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)
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
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)
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 R2 values of logarithmic and
polynomial models were tested for significance of
contribution, compared with the simple linear
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
Objective—To determine testing protocols used by
board-certified internists and dermatologists for diagnosis
of hyperadrenocorticism (HAC) in dogs.
Study Population—Board-certified internists and
Procedure—A questionnaire was mailed to 501 specialists
to gather information pertaining to diagnosis
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)
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 Services1 warns that the world's land and water resources are being exploited at unprecedented rates and that this exploitation, combined
Objectives—To determine epidemiologic factors
associated with tuberculosis (TB) in dairy cattle
slaughtered in 6 important regions for milk production
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;
Objective—To evaluate effects of one-lung ventilation
on oxygen delivery in anesthetized dogs with an open
Animals—8 clinically normal adult Walker Hound
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
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)
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.
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.