Objective—To describe time-dependent changes in
plasma concentrations of 3-methylindole (3MI) and
blood concentrations of 3-methyleneindolenine
(3MEIN)-adduct in feedlot cattle.
Animals—64 yearling steers.
Procedures—Steers were assigned to 2 groups (32
steers/group). During the first 8 weeks, blood samples
were collected from group 1 before the morning
ration was fed, whereas samples from group 2 were
collected 2 to 3 hours after the ration was fed. Blood
samples were collected from all steers approximately
4 times/wk for 3 weeks and 3 times/wk for the subsequent
5 weeks. Samples were collected at the
same time for all steers for an additional 10 weeks.
Plasma samples were analyzed for 3MI concentrations.
Blood samples collected from cattle in group 2
during the first 8 weeks were analyzed for 3MEINadduct
Results—Mean blood concentration of 3MEINadduct
increased to a maximum value on day 33 (0.80
U/μg of protein) and then decreased to a minimum on
day 54 0.40 U/μg of protein). Plasma 3MI concentrations
initially decreased and remained low until after
day 54. Group-1 cattle had lower plasma 3MI concentrations,
compared with concentrations for group-2
cattle. Blood 3MEIN-adduct concentrations and plasma
3MI concentrations were not associated with
deleterious effects on weight gains.
Conclusions and Clinical Relevance—Blood
3MEIN-adduct concentrations peaked during the period
of greatest risk for development of bovine respiratory
disease complex. Conversely, plasma 3MI concentrations
decreased during the same period.
Animal-to-animal variation in metabolic capacity to
convert 3MI to 3MEIN may be of more importance
than differences in plasma 3MI concentration. Am J Vet Res (2002;63:591–597).
Objective—To evaluate the effect of feeding aspirin and
supplemental vitamin E on growth performance, lung
lesions, plasma concentrations of 3-methylindole (3MI),
and 3-methyleneindolenine (3MEIN)-adduct concentrations
in blood and pulmonary tissues of feedlot cattle.
Animals—256 crossbred steers; 64 cattle were used in
experiment 1 and 192 cattle were used in experiment 2.
Procedures—A 2 × 2 factorial design was used for
each experiment. Treatment factors were aspirin (0 or
3 g daily) and vitamin E (200 or 1,500 IU daily). Steers
were housed in pens (8 steers/pen). Steers were
slaughtered on days 59 and 138 for experiments 1
and 2, respectively. Lungs were grossly evaluated.
Plasma 3MI concentration was determined, and
3MEIN-adduct concentrations were measured in
blood and pulmonary tissues.
Results—Treatment was not associated with
improvement or adverse effects on weight gain, drymatter
intake, or feed efficiency in experiment 2. In
experiment 1, 36 of 63 (57.1%) steers had lung
lesions. Lesions were not associated with treatment
or concentrations of 3MI and 3MEIN-adduct. Plasma
3MI concentration and concentrations of 3MEINadduct
in blood and pulmonary tissues were
3.11 µg/mL, 0.51 U/µg of protein, and 0.49 U/µg of
protein, respectively. Aspirin was associated with
increased blood concentrations of 3MEIN-adduct for
diets that did not contain supplemental vitamin E.
Conclusions and Clinical Relevance—Differences in
performance of feedlot steers were not associated with
treatment diet. It is possible that concurrent exposure of
feedlot cattle to other factors typically associated with
development of respiratory tract disease would affect
these findings. (Am J Vet Res 2002:63:1641–1647)
Objective—To describe antimicrobial susceptibility testing
practices of veterinary diagnostic laboratories in the
United States and evaluate the feasibility of collating this
information for the purpose of monitoring antimicrobial
resistance in bacterial isolates from animals.
Procedures—A questionnaire was mailed to veterinary
diagnostic laboratories throughout the United
States to identify those laboratories that conduct susceptibility
testing. Nonrespondent laboratories were
followed up through telephone contact and additional
mailings. Data were gathered regarding methods of
susceptibility testing, standardization of methods,
data management, and types of isolates tested.
Results—Eighty-six of 113 (76%) laboratories responded
to the survey, and 64 of the 86 (74%) routinely performed
susceptibility testing on bacterial isolates from
animals. Thirty-four of the 36 (94%) laboratories
accredited by the American Association of Veterinary
Laboratory Diagnosticians responded to the survey.
Laboratories reported testing > 160,000 bacterial isolates/y. Fifty-one (88%) laboratories reported using the
Kirby-Bauer disk diffusion test to evaluate antimicrobial
susceptibility; this accounted for 65% of the isolates
tested. Most (87%) laboratories used the NCCLS
(National Committee for Clinical Laboratory Standards)
documents for test interpretation. Seventy-five percent
of the laboratories performed susceptibility testing on
bacterial isolates only when they were potential
Conclusions—The veterinary diagnostic laboratories
represent a comprehensive source of data that is not
easily accessible in the United States. Variability in
testing methods and data storage would present challenges
for data aggregation, summary, and interpretation.
(J Am Vet Med Assoc 2003;222:168–173)
Objective—To develop a questionnaire for self-assessment of biosecurity practices at equine boarding facilities and to evaluate infectious disease control practices in these facilities in Colorado.
Sample Population—64 equine boarding facilities in Colorado.
Procedures—Survey questions were rated according to importance for prevention and containment of equine infectious diseases. Point values (range, 0 to 20) were assigned for possible responses, with greater values given for optimal infection control methods. Questionnaires were mailed to equine boarding facilities in Colorado advertised on the World Wide Web. Survey responses were compared with assessments made by a member of the research team during visits to 30 randomly selected facilities. Agreement among results was analyzed via a kappa test and rated as poor, fair, moderate, substantial, or nearly perfect.
Results—Survey responses were received for 64 of 163 (39%) equine boarding facilities. Scores ranged from 106 to 402 points (maximum possible score, 418). Most facilities received better scores for movement and housing of equids than for other sections of the survey. Respondents at 24 of 48 (50%) facilities that routinely received new equids reported isolation of new arrivals. Agreement between self-assessment by survey respondents and evaluation by a member of the research team was determined to be fair to substantial.
Conclusions and Clinical Relevance—Most equine boarding facilities have opportunities to improve measures for prevention or containment of contagious diseases (eg, isolation of newly arrived equids and use of written health management protocols). Most self-assessments of infection control practices were accurate.
Objective—To compare the frequency of isolation,
genotypes, and in vivo production of major lethal toxins
of Clostridium perfringens in adult dairy cows
affected with hemorrhagic bowel syndrome (HBS)
versus left-displaced abomasum (LDA).
Animals—10 adult dairy cattle with HBS (cases) and
10 adult dairy cattle with LDA matched with cases by
herd of origin (controls).
Procedure—Samples of gastrointestinal contents
were obtained from multiple sites during surgery or
necropsy examination. Each sample underwent testing
for anaerobic bacteria by use of 3 culture methods.
The genotype of isolates of C perfringens was
determined via multiplex polymerase chain reaction
assay. Major lethal toxins were detected by use of an
ELISA. Data were analyzed with multivariable logistic
regression and X2 analysis.
Results—C perfringens type A and type A with the
beta2 gene (A + beta2) were the only genotypes isolated.
Isolation of C perfringens type A and type A +
beta2 was 6.56 and 3.3 times as likely, respectively,
to occur in samples from cattle with HBS than in cattle
with LDA. Alpha toxin was detected in 7 of 36
samples from cases and in 0 of 32 samples from controls.
Beta2 toxin was detected in 9 of 36 samples
from cases and 0 of 36 samples from controls.
Conclusions and Clinical Relevance—C perfringens
type A and type A + beta2 can be isolated from the gastrointestinal
tract with significantly greater odds in cattle
with HBS than in herdmates with LDA. Alpha and beta2
toxins were detected in samples from cows with HBS
but not from cows with LDA. (J Am Vet Med Assoc 2005;227:132–138)
Objective—To evaluate the effects of footwear hygiene protocols on bacterial contamination of floor surfaces in an equine hospital.
Procedures—Footwear hygiene protocols evaluated included use of rubber overboots with footbaths and footmats containing a quaternary ammonium disinfectant, rubber overboots with footbaths and footmats containing a peroxygen disinfectant, and no restrictions on footwear type but mandatory use of footbaths and footmats containing a peroxygen disinfectant. Nonspecific aerobic bacterial counts were determined via 2 procedures for sample collection and bacterial enumeration (contact plates vs swabbing combined with use of spread plates), and the effects of each footwear hygiene protocol were compared.
Results—There were no consistent findings suggesting that any of the protocols were associated with differences in numbers of bacteria recovered from floor surfaces. Although there were detectable differences in numbers of bacteria recovered in association with different footwear hygiene protocols, differences in least square mean bacterial counts did not appear to be clinically relevant (ie, were < 1 log10).
Conclusions and Clinical Relevance—Although cleaning and disinfection of footwear are important aids in reducing the risk of nosocomial transmission of infectious agents in veterinary hospitals, the numbers of aerobic bacteria recovered from floor surfaces were not affected by use of rubber overboots or the types of disinfectant used in this study. Further study is warranted to evaluate the usefulness of footwear hygiene practices relative to their efficacy for reducing transmission of specific pathogens or decreasing nosocomial disease risk.
Objective—To report clinical and serologic findings in
horses with oral vesicular lesions that were consistent
with vesicular stomatitis (VS) but apparently
were not associated with VS virus (VSV) infection.
Design—Serial case study.
Procedure—Horses were quarantined after appearance
of oral lesions typical of VS. Severity of clinical
signs was scored every 2 to 5 days for 3 months.
Serum samples were tested for antibodies by use of
competitive ELISA (cELISA), capture ELISA for IgM,
serum neutralization, and complement fixation (CF).
Virus isolation was attempted from swab specimens
of active lesions.
Results—2 horses with oral vesicular lesions on day
1 had antibodies (cELISA and CF) against VSV; however,
results of CF were negative by day 19. Five of
the 6 remaining horses were seronegative but developed
oral lesions by day 23. Virus isolation was unsuccessful
for all horses.
Conclusion and Clinical Relevance—Horses were
quarantined for 75 days in compliance with state and
federal regulations. However, evidence suggests that
oral lesions were apparently not associated with VSV
infection. The occurrence in livestock of a vesicular
disease that is not caused by VSV could confound
efforts to improve control of VS in the United States
and could impact foreign trade.Vesicular stomatitis is
of substantial economic and regulatory concern. (J
Am Vet Med Assoc 2000;216:1399–1404)
Objective—To determine current practices regarding
use of antimicrobials in equine patients undergoing
surgery because of colic at veterinary teaching hospitals.
Sample Population—Diplomates of the American
College of Veterinary Surgeons performing equine
surgery at veterinary teaching hospitals in the United
Procedure—A Web-based questionnaire was developed,
and 85 surgeons were asked to participate. The
first part of the survey requested demographic information
and information about total number of colic
surgeries performed at the hospital, number of colic
surgeries performed by the respondent, and whether
the hospital had written guidelines for antimicrobial
drug use. The second part pertained to nosocomial
infections. The third part provided several case scenarios
and asked respondents whether they would
use antimicrobial drugs in these instances.
Results—Thirty-four (40%) surgeons responded to
the questionnaire. Respondents indicated that most
equine patients undergoing surgery because of colic
at veterinary teaching hospitals in the United States
received antimicrobial drugs. Drugs that were used
were similar for the various hospitals that were represented,
and for the most part, the drugs that were
used were fairly uniform irrespective of the type of
colic, whereas the duration of treatment varied with
the type of colic and the surgical findings. The combination
of potassium penicillin and gentamicin was the
most commonly used treatment.
Conclusions and Clinical Relevance—Results of
this study document the implementation of recommendations
by several authors in veterinary texts that
antimicrobial drugs be administered perioperatively in
equine patients with colic that are undergoing surgery.
However, the need for long-term antimicrobial drug
treatment in equine patients with colic is unknown. (J
Am Vet Med Assoc 2002;220:1359–1365)
Objective—To estimate seroprevalence of Mycobacterium
avium subsp paratuberculosis (MAP) infection
among adult dairy cows in Colorado and determine
herd-level factors associated with the risk that individual
cows would be seropositive.
Design—Cross-sectional observational study.
Animals—10,280 adult (≥ 2 years old) dairy cows in
15 herds in Colorado.
Procedure—Serum samples were tested with a commercial
ELISA. A herd was considered to be infected
with MAP if results of mycobacterial culture of ≥ 1
individual cow fecal sample were positive or if ≥ 1
culled cow had histologic evidence of MAP infection.
Results—424 of the 10,280 (4.12%) cows were
seropositive. Within-herd prevalence of seropositive
cows ranged from 0% to 7.82% (mean, 2.6%).
Infection was confirmed in 11 dairies. Cows in herds
that had imported ≥ 8% of their current herd size
annually during the preceding 5 years were 3.28
times as likely to be seropositive as were cows in
herds that imported < 8%. Cows in herds with ≥ 600
lactating cows were 3.12 times as likely to be
seropositive as were cows in herds with < 600 lactating
cows. Cows in herds with a history of clinical
signs of MAP infection were 2.27 times as likely to be
seropositive as were cows in herds without clinical
Conclusions and Clinical Relevance—Annual importation
rate, herd size, and whether cows in the herd
had clinical signs typical of MAP infection were associated
with the risk that individual cows would be
seropositive for MAP infection. (J Am Vet Med Assoc
Objective—To investigate Salmonella enterica infections at a Greyhound breeding facility.
Animal and Sample Populations—138 adult and juvenile dogs and S enterica isolates recovered from the dogs and their environment.
Procedures—The investigation was conducted at the request of a Greyhound breeder. Observations regarding the environment and population of dogs were recorded. Fecal, food, and environmental specimens were collected and submitted for Salmonellaculture. Isolates were serotyped and tested for susceptibility to 16 antimicrobials. Isolates underwent genetic analyses by use of pulsed-field gel electrophoresis and ribotyping.
Results—S enterica was recovered from 88 of 133 (66%) samples of all types and from 57 of 61 (93%) fecal samples. Eighty-three (94.3%) of the isolates were serotype Newport, 77 (87.5%) of which had identical resistance phenotypes. Genetic evaluations suggested that several strains of S enterica existed at the facility, but there was a high degree of relatedness among many of the Newport isolates. Multiple strains of Salmonella enterica serotype Newport were recovered from raw meat fed on 1 day.
Conclusions and Clinical Relevance—S enterica infections and environmental contamination were common at this facility. A portion of the Salmonellastrains detected on the premises was likely introduced via raw meat that was the primary dietary constituent. Some strains appeared to be widely disseminated in the population. Feeding meat that had not been cooked properly, particularly meat classified as unfit for human consumption, likely contributed to the infections in these dogs.