• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 11
  • 7
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 33
  • 16
  • 8
  • 7
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 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.
11

Studies on the acute phase reaction during respiratory infections in calves /

Gånheim, Charina, January 2004 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.
12

Bovine viral diarrhoea virus and other reproductive pathogens : epidemiological studies in Peruvian cattle /

Ståhl, Karl, January 2006 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 5 uppsatser.
13

Epidemiology of Neospora caninum infection in dairy cattle in Thailand /

Chanlun, Aran, January 2006 (has links) (PDF)
Diss. (sammanfattning) Uppsala, Sweden : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.
14

Associação entre a ocorrência de algumas enfermidades reprodutivas e o desempenho reprodutivo e produtivo de quatro rebanhos leiteiros da raça holandês / Association among the occurrence of some reproductive diseases and reproductive performance and milk production in four Holstein dairy herds.

SCHEID FILHO, Virgílio Balduino 02 August 2007 (has links)
Made available in DSpace on 2014-08-20T14:37:55Z (GMT). No. of bitstreams: 1 dissertacao_virgilio_scheid_filho.pdf: 278218 bytes, checksum: 162a8189af499504bde7a5330085f0e4 (MD5) Previous issue date: 2007-08-02 / Reproductive performance is a key factor for the economical success of dairy production. The objective of this study was to evaluate the association between the occurrence of diseases and the reproductive performance and milk production in four Holstein dairy herds from Castro and Carambeí (PR). An observational study was conducted through database research during the period between March and October 2006, including data corresponding to calvings occurred from March, 2004 to October, 2006. Performance parameters such as calving and calving-conception (CCI) intervals and the daily milk production (DMP) were evaluated as a function of herds, number of artificial inseminations (AI), number of calvings, number of clinical occurrences, and occurrence of mastitis, metritis and retention of fetal membranes. The CCI was longer for cows presenting three or more clinical occurrences than for those having no clinical occurrence and also with increased number of AI (P < 0.0001). Such interval was 24.1 days shorter for cows that presented retained fetal membranes than for those that did not present such condition (P = 0.0263). The CCI for cows presenting clinical mastitis up to 60 days post-partum was shorter than for those presenting mastitis after such period (P < 0.0001). The occurrence of clinical mastitis was influenced by neither the occurrence of metritis nor of retention of fetal membranes (P > 0.05). However, the occurrence of retention of fetal membranes was associated with metritis occurrence (P < 0.0001). The DMP observed for cows diagnosed with three or more clinical occurrences was higher (P < 0.0001) than for those with only one occurrence or no diagnosis, although the cows that were not diagnosed with any clinical occurrence presented the lowest DMP (P < 0.0001). / O desempenho reprodutivo é o maior fator limitante para que a produção de leite seja uma atividade economicamente eficiente. O objetivo deste estudo foi avaliar a associação entre a ocorrência clínica de algumas enfermidades e o desempenho reprodutivo e produtivo de quatro rebanhos leiteiros da raça Holandês, localizados nos municípios de Castro e Carambeí (PR). Um estudo observacional foi realizado a partir da pesquisa de índices de desempenho destes plantéis, entre março a setembro de 2006, compreendendo partos ocorridos durante o período de março de 2004 a outubro de 2006. Indicadores de desempenho como os intervalos entre partos, parto-concepção (IPC) e a produção diária de leite (PDL), foram avaliados para as quatro propriedades, em função do número de inseminações artificiais (NOIA), número de partos (NP), número de ocorrências clínicas (ND), ocorrência de mastite, metrite e retenção de membranas fetais. O IPC foi mais longo em vacas que apresentaram três ou mais ocorrências clínicas do que naquelas que não foram acometidas por doenças e em função do aumento no número de IA (P < 0,001), mas foi 24,1 dias mais curto nas vacas acometidas por retenção de membranas fetais do que nas vacas não acometidas (P = 0,0263). As vacas acometidas por mastite clínica, até os 60 dias pós-parto, apresentaram IPC mais curto que aquelas com mastite após os 60 dias pós-parto (P < 0.001). A ocorrência de mastite não foi influenciada pela ocorrência tanto de metrite, quanto de retenção de membranas fetais (P > 0,05). Porém, a ocorrência de retenção de membranas fetais foi associada com a ocorrência de metrite (P < 0,001). A PDL das vacas com três ou mais ocorrências clínicas foi superior (P < 0,001) às observadas para as vacas sem ocorrências clínicas ou com apenas uma ocorrência, mas as vacas que não apresentaram ocorrências clínica apresentaram PDL inferior a todas as outras categorias (P < 0,001).
15

異質與分群訊息在金融市場的交易行為及績效分析 / Analysis on heterogeneous and subgroup information in financial markets

楊祐宗, Yang, Yu- Tsung Unknown Date (has links)
金融市場中存在著許多預測機構, 他們各自召集信眾並且不時地釋放訊息給其會員好讓他們能在交易中獲利。每筆訊息皆代表著各機構對此資產價值的預測, 會員則依此訊息至市場上尋找機會交易。他們交易前會先理性地觀察市場過往的波動。如果市場走勢所預測的訊息與自己的訊息一致, 那交易者交易時大概不會有所顧慮。然而當市場趨勢與自己的訊息不一致時, 交易者勢必會陷入兩難。仔細地衡量斟酌兩股力量的輕重後, 進而選擇他覺得對的決定。如果交易者放棄自己的訊息而追隨前人交易的腳步, 那我們可定義這是一種群聚的行為。 如果某一機構的會員人數龐大, 則他們勢必會影響市場價格的波動。不知情的交易者在看到價格趨勢如此時, 可能會放棄自己的訊息轉而追隨過往交易者的選擇。然而此種交易伴隨著風險, 因為不知道正確的訊息為何, 當價格已經達到機構所預測的目標時, 知情的會員便開始反向操作, 而不知情的交易者可能會持續地採取此一交易策略。於是當資產真正價值揭露時, 不知情交易者便可能因此被套牢。跟隨大眾的決策相對保險, 但是當追隨的人沒有額外的訊息無法查覺情勢的變化時, 便可能面臨損失的風險。 我們建構了一個存在兩種類型交易者的市場, 一方是沒有參加機構的一般交易者, 另一方是同時參加某一機構的會員交易者。透過私有訊息與公開歷史交易預測的權衡, 交易者必須想辦法在這一次機會的交易中獲利。而我們想找出是否對任何交易者而言, 參加預測機構是有利可圖的。 想當然爾, 市場中會員交易者的多寡對於機構預測目標價位的達成頗為重要, 因為影響力的大小間接決定了市場雙方的利潤。當然每位交易者對訊息的信心也有所不同, 這些因素都會影響雙方的利潤。而本篇論文即是嘗試找出在哪種條件之下, 參與機構交易者的交易績效會比沒有參與機構交易者的績效為佳。 / Traders with their own heterogeneous hidden information are coming to the market to trade in order to maximize their expected profits. They will observe the trends of prices and compare it to their private signals and then make the right decisions. The trends might not consistent with the private signals. If the traders choose to abandon his own signals and follow the actions made by predecessors, we called the action “Herds.” In this paper, we set a mechanism to harmonize with these two powers. Also we put the traders into two subgroups, and one of the groups will send another signal to its members. For simplicity, we use a sequential trading model to see the trade patterns. Since we use the closing price to measure traders’ profits, traders in the market need to presume what the closing price will be. Then we calculate the profits of each group and find out their performance. We want to see under what kind of conditions, the performance of one group will be better than that of another group. If we can find the conditions of better performance, it is worth for the traders to join that group.
16

Évaluation de la prévalence individuelle et de troupeau de quatre pathogènes d'importance dans les troupeaux laitiers biologiques du Québec

Ramanantoanina, Andriamialisoa F. 08 1900 (has links)
INTRODUCTION La production biologique contribue de façon significative aux défis du développement durable. Les infections à Mycobacterium avium sous-espèce paratuberculosis (MAP), Neospora caninum (NC), au virus de la diarrhée virale bovine (BVD) et au virus de la rhinotrachéite infectieuse bovine (IBR) sont bien reconnues pour affecter de manière significative la production dans les élevages laitiers. Il n’existe toutefois aucune donnée sur l’importance de ces pathogènes dans les troupeaux biologiques. HYPOTHESE Ces quatre pathogènes sont présents dans les troupeaux laitiers biologiques, mais leur prévalence est moindre par rapport à l’élevage conventionnel. OBJECTIFS Estimer les séroprévalences de NC, MAP, BVD, IBR dans les troupeaux laitiers biologiques québécois. MÉTHODOLOGIE Dans la province du Québec, 60 troupeaux laitiers biologiques ont été sélectionnés aléatoirement. Un échantillon sanguin a été prélevé sur 30 vaches adultes, pour l’évaluation de NC et MAP, et sur 5 animaux plus de 6 mois non vaccinés, pour l’évaluation de BVD et IBR. Une détection d’anticorps par ELISA, pour NC et MAP, et par séroneutralisation pour BVD et IBR a été réalisée sur les sérums obtenus. Un questionnaire a été rempli par chaque éleveur. RÉSULTATS La séroprévalence individuelle de NC et MAP, avec un intervalle de confiance de 95%, étaient de 4.1% (3.2%-5.2%) et 0.8% respectivement (0.0%-1.3%). La séroprévalence de troupeau de NC, MAP, BVD, IBR, si au moins un animal est positif dans un troupeau étaient de 50.8%, 20.3%, 37.3%, 31.0% respectivement. Ces séroprévalences étaient de 30.5%, 3.4%, 28.8% et 18.9%, respectivement, si au moins deux animaux sont positifs. La taille du troupeau a un effet significatif sur le statut de BVD (p=0.02) et il y a une bonne corrélation entre le statut BVD et IBR (Kappa-0.54). DISCUSSION/CONCLUSION La séroprévalence individuelle de NC, MAP, IBR semblent être moindre dans les troupeaux laitiers biologiques comparativement au conventionnel. Il ne semble pas y avoir de grandes différences entre la séroprévalence du BVD des troupeaux biologiques et celle des conventionnels. / INTRODUCTION Organic herds are important component of sustainable development. Mycobacterium avium subspecies paratuberculosis (MAP), Neospora caninum (NC), bovine viral diarrhoea (BVD) virus and infectious bovine rhinotracheitis (IBR) virus infections are well known to have major impact on dairy production. However, there are actually no data on the prevalence of these pathogens in organic dairy herds. HYPOTHESIS These four pathogens are present among cattle organic herds but their prevalence is less than among conventional cattle herds. OBJECTIVE To evaluate the seroprevalence of NC, MAP, BVD, IBR in cattle organic herds in Québec province. METHODOLOGY In the province of Québec, 60 organic herds were randomly sampled. Thirty adult cows, to estimate NC and MAP, and 5 unvaccinated animals more than 6 months old, for BVD and IBR, were bled. An ELISA test, for NC and MAP, and seroneutralisation test for BVD and IBR were used to analyse the serum. A questionnaire was filled in by farmers. RESULTS Individual prevalence of NC and MAP (IC=95%) were 4.1% (3.2%-5.2%) and 0.8% (0.0%-1.3%) respectively. Herd level prevalence of NC, MAP, BVD, IBR, based on a herd-test cut point of 1 positive animal, were 50.8%, 20.3%, 37.3%, and 31.0% respectively. Based on a herd-test cut point of 2 positive animals, these prevalence were 30.5%, 3.4%, 28.8% and 18.9% respectively. Herd size was significantly associated with BVD herd prevalence (p=0.02).... There was a good correlation between herd prevalence of BVD and herd prevalence of IBR (Kappa=0.54). DISCUSSION/CONCLUSION Prevalence of NC, MAP, and IBR seem to be less among cattle organic herds than in cattle conventional herds. It seems that there is no difference between prevalence of BVD among organic herds and conventional herds.
17

Associação entre o índice de mastite em rebanhos bovinos leiteiros e a qualidade microbiológica do leite cru no Estado de São Paulo, Brasil / Association between mastitis rate in bovine dairy herd and the raw milk microbiological quality in São Paulo State, Brazil

Souto, Luís Ivan Martinhão 28 July 2006 (has links)
O objetivo deste trabalho foi verificar as possíveis correlações entre os índices de mastite e a qualidade microbiológica do leite cru, em 36 propriedades com atividade exploratória leiteira, no Estado de São Paulo, Brasil. Examinou-se 4662 quartos mamários de 1180 animais em lactação para se verificar a presença de mastite pelos Testes de Caneca de Fundo Escuro e CMT, e coletou-se uma amostra de cada quarto mamário positivo em pelo menos um dos testes para exame microbiológico. Para se avaliar a qualidade microbiológica do leite cru, coletou-se uma amostra de cada propriedade e fez-se a Contagem de microrganismos mesófilos aeróbios facultativos viáveis, Contagem de microrganismos psicrotróficos aeróbios facultativos viáveis, Contagem de microrganismos termófilos aeróbios facultativos viáveis, Contagem de Enterococcus spp., Contagem de Stapylococcus spp., Contagem de Streptococcus spp., Contagem de Corynebacterium spp., Contagem de bolores e leveduras, Número Mais Provável de coliformes totais e Número Mais Provável de coliformes fecais. Aplicou-se teste de Correlação de Pearson e Regressão Linear. Para comparação entre os índices de mastite, a melhor correlação foi entre o índice de resultados positivos ao teste CMT e os casos de mastite por causa infecciosa (r = 0,920 e R2 = 84,7%). Comparando-se o índice de mastite e a qualidade microbiológica do leite cru, o melhor resultado que apresentou correlação significativa foi entre o índice de casos de mastite por Staphylococcus spp. e a Contagem de microrganismos termófilos aeróbios facultativos viáveis (r = 0,522 e R2 = 27,3%). Pelo baixo número de análises que apresentaram resultado de Correlação significativa, notou-se que o índice mastite em rebanhos bovinos leiteiros não interfere na qualidade microbiológica do leite cru, nas condições estudadas neste experimento. / The purpose of this research was to investigate the possible correlations between the mastitis rate and raw milk microbiology quality, from 36 dairy farms, in São Paulo State, Brazil. It was investigated 4662 mammary quarters of 1180 lactant animals to examine mastitis cases using Tamis test and CMT. It was collected one sample of each positive mammary quarter in one test at least to microbiological analysis. To estimate the raw milk microbiological quality, it was colected one sample from each farm and realized one aerobic plate count of microorganisms mesophilic, aerobic plate count of microorganisms psychrotrophic, aerobic plate count of microorganisms termophilic, Enterococcus spp. plate count, Stahylococcus spp. plate count, Streptococcus spp. plate count, Corynebacterium spp. plate count, Yeast and Molds plate count, Most Probable Number of coliforms, Most Probable Number of fecal coliforms. It was used Pearson Correlation test and Linear Regression. In order to compare mastitis rates, the best correlation was between positives CMT test rate and the cases of mastitis caused by infections disease (r = 0,920 and R2 = 84,7%). Analysing the mastitis rate and the raw milk microbiological quality, the best result of correlation was between Staphylococcus mastitis rate and the aerobic plate count of microorganisms termophilic (r = 0,522 e R2 = 27,3%). Because of the low number of significant correlation, it was observed that the mastitis heard in dairy bovines herds do not interfere in raw milk microbiological quality, in the condition of this experiment.
18

Cornelius P. Lott and his Contribution to the Temporal Salvation of the Latter-day Saint Pioneers Through the Care of Livestock

Ford, Gary S. 01 December 2005 (has links)
This thesis combines two studies: the role of livestock in the temporal salvation of The Church of Jesus Christ of Latter-day Saints in the Mormon exodus of 1846 and Cornelius P. Lott's contribution in the care of cattle and sheep during that time period. At Winter Quarters, the Church and its members depended in large measure for their survival upon the sizeable cattle herds they had acquired prior to their exodus from Nauvoo and during their trek across Iowa. Church leaders relied on men like Lott, whose expertise in the care of livestock, contributed significantly to the salvation of the Latter-day Saints. The work investigates the American agriculture and livestock industry in the first half of the nineteenth century for the context in which the Latter-day Saints acquired livestock and subsequently herded them across Iowa. During that time period, Missouri and Illinois had an abundance of good livestock, which contributed to success of the Mormon exodus. After their expulsion from the state of Missouri in 1838, the Church was left destitute of property and had to build up their livestock again. By 1846, they had amassed numerous herds, especially as they made a concerted effort to gather livestock in preparation for their exodus from Illinois. Along the Iowa trail, they continued acquiring cattle in great number by trading many of their possessions with local settlers. As Church leaders had designed, the Latter-day Saints arrived at the Missouri River with thousands of head of livestock. Their herds, particularly cattle, provided a significant lifeline for the Church in both sustenance and trade. Because the Latter-day Saints' livestock was such a precious commodity, Church leaders had to be selective in choosing men to care for the animals. Cornelius P. Lott represents that class of skilled hands who took on such assignments. He joined the Church in 1834 and became recognized by Joseph Smith in 1838 as he played a key role as a leader in the conflict against the Missouri mobs in 1838. He demonstrated his skills with livestock when the Prophet employed him as superintendent of the Smith farm in Nauvoo. Joseph Smith became well acquainted with Lott and favored him with unique privileges, including his participation in sacred temple ordinances, unavailable to most of the Church until later. Such experiences gave Lott opportunity to associate closely with Brigham Young and the Apostles. Hence, when Young sought for trusted men at the Missouri River who could care for the livestock, Lott was a natural choice. This study is valuable to Church history because it shows the importance of livestock and the men who cared for them in contributing to the success of the Mormon exodus and the temporal salvation of the Church. It is important in American history because gives insight into the role of cattle during the westward expansion era.
19

Évaluation de la prévalence individuelle et de troupeau de quatre pathogènes d'importance dans les troupeaux laitiers biologiques du Québec

Ramanantoanina, Andriamialisoa F. 08 1900 (has links)
INTRODUCTION La production biologique contribue de façon significative aux défis du développement durable. Les infections à Mycobacterium avium sous-espèce paratuberculosis (MAP), Neospora caninum (NC), au virus de la diarrhée virale bovine (BVD) et au virus de la rhinotrachéite infectieuse bovine (IBR) sont bien reconnues pour affecter de manière significative la production dans les élevages laitiers. Il n’existe toutefois aucune donnée sur l’importance de ces pathogènes dans les troupeaux biologiques. HYPOTHESE Ces quatre pathogènes sont présents dans les troupeaux laitiers biologiques, mais leur prévalence est moindre par rapport à l’élevage conventionnel. OBJECTIFS Estimer les séroprévalences de NC, MAP, BVD, IBR dans les troupeaux laitiers biologiques québécois. MÉTHODOLOGIE Dans la province du Québec, 60 troupeaux laitiers biologiques ont été sélectionnés aléatoirement. Un échantillon sanguin a été prélevé sur 30 vaches adultes, pour l’évaluation de NC et MAP, et sur 5 animaux plus de 6 mois non vaccinés, pour l’évaluation de BVD et IBR. Une détection d’anticorps par ELISA, pour NC et MAP, et par séroneutralisation pour BVD et IBR a été réalisée sur les sérums obtenus. Un questionnaire a été rempli par chaque éleveur. RÉSULTATS La séroprévalence individuelle de NC et MAP, avec un intervalle de confiance de 95%, étaient de 4.1% (3.2%-5.2%) et 0.8% respectivement (0.0%-1.3%). La séroprévalence de troupeau de NC, MAP, BVD, IBR, si au moins un animal est positif dans un troupeau étaient de 50.8%, 20.3%, 37.3%, 31.0% respectivement. Ces séroprévalences étaient de 30.5%, 3.4%, 28.8% et 18.9%, respectivement, si au moins deux animaux sont positifs. La taille du troupeau a un effet significatif sur le statut de BVD (p=0.02) et il y a une bonne corrélation entre le statut BVD et IBR (Kappa-0.54). DISCUSSION/CONCLUSION La séroprévalence individuelle de NC, MAP, IBR semblent être moindre dans les troupeaux laitiers biologiques comparativement au conventionnel. Il ne semble pas y avoir de grandes différences entre la séroprévalence du BVD des troupeaux biologiques et celle des conventionnels. / INTRODUCTION Organic herds are important component of sustainable development. Mycobacterium avium subspecies paratuberculosis (MAP), Neospora caninum (NC), bovine viral diarrhoea (BVD) virus and infectious bovine rhinotracheitis (IBR) virus infections are well known to have major impact on dairy production. However, there are actually no data on the prevalence of these pathogens in organic dairy herds. HYPOTHESIS These four pathogens are present among cattle organic herds but their prevalence is less than among conventional cattle herds. OBJECTIVE To evaluate the seroprevalence of NC, MAP, BVD, IBR in cattle organic herds in Québec province. METHODOLOGY In the province of Québec, 60 organic herds were randomly sampled. Thirty adult cows, to estimate NC and MAP, and 5 unvaccinated animals more than 6 months old, for BVD and IBR, were bled. An ELISA test, for NC and MAP, and seroneutralisation test for BVD and IBR were used to analyse the serum. A questionnaire was filled in by farmers. RESULTS Individual prevalence of NC and MAP (IC=95%) were 4.1% (3.2%-5.2%) and 0.8% (0.0%-1.3%) respectively. Herd level prevalence of NC, MAP, BVD, IBR, based on a herd-test cut point of 1 positive animal, were 50.8%, 20.3%, 37.3%, and 31.0% respectively. Based on a herd-test cut point of 2 positive animals, these prevalence were 30.5%, 3.4%, 28.8% and 18.9% respectively. Herd size was significantly associated with BVD herd prevalence (p=0.02).... There was a good correlation between herd prevalence of BVD and herd prevalence of IBR (Kappa=0.54). DISCUSSION/CONCLUSION Prevalence of NC, MAP, and IBR seem to be less among cattle organic herds than in cattle conventional herds. It seems that there is no difference between prevalence of BVD among organic herds and conventional herds.
20

Epidemiology, detection and prevention of respiratory virus infections in Swedish cattle : with special reference to bovine respiratory syncytial virus /

Hägglund, Sara, January 2005 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

Page generated in 0.06 seconds