Objective—To determine whether use of serologic
evaluation of a sentinel sample of calves or cows for
antibodies against bovine viral diarrhea virus (BVDV)
would accurately predict whether an animal persistently
infected with BVDV could be detected in beef
Sample Population—27 cow-calf herds in which the
status of persistently infected calves was not known and
11 herds known to have persistently infected calves.
Procedure—Detection of persistently infected calves
was determined through immunohistochemical testing
of tissue obtained at necropsy of all calves that
died during calving season and skin (ear notch) specimens
obtained from all young stock in the fall of
2002. Serum samples were collected from 30 springborn
calves and 10 mature cows.
Results—Optimum serologic test performance at
time of weaning was detected when 10 calves were
evaluated. At least 3 of 10 randomly selected calves
were likely to have a titer > 1:1,000 against BVDV
type I or II in 53% of herds in which a persistently
infected calf was detected during that year (sensitivity,
53%). However, at least 3 of 10 randomly selected
calves were also likely to have a titer > 1:1,000 in
20% of herds that did not have a persistently infected
calf detected during that year (specificity, 80%).
Conclusions and Clinical Relevance—Despite the
use of a number of various cutoff values and sample
sizes, serologic evaluation of a small number of calves
or cows could not be used to accurately predict the
presence of persistently infected cattle in a herd. (Am
J Vet Res 2005;66:825–834)
Objective—To measure associations between health and productivity in cow-calf beef herds and persistent infection with bovine viral diarrhea virus (BVDV), antibodies against BVDV, or antibodies against infectious bovine rhinotracheitis (IBR) virus in calves.
Animals—1,782 calves from 61 beef herds.
Procedures—Calf serum samples were analyzed at weaning for antibodies against type 1 and type 2 BVDV and IBR virus. Skin biopsy specimens from 5,704 weaned calves were tested immunohistochemically to identify persistently infected (PI) calves. Herd production records and individual calf treatment and weaning weight records were collected.
Results—There was no association between the proportion of calves with antibodies against BVDV or IBR virus and herd prevalence of abortion, stillbirth, calf death, or nonpregnancy. Calf death risk was higher in herds in which a PI calf was detected, and PI calves were more likely to be treated and typically weighed substantially less than herdmates at weaning. Calves with high antibody titers suggesting exposure to BVDV typically weighed less than calves that had no evidence of exposure.
Conclusions and Clinical Relevance—BVDV infection, as indicated by the presence of PI calves and serologic evidence of infection in weaned calves, appeared to have the most substantial effect on productivity because of higher calf death risk and treatment risk and lower calf weaning weight.
Objective—To determine whether a combination viral
vaccine containing modified-live bovine herpesvirus-1
(BHV-1) would protect calves from infection with a
recent field isolate of BHV-1.
Design—Randomized controlled trial.
Animals—Sixty 4- to 6-month-old beef calves.
Procedure—Calves were inoculated with a placebo
42 and 20 days prior to challenge (group 1; n = 10) or
with the combination vaccine 42 and 20 days prior to
challenge (group 2; 10), 146 and 126 days prior to challenge
(group 3; 10), 117 and 96 days prior to challenge
(group 4; 10), 86 and 65 days prior to challenge (group
5; 10), or 126 days prior to challenge (group 6; 10). All
calves were challenged with BHV-1 via aerosol.
Clinical signs, immune responses, and nasal shedding
of virus were monitored for 14 days after challenge.
Results—Vaccination elicited increases in BHV-1–specific
IgG antibody titers. Challenge with BHV-1 resulted
in mild respiratory tract disease in all groups, but
vaccinated calves had less severe signs of clinical disease.
Extent and duration of nasal BHV-1 shedding following
challenge was significantly lower in vaccinated
calves than in control calves. In calves that received 2
doses of the vaccine, the degree of protection varied
with the interval between the last vaccination and
challenge, as evidenced by increases in risk of clinical
signs and extent and duration of viral shedding.
Conclusions and Clinical Relevance—Results suggest
that this combination vaccine provided protection from
infection with virulent BHV-1 and significantly reduced
nasal shedding of the virus for at least 126 days after vaccination.
(J Am Vet Med Assoc 2005;227:123–128)
Objective—To determine effects of athletic conditioning
on thyroid hormone concentrations in a population
of healthy sled dogs.
Animals—19 healthy adult sled dogs.
Procedure—Serum concentrations of thyroxine (T4),
triiodothyronine (T3), thyroid-stimulating hormone
(TSH), free T4 (fT4), free T3 (fT3), and autoantibodies
directed against T3, T4, and thyroglobulin were measured
in sled dogs that were not in training (ie, nonracing
season) and again after dogs had been training
at maximum athletic potential for 4 months.
Results—Analysis revealed significant decreases in
T4 and fT4 concentrations and a significant increase in
TSH concentration for dogs in the peak training state,
compared with concentrations for dogs in the
untrained state. Serum concentrations of T4 and fT4
were less than established reference ranges during
the peak training state for 11 of 19 and 8 of 19 dogs,
respectively; fT4 concentration was greater than the
established reference range in 9 of 19 dogs in the
Conclusions and Clinical Relevance—Decreased
total T4 and fT4 concentrations and increased serum
concentrations of TSH were consistently measured
during the peak training state in healthy sled dogs,
compared with concentrations determined during the
untrained state. Although thyroid hormone concentrations
remained within the established reference
ranges in many of the dogs, values that were outside
the reference range in some dogs could potentially
lead to an incorrect assessment of thyroid status.
Endurance training has a profound impact on the thyroid
hormone concentrations of competitive sled
dogs. ( Am J Vet Res 2004;65:333–337)
OBJECTIVE To identify whether age, sex, or breed is associated with crown height of the left and right maxillary first molar tooth (M1) measured on CT images, to develop a mathematical model to determine age of horses by use of M1 crown height, and to determine the correlation between M1 crown height measured on radiographic and CT images.
SAMPLE CT (n = 735) and radiographic images (35) of the heads of horses.
PROCEDURES Crown height of left and right M1 was digitally measured on axial CT views. Height was measured on a lateral radiographic image when available. Linear regression analysis was used to identify factors associated with crown height. Half the data set was subsequently used to generate a regression model to predict age on the basis of M1 crown height, and the other half was used to validate accuracy of the predictions.
RESULTS M1 crown height decreased with increasing age, but the rate of decrease slowed with increasing age. Height also differed by sex and breed. The model most accurately reflected age of horses < 10 years old, although age was overestimated by a mean of 0.1 years. The correlation between radiographic and CT crown height of M1 was 0.91; the mean for radiographic measurements was 2.5 mm greater than for CT measurements.
CONCLUSIONS AND CLINICAL RELEVANCE M1 crown height can be used to predict age of horses. Results for CT images correlated well with those for radiographic images. Studies are needed to develop a comparable model with results for radiographic images.
Objective—To determine associations between serum concentrations of copper, molybdenum, selenium, vitamin A, and vitamin E measured in beef cows at the start of the community pasture breeding season and pregnancy status at the end of the season.
Design—Prospective cohort study.
Animals—771 beef cows from 39 cow-calf herds.
Procedures—Serum micronutrient concentrations were measured in samples collected from cows on arrival at 5 different community pastures in Saskatchewan, Canada, in May 2008. Cows were palpated transrectally to determine pregnancy status in October 2008. Herd owners and professional herd managers were surveyed to collect individual data for cows (age, calving date, and history of exposure to bulls before the start of the breeding season) and information on herd and breeding management. Associations between animal-, herd-, and pasture-level variables and pregnancy status were examined.
Results—Serum concentrations of selenium, molybdenum, vitamin A, and vitamin E were not associated with pregnancy status after accounting for prebreeding body condition score, age, and calving-to-breeding interval. Serum copper concentrations were more commonly assessed as below adequate than were other micronutrients. Decreased serum copper concentrations were associated with increased odds of nonpregnancy in cows < 10 years of age.
Conclusions and Clinical Relevance—Prebreeding micronutrient supplementation programs should be carefully managed in herds with poor reproductive performance in areas known to be copper deficient, and evaluation of serum copper concentrations from a subset of cows should be considered before the start of the breeding season.
To describe response rate, tumor progression, patient survival times, prognostic factors associated with tumor progression and patient survival times, and radiation toxicoses (acute and latent) in dogs treated with curative-intent stereotactic body radiation therapy (SBRT) for soft tissue sarcomas (STS).
35 client-owned dogs with STS treated with curative-intent SBRT between October 2011 and May 2017.
Medical records were reviewed to identify dogs that underwent SBRT. Dogs with oral tumors, hemangiosarcoma, or histiocytic sarcoma were excluded. Data collected included patient-, STS-, and SBRT-related information, including follow-up information pertaining to tumor progression and patient survival time for ≥ 6 months, unless tumor progression or patient death occurred sooner.
Objective measurements allowing for evaluation of tumor response were available for 28 dogs, of which 13 (46%) had either a partial (10/28 [36%]) or complete (3/28 [11%]) response. Twenty-four dogs died, and the medians for progression-free survival time, time to progression of disease, overall survival time, and disease-specific survival time were 521, 705, 713, and 1,149 days, respectively. Low histologic grade and extremity locations of STSs were positive prognostic factors for patient survival times. Acute adverse effects were limited to skin, and 1 dog underwent limb amputation because of a nonhealing wound.
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated that SBRT for STS was well tolerated in most dogs and provided local tumor control. Additional studies are needed to determine the best SBRT protocol for treatment of STSs in dogs.
OBJECTIVE To describe self-reported use of x-ray personal protective equipment (PPE) by veterinary workers in Saskatchewan, Canada, and to examine factors that affected their use of x-ray PPE.
DESIGN Cross-sectional survey.
SAMPLE 331 veterinary workers.
PROCEDURES A questionnaire was distributed to Saskatchewan veterinary workers electronically and by conventional mail. Recipients were encouraged to share the questionnaire with colleagues. The questionnaire consisted of questions regarding radiation safety practices used during small animal radiographic procedures, including frequency of use of dosimeters and lead aprons, thyroid shields, eyeglasses, and gloves. Respondents were also requested to provide suggestions for increasing use of PPE.
RESULTS 460 questionnaires were completed, of which 331 were returned by workers involved with performing radiographic procedures. Two hundred eighty-five of 331 (86%) respondents reported that at least 1 worker was always in the room during x-ray exposure, and 325 (98%), 291 (88%), and 9 (3%) respondents reported always wearing a lead apron, thyroid shield, and protective eyeglasses, respectively, during radiographic imaging. Two hundred seventeen of 327 (66%) respondents used lead gloves correctly less than half the time. Mean percentage of time that gloves were worn correctly was higher for workers who were required to do so by their employers than for those who were not.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested use of PPE during radiographic procedures can be increased by employers making PPE use mandatory. Other respondent-identified factors that would increase PPE use included the availability of properly fitting and functional PPE and education of workers about health risks associated with ionizing radiation exposure.
Objective—To determine the prevalence of antibodies against a swine-origin Helicobacter pylori–like organism (HPLO) and H pylori in conventionally reared swine.
Animals—640 conventionally reared swine of various ages from 16 high-health farms in Canada, 20 sows from Ohio, and 35 gnotobiotic swine.
Procedures—Blood was collected from the cranial vena cava. Sera were collected and tested via ELISA for antibodies against antigen prepared from a swine-origin HPLO and human H pylori strain 26695.
Results—Antibodies reactive with a swine HPLO, H pylori, or both were detected in 483 of 640 swine from all 16 farms in western Canada. Seroprevalence varied with age and was low (5.6%) in suckling (≤ 4-week-old) swine and increasingly high in swine ranging from > 4 weeks old to adulthood.
Conclusions and Clinical Relevance—Findings suggested that colonization by a swine-origin HPLO, H pylori, or both and resultant seroconversion, like that of H pylori infection in humans, were common in commercial swine operations. Furthermore, data indicated that gastric infection was acquired at an early age. The relationships to gastric colonization by HPLOs and clinical manifestations of disease such as gastritis and gastroesophageal ulceration remain to be determined.
To describe self-reported radiation safety practices by equine veterinary technicians in North America and identify factors associated with these practices.
154 equine technicians.
An electronic questionnaire regarding radiation safety practices during the use of portable x-ray equipment was sent to 884 members of the American Association of Equine Veterinary Technicians and Assistants. Data were summarized, and various factors were evaluated for associations with reported safety practices.
221 of 884 (25.0%) questionnaires were completed, including 154 by equine technicians who had been involved in equine radiography as x-ray tube operators, cassette holders, or both in the previous year. Lead apron use was suboptimal, reported as “always” for 80.0% (104/130) of tube operators and 83.1% (123/148) of cassette holders. Approximately 20% of participants never wore thyroid shields, and approximately 90% never wore lead eyeglasses. Almost 50% of participants did not have lead eyeglasses available. Although > 55% of participants always held the x-ray equipment by hand, 58.4% (73/125) of tube operators and 25.0% (35/140) of cassette holders never wore gloves. Cassette holders wore lead gloves and personal radiation dose–monitoring devices significantly more frequently than did tube operators.
CONCLUSIONS AND CLINICAL RELEVANCE
Compliance of North American equine technicians with radiation safety recommendations by the National Council on Radiation Protection and Measurements was suboptimal. Improvements in radiation safety training and education, strengthening the connection between academic institutions and private practices, and greater availability and requirement of personal protective equipment use by senior clinicians and employers might aid in improving safety practices.