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  • Author or Editor: M. D. Salman x
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Abstract

Objectives—To assess the sensitivity of the current surveillance program used in Denmark for detecting outbreaks of infectious bovine rhinotracheitis (IBR) at the herd level and to evaluate the impact of alternative sample collection strategies on the sensitivity of the system in an acceptable time frame.

Sample Population—Data from the Danish Central Husbandry Register on cattle of 24,355 and 25,233 beef herds and on 13,034 and 12,003 dairy herds in the years 2000 and 2001, respectively.

Procedures—Surveillance programs were evaluated under current sample collection conditions and under 3 alternative scenarios by use of simulation modeling. Data from the current detection component of the surveillance system were used as input, taking into consideration the sensitivity and specificity of bulktank milk and serologic testing.

Results—The current system identifies infected dairy herds within a 3-month period with desired accuracy largely because of the test characteristics and number of bulk-tank milk samples. The system is less likely to detect infected beef herds in a timely manner because surveillance in beef herds depends solely on serologic testing at the time of slaughter. The efficiency of surveillance in dairy cattle herds was not decreased substantially when the slaughter-surveillance component was omitted.

Conclusions and Clinical Relevance—Geographically targeted sample collection during the high-risk season (winter) was predicted to increase the probability of rapid detection of IBR infection in cattle. This approach can be used for assessing other surveillance systems to determine the best strategies for detection of infected herds. (Am J Vet Res 2005;66:2149–2153)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the proportion of adult cattle that change test status when an ELISA for antibodies against Mycobacterium avium subsp paratuberculosis (MAP) is used to assay samples collected twice at variable intervals and to determine whether cows with an initial strong positive result were more likely to maintain positive status, compared with all cows with an initial positive result.

Design—Cross-sectional observational study.

Animals—3,757 adult dairy cattle.

Procedure—Serum samples were obtained twice from cattle at intervals ranging from 77 to 600 days between collections. Samples were tested with an ELISA for detection of antibodies to MAP.

Results—Of 157 cattle with initial positive results (value for the sample divided by the value for positivecontrol serum [S/P] ≥ 0.25), 62 (39.5%) had negative results for the second sample. Of 71 cattle with an initial S/P value ≥ 0.40, 13 (18.3%) had a negative result (S/P < 0.25) for the second sample. Of 33 cattle with an initial S/P ≥ 0.70, 3 (9.1%) had a negative result (S/P value < 0.25) for the second sample. Interval between collection of samples did not affect results.

Conclusions and Clinical Relevance—Many cows changed ELISA status between samples collected at variable intervals. Cows with an initial high S/P value (≥ 0.70) were more likely to maintain positive status than cows classified as positive on the basis of cutoff values of ≥ 0.25 or ≥ 0.40. Veterinarians should expect variability in ELISA results when repeated testing of cattle is used as part of an MAP control program. (J Am Vet Med Assoc 2002;220:1685–1689)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether logarithmic and polynomial models are superior to simple linear models for predicting reference values for M-mode echocardiographic variables in dogs with a wide range of body weights.

Animals—69 apparently healthy adult male and female dogs of various breeds, ages (range, 1 to 12 years; median, 3.5 years), and body weights (range, 3.9 to 97.7 kg; median, 25.4 kg).

Procedure—Echocardiographic M-mode measurements of the interventricular septum, left ventricular dimension (LVD), left ventricular wall, aorta, and left atrium were obtained. Simple linear, second-order polynomial, third-order polynomial, and logarithmic regression models were determined by use of the least-squares method to describe the relationship between M-mode measurements and body weight. Differences in adjusted R 2 values of logarithmic and polynomial models were tested for significance of contribution, compared with the simple linear model.

Results—Significant differences in adjusted R2 were found when comparing simple linear with logarithmic or polynomial models for LVD-diastole, LVD-systole, aorta, and left atrium. Differences in adjusted R2 between second-order polynomial, third-order polynomial, and logarithmic models were not significant for any M-mode measurement.

Conclusions and Clinical Relevance—In this study, logarithmic or second-order polynomial models predicted reference values of M-mode measurements for size of the cardiac chambers better than simple linear models for dogs with a wide range of body weights. Logarithmic and polynomial models were not superior to simple linear models for M-mode measurements of cardiac wall thickness. (Am J Vet Res 2002;63:994–999)

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in American Journal of Veterinary Research

Abstract

Objective—To determine testing protocols used by board-certified internists and dermatologists for diagnosis of hyperadrenocorticism (HAC) in dogs.

Design—Survey.

Study Population—Board-certified internists and dermatologists.

Procedure—A questionnaire was mailed to 501 specialists to gather information pertaining to diagnosis of HAC.

Results—206 surveys were returned. Only 26% of respondents indicated they would screen a dog for HAC if the dog had only a few laboratory abnormalities consistent with HAC and no clinical signs consistent with the disease; 31% indicated they would not, and 43% indicated they would sometimes. Overall, 55% of respondents indicated they preferred to use the lowdose dexamethasone suppression test for routine screening of dogs suspected to have HAC. However, many respondents indicated they would use a different screening test than usual in particular circumstances. Sixty-eight percent of respondents indicated they would perform a second screening test for confirmation if results of an initial screening test were positive but there were few clinical or laboratory abnormalities consistent with HAC. Most respondents used some sort of test to differentiate pituitary-dependent HAC from HAC secondary to an adrenal tumor (AT), but no 1 test was clearly preferred. Ultrasonography was commonly used, whereas computed tomography and magnetic resonance imaging were not, even if available.

Conclusions and Clinical Relevance—Results suggest that the low-dose dexamethasone suppression test is the test most commonly used to screen dogs for HAC but that other tests may be used in certain circumstances. A variety of tests were used to differentiate pituitary-dependent HAC from HAC secondary to an AT. (J Am Vet Med Assoc 2002;220:1643–1649)

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in Journal of the American Veterinary Medical Association

Food security is fundamental to human existence, and ensuring global food security is one of the transformative issues of our time. Veterinary academia has a responsibility to respond to this urgent, complex, and daunting challenge, especially because solutions will not be realized without the active engagement of the developed world's veterinary medical profession and the modernization of public and private veterinary services throughout the developing world.

A recent report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services 1 warns that the world's land and water resources are being exploited at unprecedented rates and that this exploitation, combined

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in Journal of the American Veterinary Medical Association

Abstract

Objectives—To determine epidemiologic factors associated with tuberculosis (TB) in dairy cattle slaughtered in 6 important regions for milk production in Mexico.

Animals—2,500 cattle.

Procedure—Tissue specimens with lesions typical of TB were obtained during routine inspection of carcasses at abbatoirs between July 1996 and January 1997. Infection with Mycobacterium organisms was confirmed by histologic examination and bacteriologic culture. Species identification was made by use of selective growth medium, conventional biochemical tests, and radiometric procedures. Epidemiologic information for affected cattle was obtained by personal interviews with cattle dealers and owners.

Results—400 (16%) of 2,500 cattle carcasses had gross lesions typical of TB. Of the 400 infected cattle, 336 (84%) had lesions in ≥ 1 lymph node. Infection was confirmed in 87% of cattle with gross lesions by histologic examination, in 77% by bacteriologic culture at a laboratory in the United States, and in 59% by bacteriologic culture at a laboratory in Mexico. Most cattle were adult females in fair to good body condition that came from large herds (> 500 cattle) and were not included in the Mexican TB control program.

Conclusions and Clinical Relevance—Mean prevalence of lesions typical of TB in dairy cattle at 6 locations in Mexico was 16%. Mycobacterium infection was confirmed by various techniques in most lesions. Recognition of typical gross lesions at slaughter may expedite TB control procedures. (Am J Vet Res 2000; 61:86–89)

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in American Journal of Veterinary Research
in American Journal of Veterinary Research

Abstract

Objective—To evaluate effects of one-lung ventilation on oxygen delivery in anesthetized dogs with an open thoracic cavity.

Animals—8 clinically normal adult Walker Hound dogs.

Procedure—Each dog was anesthetized and subjected to one-lung ventilation during a period when it had an open thoracic cavity. A Swan-Ganz catheter was used to measure hemodynamic variables and obtain mixed-venous blood samples. A catheter was inserted in the dorsal pedal artery to measure arterial pressure and obtain arterial blood samples. Oxygen delivery index was calculated and used to assess effects of one-lung ventilation on cardiopulmonary function. Effects on hemodynamic and pulmonary variables were analyzed.

Results—One-lung ventilation caused significant decreases in PaO2, arterial oxygen saturation (SaO2), mixed-venous oxygen saturation, and arterial oxygen content (CaO2). One-lung ventilation caused significant increases in PaCO2, physiologic dead space, and alveolar-arterial oxygen difference. Changes in SaO2, CaO2, and PaCO2, although significantly different, were not considered to be of clinical importance. One-lung ventilation induced a significant increase in pulmonary arterial wedge pressure, mean pulmonary artery pressure, and shunt fraction. One-lung ventilation did not have a significant effect on cardiac index, systemic vascular resistance index, pulmonary vascular resistance index, and oxygen delivery index.

Conclusions and Clinical Relevance—One-lung ventilation affected gas exchange and hemodynamic function, although oxygen delivery in clinically normal dogs was not affected during a period with an open thoracic cavity. One-lung ventilation can be used safely in healthy dogs with an open thoracic cavity during surgery. (Am J Vet Res 2003;64:443–448)

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in American Journal of Veterinary Research

Abstract

Objective—To develop a syndromic surveillance system based on visual inspection from outside the livestock pens that could be used for detection of disease among livestock entering an auction market.

Design—Cross-sectional study.

Animals—All livestock (beef and dairy cattle, sheep, goats, horses, and pigs) entering a single auction market in Colorado during 30 business days.

Procedures—Livestock were enumerated and visually inspected for clinical signs of disease by a veterinarian outside the pens, and clinical signs that were observed were categorized into 12 disease syndromes. Frequency of clinical signs and disease syndromes was then calculated.

Results—Data were recorded for a total of 29,371 animal observation days. For all species combined, the most common disease syndrome was respiratory tract disease (218.9 observations/10,000 animal observation days), followed by thin body condition and abnormal ambulation or posture (80.7 and 27.2 observations/10,000 animal observation days, respectively). Together, these 3 disease syndromes accounted for 92.8% of all clinical signs of disease observed. The syndromes least commonly identified were non–injury-related hemorrhage, death, and injury-related hemorrhage (0.0, 0.3, and 0.7 observations/10,000 animal observation days, respectively).

Conclusions and Clinical Relevance—Results suggested that a syndromic surveillance system based on visual inspection alone could be developed to identify possible disease conditions among livestock at an auction market. Further studies are needed to determine the sensitivity and specificity of visual observation in detecting disease.

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in Journal of the American Veterinary Medical Association