but may to not satisfy protein requirement for goats.

Low plant available phosphorus limits legume growth and biological nitrogen fixation (BNF). This study examined, under controlled conditions, the relationship between soil phosphorus and alfalfa and soybean BNF on two contrasting low-P soils (Ontario and Nova Scotia) from organic dairy farms. Soluble P was applied up to 135 mg P kg-1. An optimum range of 45 to 90 mg kg-1 applied P increased soybean plant growth, nodulation, N and P uptake and BNF. Significant effects of soil type reflected greater N supplying ability and lower P sorption for the Ontario soil. Alfalfa response to soluble P application was not as apparent. In addition three potentially organically acceptable amendments (MSW compost, Crystal Green® struvite and partially solubilized rock phosphate) were evaluated as alternate sources of plant available P. Compost and struvite, applied at moderate rates, sufficiently supplied P to increase plant growth and BNF comparably to that found for soluble P fertilizer.

Thesis objectives were: 1) evaluate incidence rate of producer reported clinical mastitis (IRCM) and predominant pathogen types on conventional and organic dairies; 2) investigate associations between farm type, housing and access to pasture and IRCM; 3) explore association between bulk tank somatic cell count (BTSCC) and IRCM. An investigation on 59 dairy farms in Southern Ontario, Canada, involving organic and conventional management systems was conducted from April 2011 to March 2012. Coagulase-negative staphylococci were the most frequent pathogens (20.4%); Staphylococcus aureus was the most common contagious pathogen (9.6%). The overall mean IRCM was 24.7 cases/100 cow-years. Organic farms tended to have lower IRCM than conventional farms (17.1 cases/100 cow-years vs. 28.1 cases/100 cow-years). In summary, mean IRCM tended to be lower in the organic compared to conventionally managed herds. Housing, pasture use, and BTSCC category were not associated with overall IRCM; however, these factors did impact pathogen-specific IRCM.