OBJECTIVE To determine the optimal intercostal space (ICS) for thoracoscopic-assisted pulmonary surgery for lung lobectomy in cats. SAMPLE 8 cat cadavers. PROCEDURES Cadavers were placed in lateral recumbency. A 5-cm minithoracotomy incision was made in the middle third of ICS 4 through 7 on the left side and 4 through 8 on the right side, and a wound retractor device was placed. A camera port was made in the middle third of ICS 9. Each lung lobe was sequentially exteriorized at each respective ICS. A thoracoabdominal stapler was placed to simulate a lung lobectomy, and distance from the stapler anvil to the hilus was measured. RESULTS For the left cranial lung lobe, there was no significant difference in median distance from the stapler anvil to the pulmonary hilus for ICS 4 through 6. Simulated lobectomy of the left caudal lung lobe performed at ICS 5 and 6 resulted in a significantly shorter distance, compared with lobectomy performed at ICS 4 and 7. Simulated lobectomy of the right cranial and right middle lung lobes performed at ICS 4 and 5 resulted in a significantly shorter distance, compared with lobectomy performed at ICS 7. Simulated lobectomy of the accessory and right caudal lung lobes at ICS 5 and 6 resulted in a significantly shorter distance than for lobectomy performed at ICS 8. CONCLUSIONS AND CLINICAL RELEVANCE An optimal ICS for a minithoracotomy incision was determined for thoracoscopic-assisted lung lobectomy in cats.

OBJECTIVE To evaluate the clinicopathologic, hemodynamic, and echocardiographic effects of short-term administration of anti-inflammatory dosages of prednisolone to systemically normal cats. ANIMALS 10 cats with allergic dermatitis and 10 healthy control cats. PROCEDURES Cats with allergic dermatitis were randomly allocated to 2 groups and received 2 dosages of prednisolone (1 and 2 mg/kg/d, PO, for 7 days) in a crossover design followed by 9-day tapering and 14-day washout periods. Each prednisolone-treated cat was matched to a healthy control cat on the basis of sex, neuter status, age (± 1 year), and body weight (± 10%). Control cats received no treatment during the 35-day observation period. Clinicopathologic, echocardiographic, and hemodynamic variables were measured at baseline (day 0) and predetermined times during and after prednisolone administration and compared within and between the 2 treatment groups. RESULTS Prednisolone-treated cats had expected clinicopathologic alterations (mild increases in neutrophil and monocyte counts and serum concentrations of albumin, cholesterol, and triglycerides) but systolic arterial blood pressure; blood glucose, serum potassium, and cardiac biomarker concentrations; urinary sodium excretion; and echocardiographic variables did not differ significantly from baseline at any time. Statistically significant, albeit clinically irrelevant, increases in blood glucose and N-terminal pro-B-type natriuretic peptide concentrations were observed between baseline and the prednisolone pharmacokinetic steady state (7 days after initiation) only when the 2-mg/kg dosage was administered. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated short-term oral administration of anti-inflammatory dosages of prednisolone did not cause relevant hemodynamic, echocardiographic, or diabetogenic effects in systemically normal cats with allergic dermatitis.

OBJECTIVE To determine the pharmacokinetics of enrofloxacin after IV administration in American black vultures (Coragyps atratus), to compare clearance of enrofloxacin in American black vultures with clearance of this fluoroquinolone in other avian species, and to evaluate whether allometric scaling is an appropriate tool for dose extrapolation in avian species. ANIMALS 6 healthy adult American black vultures. PROCEDURES Enrofloxacin concentrations were quantified by use of high-performance liquid chromatography. Pharmacokinetics of enrofloxacin was determined in American black vultures after IV administration. Pharmacokinetic parameters for 12 avian species obtained from 24 pharmacokinetic studies were used. Allometric analysis of enrofloxacin pharmacokinetic parameters was performed. RESULTS Volume of distribution at steady state for enrofloxacin was 3.47 L/kg, clearance was 0.147 L/h·kg, and elimination half-life was 18.3 hours. Comparisons among avian species revealed that American black vultures had the lowest extraction ratio for enrofloxacin (1.04%). Only the volume of distribution at steady state and clearance had a good allometric fit. Goodness of fit was improved when ratites were not included in the analysis. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the use of allometric scaling for the prediction of volume of distribution at steady state could provide a suitable method for extrapolation of enrofloxacin doses among avian species; however, allometric scaling could not be used to adequately predict the clearance of enrofloxacin.

OBJECTIVE To radiographically compare patellar ligament length (PLL) in dogs undergoing tibial plateau leveling osteotomy (TPLO) for unilateral cranial cruciate ligament rupture at preoperative, postoperative, and follow-up evaluations. ANIMALS 105 dogs that underwent TPLO for unilateral cranial cruciate ligament rupture at a referral veterinary hospital from October 1, 2008, through November 30, 2017. PROCEDURES Medical records were reviewed to obtain information on dog signalment, surgical procedure, and radiographically measured PLL at preoperative, postoperative, and follow-up evaluations. RESULTS Dogs undergoing TPLO had a shorter PLL at the postoperative and follow-up evaluations, compared with the PLL at the preoperative evaluation. Mean ± SD overall unadjusted PLL decreased significantly by 2.3 ± 3.4% between the preoperative and postoperative evaluation and by 2.8 ± 3.9% between the preoperative and follow-up evaluation. The PLL did not differ significantly between the postoperative and follow-up evaluation; mean PLL decreased by 0.4 ± 3.8% between the postoperative and follow-up evaluation. CONCLUSIONS AND CLINICAL RELEVANCE The PLL was shorter after TPLO in dogs, which was similar to changes observed for humans after high tibial osteotomy procedures. Further evaluation of clinical assessments, joint mobility, ultrasonographic assessments, and kinematic results are needed to determine the relevance of the PLL and whether a decrease in ligament length results in decreased mobility and persistent lameness in dogs, as has been reported for humans.

OBJECTIVE To evaluate accuracy of articular surfaces determined by use of 2 perpendicular CT orientations, micro-CT, and laser scanning. SAMPLE 23 cat cadavers. PROCEDURES Images of antebrachia were obtained by use of CT (voxel size, 0.6 mm) in longitudinal orientation (CTLO images) and transverse orientation (CTTO images) and by use of micro-CT (voxel size, 0.024 mm) in a longitudinal orientation. Images were reconstructed. Craniocaudal and mediolateral length, radius of curvature, and deviation of the articular surface of the distal portion of the radius of 3-D renderings for CTLO, CTTO, and micro-CT images were compared with results of 3-D renderings acquired with a laser scanner (resolution, 0.025 mm). RESULTS Measurement of CTLO and CTTO images overestimated craniocaudal and mediolateral length of the articular surface by 4% to 10%. Measurement of micro-CT images underestimated craniocaudal and mediolateral length by 1%. Measurement of CTLO and CTTO images underestimated mediolateral radius of curvature by 15% and overestimated craniocaudal radius of curvature by > 100%; use of micro-CT images underestimated them by 3% and 5%, respectively. Mean ± SD surface deviation was 0.26 ± 0.09 mm for CTLO images, 0.30 ± 0.28 mm for CTTO images, and 0.04 ± 0.02 mm for micro-CT images. CONCLUSIONS AND CLINICAL RELEVANCE Articular surface models derived from CT images had dimensional errors that approximately matched the voxel size. Thus, CT cannot be used to plan conforming arthroplasties in small joints and could lack precision when used to plan the correction of a limb deformity or repair of a fracture.

The objectives of this study were to describe the frequency of antimicrobial resistance (AMR) in Escherichia coli and Campylobacter spp. isolates in fecal samples from beef cow-calf herds and to examine the associations between herd management practices, reported antimicrobial use, and AMR. Baseline prevalence data are needed to evaluate the effectiveness of antimicrobial stewardship programs. A pooled fecal sample, representing 20 cows, was collected from each of 107 herds during pregnancy testing. In the 305 recovered E. coli isolates (maximum 3 per herd), resistance to ≥ 1 antimicrobial was identified in 12 isolates [4%, 95% confidence interval (CI): 2% to 7%] from 105 herds (11%, 95% CI: 7% to 19%). The most common resistances identified in E. coli isolates were to tetracycline (3%) and to both streptomycin and sulfisoxazole (3%). Only 1 E. coli isolate was resistant to an antimicrobial of very high importance to human health - amoxicillin/clavulanic acid. However, 2 E. coli isolates had intermediate susceptibility to ciprofloxacin. Resistance to 1 antimicrobial was identified in 16 of 87 Campylobacter spp. isolates (18%, 95% CI: 11% to 28%) from 87 herds. Resistance to tetracycline was reported in 15% of Campylobacter spp. isolates and to nalidixic acid in 3.4%. Herds in which cows were treated with florfenicol were more likely to have E. coli resistance to ≥ 2 antimicrobials (OR 7.1, 95% CI: 1.1 to 57, P = 0.03). Herds with calf mortality of > 5% were more likely to have E. coli with resistance to streptomycin and sulfisoxazole [odds ratio (OR): 7.8, P = 0.03]. The results of this study are consistent with previous reports from western Canada and provide a starting point for designing an ongoing antimicrobial surveillance program.

OBJECTIVE To quantify the magnitude and duration of changes in urine chondroitin sulfate concentration (uCS) as a result of oral administration of a chondroitin sulfate–containing supplement in dogs. ANIMALS 8 healthy privately owned dogs. PROCEDURES A urine sample was collected from each dog via cystocentesis on day 1; free-catch midstream urine samples were collected once daily on days 2 through 5. Pretreatment uCS was established from those samples. Each dog then received a chondroitin sulfate–containing supplement (20 to 30 mg/kg, PO, q 12 h) for 8 days (on days 7 through 14). Urine samples were collected on days 8 through 12 and day 15. For each sample, uCS was quantified by liquid chromatography–tandem mass spectrometry. Variable urine concentration was accounted for by dividing the uCS by urine creatinine concentration (uCrea) to determine the uCS:uCrea ratio. Pretreatment uCS:uCrea ratios were compared with treatment uCS:uCrea ratios to calculate the fold change in uCS after supplement administration. RESULTS Among the study dogs, oral administration of the chondroitin sulfate–containing supplement resulted in a 1.9-fold increase in the median uCS:uCrea ratio. Data obtained on days 8 through 12 and day 15 indicated that the daily increase in uCS remained consistent and was not additive. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that oral administration of supplemental chondroitin sulfate to dogs modestly increased uCS within 24 hours; however, subsequent supplement administration did not have an additive effect. A potential therapeutic benefit of persistently increased uCS in preventing recurrent urinary tract infections in dogs warrants investigation.

The goal of this study was to explore and describe fecal microbiota of captive and wild bobcats (Lynx rufus) and compare the results to those of domestic cats (Felis catus). Fecal samples from 27 bobcats (8 wild, 19 zoo-kept) were used for novel bacterial deoxyribonucleic acid (DNA) identification using next-generation sequencing of the V4 region of the bacterial 16S ribosomal ribonucleic acid (rRNA) gene, analyzed by Illumina sequencing, and then compared to data obtained from a colony of 10 domestic cats. In this study, the microbiota of both species was dominated by Firmicutes, followed by Proteobacteria, Actinobacteria, Bacteroidetes, and Verrucomicrobia. When compared, fecal samples from bobcats harbored more Proteobacteria and Actinobacteria than fecal samples from domestic cats. There was a remarkable inter-bobcat variation in the relative abundances of the main bacterial genera. There were no significant differences, however, between the main phyla of the microbiota of the wild and domestic bobcats. Proteobacteria in wild bobcats (P = 0.079) and Firmicutes in zoo-kept bobcats (P = 0.079) approached significance. There were no differences in predominant genera between wild and captive bobcats. The results of this study showed that there are notable differences in fecal bacterial communities between domestic cats and both captive and wild bobcats. The lack of significant differences in bacterial communities between wild and zoo-kept bobcats suggests that the varied diet provided for these felids can result in a fecal microbiota resembling that generated by a wild diet.

OBJECTIVE To determine whether therapeutic concentrations (> 0.5 to 1.0 μg/mL) of polymyxin B (PB) were achieved in the tarsocrural joint of horses when the drug was administered by IV regional limb perfusion (IV-RLP) via a saphenous vein at doses of 25, 50, and 300 mg and to describe any adverse systemic or local effects associated with such administration. ANIMALS 9 healthy adult horses. PROCEDURES In the first of 2 experiments, 6 horses each received 25 and 50 mg of PB by IV-RLP via a saphenous vein with at least 2 weeks between treatments. For each treatment, a tourniquet was placed at the midmetatarsus and another was placed midway between the stifle joint and tarsus. Both tourniquets were removed 30 minutes after the assigned dose was administered. Blood and tarsocrural joint fluid samples were collected for determination of PB concentration before and at predetermined times after drug administration. In experiment 2, 4 horses were administered 300 mg of PB by IV-RLP in 1 randomly selected pelvic limb in a manner identical to that used in experiment 1. RESULTS For all 3 doses, the mean synovial fluid PB concentration was > 10 times the therapeutic concentration and below the level of quantification at 30 and 1,440 minutes after drug administration, respectively. No adverse systemic or local effects were observed following PB administration. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that IV-RLP of PB might be a viable alternative for treatment of horses with synovial infections caused by gram-negative bacteria.

OBJECTIVE To evaluate the pharmacokinetics and pharmacodynamics of naloxone hydrochloride in dogs following intranasal (IN) and IV administration. ANIMALS 6 healthy adult mixed-breed dogs. PROCEDURES In a blinded crossover design involving 2 experimental periods separated by a washout period (minimum of 7 days), dogs were randomly assigned to receive naloxone IN (4 mg via a commercially available fixed-dose naloxone atomizer; mean ± SD dose, 0.17 ± 0.02 mg/kg) or IV (0.04 mg/kg) in the first period and then the opposite treatment in the second period. Plasma naloxone concentrations, dog behavior, heart rate, and respiratory rate were evaluated for 24 hours/period. RESULTS Naloxone administered IN was well absorbed after a short lag time (mean ± SD, 2.3 ± 1.4 minutes). Mean maximum plasma concentration following IN and IV administration was 9.3 ± 2.5 ng/mL and 18.8 ± 3.9 ng/mL, respectively. Mean time to maximum concentration following IN administration was 22.5 ± 8.2 minutes. Mean terminal half-life after IN and IV administration was 47.4 ± 6.7 minutes and 37.0 ± 6.7 minutes, respectively. Mean bioavailability of naloxone administered IN was 32 ± 13%. There were no notable changes in dog behavior, heart rate, or respiratory rate following naloxone administration by either route. CONCLUSIONS AND CLINICAL RELEVANCE Use of a naloxone atomizer for IN naloxone administration in dogs may represent an effective alternative to IV administration in emergency situations involving opioid exposure. Future studies are needed to evaluate the efficacy of IN naloxone administration in dogs with opioid intoxication, including a determination of effective doses.