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ABSTRACT: The objective of this study was to characterize the clinical, clinicopathological, and histopathological findings of dogs with chronic pancreatitis. The necropsy database at Texas A&M University was searched for reports of dogs with histological evidence of chronic pancreatitis defined as irreversible histologic changes of the pancreas (i.e. fibrosis or atrophy). A reference necropsy population of 100 randomly selected dogs was used for signalment and concurrent disease comparisons. Cases were categorized as clinical or incidental chronic pancreatitis based on the presence of vomiting, decreased appetite, or both vs. neither of these signs. All archived pancreas samples were scored histologically using a published scoring system. Sixty-one dogs with chronic pancreatitis were included. The most frequent clinical signs were lethargy, decreased appetite, vomiting, and diarrhea. Compared to the reference necropsy population, chronic pancreatitis cases were more likely to be older, neutered, of the non-sporting/toy breed group, and to have concurrent endocrine, hepatobiliary, or neurological disease. Clinical cases had significantly higher histological scores for pancreatic necrosis and peripancreatic fat necrosis, and were significantly more likely to have hepatobiliary or endocrine disease as well as increased liver enzyme activities, or elevated cholesterol and bilirubin concentrations. In conclusion, clinical disease resulting from chronic pancreatitis might be related to the presence of pancreatic necrosis and pancreatic fat necrosis. The signalment, presentation, and concurrent diseases of dogs with chronic pancreatitis are similar to those previously reported for dogs with acute pancreatitis.
The Veterinary Journal 07/2012; · 2.24 Impact Factor
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ABSTRACT: To examine associations between CSF biomarkers, initial neurologic dysfunction, and long-term ambulatory outcome in dogs with acute intervertebral disk herniation (IVDH).
Prospective clinical study.
54 dogs with acute thoracolumbar IVDH and 16 clinically normal dogs.
For each dog, variables, including CSF myelin basic protein (MBP), lactate, calcium, glucose, and total protein concentrations; nucleated cell count; and creatine kinase (CK) and aspartate aminotransferase activities, were measured. For dogs with thoracolumbar IVDH, initial neurologic function was characterized by use of a modified Frankel score (MFS; determined on a scale of 0 to 5, where 0 represented paraplegia with no deep nociception and 5 represented paraspinal hyperesthesia only). Long-term follow-up was assessed.
Among dogs with thoracolumbar IVDH, those with CSF CK activity ≤ 38 U/L had a 35-fold increase in the odds of long-term ambulation, compared with the odds in dogs with CSF CK activity > 38 U/L, adjusting for neurologic functioning at the evaluation. The CSF lactate, calcium, and glucose concentrations and aspartate aminotransferase activity were not predictive of long-term ambulatory outcome. Data analysis revealed that long-term functional recovery was > 98% for affected dogs, regardless of their initial MFS, when CSF CK activity was ≤ 38 U/L and MBP concentration was ≤ 3 ng/mL.
In dogs with acute thoracolumbar IVDH, CSF CK activity and MBP concentration appeared to be prognostic indicators and, along with initial MFS, can be used to predict long-term ambulatory outcome.
Journal of the American Veterinary Medical Association 03/2012; 240(5):555-62. · 1.79 Impact Factor
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ABSTRACT: One of the most important transboundary animal diseases (TADs) in the southern African region is foot-and-mouth disease (FMD). In this region, a pathway for spread of FMD virus is contacts between cattle and certain species of wildlife. The objective of this study was to evaluate contacts between cattle and wildlife in the Kruger National Park (KNP) and the adjacent Limpopo province for the time periods October 2006 to March 2007 and April to September 2007. In this study, 87 livestock owners and 57 KNP field rangers were interviewed. Fifteen (17%) livestock owners reported contacts between wildlife and cattle. More livestock owners reported observing contacts between cattle and all wildlife species during October-March than April-September (p=0.012). However, no difference was found between these periods for contacts between cattle and individual wildlife species. A total of 18 (32%) field rangers reported contacts between cattle and wildlife. The most common species-specific contacts were between cattle and buffalo (63/year), cattle and impala (17/year) and cattle and lion (10/year). There were no significant differences in rangers reporting observed contacts between cattle and wildlife during October-March versus April-September or between rangers reporting observed contacts outside versus within the KNP. Overall, there was no evidence of higher contact rates between cattle and wildlife in the study area during October-March compared to April-September. Contact data collected in this study can be used to better understand the transmission of FMD virus in this region.
Preventive Veterinary Medicine 09/2011; 103(1):16-21. · 2.05 Impact Factor
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ABSTRACT: The water buffalo is an important domestic animal worldwide, and the local Buffalypso variety was developed in Trinidad to have improved beef qualities. Brucellosis was diagnosed in Trinidad and Tobago during 1998 in both cattle and domestic water buffalo (Bubalus bubalis) populations. Brucellosis in the latter species is caused by infection with Brucella abortus, similar to bovine brucellosis. Control of brucellosis is of paramount importance to preservation of the genetic diversity of these animals in Trinidad, and this has been complicated by differences in the epidemiology of water buffalo and bovine brucellosis. Some diagnostic tests do not have comparable accuracy between the two species, and the RB51 vaccine does not adequately protect against infection in water buffalo. The water buffalo in Trinidad may also be more resistant to infection than cattle. Development of effective vaccination protocols is key to brucellosis control in Buffalypso in Trinidad, and prohibitions on import of virulent B. abortus strains for vaccine efficacy studies has impeded progress in this area. These Trinidadian strains are of variable virulence; some might be effective for challenge in vaccine efficacy studies, while other, of lower virulence, may be vaccine candidates for use in water buffalo.
Tropical Animal Health and Production 04/2011; 43(8):1479-86. · 1.12 Impact Factor
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ABSTRACT: Astrocytomas and oligodendrogliomas represent one third of histologically confirmed canine brain tumors. Our purpose was to describe the magnetic resonance (MR) imaging features of histologically confirmed canine intracranial astrocytomas and oligodendrogliomas and to examine for MR features that differentiate these tumor types. Thirty animals with confirmed astrocytoma (14) or oligodendroglioma (16) were studied. All oligodendrogliomas and 12 astrocytomas were located in the cerebrum or thalamus, with the remainder of astrocytomas in the cerebellum or caudal brainstem. Most (27/30) tumors were associated with both gray and white matter. The signal characteristics of both tumor types were hypointense on T1-weighted images (12 each) and hyperintense on T2-weighted images (11/14 astrocytomas, 12/16 oligodendrogliomas). For astrocytomas and oligodendrogliomas, respectively, common findings were contrast enhancement (10/13, 11/15), ring-like contrast enhancement (6/10, 9/11), cystic regions within the mass (7/14, 12/16), and hemorrhage (4/14, 6/16). Oligodendrogliomas were significantly more likely to contact the brain surface (meninges) than astrocytomas (14/16, 7/14, respectively, P=0.046). Contact with the lateral ventricle was the most common finding, occurring in 13/14 astrocytomas and 14/16 oligodendrogliomas. No MR features were identified that reliably distinguished between these two tumor types. Contrast enhancement was more common in high-grade tumors (III or IV) than low-grade tumors (II, P=0.008).
Veterinary Radiology & Ultrasound 03/2011; 52(2):132-41. · 1.08 Impact Factor
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ABSTRACT: Astrocytomas and oligodendrogliomas represent one third of histologically confirmed canine brain tumors. Our purpose was to describe the magnetic resonance (MR) imaging features of histologically confirmed canine intracranial astrocytomas and oligodendrogliomas and to examine for MR features that differentiate these tumor types. Thirty animals with confirmed astrocytoma (14) or oligodendroglioma (16) were studied. All oligodendrogliomas and 12 astrocytomas were located in the cerebrum or thalamus, with the remainder of astrocytomas in the cerebellum or caudal brainstem. Most (27/30) tumors were associated with both gray and white matter. The signal characteristics of both tumor types were hypointense on T1-weighted images (12 each) and hyperintense on T2-weighted images (11/14 astrocytomas, 12/16 oligodendrogliomas). For astrocytomas and oligodendrogliomas, respectively, common findings were contrast enhancement (10/13, 11/15), ring-like contrast enhancement (6/10, 9/11), cystic regions within the mass (7/14, 12/16), and hemorrhage (4/14, 6/16). Oligodendrogliomas were significantly more likely to contact the brain surface (meninges) than astrocytomas (14/16, 7/14, respectively, P=0.046). Contact with the lateral ventricle was the most common finding, occurring in 13/14 astrocytomas and 14/16 oligodendrogliomas. No MR features were identified that reliably distinguished between these two tumor types. Contrast enhancement was more common in high-grade tumors (III or IV) than low-grade tumors (II, P=0.008).
Veterinary Radiology & Ultrasound 11/2010; 52(2):132 - 141. · 1.08 Impact Factor
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ABSTRACT: Brucellosis has been documented in domestic water buffalo (Bubalus bubalis) but published literature is limited despite the importance of this species in tropical agricultural systems. The objective of this study was to compare the virulence of Brucella abortus isolates recovered from cattle and water buffalo. Nineteen strains of B. abortus from cattle and domestic water buffalo in Trinidad were intraperitoneally inoculated into BALB/c mice. Spleens were cultured for B. abortus and histopathological severity scores were calculated based on lymphoid depletion, lymphoid necrosis, splenitis, and macrophage accumulation. A general linear model approach was used to estimate the effect of isolate source (cattle versus water buffalo) on virulence. Isolates of water buffalo origin were significantly less virulent in the mouse model based on recovered B. abortus from splenic tissues, spleen/weight ratio, and lymphoid necrosis but not overall histopathological severity scores. Further investigation of isolates recovered from water buffalo might provide the key to the development of procedures for brucellosis control in tropical environments.
Tropical Animal Health and Production 10/2010; 43(1):13-6. · 1.12 Impact Factor
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ABSTRACT: To compare the accuracy of radiography and computed tomography (CT) in predicting implant position in relation to the vertebral canal in the cervical and thoracolumbar vertebral column.
In vitro imaging and anatomic study.
Medium-sized canine cadaver vertebral columns (n=12).
Steinmann pins were inserted into cervical and thoracolumbar vertebrae based on established landmarks but without predetermination of vertebral canal violation. Radiographs and CT images were obtained and evaluated by 6 individuals. A random subset of pins was evaluated for ability to distinguish left from right pins on radiographs. The ability to correctly identify vertebral canal penetration for all pins was assessed both on radiographs and CT. Spines were then anatomically prepared and visual examination of pin penetration into the canal served as the gold standard.
Left/right accuracy was 93.1%. Overall sensitivity of radiographs and CT to detect vertebral canal penetration by an implant were significantly different and estimated as 50.7% and 93.4%, respectively (P<.0001). Sensitivity was significantly higher for complete versus partial penetration and for radiologists compared with nonradiologists for both imaging modalities. Overall specificity of radiographs and CT to detect vertebral canal penetration was 82.9% and 86.4%, respectively (P=.049).
CT was superior to radiographic assessment and is the recommended imaging modality to assess penetration into the vertebral canal.
CT is significantly more accurate in identifying vertebral canal violation by Steinmann pins and should be performed postoperatively to assess implant position.
Veterinary Surgery 04/2010; 39(6):680-7. · 1.26 Impact Factor
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ABSTRACT: Bovine anaplasmosis (BA) is a hemoparasitic disease of great importance in cattle within the tropical and subtropical regions of the world. Control programs for BA require accurate diagnostic assays but validation can be challenging because the true disease status of all animals is frequently not known with certainty. The objective of this study was to estimate the accuracy of assays for detection of Anaplasma marginale infection in lactating dairy cattle of Puerto Rico using Bayesian methods without a perfect reference test. There were 2,331 cattle with complete diagnostic results sampled from 79 herds, and the prevalence of BA was estimated as 22% (95% probability interval [PI]: 19-25%). The sensitivity (Se) and specificity (Sp) of a major surface protein 5 competitive enzyme-linked immunosorbent assay (MSP-5 cELISA) were estimated as 99% (95% PI: 96-100%) and 89% (95% PI: 87-92%), respectively. The Se and Sp of a quantitative polymerase chain reaction (qPCR) were 67% (95% PI: 60-74%) and 99% (95% PI: 99-100%). The Se and Sp of a card agglutination test were 34% (95% PI: 29-39%) and 99% (95% PI: 99-100%). Area under the receiver-operating characteristic curve for the MSP-5 cELISA was 0.748 (95% PI: 0.71-0.79). The MSP-5 cELISA appears to be the test of choice for screening cattle for subclinical BA based on the high estimated Se, rapidity of results, relative low cost, and ease of standardization.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 03/2010; 22(2):192-9. · 1.21 Impact Factor
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ABSTRACT: Incentives are used to increase response proportions to postal questionnaires. Our objective was to compare the response proportions between incentive groups receiving a $1 bill, pen, both and none with a postal questionnaire for a veterinary public health survey conducted among veterinarians in Texas. We mailed questionnaires to a random sample of veterinarians (n=683) from Texas with three types of incentives viz. $1 bill (n=118), pen (n=111), $1 bill with pen (n=114), and questionnaire only (n=340). A total of 303 (44%; 95% confidence interval, CI: 41-48) responses were received with the lowest response proportion of 37% (95% CI: 32-43) in the no incentive group and highest response proportion of 57% (95% CI: 47-66) in $1 bill incentive group. Compared to no incentive, the response proportions were significantly higher (P<0.01) in groups receiving $1 bill, $1 bill with pen, and all incentives combined ($1 bill, a pen or both). The addition of a pen only did not improve response proportion. These findings support the use of $1 bill but not a pen alone as an effective incentive to increase response proportions to a postal questionnaire.
Preventive Veterinary Medicine 11/2009; 93(1):62-5. · 2.05 Impact Factor
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ABSTRACT: As concerns over the global spread of highly pathogenic avian influenza H5N1 have heightened, more countries are faced with increased surveillance efforts and incident response planning for handling a potential outbreak. The incorporation of molecular techniques in most diagnostic laboratories has enabled fast and efficient testing of many agents of concern, including avian influenza. However, the need for high-throughput testing remains. In this study, the use of a 384-well format for high-throughput real-time reverse transcription polymerase chain reaction (real-time RT-PCR) testing for avian influenza is described. The analytical sensitivity of a real-time RT-PCR assay for avian influenza virus matrix gene with the use of both 96- and 384-well assay formats and serial dilutions of transcribed control RNA were comparable, resulting in similar limits of detection. Of 28 hunter-collected cloacal swabs that were positive by virus isolation, 26 (92.9%) and 27 (96.4%) were positive in the 96- and 384-well assays, respectively; of the 340 hunter-collected swabs that were negative by virus isolation, 45 (13.2%) and 23 (6.8%) were positive in the 96- and 384-well assays, respectively. The data presented herein supports the utility of the 384-well format in the event of an avian influenza outbreak for high-throughput real-time RT-PCR testing.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 10/2009; 21(5):679-83. · 1.21 Impact Factor
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Journal of Small Animal Practice 10/2009; 50(10):507-8. · 1.00 Impact Factor
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ABSTRACT: One thousand three hundred and twenty-four adult beef cattle were tested for paratuberculosis using 2 antibody enzyme-linked immunosorbent assays (ELISA), an interferon-gamma (INF-gamma) ELISA, and radiometric bacterial culture of feces from 5 populations. Two populations of cattle (n=226) had data available to calculate a ratio of humoral to cell-mediated immunity based on results from one antibody test and the INF-gamma ELISA. Latent class analysis was used to estimate accuracy of the 4 paratuberculosis assays within a Bayesian framework. Determination of test accuracy and paratuberculosis prevalence in the latent class analysis allowed for estimation of predictive value positive (PVP) functions. The estimated PVP functions were used to iteratively assign paratuberculosis status to sampled cattle. Accuracy of the immunity ratio, an antibody ELISA, and the INF-gamma ELISA were determined for multiple cutoffs based on probabilistically assigned paratuberculosis status. Area under the receiver-operating characteristic (ROC) curves (95% probability interval) were estimated as 0.78 (0.66, 0.89), 0.81 (0.68, 0.92), and 0.59 (0.47, 0.71) for the immunity ratio, antibody ELISA, and INF-gamma ELISA, respectively. The Youden index (sensitivity+specificity-1) peaked at immunity ratios of 0.5 (J=0.48) and 1.0 (J=0.46). Sensitivity and specificity (95% probability interval) at an immunity ratio cutoff of 0.5 were 0.65 (0.44, 0.85) and 0.83 (0.78, 0.88), respectively. Sensitivity and specificity (95% probability interval) at the 1.0 cutoff were 0.55 (0.33, 0.77) and 0.91 (0.87, 0.95), respectively. An immunity ratio could be used to diagnosis paratuberculosis in beef cattle but requires further investigation.
Preventive Veterinary Medicine 08/2009; 91(2-4):226-33. · 2.05 Impact Factor
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ABSTRACT: To compare the effectiveness of 3 treatment regimens for small ruminants with caseous lymphadenitis.
Randomized clinical trial.
44 client-owned sheep and goats.
Aspirates were obtained from 48 lesions of 44 enrolled animals and submitted for bacterial culture. Animals were randomly assigned to 1 of 3 treatment groups. Treatment for group A (n = 15 lesions) consisted of opening, draining, and flushing the lesions and SC administration of procaine penicillin G. Treatment for group B (n = 15 lesions) consisted of closed-system lavage and intralesional administration of tulathromycin. Treatment for group C (n = 18 lesions) consisted of closed-system lavage and SC administration of tulathromycin. All animals were reexamined approximately 1 month after treatment, unless treatment failure was detected prior to that time.
43 animals with lesions had positive results (Corynebacterium pseudotuberculosis) for bacterial culture. Proportions of lesions that had resolution of infection by 1 month after treatment did not differ significantly among the treatment groups (group A, 13/14 [92.9%]; 95% confidence interval [CI], 69.5% to 99.6%; group B, 10/12 [83.3%]; 95% CI, 54.9% to 97.1%; and group C, 14/17 [82.4%]; 95% CI, 59.1% to 95.3%).
Acceptable alternatives to opening, draining, and flushing of lesions may exist for treatment of sheep and goats with caseous lymphadenitis. Use of tulathromycin and penicillin in this study constituted extralabel drug use, which would require extended withholding times before milk or meat of treated sheep and goats can be sold for human consumption.
Journal of the American Veterinary Medical Association 06/2009; 234(9):1162-6. · 1.79 Impact Factor
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Geoffrey T Fosgate
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ABSTRACT: The likelihood that a study will yield statistically significant results depends on the chosen sample size. Surveillance and diagnostic situations that require sample size calculations include certification of disease freedom, estimation of diagnostic accuracy, comparison of diagnostic accuracy, and determining equivalency of test accuracy. Reasons for inadequately sized studies that do not achieve statistical significance include failure to perform sample size calculations, selecting sample size based on convenience, insufficient funding for the study, and inefficient utilization of available funding. Sample sizes are directly dependent on the assumptions used for their calculation. Investigators must first specify the likely values of the parameters that they wish to estimate as their best guess prior to study initiation. They further need to define the desired precision of the estimate and allowable error levels. Type I (alpha) and type II (beta) errors are the errors associated with rejection of the null hypothesis when it is true and the nonrejection of the null hypothesis when it is false (a specific alternative hypothesis is true), respectively. Calculated sample sizes should be increased by the number of animals that are expected to be lost over the course of the study. Free software routines are available to calculate the necessary sample sizes for many surveillance and diagnostic situations. The objectives of the present article are to briefly discuss the statistical theory behind sample size calculations and provide practical tools and instruction for their calculation.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 02/2009; 21(1):3-14. · 1.21 Impact Factor
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ABSTRACT: To estimate associations between dietary factors and pancreatitis in dogs. Design-Retrospective case-control study.
198 dogs with a clinical diagnosis of pancreatitis and 187 control dogs with a diagnosis of renal failure without clinical evidence of pancreatitis.
Information on signalment, weight, body condition, dietary intake, medical history, diagnostic tests performed, concurrent diseases, treatments, duration of hospitalization, and discharge status was extracted from medical records. Information on dietary intake, signalment, weight, and medical, surgical, and environmental history was collected through a telephone questionnaire. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals.
On the basis of information extracted from the medical record, ingesting unusual food items (OR, 4.3) increased the odds of pancreatitis. On the basis of information gathered through the telephone questionnaire, ingesting unusual food items (OR, 6.1), ingesting table scraps the week before diagnosis (OR, 2.2) or throughout life (OR, 2.2), and getting into the trash (OR, 13.2) increased the odds of pancreatitis. Multivariable modeling indicated that reporting exposure to > or = 1 dietary factor during the telephone questionnaire (OR, 2.6), being overweight (OR, 1.3) or neutered (OR, 3.6), previous surgery other than neutering (OR, 21.1), and the interaction between neuter status and previous surgery other than neutering (OR, 0.1) were associated with the odds of pancreatitis.
Results suggested that dietary factors, being neutered, and previous surgery other than neutering increased the odds of pancreatitis in dogs.
Journal of the American Veterinary Medical Association 11/2008; 233(9):1425-31. · 1.79 Impact Factor
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ABSTRACT: Surveillance and monitoring are important for measuring the level of disease in a population, documenting changes in prevalence over time, determining high-risk areas for implementation of control measures, eradicating disease, and documenting freedom from disease. The documentation of freedom from disease has importance for international trade and the resumption of production after an outbreak. Johne's disease (JD) is an example of an endemic disease of cattle that has variable prevalence related to environmental and animal-level factors. Three methods of sample collection were used to describe the prevalence and distribution of JD seropositivity in Texas. Sampled cattle were: (1) extensively managed herds, (2) market cattle, and (3) clinically ill cattle examined by practicing veterinarians throughout Texas. Samples were evaluated for JD using a commercially available serum ELISA. Proportion of seropositive samples was compared and spatial distributions were evaluated for clustering. Difference of JD seropositivity was observed among the three sample populations suggesting that estimation of disease prevalence is dependant upon the source of samples.
Preventive Veterinary Medicine 09/2008; 86(1-2):1-7. · 2.05 Impact Factor
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Geoffrey T Fosgate
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ABSTRACT: To identify predictors of veterinary students and veterinarians having an interest in veterinary public health and epidemiology (PH&E).
Cross-sectional study.
Veterinary students enrolled in the College of Veterinary Medicine and Biomedical Sciences at Texas A&M University and veterinarians with membership in a Texas veterinary professional organization.
2 questionnaires were designed and administered to investigate hypothesized predictors of PH&E interests among veterinary students and veterinarians. Descriptive statistics were calculated for all variables from both questionnaires. Prevalence ratios, 95% confidence intervals, and chi(2) tests were used to evaluate bivariate associations between variables and an interest in PH&E. Multivariable logistic regression was used to adjust for the effects of multiple variables on the outcome.
70% (215/305) of students believed that a course in PH&E was necessary, and 46% (140/304) believed that more courses in PH&E would improve the veterinary curriculum. Ninety-nine percent (299/303) of veterinarians believed that a course in PH&E was necessary in the curriculum. Ninety-two percent (272/297) of veterinarians agreed that knowledge related to PH&E was important to perform the functions of their job. History of raising animals and membership in 4-H or Future Farmers of America were significant predictors of veterinary students having an interest in PH&E. Being male and growing up in a rural environment were not significant predictors.
Most veterinary students and veterinarians agreed that knowledge of PH&E is important. Variables identified as associated with an interest in PH&E may be useful for designing mitigation strategies to increase the number of veterinarians entering public health careers.
Journal of the American Veterinary Medical Association 07/2008; 233(2):240-7. · 1.79 Impact Factor
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ABSTRACT: The objective of this cross-sectional study was to estimate familial associations with paratuberculosis ELISA status in beef cattle. Texas Longhorn cattle (n=715) greater than 2years of age were sampled for paratuberculosis testing using ELISA and fecal culture. Diagnostic test results were indicative of substantial numbers of false-positive serological reactions consistent with environmental exposure to non-MAP Mycobacterium spp. Associations between ancestors and paratuberculosis ELISA status of offspring were assessed using conditional logistic regression. The association between ELISA status of the dam and her offspring was assessed using linear mixed-effect models. Significant associations were identified between some ancestors and offspring ELISA status. The odds of being classified as "suspect" or greater based on ELISA results were 4.6 times greater for offspring of dams with similarly increased S:P ratios. A significant positive linear association was also observed between dam and offspring log-transformed S:P ratios. Results indicate that there is familial aggregation of paratuberculosis ELISA results in beef cattle and suggest that genetic selection based on paratuberculosis ELISA status may decrease seroprevalence. However, genetic selection may have minimal effect on paratuberculosis control in herds with exposure to non-MAP Mycobacterium spp.
Veterinary Microbiology 06/2008; 129(1-2):131-8. · 3.33 Impact Factor
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ABSTRACT: The objective of this study was to assess genetic similarity of beef cattle using microsatellite markers and to use this information to describe familial aggregation of paratuberculosis test results in Texas beef cattle. Paratuberculosis testing was performed on 2622 adult beef cattle using two commercially available serum ELISAs and radiometric fecal culture. Pedigree records were collected for registered purebred herds and herds with sufficiently detailed production records to identify parent-offspring pairs. Cases were defined as cattle with at least one positive paratuberculosis test result. Three controls were matched by herd of residence for each case. All parent-offspring pairs, cases, and controls were genotyped for 12 microsatellites. Bayesian analysis of allele frequency data was used to describe population substructure and assign individual cattle into groups of genetically similar cattle. The proportion of known parent-offspring pairs assigned to the same cluster was used to assess the validity of the approach to identify familial structure. Conditional logistic regression was used to describe the association between cluster assignment and paratuberculosis test-status matched by herd. Nine clusters of genetically similar individuals were identified and were supported by the proportion of parent-offspring pairs assigned to the same clusters. Increased odds of having at least one positive paratuberculosis test result were identified for two clusters compared to the cluster with the lowest proportion of positive paratuberculosis test results after conditioning on herd. The results of this study demonstrate that population substructure can be used to describe familial aggregation of paratuberculosis test results in beef cattle of unknown pedigree.
Preventive Veterinary Medicine 05/2008; 84(1-2):121-34. · 2.05 Impact Factor
