OBJECTIVE To evaluate the influence of respiratory tract disease (ie, recurrent airway obstruction [RAO]) and mode of inhalation on detectability of inhaled budesonide in equine plasma and urine samples. ANIMALS 16 horses (8 healthy control horses and 8 horses affected by RAO, as determined by results of clinical examination, blood gas analysis, bronchoscopy, and cytologic examination of bronchoalveolar lavage fluid). PROCEDURES 4 horses of each group inhaled budesonide (3 μg/kg) twice daily for 10 days while at rest, and the remaining 4 horses of each group inhaled budesonide during lunging exercise. Plasma and urine samples were obtained 4 to 96 hours after inhalation and evaluated for budesonide and, in urine samples, the metabolites 6β-hydroxybudesonide and 16α-hydroxyprednisolone. RESULTS Detected concentrations of budesonide were significantly higher at all time points for RAO-affected horses, compared with concentrations for the control horses. All samples of RAO-affected horses contained budesonide concentrations above the limit of detection at 96 hours after inhalation, whereas this was found for only 2 control horses. Detected concentrations of budesonide were higher, but not significantly so, at all time points in horses that inhaled budesonide during exercise, compared with concentrations for inhalation at rest. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study indicated that the time interval between inhalation of a glucocorticoid and participation in sporting events should be increased when inhalation treatment is administered during exercise to horses affected by respiratory tract disease.

OBJECTIVE To measure serum homocysteine concentrations in dogs with myxomatous mitral valve disease (MMVD) and identify any association between this variable and stage of MMVD. ANIMALS 53 client-owned dogs with MMVD and 10 healthy control Beagles. PROCEDURES Dogs with MMVD were allocated to 3 groups in accordance with the staging system for chronic valvular heart disease in dogs and cats of the American College of Veterinary Internal Medicine. Blood samples were collected from all dogs, and serum homocysteine and cardiac troponin 1 concentrations were measured by enzyme immunoassay and chemiluminescence immunoassay, respectively. Analyte values were tested for associations with each other and with stage of MMVD. RESULTS A significant correlation was identified between serum homocysteine concentration and stage of MMVD. Mean ± SD concentrations were 6.72 ± 1.65 μmol/L for control dogs, 13.37 ± 4.16 μmol/L for dogs with stage B MMVD, 18.86 ± 6.73 μmol/L for dogs with stage C disease, and 28.26 ± 4.48 μmol/L for dogs with stage D disease. In addition, serum homocysteine concentration was correlated with serum cardiac troponin 1 (r = 0.34) and creatinine (r = 0.46) concentrations, systolic blood pressure (r = 0.57), and left atrium-to-aortic root ratio (r = 0.28), all of which were positively correlated with stage of MMVD. CONCLUSIONS AND CLINICAL RELEVANCE Serum homocysteine concentrations of dogs with MMVD were significantly higher than those of control dogs, and significant correlations were identified between these values and several risk factors for heart failure. Measurement of serum homocysteine concentration may be useful in the prediction of severity of disease in dogs with MMVD.

OBJECTIVE To evaluate gene expression and DNA copy number in adipose tissue-derived stromal cells (ADSCs) and in ADSC-derived neurosphere-like cell clusters (ADSC-NSCs) generated from tissues of chronically paraplegic dogs. ANIMALS 14 client-owned paraplegic dogs. PROCEDURES Dorsal subcutaneous adipose tissue (< 1 cm3) was collected under general anesthesia; ADSCs were isolated and cultured. Third-passage ADSCs were cultured in neural cell induction medium to generate ADSC-NSCs. Relative gene expression of mesenchymal cell surface marker CD90 and neural progenitor marker nestin was assessed in ADSCs and ADSC-NSCs from 3 dogs by quantitative real-time PCR assay; expression of these and various neural lineage genes was evaluated for the same dogs by reverse transcription PCR assay. Percentages of cells expressing CD90, nestin, glial fibrillary acidic protein (GFAP), and tubulin β 3 class III (TUJ1) proteins were determined by flow cytometry for all dogs. The DNA copy number stability (in samples from 6 dogs) and neural cell differentiation (14 dogs) were assessed with array-comparative genomic hybridization analysis and immunocytochemical evaluation, respectively. RESULTS ADSCs and ADSC-NSCs expressed neural cell progenitor and differentiation markers; GFAP and microtubule-associated protein 2 were expressed by ADSC-NSCs but not ADSCs. Relative gene expression of CD90 and nestin was subjectively higher in ADSC-NSCs than in ADSCs. Percentages of ADSC-NSCs expressing nestin, GFAP, and TUJ1 proteins were substantially higher than those of ADSCs. Cells expressing neuronal and glial markers were generated from ADSC-NSCs and had no DNA copy number instability detectable by the methods used. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested ADSCs can potentially be a safe and clinically relevant autologous source for canine neural progenitor cells. Further research is needed to verify these findings.

OBJECTIVE To determine the pharmacokinetics of meloxicam in domestic hens and duration and quantity of drug residues in their eggs following PO administration of a single dose (1 mg of meloxicam/kg). ANIMALS 8 healthy adult White Leghorn hens. PROCEDURES Hens were administered 1 mg of meloxicam/kg PO once. A blood sample was collected immediately before and at intervals up to 48 hours after drug administration. The hens' eggs were collected for 3 weeks after drug administration. Samples of the hens' plasma, egg whites (albumen), and egg yolks were analyzed by high-performance liquid chromatography. RESULTS The half-life, maximum concentration, and time to maximum concentration of meloxicam in plasma samples were 2.8 hours, 7.21 μg/mL, and 2 hours, respectively. Following meloxicam administration, the drug was not detected after 4 days in egg whites and after 8 days in egg yolks. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that meloxicam administered at a dose of 1 mg/kg PO in chickens appears to maintain plasma concentrations equivalent to those reported to be therapeutic for humans for 12 hours. The egg residue data may be used to aid establishment of appropriate drug withdrawal time recommendations.

OBJECTIVE To determine factors affecting race speed in Swedish Standardbred horses undergoing surgery of the carpal flexor sheath (CFS), to investigate whether preoperative racing speed was associated with specific intraoperative findings and whether horses returned to racing, and to compare the performance of horses undergoing surgery of the CFS with that of age- and sex-matched control horses. ANIMALS 149 Swedish Standardbred trotters undergoing surgery of the CFS and 274 age- and sex-matched control horses. PROCEDURES Medical records of CFS horses were examined. Racing data for CFS and control horses were retrieved from official online records. Generalizing estimating equations were used to examine overall and presurgery racing speeds and the association of preoperative clinical and intraoperative findings with preoperative and postoperative speeds. Multivariable regression analysis was used to examine career earnings and number of career races. Kaplan-Meier survival analysis was used to compare career longevity between CFS and control horses. RESULTS CFS horses were significantly faster than control horses. The CFS horses that raced before surgery were slower as they approached the surgery date, but race speed increased after surgery. There were 124 of 137 (90.5%) CFS horses that raced after surgery. No intrathecal pathological findings were significantly associated with preoperative racing speed. Career longevity did not differ between CFS and control horses. CONCLUSIONS AND CLINICAL RELEVANCE Horses undergoing surgery of the CFS had a good prognosis to return to racing after surgery. Racing careers of horses undergoing surgery of the CFS were not significantly different from racing careers of control horses.

OBJECTIVE To characterize aminoaciduria and plasma amino acid concentrations in dogs with hepatocutaneous syndrome (HCS). ANIMALS 20 client-owned dogs of various breeds and ages. PROCEDURES HCS was definitively diagnosed on the basis of liver biopsy specimens (n = 12), gross and histologic appearance of skin lesions (4), and examination of skin and liver biopsy specimens (2) and presumptively diagnosed on the basis of cutaneous lesions with compatible clinicopathologic and hepatic ultrasonographic (honeycomb or Swiss cheese pattern) findings (2). Amino acid concentrations in heparinized plasma and urine (samples obtained within 8 hours of each other) were measured by use of ion exchange chromatography. Urine creatinine concentration was used to normalize urine amino acid concentrations. Plasma amino acid values were compared relative to mean reference values; urine-corrected amino acid values were compared relative to maximal reference values. RESULTS All dogs had generalized hypoaminoacidemia, with numerous amino acid concentrations < 50% of mean reference values. The most consistent and severe abnormalities involved glutamine, proline, cysteine, and hydroxyproline, and all dogs had marked lysinuria. Urine amino acids exceeding maximum reference values (value > 1.0) included lysine, 1-methylhistidine, and proline. CONCLUSIONS AND CLINICAL RELEVANCE Hypoaminoacidemia in dogs with HCS prominently involved amino acids associated with the urea cycle and synthesis of glutathione and collagen. Marked lysinuria and prolinuria implicated dysfunction of specific amino acid transporters and wasting of amino acids essential for collagen synthesis. These findings may provide a means for tailoring nutritional support and for facilitating HCS diagnosis.

OBJECTIVE To compare heat generation and mechanical bone damage for tapered and cylindrical transfixation pins during drilling, tapping, and pin insertion in equine third metacarpal bones. SAMPLE 16 pairs of cadaveric equine third metacarpal bones. PROCEDURES For cylindrical pin insertion, a 6.2-mm hole was drilled and tapped with a cylindrical tap, and then a standard 6.3-mm pin was inserted. For tapered pin insertion, a 6.0-mm hole was drilled, reamed with a tapered reamer, and tapped with a tapered tap, and then a 6.3-mm tapered pin was inserted. Paired t tests and 1-way ANOVAs were used to compare heat generation (measured by use of thermocouples and thermography), macrodamage (assessed by use of stereomicroscopy), and microdamage (assessed by examination of basic fuchsin–stained histologic specimens) between cylindrical and tapered pins and between tapered pins inserted to various insertion torques. RESULTS Tapered pin insertion generated less heat but resulted in more bone damage than did cylindrical pin insertion when pins were inserted to the same insertion torque. Insertion of tapered pins to increasing insertion torques up to 16 N•m resulted in increased heat generation and bone damage. CONCLUSIONS AND CLINICAL RELEVANCE Tapered pin insertion resulted in lower heat production than did cylindrical pin insertion. However, tapered pin insertion resulted in greater bone damage, which likely was attributable to differences in the tapered and cylindrical taps. A tapered pin may be preferable to a cylindrical pin for insertion in equine cortical bone provided that improvements in tap design can reduce bone damage during insertion.

To investigate the effects of a xylazine infusion during isoflurane anesthesia on global perfusion parameters and gastrointestinal oxygenation and microperfusion, 8 adult warmblood horses were sedated with xylazine and anesthesia induced with midazolam and ketamine. Horses were mechanically ventilated during anesthesia. After 3 h of stable isoflurane anesthesia (FEIso 1.3 Vol %), a xylazine infusion with 1 mg/kg body weight (BW) per hour was started for 1 h and then stopped. Before, during, and after xylazine infusion, heart rate (HR), arterial blood pressure (MAP), cardiac output (CO), central venous pressure (CVP), and pulmonary artery pressure (PAP) were measured and systemic vascular resistance (SVR) was calculated. Arterial blood gases were taken and oxygen delivery (DO2) and alveolar dead space (VDalv) were calculated. Further intestinal oxygen and microperfusion were measured using white light spectroscopy and laser Doppler flowmetry. Surface probes were placed via median laparotomy on the stomach, the jejunum, and the colon. Wilcoxon rank-sum test was used to compare values over time (P < 0.05). During xylazine infusion, MAP, CVP, PAP, SVR, and VDalv increased significantly, whereas CO, DO2, and intestinal microperfusion decreased. Intestinal oxygenation remained unchanged. All parameters returned to pre-xylazine values within 1 h after stopping xylazine infusion. A xylazine infusion during constant isoflurane anesthesia in horses impairs global and intestinal perfusion without changing tissue oxygenation in normoxic healthy horses. Further studies are necessary, however, to evaluate whether a possible reduction of isoflurane concentration by xylazine infusion will ameliorate these negative effects.

OBJECTIVE To determine pharmacokinetics after IM and oral administration of a single dose of meloxicam to American flamingos (Phoenicopertus ruber). ANIMALS 14 adult flamingos. PROCEDURES Flamingos were allocated to 2 groups. Each group received a dose of meloxicam (1 mg/kg) by the IM or oral route. After a 4-week washout period, groups received meloxicam via the other route of administration. Plasma meloxicam concentrations were measured with high-performance liquid chromatography. Data for each bird were analyzed. Estimated values of selected pharmacokinetic parameters were compared by use of a linear mixed-effects ANOVA. Pooled concentration-time profiles for each route of administration were analyzed to examine the influence of body weight on pharmacokinetics. RESULTS Mean ± SD maximum plasma concentration was 1.00 ± 0.88 μg/mL after oral administration. This was approximately 15% of the mean maximum plasma concentration of 5.50 ± 2.86 μg/mL after IM administration. Mean time to maximum plasma concentration was 1.33 ± 1.32 hours after oral administration and 0.28 ± 0.17 hours after IM administration. Mean half-life of the terminal phase after oral administration (3.83 ± 2.64 hours) was approximately twice that after IM administration (1.83 ± 1.22 hours). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent and rate of meloxicam absorption were less after oral administration than after IM administration. Intramuscular administration resulted in a short period during which mean plasma concentrations met or exceeded reported efficacious analgesic concentrations in other species, whereas oral administration did not. These results suggested that higher doses may be required for oral administration.

In May of 2013, porcine epidemic diarrhea virus (PEDV) was detected in swine for the first time in North America. It spread rapidly, in part due to contaminated livestock trailers. The objective of this study was to test the efficacy of an accelerated hydrogen peroxide disinfectant for inactivating PEDV in the presence of feces on metal surfaces, such as those found in livestock trailers. Three-week-old barrows were inoculated intragastrically with 5 mL of PEDV-negative feces for the negative control, 5 mL of untreated PEDV-positive feces for the positive control, and 5 mL or 10 mL of PEDV-positive feces that was subjected to treatment with a 1:16 or 1:32 concentrations of accelerated hydrogen peroxide disinfectant for a contact time of 30 min at 20°C. These pigs served as a bioassay to determine the infectivity of virus following treatment. Rectal swabs collected from the inoculated pigs on days 3 and 7 post-inoculation were tested by using PEDV-specific real-time reverse transcription polymerase chain reaction and the proportion of pigs in each group that became infected with PEDV was assessed. None of the pigs used for the bioassay in the 4 treatment groups and the negative control group became infected with PEDV, which was significantly different from the positive control group (P < 0.05) in which all pigs were infected. The results suggest that the application of the accelerated hydrogen peroxide under these conditions was sufficient to inactivate the virus in feces found on metal surfaces.