American journal of veterinary research最新文献

Objective: To determine if activity associates with core temperature and biomarker changes in exercising hunting dogs.

Methods: A group of local, versatile hunting dogs participated in a single-day mock hunt trial consisting of 2 repeated runs separated by 15 minutes on March 4, 2024. Venipuncture for exercise biomarkers occurred just prior to run 1 and immediately after completion of both runs. Core temperature (ingested thermistors) and activity (collar-mounted Global Positioning System and accelerometer) data were recorded every minute.

Results: 18 dogs completed the trial (median age, 3.5 years). Myoglobin significantly increased at each time point, whereas lactate and creatine kinase were unchanged. There was variable significance associated with increases of AST, cortisol, and heat shock protein 70. Biomarkers failed to correlate with activity or core temperature. Core temperatures over time demonstrated a pattern in which near steady-state temperatures (median, 40.27 °C; range, 39.38 to 41.28) were reached at an "inflection point" occurring at a median of 19.5 minutes (range, 11.0 to 29.0) from exercise initiation. Analysis of activity and temperature until inflection revealed weak to modest positive correlations between speed and both and rate of temperature change (R2 = 0.31) and temperature differential (R2 = 0.38).

Conclusions: Myoglobin was the most sensitive biomarker of exercise but failed to correlate to activity. Faster speeds during initial exercise are associated with larger and faster increases in core temperature.

Clinical relevance: Myoglobin may act as a potential marker for subclinical exercise stress in dogs. Speed may be an important canine activity measure contributing to initial core temperature changes during exercise.

Objective: To create an IA reconstruction system resembling the natural cranial cruciate ligament (CCL) to stabilize CCL-deficient stifles in dogs and to assess the stability and biomechanical properties of the intact canine stifle versus the CCL-deficient stifle stabilized with the proposed reconstruction system.

Methods: The study was conducted over a 1-year period (March 2022 to March 2023) on 21 limbs from 14 skeletally mature mixed-breed cadaveric dogs with normal limbs. Cranial cruciate ligament inclination was measured in 21 stifles. Tensile strength and elongation were tested for 7 intact CCLs. Cranial cruciate ligament dimensions and volume were measured in 14 stifles. Seven CCL-severed stifles were stabilized with 3-D-braided silk/polyester (50:50), 2 H-buttons, and FiberWire and tested biomechanically. The graft was studied micromorphologically and biomechanically.

Results: Mean CCL dimensions were 7.5 ± 1.3 mm wide, 2.3 ± 0.5 mm thick, and 13.14 ± 2.9 mm long, with a volume of 250.4 ± 107.8 mm3. Mean ± SD tensile strength of the 3-D-braided silk-polyethylene terephthalate (S-PET) before (raw S-PET; 645.8 ± 61.1 N) and after (implanted S-PET; 952.6 ± 126.2 N) reconstruction was greater than that for intact CCL (518.4 ± 97.5 N). Mean elongation at break differed among groups: implanted S-PET (90 ± 19.79%), raw S-PET (18.1 ± 2.7%), and intact CCL (49.3 ± 5.3%). Cranial cruciate ligament dogs' age and body weight strongly correlated with CCL volume.

Conclusions: IA reconstruction using 3-D-braided S-PET and H-buttons effectively stabilized CCL-deficient canine stifles ex vivo.

Clinical relevance: This technique offers an alternative to extracapsular or osteotomy-based procedures and warrants further in vivo evaluation of long-term outcomes.

Objective: To quantify circulating levels of myokines with a known role in bone remodeling (receptor activator of nuclear factor κ B ligand [RANK-L], matrix metalloproteinase 2 [MMP-2], and irisin) in foals in response to exercise and over the first year of life.

Methods: 12 foals were enrolled in the study; 6 underwent an 8-week exercise program, and 6 were nonexercised controls. Blood samples were collected between 2 and 11 months of age. Receptor activator of nuclear factor κ B ligand, MMP-2, and irisin were quantified using equine-specific ELISAs.

Results: RANK-L, MMP-2, and irisin did not change directly in response to a modest exercise regimen in young foals. Exercised females had greater circulating irisin than their male counterparts; this difference was not present in control foals. Irisin decreased with age, and RANK-L trended toward a small increase with age over the course of the study, whereas MMP-2 did not change.

Conclusions: RANK-L may be worth further investigation as a biomarker for musculoskeletal remodeling during growth, but it could not discriminate between exercised and nonexercised groups in this study cohort. The sex-specific response of irisin in the exercise cohort was unexpected and supports further investigation into the complex interactions between the musculoskeletal system, hormones, and exercise in young foals. Additional studies are warranted to validate these study findings under various exercise conditions and correlate circulating myokine levels with changes in the bone properties of foals.

Clinical relevance: The use of serum levels of myokines as a proxy to evaluate active skeletal remodeling could provide a minimally invasive mechanism for assessing changes during normal growth and in response to exercise.

Objective: To determine whether cats meet National Research Council (NRC) recommendations for essential nutrient intake when energy restricted on various diets.

Methods: 3 diets for each diet group-veterinary weight loss, over-the-counter low calorie (LOWCAL), and OTC adult maintenance (ADULT)-were analyzed for amino acids and vitamins. Theoretical nutrient intakes with each diet under energy restriction were calculated using body weight (BW) and body condition score data of 16 adult obese cats from a previous in vivo weight-loss study. Six energy calculations (R1-6) were used: R1, 70 kcal/current BW0.75; R2, 0.8 X 70 kcal/cBW0.75; R3, 70 kcal/ideal BW (iBW)0.75; R4, 0.6 X 130 kcal/cBW0.4; R5, 0.8 X 70 kcal/iBW0.75; and R6, 0.6 X 130 kcal/iBW0.4. Calculated intakes were compared to NRC recommended allowance (RA) and minimum requirements for adult cats.

Results: Crude protein intake was below RA for LOWCAL at R4 and ADULT at R6 and below minimum requirements for ADULT at R6. Tryptophan and phenylalanine plus tyrosine intakes were below RA for ADULT at R4. Choline intake was below RA for veterinary weight loss at R2 and R4 through R6, for LOWCAL at R4 and R6, and for ADULT at R1 through R6.

Conclusions: Theoretical energy restriction using purpose-formulated weight-loss food resulted in only choline being below NRC recommendations. Most nutrient intakes met NRC recommendations for LOWCAL and ADULT, except for crude protein, tryptophan, phenylalanine plus tyrosine, and choline intakes.

Clinical relevance: Veterinary professionals should exercise caution when restricting energy for weight loss, particularly with over-the-counter diets, as they may not meet essential nutrient requirements at lower caloric intakes. Veterinary weight-loss foods are recommended to reduce the risk of nutrient deficiencies.

Objective: This study assessed the prevalence of compassion fatigue in Chilean small animal veterinarians and its relationship with years of practice, euthanasia frequency, and personality profiles.

Methods: A cross-sectional survey was conducted during October and December 2022 using the Secondary Traumatic Stress Scale and the Dominance, Influence, Stability, and Conscientiousness personality test. Questionnaires were distributed to registered veterinarians (n = 20,000) via email and social media, with inclusion criteria of ≥ 25 h/wk in a small animal practice. Statistical analyses included χ2 test, ANOVA, t tests, z tests, and Pearson correlations.

Results: A total of 197 veterinarians responded. All showed medium, high, or severe compassion fatigue. Of these, 179 (90.1%) had moderate-to-severe fatigue, with mean ± SD Secondary Traumatic Stress Scale scores of 62.9 ± 8.7 for severe (n = 141), 45.8 ± 1.3 for high (19), and 41.3 ± 1.5 for moderate (19). No significant differences were observed by gender. The most common Dominance, Influence, Stability, and Conscientiousness profile was perfectionist (n = 80 [40.6%]), which showed weak or no correlation with fatigue (r = -0.14 to 0.11). Years of practice and euthanasia frequency were also unrelated to fatigue severity.

Conclusions: Compassion fatigue is highly prevalent among Chilean small animal veterinarians, independent of gender, personality profile, or clinical experience.

Clinical relevance: The findings highlight the urgent need for proactive interventions to preserve veterinary well-being. Strategies include resilience and business training during veterinary education, emotional competency development, and workplace policies promoting mental health and work-life balance, all essential for ensuring sustainable and healthy veterinary practice.

Objective: To establish the feasibility of noncontrast microvascular flow ultrasonography for assessing renal cortical perfusion in cats.

Methods: 6 healthy, young neutered male anesthetized cats were enrolled in this prospective, exploratory, analytical study. Microvascular flow-based vascular index (VI) measurements were acquired from bilateral kidneys at normal (70 to 100 mm Hg mean arterial pressure [MAP]), low (< 60 mm Hg MAP), and high (> 100 mm Hg MAP) blood pressures as measured by an indwelling femoral arterial catheter. Renal interlobar artery resistive indices (RIs) were measured to confirm blood pressure effects on renal blood flow.

Results: For the 12 kidneys, the median VI and RI values (with IQR) at hypotension, normotension, and hypertension were VI, 41.6% (IQR, 36.8 to 46.8) and RI, 0.87 (IQR, 0.81 to 0.89); VI, 74.6% (IQR, 71.4 to 79) and RI, 0.70 (IQR, 0.62 to 0.73); and VI, 80.4% (IQR, 72.3 to 86.1) and RI, 0.59 (IQR, 0.55 to 0.67), respectively. The hypotension VI values were significantly lower than at normotension. Normotension VI values were not statistically different than hypertensive VI values, with overlapping IQR. There were strong correlations between RI and MAP (r = -0.785), between VI and MAP (r = +0.711), and between VI and RI (r = -0.751).

Conclusions: The study results confirm the feasibility of performing noncontrast microvascular flow ultrasound imaging in cats for the evaluation of renal cortical perfusion.

Clinical relevance: Data from this study will be utilized for study design development of future prospective clinical studies investigating clinical applications for noncontrast microvascular ultrasound assessment of renal cortical perfusion in cats with acute and chronic kidney disease.

Objective: To evaluate the pharmacokinetics of mirtazapine (MRZ) after single-dose oral administration in healthy adult alpacas and compare concentrations at 2 venous sampling sites.

Methods: This study was conducted during the weeks of January 29, 2024, and February 15, 2024. A single dose of 2 mg/kg MRZ was administered orally via syringe to 7 healthy adult alpacas. Blood was collected from jugular vein (JV; n = 7) and cephalic vein (CV; 5) catheters immediately prior to and at predetermined times for 24 hours after administration. Plasma MRZ concentrations were determined by UPLC-MS-MS. Pharmacokinetic parameters were determined for each sampling site, and statistical analysis was performed by paired t tests.

Results: Mean maximum plasma concentrations (Cmax) from JV samples (183 ± 95.2 ng/mL) occurred at time 0.0281 ± 0.029 hours and were significantly higher than CV samples' Cmax (4.84 ± 2.37 ng/mL), which occurred at time 0.464 ± 0.093 hours. Comparison of dose-corrected Cmax and area under the concentration-time curve from time zero extrapolated to infinity with those previously reported show the Cmax from JV samples in alpacas is similar to cats (166 ng/mL), but the Cmax from the CV samples failed to reach that reported in dogs (140 ng/mL) and people (123 ng/mL).

Conclusions: Plasma concentrations of MRZ were significantly different between sampling sites, resulting in different interpretations for potential use in alpacas.

Clinical relevance: Additional information is needed before using oral MRZ in alpacas, including studies of different doses, formulations, or routes of administration.

Objective: To evaluate the diagnostic performance of ELISA and PCR for detecting pathogenic oomycete infections and to explore associations with clinical presentation and treatment status.

Methods: Canine sera (n = 796) submitted to Pythium Serology Diagnostic Laboratory (from 2023 through 2025) were analyzed by ELISA to detect anti-Pythium antibodies and a PCR targeting Pythium insidiosum, Lagenidium spp, and Paralagenidium spp. Clinical records were reviewed for a subset of submissions. Analyses included χ2 tests, a linear mixed-effects model, and Cohen κ for ELISA-PCR agreement.

Results: Across all 697 samples tested by both methods, 69 (9.9%) were positive and 495 (71.0%) were negative by both assays, yielding an overall concordance of 81%. Polymerase chain reaction identified 5 cases, including cutaneous infections and Lagenidium infections tested to be negative by ELISA. Among confirmed positive submissions, ELISA detected anti-Pythium antibodies in 99.4% (182 of 183), whereas PCR detected Pythium DNA in 45.6% (72 of 158).

Conclusions: While ELISA is well suited for first-line screening due to its high sensitivity, PCR provides critical specificity and broader detection, especially in challenging cutaneous cases and when alternative pathogenic oomycetes are suspected. Enzyme-linked immunosorbent assay was highly effective for initial diagnosis and monitoring treatment response, and PCR was most useful for identifying active infections or relapses.

Clinical relevance: The combined use of ELISA and PCR enhances diagnostic accuracy, improves detection of misdiagnosed Lagenidium infections, and guides clinical decision-making and epidemiological surveillance of this emerging and serious disease.

Objective: To characterize healthy foot perfusion patterns under static weight-bearing load using 18F-fluorodeoxyglucose (18F-FDG) PET.

Methods: In 8 healthy adult light-breed horses (from May 2021 through September 2024), 18F-FDG was injected while horses stood continuously weight-bearing (CWB) for a 20-minute scan period. A repeat scan was then performed after 20 minutes of ambulation. On a separate occasion, scans were performed with ambulation allowed between injection and scanning (Amb_Control). 18F-fluorodeoxyglucose uptake was quantified via metabolic volume and standardized uptake values for coronary band, lamellae, and sole and compared using Friedman analyses.

Results: Discrete 18F-FDG uptake deficits of varying size were present in CWB scans, most commonly medially in both the sole (8 of 8) and quarter lamellae (7 of 8), reflected in reduced median metabolic volume (cubic centimeters) in the medial sole (14.5 CWB [IQR, 9.0 to 19.6] vs 22.2 Amb_Control [IQR, 20 to 22.8]) and medial lamellae (23.4 CWB [IQR, 19.6 to 26.3] vs 26.8 Amb_Control [IQR, 24.7 to 28.1]). The lamellar standardized uptake value mean was also reduced in CWB (1.35; IQR, 1.26 to 1.53) vs Amb_Control (1.58; IQR, 1.4 to 1.77). Uptake deficits partially resolved in the rescan and were absent in Amb_Control scans.

Conclusions: In healthy limbs scanned under static weight-bearing conditions, discrete regions of the medial sole and lamellae were devoid of 18F-FDG uptake, consistent with weight-bearing-associated perfusion deficits. The size and nature of these perfusion deficits varied between individuals, but they consistently resolved upon ambulation.

Clinical relevance: The role of weight-bearing-related perfusion deficits (detectable using PET) in the development of supporting-limb laminitis warrants further investigation in clinical patients.

Objective: To compare maximal lactate steady-state (MLSS) speeds determined using a treadmill-dependent invasive reference method (RM) with 2 noninvasive methods based on heart rate variability-focused analysis of exercise ECGs.

Methods: This was a randomized, blinded study using 7 fit Thoroughbreds. A standardized incremental exercise treadmill test (SET) where blood lactate concentration ([La]) was measured after every step facilitated calculation of speeds at which [La] was 1.5, 2.0, and 2.5 mmol/L. The RM required steady-state exercise (SS) at each of these speeds for 25 minutes or until [La] increased > 1 mmol/L from that after 5 minutes of exercise. The fastest speed at which a horse ran was 25 minutes at SS = MLSS. Electrocardiograms were recorded for each SET and SS, assigned randomized numbers, and distributed for analyses using (1) detrended fluctuation analysis-α1 (DFAα1), and (2) smartphone-capable 4- to 30-Hz spectral analysis to determine the speed associated with the minimum number of major peaks (MPs). Bland-Altman plots assessed agreement between methods and paired t tests compared RM MLSS speeds with those calculated from the SET and SS by DFAα1 and MPs, respectively (P < .05).

Results: The RM MLSS was not different from MLSS determined by MPs from SS runs, and Bland-Altman plots revealed good agreement between these speeds but wide 95% agreement intervals. Comparisons of RM MLSS with other methods showed an approximately equal to 1-m/s bias and poor agreement.

Conclusions: Major peaks but not DFAα1 provided acceptable estimates of MLSS from ECGs recorded during SS.

Clinical relevance: Major peaks may be a practically useful noninvasive exercise ECG-based field method for estimating MLSS if the variability between calculated MP and MLSS speeds can be reduced.