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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
401

Echecs précoces de gestation chez la vache laitière de race Holstein : incidences, implication dans la baisse de fertilité et facteurs de risque

Ledoux, Dorothee 08 July 2011 (has links) (PDF)
Actuellement en France et aux Etats-Unis, seules 30 à 35 % des premières inséminations artificielles chez la vache Holstein aboutissent à un vêlage. Les échecs de gestation ont lieu le plus souvent au cours du développement embryonnaire (Non-Fécondation-Mortalité Embryonnaire Précoce (NF-MEP) entre 0 et 16 jours, Mortalité Embryonnaire Tardive (MET) entre 16 et 45 jours après insémination). Ces échecs précoces de gestation expliquent en grande partie les différences de fertilité observées en France entre la race Holstein et les autres races plus fertiles. Les facteurs de risque de l'interruption de la gestation sont multiples : liés à l'animal, à l'environnement et à la conduite de l'élevage. Trois facteurs cependant ont évolué au cours du temps pour les vaches Holstein : le potentiel génétique, les anomalies de reprise de la cyclicité après vêlage, le déficit énergétique en début de lactation. Notre objectif a été d'identifier l'influence de ces trois facteurs sur les échecs précoces de gestation après première insémination postpartum chez la vache de race Holstein. Le potentiel génétique a été associé à l'incidence de NF-MEP et de MET. Les phases lutéales prolongées sembleraient être à l'origine d'une augmentation d'incidence de MET. Le déficit énergétique a eu un effet sur la NF-MEP et sur la MET. L'effet du déficit énergétique postpartum sur la qualité des ovocytes au moment de la mise à la reproduction reste hypothétique. Notre travail sur les échecs précoces de gestation a permis de contribuer à fournir des outils d'amélioration de conduite d'élevage aux professionnels.
402

Zemědělská stavba / Farm building

Bank, Martin January 2014 (has links)
The aim of the master’s thesis is a project documentation of an farm building. It is a new building of stable for breeding of cows of Holstein cattle and accessories necessary for securing it is operation. The building is located in the cadastral territory of municipality Chromeč, district Šumperk. Base consist of a single building object and a stable construction builds up a second object. These two objects are operationally linked and they are connected by the gangway. The stable is designed for a maximum of 278 heads of Holstein cattle. The stable is a single-storey indoor building. In the background there are rooms and equipment necessary to procuring stable operation. A Base is a brick object with two floors. On the ground floor is a waiting room, parlour, technical facilities, rooms for a production of cheese and a cheese shop. Attic there is a background of employees, which is only over a part of the object. Roofs are slanting saddle-shaped. Building estate is situated in the flat terrain.
403

Genetic Parameter Estimates of Milkability Traits in South African Holstein Cattle

Tshilate, Thendo Stanley 18 September 2017 (has links)
MSCAGR (Animal Science) / Department of Animal Science / Milkability, or ease of milking, is the rate at which milk can be completely drawn from a cow’s udder. It is an important functional trait with regard to milking costs as well as udder health. Milkability traits have not been included in the breeding objectives of South African dairy cattle and their genetic parameters in the population have not been estimated. The primary objective of the study was to estimate genetic parameters for milkability traits in South African Holstein cattle. Data consisted of production and milkability records of 1 532 Holstein cows, from 6 herds, participating in the South African National Dairy Animal Recording and Improvement Scheme during the period 2015 to 2016 . Measures of milkability were average milk flow (AMF), maximum milk flow (MMF) and milking time (MT). Genetic parameters were estimated by a multi-trait sire model using the Restricted Maximum Likelihood (REML) procedure. Means for AMF, MMF and MT were 1.99 kg/min, 3.02 kg/min and 5.50 min, respectively. Non-genetic factors affecting variation in milkability traits were herd-year-season of calving, parity and milk yield. Heritability estimates for AMF, MMF, and MT were 0.23±0.09, h2 = 0.41±0.12 and h2 = 0.36±0.11, respectively. Genetic correlations between the three milkability traits were medium to high, ranging from -0.35±0.23 between AMF and MT to 0.79±0.09 between AMF and MMF. Correlations were positive between AMF and MMF and negative between MT and the other two traits. There was an increase in the mean EBV for AMF of 0.002 kg/min (0.0001 kg/min per year) during the period 2002 to 2014. Maximum milk flow also showed an increasing genetic trend of 0.04 kg/min (0.0003 kg/min per year) over the same period. The genetic trend for MT was undesirable, as it increased by 0.0003 kg/min. There is scope for improving milkability through selection, in South African Holstein cattle, as indicated by the moderate to high heritability estimates. The favourable genetic correlations among milkability traits imply that selection on one trait will result in a correlated improvement in the others. Results of the current study provide a basis for including milkability traits in the breeding objective for South African Holstein cattle.
404

Genetic polymorphisms in the stearoyl-CoA desaturase1 (SCD1) gene and their influence on the conjugated linoleic acid (CLA) and monounsaturated fatty acids (MUFA) content of milk fat of Canadian Holstein and Jersey cows

Kgwatalala, Patrick M., 1973- January 2008 (has links)
No description available.
405

Transcription and Critical Edition of Carl Nielsen's Songs, Op. 4 and 10 for Flute and Piano

Pillman, Laura, 1990- 08 1900 (has links)
Widely regarded as one of the most significant composers of the late nineteenth and early twentieth centuries, Carl Nielsen and his music have come to define the early twentieth-century musical traditions of Denmark. His original songs for voice and piano are often revered as popular folk tunes and contributed to his status as a national icon. My dissertation explores Nielsen's vocal repertoire through a multipart project that includes transcribing and editing eleven of Nielsen's early songs from Op. 4 (1891) and Op. 10 (1894), originally for voice and piano, for flute and piano. I discuss the reception history and context of Nielsen's Songs, the important role of transcription in flute literature, and provide full score transcription of the original works for flute and piano. Many vocal works have been transcribed for flute from the original vocal score, providing variety in programming and attracting diverse audiences to performances. Transcription offers scholars a new view into a work, by determining what elements of the piece are integral to maintain the composer's intentions.
406

Les cantates de Nicolaus Bruhns (1665-1697) / The cantatas of Nicolaus Bruhns (1665-1697)

Fructus, Michel 03 December 2009 (has links)
Nicolaus Bruhns (1665-1697) fut organiste à la Marienkirche de Husum (Schleswig-Holstein), et Kapellmeister au service des ducs de Schleswig-Holstein-Gottorf. Si nous ne possédons aujourd’hui qu’une poignée de ses pièces pour orgue (quatre praeludia et un choral-fantaisie), nous pouvons apprécier l’ingéniosité de cet auteur à travers sa production d’œuvres sacrées, douze cantates où règne une énergie comparable à celle de son professeur Dietrich Buxtehude.Soucieux de mieux cerner les enjeux de l’identité créatrice, nous proposerons une approche contradictoire, fondée sur deux conceptions opposées de l’œuvre d’art : elle est par voie de conséquence le produit d’une culture (parce qu’elle est liée au contexte artistique qui la précède, au regard des éléments qui la constituent et qui sont facilement identifiables dans les œuvres du passé, toute œuvre peut être perçue et pensée comme une synthèse de différents modèles, une forme d’aboutissement culturel), mais aussi le fruit d’une individualité (une œuvre d’art est une élaboration unique, indépendante de toute autre production, au regard des facteurs d’unité qui la structurent ; toute œuvre peut alors être perçue et pensée comme une entité autonome).Cette étude nous permettra de mettre à jour un soubassement de l’activité psychique : l’estimation de la distance entre le fixe et le muable. / Nicolaus Bruhns (1665-1697) was an organist at the Marienkirche in Husum (Schleswig-Holstein), and Kapellmeister to the dukes of Schleswig-Holstein-Gottorf. If we own today only a handful of his pieces for organ (four praeludia and a chorale-fantasia), we can appreciate the cleverness of this author through his production of sacred works, twelve cantatas where the energy which appears is similar to that of his professor Dietrich Buxtehude.With the concern to better define the stakes of creative identity, we shall put forward a contradictory approach based on two opposite conceptions of the work of art : it is in essence the product of a culture (since it is linked to the artistic context which precedes it, according to the elements which constitute it and which are easily identifiable in the works of the past, any work can be perceived and thought as a synthesis of various models, a form of cultural achievement), but also the result of individuality (a work of art is a unique construction, independent from any other production according to the factors of unity which structure it ; any work may then be perceived and thought as an autonomous entity).This study will enable us to bring to light a basis of the psychic activity : the appraisal of the distance between the fixed and the changing.
407

Structural equation models applied to quantitative genetics / Modelos de equações estruturais aplicados à genética quantitativa

Cerqueira, Pedro Henrique Ramos 03 September 2015 (has links)
Causal models have been used in different areas of knowledge in order to comprehend the causal associations between variables. Over the past decades, the amount of studies using these models have been growing a lot, especially those related to biological systems where studying and learning causal relationships among traits are essential for predicting the consequences of interventions in such system. Graph analysis (GA) and structural equation modeling (SEM) are tools used to explore such associations. While GA allows searching causal structures that express qualitatively how variables are causally connected, fitting SEM with a known causal structure allows to infer the magnitude of causal effects. Also SEM can be viewed as multiple regression models in which response variables can be explanatory variables for others. In quantitative genetics studies, SEM aimed to study the direct and indirect genetic effects associated to individuals through information related to them, beyond the observed characteristics, such as the kinship relations. In those studies typically the assumptions of linear relationships among traits are made. However, in some scenarios, nonlinear relationships can be observed, which make unsuitable the mentioned assumptions. To overcome this limitation, this paper proposes to use a mixed effects polynomial structural equation model, second or superior degree, to model those nonlinear relationships. Two studies were developed, a simulation and an application to real data. The first study involved simulation of 50 data sets, with a fully recursive causal structure involving three characteristics in which linear and nonlinear causal relations between them were allowed. The second study involved the analysis of traits related to dairy cows of the Holstein breed. Phenotypic relationships between traits were calving difficulty, gestation length and also the proportion of perionatal death. We compare the model of multiple traits and polynomials structural equations models, under different polynomials degrees in order to assess the benefits of the SEM polynomial of second or higher degree. For some situations the inappropriate assumption of linearity results in poor predictions of the direct, indirect and total of the genetic variances and covariance, either overestimating, underestimating, or even assign opposite signs to covariances. Therefore, we conclude that the inclusion of a polynomial degree increases the SEM expressive power. / Modelos causais têm sido muitos utilizados em estudos em diferentes áreas de conhecimento, a fim de compreender as associações ou relações causais entre variáveis. Durante as últimas décadas, o uso desses modelos têm crescido muito, especialmente estudos relacionados à sistemas biológicos, uma vez que compreender as relações entre características são essenciais para prever quais são as consequências de intervenções em tais sistemas. Análise do grafo (AG) e os modelos de equações estruturais (MEE) são utilizados como ferramentas para explorar essas relações. Enquanto AG nos permite buscar por estruturas causais, que representam qualitativamente como as variáveis são causalmente conectadas, ajustando o MEE com uma estrutura causal conhecida nos permite inferir a magnitude dos efeitos causais. Os MEE também podem ser vistos como modelos de regressão múltipla em que uma variável resposta pode ser vista como explanatória para uma outra característica. Estudos utilizando MEE em genética quantitativa visam estudar os efeitos genéticos diretos e indiretos associados aos indivíduos por meio de informações realcionadas aos indivíduas, além das característcas observadas, como por exemplo o parentesco entre eles. Neste contexto, é tipicamente adotada a suposição que as características observadas são relacionadas linearmente. No entanto, para alguns cenários, relações não lineares são observadas, o que torna as suposições mencionadas inadequadas. Para superar essa limitação, este trabalho propõe o uso de modelos de equações estruturais de efeitos polinomiais mistos, de segundo grau ou seperior, para modelar relações não lineares. Neste trabalho foram desenvolvidos dois estudos, um de simulação e uma aplicação a dados reais. O primeiro estudo envolveu a simulação de 50 conjuntos de dados, com uma estrutura causal completamente recursiva, envolvendo 3 características, em que foram permitidas relações causais lineares e não lineares entre as mesmas. O segundo estudo envolveu a análise de características relacionadas ao gado leiteiro da raça Holandesa, foram utilizadas relações entre os seguintes fenótipos: dificuldade de parto, duração da gestação e a proporção de morte perionatal. Nós comparamos o modelo misto de múltiplas características com os modelos de equações estruturais polinomiais, com diferentes graus polinomiais, a fim de verificar os benefícios do MEE polinomial de segundo grau ou superior. Para algumas situações a suposição inapropriada de linearidade resulta em previsões pobres das variâncias e covariâncias genéticas diretas, indiretas e totais, seja por superestimar, subestimar, ou mesmo atribuir sinais opostos as covariâncias. Portanto, verificamos que a inclusão de um grau de polinômio aumenta o poder de expressão do MEE.
408

Structural equation models applied to quantitative genetics / Modelos de equações estruturais aplicados à genética quantitativa

Pedro Henrique Ramos Cerqueira 03 September 2015 (has links)
Causal models have been used in different areas of knowledge in order to comprehend the causal associations between variables. Over the past decades, the amount of studies using these models have been growing a lot, especially those related to biological systems where studying and learning causal relationships among traits are essential for predicting the consequences of interventions in such system. Graph analysis (GA) and structural equation modeling (SEM) are tools used to explore such associations. While GA allows searching causal structures that express qualitatively how variables are causally connected, fitting SEM with a known causal structure allows to infer the magnitude of causal effects. Also SEM can be viewed as multiple regression models in which response variables can be explanatory variables for others. In quantitative genetics studies, SEM aimed to study the direct and indirect genetic effects associated to individuals through information related to them, beyond the observed characteristics, such as the kinship relations. In those studies typically the assumptions of linear relationships among traits are made. However, in some scenarios, nonlinear relationships can be observed, which make unsuitable the mentioned assumptions. To overcome this limitation, this paper proposes to use a mixed effects polynomial structural equation model, second or superior degree, to model those nonlinear relationships. Two studies were developed, a simulation and an application to real data. The first study involved simulation of 50 data sets, with a fully recursive causal structure involving three characteristics in which linear and nonlinear causal relations between them were allowed. The second study involved the analysis of traits related to dairy cows of the Holstein breed. Phenotypic relationships between traits were calving difficulty, gestation length and also the proportion of perionatal death. We compare the model of multiple traits and polynomials structural equations models, under different polynomials degrees in order to assess the benefits of the SEM polynomial of second or higher degree. For some situations the inappropriate assumption of linearity results in poor predictions of the direct, indirect and total of the genetic variances and covariance, either overestimating, underestimating, or even assign opposite signs to covariances. Therefore, we conclude that the inclusion of a polynomial degree increases the SEM expressive power. / Modelos causais têm sido muitos utilizados em estudos em diferentes áreas de conhecimento, a fim de compreender as associações ou relações causais entre variáveis. Durante as últimas décadas, o uso desses modelos têm crescido muito, especialmente estudos relacionados à sistemas biológicos, uma vez que compreender as relações entre características são essenciais para prever quais são as consequências de intervenções em tais sistemas. Análise do grafo (AG) e os modelos de equações estruturais (MEE) são utilizados como ferramentas para explorar essas relações. Enquanto AG nos permite buscar por estruturas causais, que representam qualitativamente como as variáveis são causalmente conectadas, ajustando o MEE com uma estrutura causal conhecida nos permite inferir a magnitude dos efeitos causais. Os MEE também podem ser vistos como modelos de regressão múltipla em que uma variável resposta pode ser vista como explanatória para uma outra característica. Estudos utilizando MEE em genética quantitativa visam estudar os efeitos genéticos diretos e indiretos associados aos indivíduos por meio de informações realcionadas aos indivíduas, além das característcas observadas, como por exemplo o parentesco entre eles. Neste contexto, é tipicamente adotada a suposição que as características observadas são relacionadas linearmente. No entanto, para alguns cenários, relações não lineares são observadas, o que torna as suposições mencionadas inadequadas. Para superar essa limitação, este trabalho propõe o uso de modelos de equações estruturais de efeitos polinomiais mistos, de segundo grau ou seperior, para modelar relações não lineares. Neste trabalho foram desenvolvidos dois estudos, um de simulação e uma aplicação a dados reais. O primeiro estudo envolveu a simulação de 50 conjuntos de dados, com uma estrutura causal completamente recursiva, envolvendo 3 características, em que foram permitidas relações causais lineares e não lineares entre as mesmas. O segundo estudo envolveu a análise de características relacionadas ao gado leiteiro da raça Holandesa, foram utilizadas relações entre os seguintes fenótipos: dificuldade de parto, duração da gestação e a proporção de morte perionatal. Nós comparamos o modelo misto de múltiplas características com os modelos de equações estruturais polinomiais, com diferentes graus polinomiais, a fim de verificar os benefícios do MEE polinomial de segundo grau ou superior. Para algumas situações a suposição inapropriada de linearidade resulta em previsões pobres das variâncias e covariâncias genéticas diretas, indiretas e totais, seja por superestimar, subestimar, ou mesmo atribuir sinais opostos as covariâncias. Portanto, verificamos que a inclusão de um grau de polinômio aumenta o poder de expressão do MEE.
409

VALUE OF SYSTEMATIC THORACIC ULTRASONOGRAPHY INFORMATION FOR DETECTING BOVINE RESPIRATORY DISEASE (BRD) RELATED LUNG DAMAGE IN CROSSBRED DAIRY CALVES

Evan Bryant Long (10715370) 28 April 2021 (has links)
The purpose of this study is to evaluate the value of systematic thoracic ultrasonography (TUS) for detecting bovine respiratory disease (BRD) related lung damage in Holstein x Angus crossbred calves. Because the dairy industry is known to operate on small profit margins, it is important to assess the potential of this technology to help prevent the main source of financial loss related to calf production that dairy producers face. Studies have shown that BRD may impact nearly a fourth of all dairy calves before weaning. In an industry that is currently growing and evolving, it is important that producers have all the necessary resources to operate efficiently. TUS is known to be a quick and accurate predictor of BRD related lung damage, but this study focuses on the financial implications of BRD related lung damage on calf growth and efficiency—average daily gain (ADG) and milk-to-gain (M:G)—and the value of implementing TUS information to make sound management decisions. TUS along with BRD diagnosis information give producers a unique perspective on future growth and development of calves and could be part of the solution to promote larger profit margins for dairy producers. We find that the value associated with TUS and BRD diagnosis information is between $0.88/head and $13.44/head and depends on BRD incidence rate, feed price, and feeder price. Depending on the cost to the farm, it may be beneficial to implement this as a way to manage BRD damage, which we know to influence calf growth and efficiency.

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