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 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.
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 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 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 assess outcomes, factors associated with survival time, and radiation-induced toxicoses in dogs treated for nasal tumors with curative-intent stereotactic body radiation therapy (SBRT).
DESIGN Retrospective case series.
ANIMALS 28 client-owned dogs.
PROCEDURES By use of a 6-MV linear accelerator, dogs were treated with SBRT (3 consecutive-day fractions of 9 or 10 Gy or once with 1 fraction of 20 Gy). Data regarding adverse effects, outcomes, and survival times were obtained from the medical records.
RESULTS The median survival time to death due to any cause was 388 days. Of the 24 dogs known to be dead, 14 (58%) died or were euthanized because of local disease progression. Acute radiation-induced adverse effects developed in the skin (excluding alopecia) in 26% (6/23) of dogs and in the oral cavity in 30% (7/23) of dogs. Acute ocular adverse effects included discharge in 26% (6/23) of dogs and keratoconjunctivitis sicca in 4% (1/23) of dogs. Among the 22 dogs alive at > 6 months after SBRT, 4 (18%) developed a unilateral cataract; 4 (18%) developed other complications that may have been late-onset radiation toxicoses (excluding leukotrichia and skin hyperpigmentation).
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs treated with SBRT had outcomes comparable to those reported for dogs with nasal carcinomas and sarcomas that undergo conventionally fractionated radiation therapy. Administration of SBRT was associated with a comparatively lower frequency of acute radiation-induced adverse effects. For SBRT and conventionally fractionated radiation therapy, the frequencies of serious late-onset adverse effects appear similar.
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 measure respiratory motion of the thoracic wall region in dogs using a real-time motion tracking system and compare the amount of respiratory motion between dogs positioned with and without a vacuum-formable cushion.
Procedures—Dogs were anesthetized and positioned in sternal and dorsal recumbency with and without a vacuum-formable cushion. Three-dimensional movement of anatomic landmarks was measured with a real-time motion capture system that tracked the locations of infrared light–emitting diodes attached externally to the dorsal or ventral and lateral aspects of the thoracic wall.
Results—Dogs positioned in sternal recumbency had significantly less cranial-to-caudal and left-to-right respiratory motion at the lateral aspect of the thoracic wall, compared with dogs positioned in dorsal recumbency, whether or not a cushion was used. For dogs treated in sternal recumbency, use of a cushion significantly increased the peak displacement vector (overall movement in 3-D space) for 3 of 4 marker locations on the dorsal thoracic wall. As respiratory rate increased, respiratory motion at the lateral and ventral aspects of the thoracic wall decreased when data for all dogs in dorsal recumbency were evaluated together.
Conclusions and Clinical Relevance—Associations between respiratory rate and respiratory motion suggested that the use of rapid, shallow ventilation may be beneficial for dogs undergoing highly conformal radiation treatment. These results provide a basis for further research on respiratory motion in anesthetized dogs.
Objective—To describe the degree of and variability
in the level of client compliance and identify determinants
of client compliance with short-term administration
of antimicrobial medications to dogs.
Sample Population—90 owners of dogs prescribed
Procedure—Eligible clients were invited to participate
when antimicrobial medications were dispensed. Data
were collected during a follow-up appointment by use of
a client questionnaire, residual pill count, and return of an
electronic medication monitoring device. Attending veterinarians
also completed a questionnaire that asked
them to predict client compliance. Methods of assessing
compliance were compared with nonparametric
tests. Generalized estimating equations were used to
investigate potential determinants of compliance.
Results—Median compliance rates of 97% of prescribed
container openings, 91% of days when the
correct number of doses were given, and 64% of
doses given on time as assessed by the electronic
medication monitoring devices were significantly
lower than the median compliance rates of 100% for
client self-report of missing doses and pill count.
Veterinarians were unable to predict client compliance.
The dosage regimen significantly determined
compliance. Clients giving antimicrobials once or
twice daily were 9 times more likely to be 100% compliant,
compared with 3 times daily dosing.
Conclusions and Clinical Relevance—The combination
of reported missed doses and pill counts was a
significant predictor of compliance as measured by
electronic monitoring. Electronic monitoring caps provided
useful information only when they were used
appropriately. Asking clients about missed doses and
performing pill counts are the most practical assessments
of compliance in practice. (J Am Vet Med Assoc