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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.
41

Ocorrência e efeito temporal das espécies do gênero Eimeria Schneider, 1875 em cordeiros confinados /

Rahal, Natália Machado January 2018 (has links)
Orientador: Luiz Claudio Nogueira Mendes / Coorientador: Marcelo Vasconcelos Meireles / Banca: Alex Akira Nakamura / Banca: Fernanda Bovino / Resumo: A infecção patogênica por Eimeria spp., denominada eimeriose ou coccidiose, tem sido indicada como responsável por mortes, queda no desenvolvimento e baixa produtividade em criações animais, ocorrendo principalmente em indivíduos jovens devido à imaturidade do sistema imunológico. Quando são submetidos a um sistema intensivo de produção, como em situação de confinamento, cordeiros podem se tornar ainda mais susceptíveis às infecções por espécies de Eimeria, devido à alta concentração de indivíduos, que potencializa a dispersão do parasito, e ao estresse associado à criação. No estado de São Paulo, já foram identificadas dez espécies de Eimeria em estudos prévios e, dentre elas, E. ovinoidalis foi considerada a mais patogênica para ovinos. Dessa forma, o objetivo deste trabalho foi descrever as espécies do gênero Eimeria Schneider, 1875 que ocorreram em um confinamento de cordeiros, bem como as dinâmicas da eliminação de oocistos no ambiente e correlação com o ganho de peso médio diário (GMD) durante nove semanas. Cento e quatro cordeiros de diversas raças e cruzas, com aproximadamente 60 dias de vida, foram confinados e submetidos a pesagens, avaliações clínicas e coprológicas periódicas. Amostras de fezes que continham mais de 500 oocistos de Eimeria por gramas de fezes (OoPG) foram separadas para esporulação, posteriormente determinando-se as espécies às quais os oocistos pertenciam. Dentre os 677 oocistos avaliados, as seguintes espécies foram identificadas: E. parva Kotla... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Pathogenic infection caused by Eimeria spp., denominated eimeriosis or coccidiosis, has been pointed out as responsible for deaths, decreased development and low productivity for livestock animals, affecting mainly young individuals due to immature immunological system. When submitted to an intensive breeding system, as a feedlot, lambs can become even more susceptible to Eimeria infections, due to high concentration of animals, which potentializes parasite dispersion, and to stress generated by farming conditions. In São Paulo State, ten Eimeria species were identified in previous studies and, among them, E. ovinoidalis, was considered the most pathogenic for ovine. So, this study aimed to describe species of the Eimeria Schneider, 1875 that occurred in a lamb feedlot, as well as the dynamics of oocyst output in the environment and its correlation with daily weight gain (DWG) during nine weeks. One hundred and four lambs of various breeds and crossbreeds, at approximately 60 days old, were placed in a feedlot and submitted to periodic weighing, clinical and coprological evaluations. Fecal samples that had more than 500 Eimeria spp. oocysts per gram (OPG) were separated for sporulation, and oocysts were identified at species level. Among the 677 evaluated oocysts, the following species were identified: E. parva Kotlan, Moscy & Vajda, 1929, E. crandallis Honess, 1942, E. ovinoidalis McDougald, 1979, E. weybridgensis Norton, Joyner & Catchpole 1974, E. bakuensis Musaev, 1970 (s... (Complete abstract click electronic access below) / Mestre
42

Role of Vaccination in the Control of Turkey Coccidiosis: Vaccine Associated Oocyst Shedding, Lesions, and Mucosal Gene Expression

Behl, Michelle 1983- 02 October 2013 (has links)
Coccidiosis vaccine associated side effects, oocyst shedding patterns, intestinal lesions, and mucosal gene expression in the turkey were studied. The first study examined vaccine associated side effects and oocyst shedding patterns under experimental conditions. Peak oocyst shedding occurred on days 5-6, 13-17, and 19-20 days post vaccination. Throughout the course of the study, several poults exhibited clinical coccidiosis. Based on body weights, growth was correlated with vaccine cycling. The second study examined coccidiosis vaccine induced lesions and changes in mucosal gene expression on day 5, 10, 13, 17, and 20 days post vaccination. Poults were gavaged the equivalent of 0x, 1/2x, 1x, and 2x the available vaccine dose. Intestinal sections adjacent to the Meckel's diverticulum, ileocecal junction, and middle of the ceca were collected for histological analysis and gene expression. Measurements from the tip of the villus to the base of the lamina propria, villus width, and the muscularis mucosae thickness were acquired from the histological sections. Interleukin-10, IL-1beta, and GAPDH gene expression were measured by extracting mRNA in the tissues and quantified using real-time RT-qPCR. Starting on day five post vaccination, the control group weighed significantly more than the group that received the 2x dose. Body weight and oocyst dose were inversely related through day 17. Intestinal measurements did not necessarily correlate with the vaccine dose, although there appears to be some correlation on day five. There were no significant changes in the mucosal gene expression of IL-10 and IL-1beta in the intestinal tissue adjacent to the Meckel's diverticulum throughout the course of the study. On day five post vaccination, IL-10 and IL-1beta were significantly upregulted in the ileocecal junction. Interleukin-10 was significantly upregulated on day 17 and IL-1beta was significanlty down regulated on day 20 in the ileocecal junction. Both IL-10 and IL-1beta were significantly upregulated in the ceca days 5, 10, and 13 post vaccination. Interleukin-10 was significnalty upregulated in the ceca on day 17 and significantly down regulated on day 20. Individual variation among poults in the same group merits further attention.
43

Studien zur Behandlung der Eimeria bovis - Kokzidiose des Kalbes mit Toltrazuril

Uebe, Friederike 24 November 2011 (has links) (PDF)
Ziel der vorliegenden Arbeit war es, ein Infektionsmodell für Eimeria bovis zu etablieren und die induzierte Kokzidiose mit unterschiedlichen Anwendungen von Toltrazuril zu behandeln. Zusätzlich wurde eine histopathologische Studie durchgeführt, in der zu unterschiedlichen Zeitpunkten mit der gleichen Dosis Toltrazuril behandelt wurde. In der ersten Studie wurde die effektive Dosis Toltrazuril bei einer experimentellen E. bovis – Kokzidiose bestimmt. Nach der experimentellen Infektion mit 50000 Oozysten pro Kalb wurden die Tiere mit 5, 15 oder 25 mg/kg LM Toltrazuril oder mit einem Plazebo in der Präpatenz behandelt. In der Plazebogruppe entwickelten alle Tiere Durchfall, zwei Tiere auch hämorrhagische Diarrhoe. In den Behandlungsgruppen trat keine hämorrhagische Diarrhoe auf, sondern im Fall klinischer Kokzidiose nur katarrhalischer Durchfall. Auch in der durchschnittlichen Erkrankungsdauer unterschied sich die Plazebogruppe von den Behandlungsgrupppen ( 9,1 Tage bzw. 4,6, 4,3 oder 3,3 Tage). Bei der Oozystenausscheidung war ebenfalls ein statistisch signifikanter Unterschied zwischen der Plazebogruppe und den Behandlungsgruppen nachweisbar; ebenfalls war ein statistisch signifikanter Unterschied der Oozystenausscheidung der mit 5 mg/kg LM und den mit 15 bzw. 25 mg/kg LM behandelten Kälbern nachweisbar. Das Gewicht unterschied sich in dieser Studie nicht statistisch signifikant, was vermutlich auf die geringen Tierzahlen und begleitende Atemwegserkrankungen zurückzuführen ist. In der zweiten Studie wurde die Infektionsdosis auf 100000 Oozysten pro Kalb verdoppelt und zwei Behandlungsgruppen gebildet: unbehandelte Kontrollgruppe und 15 mg/kg LM Toltrazuril. Auch in dieser Studie traten signifikante Unterschiede zwischen den Gruppen auf. Dies betraf Kotkonsistenz, Oozystenausscheidung und Gewicht. Die unbehandelten Kälber wiesen alle hämorrhagische Diarrhoe mit Gewebefetzen auf, in der Behandlungsgruppe trat dies nur bei einem Tier auf, alle anderen Kälber wiesen nur eine katarrhalische Diarrhoe auf. Alle Tiere (n=9) der Kontrollgruppe schieden erhebliche Mengen von Oozysten aus, bei den behandelten Tieren schieden nur 2 von 9 Kälbern Oozysten aus, auch die OpG lagen deutlich niedriger. In der dritten Studie mit histopathologischer Untersuchung wurden die Tiere in drei Gruppen aufgeteilt, die jeweils aus 8 Tieren bestanden; alle Tiere wurden mit 100000 Oozysten pro Kalb infiziert. Eine Gruppe erhielt in der Präpatenz eine Plazebobehandlung, eine in der Präpatenz metaphylaktisch 15 mg/kg LM Toltrazuril und eine therapeutisch 15 mg/kg LM Toltrazuril. Die Untersuchungstermine für die Pathologie wurden in der Präpatenz und der frühen und späten Patenz, bzw. Postpatenz gewählt. Auch in dieser Studie unterschieden sich die Kotkonsistenz und die Oozystenausscheidung deutlich zwischen der metaphylaktisch behandelten Gruppe und den beiden anderen Gruppen. Auch die Gewichtszunahme lag in der metaphylaktisch behandelten Gruppe deutlich höher als in den beiden anderen Gruppen. Die pathologischen Ergebnisse zeigen ebenfalls einen deutlichen Unterschied zwischen der metaphylaktisch behandelten Gruppe und den beiden anderen Gruppen. Insgesamt lassen die Ergebnisse den Schluß zu, daß eine metaphylaktische Behandlung mit Toltrazuril in der Lage ist, eine massive klinische Kokzidiose, hervorgerufen durch E. bovis, zu verhindern. Da eine therapeutische Anwendung keinen deutlichen Effekt auf die klinische Ausprägung und die Oozystenausscheidung zeigt, ist es in der Praxis wesentlich, mit der Epidemiologie in dem zu behandelnden Bestand vertraut zu sein, um eine effektive Behandlung zu ermöglichen. Durch eine Behandlung in der Präpatenz kann über die Verringerung der Ausscheidung von Oozysten der Infektionsdruck für nachfolgende Kälbergruppen gesenkt werden.
44

Efectos de la suplementación con salinomicina y nicarbazina sobre los parámetros productivos en pollos de engorde

Zavala De La Jara, Casandra Mónica January 2017 (has links)
Evalúa la eficacia en el control de la coccidiosis mediante la combinación de dos drogas anticoccidiales, salinomicina y nicarbazina, suministradas en el alimento a una dosis de 40 ppm, por medio de la evaluación de parámetros productivos en pollos de engorde desafiados experimentalmente con cepas locales de coccidias y criados hasta los 42 días de edad. Se criaron 450 pollos de engorde de la Línea Cobb Vantress 500, divididos en tres grupos experimentales de 150 animales cada uno, cada grupo se dividió en 6 repeticiones de 25 aves.G1: Aves no desafiadas y tratadas con la combinación anticoccidial Salinomicina y Nicarbazina, G2: aves desafiadas y tratadas con la combinación anticoccidial Salinomicina y Nicarbazina; y G3: aves desafiadas y no tratadas. Se evaluaron los parámetros productivos (peso vivo promedio, ganancia de peso, consumo de alimento, índice de conversión alimenticia, viabilidad e índice de eficiencia productiva europeo). Se desafiaron a las aves de los grupos G2 y G3 al día 14 de edad con 1 mL de inóculo de coccidias conteniendo ooquistes esporulados de Eimeria acervulina (105 ), E. maxima (3x102 ) y E. tenella (104 ). Al final del estudio se obtuvo un peso vivo promedio de: 2650.4, 2431.6 y 2111.6 g; ganancia acumulada de peso: 2604.1, 2384.0 y 2063.8 g; ganancia diaria de peso: 63.1, 57.9 y 50.3 g; conversión alimenticia: 1.53, 1.61 y 1.65; índice de eficiencia productiva: 408.67, 355.94 y 282.00; para G1, G2 y G3 respectivamente. Todos los valores con diferencia estadística significativa. Se concluye que la combinación anticoccidial (salinomicina/nicarbazina) fue eficaz en el control de la coccidiosis al evaluar los parámetros productivos de pollos de engorde criados hasta los 42 días de edad. / Tesis
45

Use of Nutrition and Precision Technology to Improve Health, Performance, and Alleviate Stress of Beef Cattle

Pancini, Stefania 14 June 2023 (has links)
Concerns about beef production are growing among consumers, questioning the use of antibiotics, hormones, and metaphylactic treatments, as well as its environmental footprint. Therefore, beef production systems need to be more efficient to increase productivity while using less resources to become sustainable and reduce environmental impact. There is a need to develop and apply non-pharmaceutical alternatives to improve health, feed efficiency and performance of beef cattle. We investigated four different targeted strategies to enhance performance of beef cattle: 1) The effect of an injectable multi-mineral complex supplementation for grazing beef cows on overall mineral status, fertility, and subsequent offspring performance. Two doses of the trace mineral injection increased in pregnancy rate after artificial insemination, with a greater impact on cows with poor body condition score; 2) Inclusion of a yeast-derived product combining live yeast (probiotics) and cell wall components (prebiotics), on performance and physiological responses of beef steers during backgrounding and finishing phases. Including a yeast-derived product into a finishing diet containing monensin did not improve performance, physiological responses, and carcass quality of feedlot cattle. Nonetheless, inclusion of the yeast derived product as a substitute of monensin during the backgrounding and finishing phases decreased feed intake without affecting growth, with an overall improvement in feed efficiency; 3) Use of phytotherapy (condensed tannins) to reduce protozoa parasites load and prevent coccidiosis in peripartum beef heifers and their newborn calves. Daily supplementation of condensed tannins reduced coccidia load in heifers and newborn calves, although this reduction was transient; and 4) following the smart farming approach, validate the use of an automated scale system for grazing or feedlot beef cattle, which was able to accurately measures body weight in grazing and feedlot systems for growing and mature beef cattle while reducing cattle handling, without disrupting feeding behavior, decreasing the probability of animal lesions, accidents and optimizing labor. / Doctor of Philosophy / Diet diversification is a response of a growing economy, growing population, and urbanization, which increases the demand of meat products, especially beef, in substitution of staple foods. However, concerns around beef production and its impact on the environment are becoming more relevant for consumers. The need to produce more with less resources requires a sustainable intensification process. Specifically, beef cattle production systems are less efficient when compared to poultry or swine in terms of time and amount of feed required. Beef production systems need to focus on environmental and socially conscious strategies to satisfy the demand, increase animal health, productivity, and profitability. One approach is based on nutritional strategies and applied technologies to enhance productivity, efficiency, welfare, and health. In this dissertation we present three different strategies to improve efficiency of beef production systems: 1) using injectable trace minerals supplementation to ensure adequate mineral nutrition in grazing cows, improving their pregnancy rate to artificial insemination, particularly when cows are in poor body condition; 2) use of yeast as natural additives to successfully substitute antibiotics as growth promotants in feedlot diets with an improvement in feed efficiency; 3) use of secondary plant compounds, such as tannins, to substitute prophylactic antibiotic utilization for coccidiosis in cows and newborn calves. We demonstrate three successful strategies that can improve health, feed efficiency and reproductive performance of beef cattle, all of which are important to achieve greater productivity and profitability in beef production systems.
46

Effects of the in ovo injection of vitamin D3 sources on the hatchability, performance, breast meat yield, small intestine morphology, and immunity of Ross 708 broilers subjected to dietary insufficiency and pathogenic agents

Fatemi, Seyed Abolghasem 13 December 2019 (has links)
Effects of varying dosages (0.6 to 4.8 μg/egg) of vitamin D3 (D3) and 25-hydroxycholecalciferol (25OHD3), administrated by in ovo (amniotic) injection, on various embryonic and post-hatch physiological variables in Ross 708 broilers were investigated. The in ovo injection of 1.2 to 4.8 μg of both D3 and 25OHD3 increased serum 25OHD3 concentrations in broiler embryos in comparison to non-injected and diluent-injected control groups. Furthermore, the effects of 2.4 μg of D3 and 25OHD3 alone and in combination on the performance, meat yield and quality, small intestine morphology, and immunity of the broilers fed a diet restricted in calcium and phosphorous (ReCaP) content by 20% throughout grow out, period were investigated. In comparison to the in ovo injection of diluent or the combination of D3 and 25OHD3, the in ovo injection of 2.4 μg of 25OHD3 increased breast meat yield at 14 and 40 days of age (doa). In addition, Serum IgM increased in response to the in ovo injection of 25OHD3 at 14 doa. Furthermore, increases in villus length VL to crypt depth ratio (RVC) at both 14 and 40 doa in response to the injection of 25OHD3 alone were observed. The improvements in these observed factors may be due to an improvement in small intestine morphology in response to the in ovo injection of 25OHD3 alone. Lastly, the effects of 2.4 μg of D3 and 25OHD3 alone or in combination on the performance, meat yield and quality, small intestine morphology, and immunity of Ross 708 broilers after being subjected to a coccidiosis challenge at 14 doa were investigated. The in ovo injection of 25OHD3 alone increased broiler BW gain from 29 to 41 doa in comparison to those injected with diluent or D3 alone. Furthermore, the RVC of birds increased before and 2 weeks after a coccidiosis challenge when in ovo-injected with 25OHD3 alone in comparison to being injected with diluent or D3 alone. These results indicate that 25OHD3 alone may improve small intestine morphology, growth performance, and increase meat yield and antibody production of broilers subjected to a coccidiosis infection.
47

In vivo evaluation of riboflavin and Bacillus Subtilis on growth performance and intestinal health of male broilers challenged with coccidiosis

Poudel, Sabin 07 August 2020 (has links)
The effects of supplementation of riboflavin along with Bacillus subtilis was investigated on growth performance and intestinal health of broilers under coccidial challenge. Treatments are 3 × 2 × 2 factorial arrangement, which includes 3 levels of riboflavin (0.75, 6.6 (recommended), and 20 ppm), with or without Bacillus subtilis, and with or without coccidial challenge. Coccidial challenge impaired the intestinal morphology and reduced body weight (BW), body weight gain (BWG), and feed intake and increased FCR between d 14-28. However, the cocci impact on birds was reduced along with age, as the effects on internal organs was reduced, which allowed birds to recover. However, coccidiosis reduced overall BW and BWG and increased abdominal fat pad weight and slight woody breast incidence. In conclusion, riboflavin at tested level was unable to enhance growth performance and intestinal health, but its inclusion altered birds response to coccidial challege other than feeding Bacillus subtlis alone.
48

Effects of Whole Yeast Cell Product Supplementation in Chickens Post-coccidial and Post-Salmonella Challenge

Markazi, Ashley 14 October 2015 (has links)
No description available.
49

A study of bovine coccidiosis

Morley, Leland Curtis January 1932 (has links)
no abstract provided by author / Master of Science
50

The effects of Bacillus subtilis, dietary calcium and coccidial vaccines in broilers experiencing naturally occurring necrotic enteritis

Calvert, Alamanda J. 03 June 2022 (has links)
Necrotic enteritis (NE) is a disease that negatively affects broiler performance and has increasingly become a problem with the reduced use of antibiotics. There is increased interest to utilize alternative methods including coccidial vaccines and direct fed microbials (DFM) to reduce or prevent NE. Additionally, it has been demonstrated that reduced dietary Ca can reduce NE mortality. The objective of the first study was to examine the effects of Bacillus subtilis (DFM) in combination with attenuated (AV) and non-attenuated (NV) coccidial vaccines in broilers with NE. The objective of the second study was to determine the effects of DFM, antibiotic (BMD) or negative control (NC) with standard dietary Ca (0.9%) or below standard Ca (0.75%, 0.6%) in broilers with NE. To induce a natural NE occurrence, birds were vaccinated with the appropriate coccidial vaccine and then placed on reused litter from a previous flock exhibiting NE lesions and mortality. In the first trial DFM reduced BW and BW gain (P ≤ 0.05) during the starter phase (0 to 14 d). The addition of a DFM in the AV group resulted in decreased (P ≤ 0.05) BW gain and BW at 42 d. The DFM in the NV group resulted in improved (P ≤ 0.05) mortality corrected feed conversion ratio from 0 to 42 d. Overall, with a natural NE occurrence, the effect of DFM was variable depending on what type of coccidial preventative was utilized and was beneficial when used with NV. In the second trial BW and BW gain were increased in broilers fed 0.60% dietary Ca and DFM compared to 0.90% Ca and NC (P ≤ 0.05). Broilers fed 0.60% Ca had reduced NE mortality compared to broilers fed 0.90% Ca (P ≤ 0.05). Reducing dietary Ca to below industry standards was able to lessen the severity of NE though the addition of DFM was needed to improve BW. Overall, with a natural NE occurrence, the DFM was beneficial when used with NV and in diets with 0.6% dietary Ca. / Doctor of Philosophy / Necrotic enteritis (NE) is caused by the bacterium Clostridium perfringens and is a disease that reduces growth of broiler chicks and has increasingly become a problem in the chicken industry with the reduced use of antibiotics. Coccidiosis is a protozoal disease that causes intestinal damage and predisposes broilers to developing NE. Prevention of coccidiosis can be through medication or coccidial vaccines. Probiotics or direct fed microbials (DFM) have demonstrated the potential to reduce both coccidiosis and NE symptoms. Additionally, it has been shown that reducing the amount of calcium (Ca) in the diet can reduce chick death from NE. The first study examined the effects of a beneficial bacterium, Bacillus subtilis (DFM) in combination with two types of coccidial vaccines, attenuated (AV) and non-attenuated (NV). The second study investigated DFM with standard dietary Ca (0.9%) or below standard Ca levels (0.75%, 0.6%). To induce a "natural" NE disease occurrence, birds were vaccinated with the appropriate coccidial vaccine and then placed into pens. Pens contained reused litter from a previous flock of birds with NE (contained spores of Clostridium perfringens). In the first trial DFM reduced body weight of broilers during the first two weeks (P ≤ 0.05). The DFM decreased (P ≤ 0.05) BW gain and BW in the AV group but improved feed efficiency in the NV group (P ≤ 0.05). In the second trial BW and BW gain were increased in broilers fed DFM and lower Ca diets (0.6%) compared to those fed the standard (0.90%) Ca diets without DFM (P ≤ 0.05). Dead birds were reduced when broilers were fed lower Ca diets (0.6%) compared to broilers fed standard (0.90%) Ca diets (P ≤ 0.05). In conclusion, the DFM was beneficial when used with NV and in diets with lower Ca (0.6%) during a natural NE occurrence.

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