Download or read book Seroprevalence Production Impacts Economics and Risk Factors of Mycobacterium Avium Subspecies Paratuberculosis in Canadian Dairy Cattle written by Ashwani Tiwari and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For the MAP-seropositive Canadian dairy herds, the mean loss per 61-cow herd was CD $2,992 (95% C. L, $143--$9741) annually, or CD $49 per cow per year. Herd additional culling losses were responsible for 46% (CD $1374) of the total losses from MAP. Decreased milk production, mortality and reproductive losses accounted for 9% (CD $254), 16% (CD $488) and 29% (CD $875) of the losses, respectively.
Download or read book Shedding of Mycobacterium Avium Subsp Paratuberculosis in Naturally Exposed Dairy Calves and Associated Risk Factors written by Michael William Bolton and published by . This book was released on 2009 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Paratuberculosis written by Marcel A. Behr and published by CABI. This book was released on 2020-09-24 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Paratuberculosis, also referred to as Johne's disease, affects principally cattle, goats, sheep, buffalo, deer and other ruminants. It is common worldwide and responsible for significant economic losses in the ruminant livestock industries. A timely follow up to the first book on Paratuberculosis, this new edition is still the only comprehensive text providing both historical context and the latest developments in the field. Examining the epidemiology of paratuberculosis, the organism that causes the disease, and practical aspects of its diagnosis and control, it also addresses the link between paratuberculosis in the food chain and human health implications, including Crohn's disease.
Download or read book Study of Prevalence Risk Factors and Lifetime Impacts of Infection with Bovine Leukemia Virus in the Canadian Dairy Industry written by Omid A. Nekouei and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall goal of the research described in this thesis was to lay a proper foundation for designing and conducting efficient control and eradication programs for infection with bovine leukemia virus (BLV) in the Canadian dairy industry. The objective in Chapter 2 was to identify potentially important risk factors for BLV infection in Canadian dairy herds. Of 272 study herds, from 8 provinces of Canada and tested during 1998-2003, 78% were BLV-positive. Over 15 management determinants for the infection were evaluated. Herds with clinical cases of leukosis during the 12 months prior to sampling, as well as herds which purchased animals with unknown BLV infection status in the last five years, had a significantly increased proportion of BLV-positive cows. Herds from eastern provinces and those not purchasing cows in the last five years were more likely to be free from BLV compared to western provinces and farms purchasing cows in the last five years. The objective in Chapter 3 was to determine the lifetime effects of BLV infection on milk production and longevity of dairy cows in Canada. Overall, 4052 cows from 348 herds were enrolled in a historical cohort study, based on test results from 1998-2003 and lactation and culling records post-testing until 2013. Positive cows to BLV had consistently greater probability of being culled (or dying) than the negative cows (over lifetime lactations 2-7). Only BLV-positive cows with short longevity (2 and 3 lifetime lactations) had a significantly lower lifetime milk production compared with their negative counterparts. As the cows lived longer (> 3 lactations), the difference in milk production between the two cohorts was no longer significant. The objectives of Chapter 4 were: 1) to assess the potential for carryover of antibodies against BLV in milk samples obtained from shared meters; and 2) to determine if adjustment of the diagnostic test cut-off value would improve the test characteristics for meter-collected milk ELISA results. The study included 236 paired milk samples from 8 dairy farms in Prince Edward Island collected in 2013. Two simultaneous milk samples, one hand-collected at the beginning of milking, and the other from the corresponding milk meter, were taken from all lactating cows that were milked at the selected meters. The sequence of cows using each meter was recorded. Carryover of BLV antibodies at shared milk meters was significant. For low-titer cows, the carryover effect was positively associated with the titer of the preceding cows. This could result in generating false-positive results in the BLV antibody-ELISA test on meter-collected samples from dairy herd improvement (DHI) procedures. Based on a new optimal cut-point, a suspicious category on the ELISA titers was defined, and a retest on the samples falling within this range was recommended to reduce the false positive rate. The objectives for Chapter 5 were: 1) to determine the prevalence of BLV infection at the herd level using a bulk-tank milk (BTM) antibody ELISA in the Maritime region of Canada ; and 2) to develop applied statistical models for predicting within-herd prevalence of BLV infection using the BTM antibody levels. To detect BLV infection and the antibody levels, a census was implemented on BTM samples from all dairy farms in the Maritime region in 2013 (3 monthly rounds of sampling on 623 farms). Another round of BTM sampling was coincided with individual cow sampling (all cows that contributed milk to the fourth BTM) in 90 selected herds. Herd-level prevalence of BLV in the Maritime region was 90.8%. In the individual testing, 30.4% of cows were positive. The statistical models developed in this study were able to predict true within-herd prevalence of BLV reasonably well based only on the BTM results. The model including all BTM tests (4 rounds of sampling) as the predictor had the best fit, although the models using 2 and 3 BTM tests provided similar results to 4 repeated tests. The focus for Chapter 6 was to assess the diagnostic performance of a commercially available ELISA for detecting BLV antibodies in BTM samples collected from dairy herds in Eastern Canada in 2013. Of 133 tested herds, 108 herds were found to be truly infected. At the resulting optimal cut-point, sensitivity and specificity of the BTM ELISA were estimated at 0.972 (0.921 - 0.994) and 1 (0.863 - 1), respectively. With the high prevalence of BLV infection across Canada and its detrimental economic impacts, pursuing broad-based control programs is necessary. All of the findings in the present research could contribute to designing and conducting efficient BLV control programs.
Download or read book Diagnosis and Control of Johne s Disease written by National Research Council and published by National Academies Press. This book was released on 2003-08-13 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Johne's Disease is a chronic, progressive intestinal disease caused by infection with Mycobacterium avium subspecies paratuberculosis (Map) that affects primarily ruminant animals. In recent decades there has been growing concern over the lack of effective control of this disease and questions have arisen regarding the possibility that Map infection could be a cause of some cases of Crohn's disease in humans. This report presents a broad outline of the steps that should be taken to control Johne's disease, reduce the spread of Map, and minimize effects of the disease in animals. The report also describes the weaknesses of our current research agenda and provides recommendations for a new research strategy to resolve the question of whether there is a link between Johne's and Crohn's diseases.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Epidemiology Detection and Milk Production Effects of Mycobacterium Avium Subspecies Paratuberculosis on California Dairies written by Sharif Shafik Aly and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Johne's disease is a granulomatous enteritis of cattle caused by Mycobacterium avium subsp. paratuberculosis (MAP). Interest in Johne's is promoted by reports of decreased milk production, however, most publications were cross-sectional. The longitudinal studies available lack an assessment of confounding and model the standard lactation curve rather than that expressed by each cow. For the first study, mixed models based on causal diagrams were used to estimate the association between MAP and milk production, using cow-specific splines. Compared to test-negative cows, MAP seropositive and shedding cows produced 2.5 and 2.2 Kg less of milk per day, respectively. Environmental sampling and pooled fecal culture were used to identify super-shedders, cows that shed MAP in tens of thousands per gram of feces. The objective was to estimate the cost-effectiveness of diagnostic strategies to identify super-shedders such as ranking pens on a dairy by MAP bioburden using environmental samples. Subsequently, cows in high MAP bioburden pens would be tested. Results of the second study found that the reliability of environmental sampling across collectors and over 5 days was excellent (81%) and good (67%), respectively. Due to routine moving of cows between pens for management purposes, pen rankings must be available within 2-3 days. The availability of quantitative real-time PCR (qrt-PCR) made it possible to quantify MAP in samples within days compared to weeks using culture. Results of the third study found good correlation between assays for pooled and environmental samples ( -0.66 and -0.76, respectively) and a non-linear association between results of both assays that differed in magnitude between fresh and thawed samples. A whole herd test was conducted including combinations of serum or milk ELISA, qrt-PCR or culture of environmental, individual or pooled fecal samples. Results of all the tests were used to simulate 15 diagnostic strategies to detect super-shedders on a large dairy and estimate their cost-effectiveness. A whole herd qrt-PCR survey sample was the most sensitive (80%) of all 15 strategies. The most cost-effective strategy was to rank milking pens by MAP bioburden, ELISA test milk of cows in high MAP bioburden pens, followed by qrt-PCR testing of ELISA positive cows.
Download or read book Control Strategies for Johne s Disease in Dairy Cattle written by Roxanne Bee Pillars and published by . This book was released on 2008 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Johne s Disease paratuberculosis written by Leonard Russell Stephens and published by . This book was released on 1986 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Mycobacterium Avium Subsp Paratuberculosis in Dairy Herds written by Annabelle Beaver and published by . This book was released on 2017 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Johne’s disease, a severe granulomatous enteritis of ruminant animals, is caused by Mycobacterium avium subsp. paratuberculosis (MAP). MAP infections have detrimental consequences for animal health and reduce dairy-herd productivity. Bacterial fastidiousness and slow generation time encumber diagnostic testing strategies. MAP is also a potential etiologic agent of human Crohn’s disease, with the bulk-milk supply serving as a possible transmission vector. The objective of this dissertation is to explore MAP infection dynamics on dairy farms, with an emphasis on the routes of bulk-milk contamination, transmission risk across production type, and the interplay between diagnostic testing outcomes. Accordingly, we have applied statistical and mathematical approaches to both cross-sectional and longitudinal datasets. Using questionnaire data from 292 U.S. dairies, we conducted a comparative risk assessment of organic vs. conventional management and determined that organic herds were at higher risk for new MAP infections. We concluded, empirically, that organic farms were more susceptible to a synergism of risk factors within the maternity pen and should improve calving-area hygiene if electing to permit cow-calf contact. Bulk-milk testing was also conducted for these herds. Most high ELISA tanks were PCR negative, implying that ELISA is not a perfect predictor of bulk-milk MAP status; for accurate risk assessment, bulk-milk ELISA should be used in tandem with PCR. A combination of ELISA and PCR may also aid in determining the specific route of bulk-milk contamination (either environmental or direct shedding). To extend the investigation to individual animals, longitudinal data were obtained from 14 MAP-positive cows in 2 low-prevalence herds. Robust relationships between culture, fecal qPCR, and milk ELISA were revealed, using mixed linear modeling to adjust for cow characteristics. We explored temporal relationships and observed that spikes in fecal shedding were predictive of subsequent high milk ELISA results. We also noted that disease “Progressors,” (infected animals with increasing fecal MAP CFU over time) had higher antibody titers overall. Interestingly, the paucity of positive milk samples, from both individual and bulk- tank sources, suggests that milk contamination is not a chief concern in low-prevalence herds. Armed with insights from these studies, in addition to published literature, we developed a mathematical model to explore the interaction between categories of infection, environmental MAP burden, and bulk-tank contamination. Direct shedding into milk accounted for
Download or read book Genetic Epidemiology and Familial Risk Factors for Paratuberculosis Seropositivity in Beef Cattle written by Jason Barrett Osterstock and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Paratuberculosis is an intestinal infection of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). Genetic associations with paratuberculosis have been described in Holstein cattle. The objectives were to describe the association between paratuberculosis status of the dam and her offspring in beef cattle, develop methods to assess familial aggregation of paratuberculosis in cattle of unknown pedigree, and model the paratuberculosis status of beef cattle given familial and herdlevel covariates. Texas beef cattle were tested for paratuberculosis using serum antibody and microbiologic culture of feces. Available pedigree data were used to confirm familial relationships. The association between the paratuberculosis ELISA status of the dam and her offspring was assessed using mixed-effects models. Increased odds of being classified as a "suspect" or greater based on ELISA results were observed if the dam was classified as a "suspect" or greater. A positive linear association was observed between the ELISA value of the dam and her offspring. Analysis of pedigree data using conditional logistic regression identified ancestors associated with significantly increased odds of being classified as "low positive" or greater. Microsatellite markers were used to classify cattle into genetically similar groups using allele frequency data. Nine clusters of genetically similar cattle were identified among paratuberculosis test positive cattle, herd matched controls, and pedigreed cattle. Clusters were validated using animals of known pedigree. Increased odds of paratuberculosis seropositivity were observed for some clusters compared to the cluster with the lowest seroprevalence. A predictive model was developed using a Bayesian framework to assess the association between antibody status of the dam and her offspring adjusted for herd-level risk factors. Predictors associated with highly probable increased odds of seropositivity included herd seroprevalence and herd fecal prevalence of MAP. The association between dam and offspring ELISA status was small (OR 1.35) and not highly probable. The results of this work support familial aggregation of paratuberculosis ELISA status, but herd-level risk factors appear to be more important in predicting ELISA status. A large proportion of observed serological reactions were not supported by fecal culture results; therefore, observed associations might be limited to humoral responses to Mycobacterium spp.
Download or read book Epidemiologic Investigations of Mycobacterium Avium Subspecies Paratuberculosis Infections in Ohio Dairy Herds written by Alecia Larew Naugle and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The development of effective control programs for Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease, requires a complete understanding of the epidemiology of this agent in animal populations. The research described herein addresses several aspects of the epidemiology of this infection in dairy cattle. Fecal culture and ELISA results collected from nine Ohio dairy herds involved in Johne's disease testing programs are described, and likelihood ratios for multiple levels of ELISA S/P ratios are calculated using these test records. The likelihood ratios calculated here suggest that the quantitative use of ELISA S/P ratios to predict the infection status of an individual cow from a MAP-infected dairy herd provides the most confidence when S/P ratios are considerably higher than the manufacturer's recommended cut-off value. A prospective study of 55 Ohio dairy herds evaluated the relationships between farm management practices, milk production parameters and fecal cortisol levels. The influence of herd MAP-infection status on fecal cortisol levels was also assessed. Herd, management groups within herds and time of sample collection appear to significantly influence fecal cortisol levels; however, few specific management practices or milk production parameters that consistently influence these values were identified. Production data for individual dairy cows were matched with results for MAP tests in order to compare testday production parameters between cows that were test-positive relative to those that were test-negative for both the ELISA and fecal culture. On a given testday, significant losses in milk production were identified for both fecal culture and ELISA-positive cows relative to test-negative cows. These observations provide additional information for dairy producers to consider as they make culling decisions regarding MAP test-positive cows. Finally, a mail survey comparing the adoption of management practices recommended for Johne's disease control between Ohio dairy herds involved in testing programs relative to those herds that were not testing is described. Results of this survey demonstrate that, even if a producer believed his/her herd was not infected, participation in a testing program was associated with the adoption of management practices recommended for Johne's disease control.
Download or read book Large Animal Internal Medicine E Book written by Bradford P. Smith and published by Elsevier Health Sciences. This book was released on 2008-06-02 with total page 2920 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large Animal Internal Medicine, 4th Edition features a problem-based approach with discussions of over 150 clinical signs. This is the first internal medicine reference that enables you to efficiently diagnose horses, cattle, sheep, and goats based on clinical observation and laboratory and diagnostic testing. With this user-friendly format, you can find essential information about specific diseases and reach a diagnosis by simply identifying the signs. A unique problem-based approach with discussions of over 150 clinical signs and manifestations helps you quickly reach a diagnosis based on observations and laboratory tests. Causes of Presenting Signs boxes provide easy access to complete lists of common, less common, and uncommon diseases associated with manifestations or signs of disease. Complete lists of diseases associated with a given lab abnormality in Causes of Abnormal Laboratory Values boxes help you easily interpret abnormalities in clinical chemistry, hematology, blood proteins, and clotting tests. An expert team of over 180 authors contributing information in their areas of expertise ensures you are using the most accurate and up-to-date information available. Color plates accompanying Diseases of the Eye and Diseases of the Alimentary Tract enable you to visually recognize the clinical appearance of ophthalmologic conditions and alimentary tract disorders for quick and easy diagnosis and treatment. Six all-new chapters provide in-depth coverage of diagnostic testing, critical care and fluid therapy, biosecurity and infection control, and genetic disorders.
Download or read book Johne s Disease written by AR Milner and published by CSIRO PUBLISHING. This book was released on 1989 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Johne's disease (paratuberculosis) afflicts cattle worldwide and causes significant economic losses. It is also prevalent in goats and sheep and has been implicated in Johne's disease in humans. The book is divided into six sections covering all aspects of the prevalence, management, diagnosis, control and research on Johne's disease. ]ohne's disease is an international animal health problem, and is of particular importance in the southern States of Australia, especially in the major dairy areas of Victoria where approximately 10% of dairy herds are infected.
Download or read book Public Health Significance of Urban Pests written by Xavier Bonnefoy and published by World Health Organization. This book was released on 2008 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second half of the 20th century and the beginning of the 21st century witnessed important changes in ecology, climate and human behaviour that favoured the development of urban pests. Most alarmingly, urban planners now face the dramatic expansion of urban sprawl, in which city suburbs are growing into the natural habitats of ticks, rodents and other pests. Also, many city managers now erroneously assume that pest-borne diseases are relics of the past. All these changes make timely a new analysis of the direct and indirect effects of present-day urban pests on health. Such an analysis should lead to the development of strategies to manage them and reduce the risk of exposure. To this end, WHO invited international experts in various fields - pests, pest-related diseases and pest management - to provide evidence on which to base policies. These experts identified the public health risk posed by various pests and appropriate measures to prevent and control them. This book presents their conclusions and formulates policy options for all levels of decision-making to manage pests and pest-related diseases in the future. [Ed.]
Download or read book Textbook of Rabbit Medicine E Book written by Molly Varga and published by Elsevier Health Sciences. This book was released on 2013-08-19 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Textbook of Rabbit Medicine second edition is the completely revised and updated new edition of Frances Harcourt Brown’s acclaimed text covering all aspects of rabbit medicine. While the authoritative and evidence-based approach that made the original book so successful has been retained, in this new second edition well-known rabbit expert Molly Varga adds a stronger clinical focus that makes the Textbook invaluable as a point-of-care resource as well as a respected reference. With many additional features introduced for this update, the Textbook of Rabbit Medicine second edition remains the definitive and comprehensive reference of choice for all veterinary practitioners seeking information on the pet rabbit. Comprehensive, in-depth and authoritative coverage of the health and diseases of the domestic rabbit Detailed and explicit line artwork provides a clear understanding of physiological processes A practical, evidence-based resource for the effective treatment of pet rabbits. Entire text reviewed and updated by a leading expert, with major revision of therapeutics, anaesthesia, abscesses and neurology chapters. New clinical emphasis with clinical tips boxes throughout the text increase its practical focus Ancillary website presents clips of key procedures, an image library and podcasts Completely redesigned with more user-friendly text layout and full colour throughout. Many more illustrations specially commissioned for this edition
Download or read book Bovine Reproduction written by Richard M. Hopper and published by John Wiley & Sons. This book was released on 2014-08-18 with total page 2206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bovine Reproduction is a comprehensive, current reference providing information on all aspects of reproduction in the bull and cow. Offering fundamental knowledge on evaluating and restoring fertility in the bovine patient, the book also places information in the context of herd health where appropriate for a truly global view of bovine theriogenology. Printed in full color throughout, the book includes 83 chapters and more than 550 images, making it the most exhaustive reference available on this topic. Each section covers anatomy and physiology, breeding management, and reproductive surgery, as well as obstetrics and pregnancy wastage in the cow. Bovine Reproduction is a welcome resource for bovine practitioners, theriogenologists, and animal scientists, as well as veterinary students and residents with an interest in the cow.
