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Abstract

OBJECTIVE

The goal of this study was to determine plasma, urine, and synovial fluid concentrations and describe the effects on biomarkers of cartilage toxicity following intra-articular dexmedetomidine administration to horses.

ANIMALS

12 research horses.

PROCEDURES

Horses received a single intra-articular administration of 1 μg/kg or 5 μg/kg dexmedetomidine or saline. Plasma, urine, and synovial fluid were collected prior to and up to 48 hours postadministration, and concentrations were determined. The effects on CS846 and C2C were determined in synovial fluid at 0, 12, and 24 hours postadministration using immunoassays.

RESULTS

Plasma concentrations of dexmedetomidine fell below the limit of quantification (LOQ) (0.005 ng/mL) by 2.5 and 8 hours postadministration of 1 and 5 μg/kg, respectively. Synovial fluid concentrations were above the LOQ (0.1 ng/mL) of the assay at 24 hours in both dose groups. Drug was not detected in urine samples at any time postdrug administration. CS846 concentrations were significantly decreased relative to baseline at 12 hours postadministration in the saline group and significantly increased in the 5-μg/kg-dose group at 24 hours. Concentrations of C2C were significantly decreased at 12 and 24 hours postadministration in the saline treatment group. There were no significant differences in CS846 or C2C concentrations between dose groups at any time.

CLINICAL RELEVANCE

Systemic concentrations of dexmedetomidine remained low, compared to synovial fluid concentrations. CS846, a marker of articular cartilage synthesis, increased in a dose-dependent fashion. Based on these findings, further dose titration and investigation of analgesic and adverse effects are warranted.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate the pharmacokinetics of terbinafine administered to western pond turtles (Actinemys marmorata) via oral gavage and bioencapsulated in earthworms.

ANIMALS

7 western pond turtles.

PROCEDURES

A randomized complete crossover single-dose pharmacokinetic study was performed. Compounded terbinafine (25 mg/mL; 30 mg/kg) was administered through oral gavage (OG) directly into the stomach or bioencapsulated (BEC) into an earthworm vehicle. Blood (0.2 mL) was drawn from the jugular vein at 0, 0.5, 1, 2, 4, 8, 12, 24, 48, 72, and 120 hours after administration. Plasma terbinafine levels were measured using high-performance liquid chromatography.

RESULTS

Peak plasma terbinafine concentrations of 786.9 ± 911 ng/mL and 1,022.2 ± 911 were measured at 1.8 ± 2.8 and 14.1 ± 12.3 hours after OG and BEC administration, respectively. There was a significant (P = .031) increase in area under the curve with BEC compared to OG. Using steady-state predictions, with once-daily terbinafine administration, 3/7 and 7/7 turtles had plasma concentrations persistently greater than the minimum inhibitory concentration (MIC) for Emydomyces testavorans for the OG and BEC administration routes of administration, respectively. With administration every 48 hours, 3/7 turtles for the OG phase and 6/7 turtles for the BEC phase had concentrations greater than the E. testavorans MIC throughout the entire dosing interval.

CLINICAL RELEVANCE

Administration of terbinafine (30 mg/kg) every 24 or 48 hours via earthworm bioencapsulation in western pond turtles may be appropriate for the treatment of shell lesions caused by E. testavorans. Clinical studies are needed to assess the efficacy of treatment.

Open access
in American Journal of Veterinary Research

Abstract

Longevity and herd turnover rate are becoming common topics of discussion as the dairy industry strives for continuous improvement in efficiency, profitability, animal welfare, and environmental sustainability. Having the most productive animal fill each slot on a dairy makes strategic replacement and the resulting herd turnover an important tool for producers. Dairy operations can be considered to have slots available to be occupied by cows. The number of slots available is governed by dairy characteristics including parlor size and facility design. With sustainability and profitability goals, producers should aim to fill each slot with the most productive animal. The advantages of a modest surplus of replacement heifers allowing for a higher herd turnover rate are examined and shown to improve herd profitability, enhance welfare, and reduce environmental impact. A model assuming constant demand for dairy foods is presented with increased herd turnover rate leading to more milk production per cow and reduced enteric methane emissions. This analysis demonstrates that all else being equal, raising more replacements (having a relatively higher herd turnover rate and decreased herd-level longevity) improves sustainability compared to management aimed at lower herd turnover rates. Understanding the drivers of herd turnover in dairy production has important implications for the components of one health: animal well-being, food production, and environmental stewardship. The present work examines one tool toward this goal, while the companion Currents in One Health by Nguyen et al, JAVMA, January 2023, takes a broader view of many aspects of dairy sustainability.

Open access
in American Journal of Veterinary Research
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association
Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To estimate the effects of practice ownership on wellbeing of US private practice veterinarians.

Sample

1,217 practice owners and 1,414 associate veterinarians (ie, nonowners) who participated in the 2021 AVMA Census of Veterinarians and Practice Owners Survey.

Procedures

A professional quality of life instrument was used to measure compassion satisfaction (CS; a positive attribute), burnout (BO), and secondary traumatic stress (STS) in practice owners and nonowners both as scores and as score categories (low, moderate, and high CS, BO, and STS). For hypothesis tests, propensity score matching was used, with owners (n = 595) matched to nonowners (595) on several demographic and employment factors.

Results

Owners had significantly (P < .001) higher CS scores (mean ± SE, 34.1 ± 0.3) and lower BO scores (26.1 ± 0.3) than nonowners (32.8 ± 0.3 and 26.9 ± 0.3, respectively), but STS scores were comparable between groups (27.4 ± 0.3 and 27.5 ± 0.3; P = .55). The prevalence of low CS scores and high BO scores was significantly (P < .001) higher for nonowners versus owners (53.8% vs 42.7% and 51.6% vs 46.4%, respectively). Both owners and nonowners had a high prevalence of high STS scores (81.8% and 83.2%, respectively; P = .53).

Clinical Relevance

Results suggested that practice ownership confers a benefit to private practice veterinarians in terms of CS and BO, but not STS. The prevalence of poor CS, BO, and STS scores was higher than reported previously for 2016 to 2018, suggesting an impact of the COVID-19 pandemic. The high prevalence of high STS scores in both groups warrants attention and action to protect the welfare of the veterinary workforce and support optimal patient care.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To measure the mitral annulus in dogs. Our hypothesis was that mitral measurement would be possible and consistent among observers using CT.

SAMPLE

Thoracic CT scans of dogs without known heart disease.

PROCEDURES

Five trained investigators measured 4 aspects of the mitral valve and the fourth thoracic vertebrae (T4) length using multiplanar reformatting tools. Ten randomly chosen animals were measured by all investigators to determine interobserver reliability.

RESULTS

There were 233 CT scans eligible for inclusion. Dogs weighed 2 to 96 kg (mean, 28.1 kg), with a variety of breeds represented. Golden Retrievers (n = 28) and Labrador Retrievers (n = 37) were overrepresented. The intraclass correlations were all greater than 0.9, showing excellent agreement between observers. The means and SDs of each measurement were as follows: trigone-to-trigone distance, 17.2 ± 4.7 mm; the remaining circumference, 79.0 ± 17.5 mm; commissure-to-commissure distance, 30.8 ± 6.5 mm; septal leaflet-to-lateral leaflet distance, 26.3 ± 6.0 mm; T4 length, 16.9 ± 3.1 mm; and the total circumference normalized by T4, 5.7 ± 0.7 mm.

CLINICAL RELEVANCE

This study provides information that may help in the development of future treatment for mitral valve dysfunction and subsequent annular enlargement.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine luteinizing hormone receptor (LHR) expression and response to LHR activation in isolated canine splenic hemangiosarcoma cell lines in vitro.

SAMPLES

In vitro cultures of commercially available canine splenic hemangiosarcoma cell lines (EFS, GRACE-HSA, and DAL-4).

PROCEDURES

The percentage of each cell line expressing LHR was determined by immunocytochemistry. Cells were then treated with increasing doses (7.5 ng/mL, 75 ng/mL) of recombinant canine luteinizing hormone (cLH) for 48 hours and evaluated using a cell proliferation assay.

RESULTS

The percentage of cells expressing LHR was 17.2 ± 4.5%, 11.8 ± 3.1%, and 6.9 ± 2.5% in EFS, GRACE-HSA, and DAL-4, respectively. There was significant increase in cell count in the DAL-4 and EFS cell lines following a 48-hour incubation at the highest cLH concentration (P = .028 and P = .019, respectively). There was not a significant increase in cell count in the GRACE-HSA cell line at either cLH concentration.

CLINICAL RELEVANCE

Activation of LHR results in cell proliferation in some canine splenic hemangiosarcoma cell lines. These results may explain why spayed and castrated dogs with high circulating LH concentrations may develop hemangiosarcoma more frequently than intact dogs.

Open access
in American Journal of Veterinary Research