Objective—To evaluate the effect of an indwelling
nasogastric tube on gastric emptying of liquids in
Animals—9 healthy adult horses.
Procedure—A randomized block crossover design
was used. For treatment group horses, a nasogastric
tube was placed and 18 hours later, acetaminophen
was administered; the nasogastric tube remained in
place until the experiment was complete. For control
group horses, a nasogastric tube was passed into the
stomach, acetaminophen was administered, and the
nasogastric tube was removed immediately. Serial
blood samples were collected 15 minutes before and
after administration of acetaminophen. Serum concentration
of acetaminophen was determined by use
of fluorescence polarization immunoassay. The variables,
time to maximum acetaminophen concentration
(Tmax) and the appearance constant for acetaminophen
(Kapp), were determined. The values for
Kapp and Tmax in horses with and without prolonged
nasogastric tube placement were compared.
Results—No significant difference was found in Kapp
between horses with and without prolonged nasogastric
tube placement; the median difference in Kapp
was 0.01 min–1 (range, –0.48 to 0.80 min–1). No significant
difference was found in Tmax between horses
with and without prolonged nasogastric tube placement;
the median difference in Tmax was 5 minutes
(range, –30 to 50 minutes). Reanalysis of data following
the removal of possible outlier values from 1
horse resulted in a significant difference in Tmax
between horses with and without prolonged nasogastric
Conclusions and Clinical Relevance—Although no
clinically important impact of 18 hours of nasogastric
intubation was found on gastric emptying in healthy
horses, considerable variability in Kapp and Tmax was
found among horses. (Am J Vet Res 2005;66:642–645)
Objective—To assess signalment, history, results of
clinical and laboratory testing, and outcome for beef
cattle with a left displaced abomasum (LDA), right displaced
abomasum (RDA), or abomasal volvulus (AV).
Animals—19 beef cattle with an AV, LDA, or RDA.
Procedure—Signalment; history; results of physical
examination, diagnostic testing, and surgical exploration;
and condition of the animal at discharge were
obtained from medical records.
Results—Fourteen cattle had an AV, 4 had an RDA,
and 1 had an LDA. Duration of clinical signs ranged
from 1 to 21 days. Eighteen cattle had an AV or RDA;
7 were Brahmans, 12 were males, and median age
was 10 months. Abdominal distention was observed
in 11 cattle, heart rate of ≥ 100 beats/minute was
detected in 14, and the abomasum was palpable per
rectum in all cattle in which per rectal examination
was performed. Leukocytosis, neutrophilia, hyperglycemia,
azotemia, hypochloremia, and hypokalemia
were common laboratory findings. At surgery, 3 cattle
with an AV or RDA had a ruptured abomasum. Of the
remaining 15 cattle, 12 survived.
Conclusions—Clinical course in beef cattle with an
AV or RDA was more protracted than that typically
associated with these conditions in dairy cattle, but
survival rate in beef cattle that did not have rupture of
the abomasum was sim ilar to that of dairy cattle.
Clinical Relevance—Abomasal displacement should
be considered for beef cattle with abdominal distention.
Prognostic indicators recommended for use in
dairy cattle may not be useful for beef cattle. (J Am
Vet Med Assoc 2000;216:730–733)
Objective—To evaluate effects of IV administration of
penicillin G potassium (KPEN) or potassium chloride
(KCl) on defecation and myoelectric activity of the
cecum and pelvic flexure of horses.
Animals—5 healthy horses.
Procedure—Horses with 12 bipolar electrodes on the
cecum and pelvic flexure received KPEN or KCl solution
by IV bolus 4 hours apart. Each horse received
the following: 2 × 107 U of KPEN (high-dose KPEN) followed
by 34 mEq of KCl (high-dose KCl), 1 × 107 U of
KPEN (low-dose KPEN) followed by 17 mEq of KCl
(low-dose KCl), high-dose KCl followed by high-dose
KPEN, and low-dose KCl followed by low-dose KPEN.
Number of defecations and myoelectric activity were
recorded for 60 minutes. The first three 5-minute segments
and first four 15-minute segments of myoelectric
activity were analyzed.
Results—Number of defecations during the first 15-
minute segment was greater after high-dose KPEN
treatment than after high-dose or low-dose KCl treatment.
Compared with reference indexes, myoelectric
activity was greater in the pelvic flexure for the first 5-
minute segment after high-dose KCl treatment, in the
cecum and pelvic flexure for the first 5-minute segment
and in the pelvic flexure for the first 15-minute
segment after low-dose KPEN treatment, and in the
pelvic flexure for the first and second 5-minute segments
and the first three 15-minute segments after
high-dose KPEN treatment.
Conclusions and Clinical Relevance—IV administration
of KPEN stimulates defecation and myoelectric
activity of the cecum and pelvic flexure in horses.
Effects of KPEN may be beneficial during episodes of
ileus. (Am J Vet Res 2003;64:1360–1363)
Objective—To evaluate the effect of erythromycin on
motility of the ileum, cecum, and pelvic flexure of horses
during the postoperative and post-recovery periods.
Animals—8 healthy adult horses.
Procedure—Horses were anesthetized and bipolar
electrodes were implanted in smooth muscle of the
ileum, cecum, and pelvic flexure. Approximately 4, 16,
and 24 hours (postoperative recording sessions) and
at least 8 days (post-recovery recording session) after
surgery, myoelectric activity was recorded before and
after administration of erythromycin (0.5 mg/kg).
Results—Following erythromycin administration,
myoelectric activity was increased in the ileum during
all postoperative recording sessions but not during
the post-recovery recording session. Myoelectric
activity was increased in the cecum following erythromycin
administration only during the post-recovery
recording session. Myoelectric activity was
increased in the pelvic flexure following erythromycin
administration during all recording sessions. During
several recording sessions, there were short periods
during which myoelectric activity was significantly
decreased following erythromycin administration.
Conclusions and Clinical Relevance—Results suggest
that erythromycin has an effect on myoelectric
activity of the ileum, cecum, and pelvic flexure in
horses; however, prokinetic effects of erythromycin
administered during the postoperative period were
not always the same as effects obtained when the
drug was administered after horses had recovered
from the effects of surgical implantation of recording
devices. Therefore, caution must be exercised when
extrapolating results of prokinetic studies in healthy
animals to animals with abnormal gastrointestinal
tract motility. (Am J Vet Res 2000;61:420–424)
Objective—To determine results of ultrasound-guided cystocentesis and percutaneous infusion of Walpole's solution for treatment of male goats with urolithiasis.
Design—Retrospective case series.
Animals—25 male goats with urolithiasis treated with Walpole's solution.
Procedures—Information obtained from the medical records included signalment, degree of urethral obstruction (partial vs complete), pertinent examination findings, concurrent illnesses, diet, other treatments administered, duration of hospitalization, whether the obstruction resolved, and outcome (ie, discharged vs euthanized).
Results—14 (58%) animals had complete urethral obstruction, and 10 (42%) had partial obstruction (degree of urethral patency was not recorded in 1 animal). Walpole's solution was infused once in 18 (72%) animals, twice in 6 (24%) animals, and 3 times in 1 (4%) animal. The amount of Walpole's solution required to achieve the target urine pH of 4 to 5 ranged from 50 to 250 mL. In 20 (80%) goats, the urethral obstruction resolved, and the goat was discharged. The remaining 5 (20%) goats were euthanized because of unresolved urethral obstruction. Six of the 20 (30%) goats that were discharged were reexamined because of recurrence of urethral obstruction.
Conclusions and Clinical Relevance—Results suggested that ultrasound-guided cystocentesis in combination with percutaneous infusion of Walpole's solution may be a useful treatment in male goats with obstructive urolithiasis.
Objective—To develop a better system for classification of herd infection status for paratuberculosis (Johne's disease [JD]) in US cattle herds on the basis of the risk of potential transmission of Mycobacterium avium subsp paratubeculosis.
Sample—Simulated data for herd size and within-herd prevalence; sensitivity and specificity for test methods obtained from consensus-based estimates.
Procedures—Interrelationships among variables influencing interpretation and classification of herd infection status for JD were evaluated by use of simulated data for various herd sizes, true within-herd prevalences, and sampling and testing methods. The probability of finding ≥ 1 infected animal in herds was estimated for various testing methods and sample sizes by use of hypergeometric random sampling.
Results—2 main components were required for the new herd JD classification system: the probability of detection of infection determined on the basis of test results from a sample of animals and the maximum detected number of animals with positive test results. Tables were constructed of the estimated probability of detection of infection, and the maximum number of cattle with positive test results or fecal pools with positive culture results with 95% confidence for classification of herd JD infection status were plotted. Herd risk for JD was categorized on the basis of 95% confidence that the true within-herd prevalence was ≤ 15%, ≤ 10%, ≤ 5%, or ≤ 2%.
Conclusions and Clinical Relevance—Analysis of the findings indicated that a scientifically rigorous and transparent herd classification system for JD in cattle is feasible.
The report provided here contains a simplified set of diagnostic testing recommendations. These recommendations were developed on the basis of research funded by the USDA–Animal and Plant Health Inspection Service–Veterinary Services through a cooperative agreement. The report is intended to provide simple, practical, cost-effective consensus testing recommendations for cattle herds that are not enrolled in the US Test-Negative Program. The information has been reviewed by paratuberculosis (Johne's disease) experts at the USDA and academic centers as well as stakeholders in various segments of the cattle industry. The recommendations were accepted by the National Johne's Working Group and Johne's Disease Committee of the US Animal Health Association during their annual meetings in October 2006.
The report is intended to aid veterinarians who work with cattle producers in the United States. The recommendations are based on information available up to October 2006. There is a paucity of large-scale, high-quality studies of multiple tests conducted on samples obtained from the same cattle. It is understood that there may be special circumstances that require deviation from these recommendations. Furthermore, as new information becomes available and assays are improved and their accuracy is critically evaluated, changes to these recommendations may be necessary.
Objective—To evaluate the seroprevalence of paratuberculosis by use of 2 commercial ELISAs in association with prevalence of fecal shedding of mycobacteria within beef cattle herds.
Design—Cross-sectional field study.
Animals—Six beef herds (affected herds; 522 cattle) with and 3 geographically matched herds (181 cattle) without high seroprevalence of paratuberculosis.
Procedures—Blood and fecal samples were collected from adult cattle and assessed for serum anti–Mycobacterium avium subsp paratuberculosis (MAP) antibodies with 2 commercial ELISA kits and submitted for bacterial culture for MAP and environmental bacteria (termed environmental mycobacteria) via a radiometric method, respectively. Species of mycobacterial isolates were identified, and sensitivities and specificities of the 2 ELISAs were compared.
Results—Compared with comparison cattle, cattle from affected herds were 9.4 times as likely to have environmental mycobacteria isolated from feces. Among the 6 affected and 3 comparison herds, the proportions of cattle shedding environmental mycobacteria were 0.225 (range, 0.1 to 0.72) and 0.04 (range, 0 to 0.06), respectively. Although relative MAP-detection specificities (compared with bacterial culture of feces) were different between the 2 ELISAs, sensitivities were not. Nine environmental mycobacterial species were iden-tified from participating herds. All affected herds apparently had ≥ 1 bovid infected with MAP, although MAP was not isolated from any cattle in comparison herds.
Conclusions and Clinical Relevance—In beef herds with persistently high rates of false-positive ELISA results, which may be associated with recovery of environmental myco-bacteria from feces, organism detection via bacterial culture of feces or PCR assay should direct paratuberculosis control measures.
Objective—To evaluate the effect of exposure to environmental mycobacteria on results of 2 commercial ELISAs for paratuberculosis in cattle.
Animals—19 weaned crossbred beef calves.
Procedures—Calves were inoculated SC with 1 of 5 mycobacterial isolates (3 calves/isolate) derived from herds with high proportions of false-positive serologic reactions for paratuberculosis, Mycobacterium avium subsp paratuberculosis (MAP; positive control inoculum; 2 calves), or mineral oil (negative control inoculum; 2 calves). Sera were assessed at intervals by use of 2 ELISAs (A and B) for paratuberculosis in cattle, and all calves underwent tuberculosis testing at the end of the study.
Results—Neither mineral oil–inoculated calf had positive results with either ELISA during the study. Both MAP-inoculated calves were identified as seropositive via ELISA-A, and 1 calf was identified as seropositive via ELISA-B. By use of ELISA-A, ≥ 1 false-positive reaction over time was detected in 2, 3, 3, and 1 of the 3 calves injected with Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium scrofulaceum, or Mycobacterium terrae, respectively. By use of ELISA-B, only M scrofulaceum induced false-positive reactions (2/3 calves). Calves that had at least 1 positive ELISA-A result were more likely to be classified as suspect reactors via the caudal fold tuberculosis test.
Conclusions and Clinical Relevance—False-positive serologic reactions may occur during use of commercially available ELISAs for paratuberculosis in calves experimentally exposed to environmental mycobacteria; naturally occurring exposures with these mycobacteria may represent a cause for high proportions of false-positive serologic reactions for paratu-berculosis in some cattle herds.