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排序方式: 共有304条查询结果,搜索用时 15 毫秒
181.
182.
Assessment of the economic impact of porcine reproductive and respiratory syndrome on swine production in the United States 总被引:5,自引:0,他引:5
Neumann EJ Kliebenstein JB Johnson CD Mabry JW Bush EJ Seitzinger AH Green AL Zimmerman JJ 《Journal of the American Veterinary Medical Association》2005,227(3):385-392
OBJECTIVE: To estimate the annual cost of infections attributable to porcine reproductive and respiratory syndrome (PRRS) virus to US swine producers. DESIGN: Economic analysis. SAMPLE POPULATION: Data on the health and productivity of PRRS-affected and PRRS-unaffected breeding herds and growing-pig populations were collected from a convenience sample of swine farms in the midwestern United States. PROCEDURE: Health and productivity variables of PRRS-affected and PRRS-unaffected swine farms were analyzed to estimate the impact of PRRS on specific farms. National estimates of PRRS incidence were then used to determine the annual economic impact of PRRS on US swine producers. RESULTS: PRRS affected breeding herds and growing-pig populations as measured by a decrease in reproductive health, an increase in deaths, and reductions in the rate and efficiency of growth. Total annual economic impact of these effects on US swine producers was estimated at dollar 66.75 million in breeding herds and dollar 493.57 million in growing-pig populations. CONCLUSIONS AND CLINICAL RELEVANCE: PRRS imposes a substantial financial burden on US swine producers and causes approximately dollar 560.32 million in losses each year. By comparison, prior to eradication, annual losses attributable to classical swine fever (hog cholera) and pseudorabies were estimated at dollar 364.09 million and dollar 36.27 million, respectively (adjusted on the basis of year 2004 dollars). Current PRRS control strategies are not predictably successful; thus, PRRS-associated losses will continue into the future. Research to improve our understanding of ecologic and epidemiologic characteristics of the PRRS virus and technologic advances (vaccines and diagnostic tests) to prevent clinical effects are warranted. 相似文献
183.
Nine generations of selection for high ovulation rate were followed by two generations of random selection and then eight generations of selection for increased litter size at birth, decreased age at puberty, or continued random selection in the high ovulation rate line. A control line was maintained with random selection. Line means were regressed on generation number and on cumulative selection differentials to estimate responses to selection and realized heritabilities. Genetic parameters also were estimated by mixed-model procedures, and genetic trends were estimated with an animal model. Response to selection for ovulation rate was about 3.7 eggs. Response in litter size to selection for ovulation rate was .089 +/- .058 pigs per generation. Average differences between the high ovulation rate and control lines over generations 10 to 20 were 2.86 corpora lutea and .74 pigs (P less than .05). The regression estimate of total response to selection for litter size was 1.06 pigs per litter (P less than .01), and the realized heritability was .15 +/- .05. When the animal model was used, the estimate of response was .48 pigs per litter. Total response in litter size to selection for ovulation rate and then litter size was estimated to be 1.8 and 1.4 pigs by the two methods. Total response to selection for decreased age at puberty was estimated to be -15.7 d (P less than .01) when data were analyzed by regression (realized heritability of .25 +/- .05) and -17.1 d using the animal model. No changes in litter size occurred in the line selected for decreased age at puberty. Analyses by regression methods and mixed-model procedures gave similar estimates of responses and very similar estimates of heritabilities. 相似文献
184.
Zimmerman AD Boots RE Valli JL Chase CC 《Journal of the American Veterinary Medical Association》2006,228(11):1757-1761
OBJECTIVE: To evaluate the efficacy of an adjuvanted modified-live bovine viral diarrhea virus (BVDV) vaccine against challenge with a virulent type 2 BVDV strain in calves with or without maternal antibodies against the virus. DESIGN: Challenge study. ANIMALS: 23 crossbred dairy calves. PROCEDURES: Calves were fed colostrum containing antibodies against BVDV or colostrum without anti-BVDV antibodies within 6 hours of birth and again 8 to 12 hours after the first feeding. Calves were vaccinated with a commercial modified-live virus combination vaccine or a sham vaccine at approximately 5 weeks of age and challenged with virulent type 2 BVDV 3.5 months after vaccination. Clinical signs of BVDV infection, development of viremia, and variation in WBC counts were recorded for 14 days after challenge exposure. RESULTS: Calves that received colostrum free of anti-BVDV antibodies and were vaccinated with the sham vaccine developed severe disease (4 of the 7 calves died or were euthanatized). Calves that received colostrum free of anti-BVDV antibodies and were vaccinated and calves that received colostrum with anti-BVDV antibodies and were vaccinated developed only mild or no clinical signs of disease. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the modified-live virus vaccine induced a strong protective immune response in young calves, even when plasma concentrations of maternal antibody were high. In addition, all vaccinated calves were protected against viral shedding, whereas control calves vaccinated with the sham vaccine shed virus for an extended period of time. 相似文献
185.
Patel JM Rosypal AC Zimmerman KL Monroe WE Sriranganathan N Zajac AM Yabsley MJ Lindsay DS 《Veterinary parasitology》2012,187(3-4):394-398
Trypanosoma cruzi was demonstrated in blood smears and heart tissue from a 5-year old, female, English Cocker Spaniel that had never been outside of the state of Virginia, USA. Plasma from the dog was positive in a commercially available immunochromatographic dipstick assay for T. cruzi and negative in an immunochromatographic dipstick assay for visceral Leishmania spp. The plasma from the dog had an indirect immunofluorescent antibody titer of 1:800 against epimastigotes of T. cruzi while the titer was 1:50 against promastigotes of L. infantum. The parasite was isolated from the blood in vitro from the dog (TcVT-1 isolate) and used to experimentally infect female C3H and ICR mice. The parasite was nonpathogenic for experimentally inoculated mice. DNA was isolated from parasites grown in vitro and used to determine that the genotype of T. cruzi present in the dog was genotype TcIV. This genotype is common in raccoons, Procyon lotor, in North America and suggests that raccoons may serve as reservoirs for canine infection. 相似文献
186.
Ramirez A Wang C Prickett JR Pogranichniy R Yoon KJ Main R Johnson JK Rademacher C Hoogland M Hoffmann P Kurtz A Kurtz E Zimmerman J 《Preventive veterinary medicine》2012,104(3-4):292-300
Currently virus surveillance in swine herds is constrained by the cost-effectiveness and efficiency of sampling methods. The objective of this study was to assess the value of using oral fluids collected by barn personnel as a method of surveillance based on PCR testing. Approximately 12,150 pigs in 10 wean-to-finish barns on 10 farms were monitored for the presence of porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Torque teno virus genogroups 1 (TTV1) and 2 (TTV2) by sampling oral fluid specimens. Oral fluid samples were collected from 6 pens at each site starting at the time of pig placement (~3 weeks of age) and continuing thereafter at 2-week intervals for a period of 18 weeks. Data were analyzed both on a pen basis and barn basis. Overall, 508 (85%) samples were positive for PCV2, 73 (12%) for PRRSV, 46 (8%) for IAV, 483 (81%) for TTV2, and 155 (26%) for TTV1 during the study period. The estimated arithmetic means of the quantitative PCR-positive oral fluids for PCV2, PRRSV, and IAV were 1×10(4.62), 1×10(4.97), and 1×10(5.49)per ml. With a single exception, all barns were positive for PCV2 and TTV2 at every sampling point in the study. Virus detection varied among barns, particularly for IAV and PRRSV. The pen level, cumulative distribution of agent combinations between all 10 barns were statistically different. The most commonly observed patterns were PCV2+TTV2 (239 pen samples, 40%), PCV2+TTV1+TTV2 (88 pen samples, 15%), and PCV2 alone (66 pen samples, 11%). This "proof-of-concept" project showed that a variety of viruses could be detected either intermittently or continuously in pig populations and demonstrated that barn herd virus status is highly variable, even among barns in the same production system. Oral fluid sampling is a promising approach for increasing the efficiency and cost effectiveness of virus surveillance in swine herds. 相似文献
187.
Reasons for performing study: There has been no objective study comparing radiological features of spinous processes (SPs) in the thoracolumbar region and/or scintigraphic findings with clinical signs. Objectives: To investigate the relationship between the presence or absence of clinical signs of back pain and: 1) radiological findings of close, impinging or overriding SPs; 2) increased radiopharmaceutical uptake (IRU) in the SPs; and 3) the combination of radiological findings and IRU. Also to determine the prevalence of concurrent osseous pathology. Methods: Five‐hundred and eighty‐two horses, presented for perceived back pain and poor performance, underwent comprehensive clinical investigation including diagnostic analgesia of the forelimbs, hindlimbs, back and sacroiliac joints, and radiographic and scintigraphic evaluation of the thoracolumbar spine. Radiological and scintigraphic grades were determined subjectively. Statistical analysis was performed to determine the relationships between clinical signs of back pain, radiological and scintigraphic features, age, breed, gender, discipline, height and weight. Results: Thoroughbreds (TBs) were over‐represented with thoracolumbar pain compared with Warmbloods and TB cross breeds. There was a significant association between maximum and total radiological grades of the SPs and thoracolumbar pain, between maximum and total grades of IRU and thoracolumbar pain, and between a combination of radiological and scintigraphic abnormalities and thoracolumbar pain. Horses with osteoarthritis (OA) of the synovial intervertebral articulations (SIAs) were more likely to have thoracolumbar pain than horses with lesions of the SPs alone, but the presence of OA of the SIAs and lesions of the SPs was associated with the highest likelihood of thoracolumbar pain. Conclusions and potential relevance: Fore‐ or hindlimb lameness and/or pain associated with the sacroiliac joints could mimic primary thoracolumbar pain. A combination of radiology and scintigraphy gives the most accurate prediction of thoracolumbar pain, but diagnostic analgesia is crucial for accurate diagnosis. 相似文献
188.
Wills C Harms KE Condit R King D Thompson J He F Muller-Landau HC Ashton P Losos E Comita L Hubbell S Lafrankie J Bunyavejchewin S Dattaraja HS Davies S Esufali S Foster R Gunatilleke N Gunatilleke S Hall P Itoh A John R Kiratiprayoon S de Lao SL Massa M Nath C Noor MN Kassim AR Sukumar R Suresh HS Sun IF Tan S Yamakura T Zimmerman J 《Science (New York, N.Y.)》2006,311(5760):527-531
An ecological community's species diversity tends to erode through time as a result of stochastic extinction, competitive exclusion, and unstable host-enemy dynamics. This erosion of diversity can be prevented over the short term if recruits are highly diverse as a result of preferential recruitment of rare species or, alternatively, if rare species survive preferentially, which increases diversity as the ages of the individuals increase. Here, we present census data from seven New and Old World tropical forest dynamics plots that all show the latter pattern. Within local areas, the trees that survived were as a group more diverse than those that were recruited or those that died. The larger (and therefore on average older) survivors were more diverse within local areas than the smaller survivors. When species were rare in a local area, they had a higher survival rate than when they were common, resulting in enrichment for rare species and increasing diversity with age and size class in these complex ecosystems. 相似文献
189.
Reid K. Nakamura Sarah A. Zimmerman Ashley J. Lange Michael B. Lesser 《Journal of Veterinary Cardiology》2012,14(4):531-536
A 4-year-old male castrated Borzoi dog presented on referral for evaluation of pleural effusion, ventricular arrhythmias, and suspected dilated cardiomyopathy. Echocardiogram identified several masses along the chordae tendineae, as well as a long the annulus of the mitral valve. A blood culture was positive for methicillin resistant Staphylococcus lugdunensis. The dog was also positive for Bartonella DNA on PCR testing. Aggressive antibiotic therapy was instituted. However, the dog continued to have recurrent pleural effusion and progressive azotemia. The dog was euthanized 39 days after diagnosis. Necropsy confirmed the presence of intracardiac abscesses, thrombosis and endocarditis. S. lugdunensis is a recently identified rare cause of endocarditis in humans characterized by intracardiac abscess formation, highly destructive valvular lesions preferentially affecting the mitral valve and a high mortality rate. This is the first reported case of S. lugdunensis isolation in a dog with endocarditis. 相似文献
190.
S.D. Kemp K.L. Zimmerman D.L. Panciera W.E. Monroe M.S. Leib 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(1):58-62