Objective: To determine whether the concentrations of airborne virulent Rhodococcus equi in stalls housing foals during the first 2 weeks after birth are associated with subsequent development of R equi pneumonia in those foals. Sample: Air samples collected from foaling stalls and holding pens in which foals were housed during the first 2 weeks after birth. Procedures: At a breeding farm in Texas, air samples (500 L each) were collected (January through May 2011) from stalls and pens in which 121 foals were housed on day 1 and on days 4, 7, and 14 after birth. For each sample, the concentration of airborne virulent R equi was determined with an immunoblot technique. The association between development of pneumonia and airborne R equi concentration was evaluated via random-effects Poisson regression analysis. Results: Some air samples were not available for analysis. Of the 471 air samples collected from stalls that housed 121 foals, 90 (19%) contained virulent R equi. Twenty-four of 121 (20%) foals developed R equi pneumonia. Concentrations of virulent R equi in air samples from stalls housing foals that developed R equi pneumonia were significantly higher than those in samples from stalls housing foals that did not develop pneumonia. Accounting for disease effects, air sample concentrations of virulent R equi did not differ significantly by day after birth or by month of birth. Conclusions and Clinical Relevance: Exposure of foals to airborne virulent R equi during the first 2 weeks after birth was significantly (and likely causally) associated with development of R equi pneumonia.

Objective: To investigate the effects of bevacizumab, a human monoclonal antibody against vascular endothelial growth factor, on the angiogenesis and growth of canine osteosarcoma cells xenografted in mice. Animals: 27 athymic nude mice. Procedures: To each mouse, highly metastasizing parent osteosarcoma cells of canine origin were injected into the left gastrocnemius muscle. Each mouse was then randomly allocated to 1 of 3 treatment groups: high-dose bevacizumab (4 mg/kg, IP), low-dose bevacizumab (2 mg/kg, IP), or control (no treatment). Tumor growth (the number of days required for the tumor to grow from 8 to 13 mm), vasculature, histomorphology, necrosis, and pulmonary metastasis were evaluated. Results: Mice in the high-dose bevacizumab group had significantly delayed tumor growth (mean ± SD, 13.4 ± 3.8 days; range, 9 to 21 days), compared with that for mice in the low-dose bevacizumab group (mean ± SD, 9.4 ± 1.5 days; range, 7 to 11 days) or control group (mean ± SD, 7. 2 ± 1.5 days; range, 4 to 9 days). Mice in the low-dose bevacizumab group also had significantly delayed tumor growth, compared with that for mice in the control group. Conclusions and Clinical Relevance: Results indicated that bevacizumab inhibited growth of canine osteosarcoma cells xenografted in mice, which suggested that vascular endothelial growth factor inhibitors may be clinically useful for the treatment of osteosarcoma in dogs. Impact for Human Medicine: Canine osteosarcoma is used as a research model for human osteosarcoma; therefore, bevacizumab may be clinically beneficial for the treatment of osteosarcoma in humans.

Objective-To characterize and quantitatively assess the typical pulmonary anatomy of healthy adult alpacas with multidetector row CT. Animals-10 clinically normal adult female alpacas. Procedures-CT examination of the thorax was performed before and after IV administration of iodinated contrast medium in sedated alpacas in sternal recumbency. Measurements of the trachea, bronchi and related blood vessels, and selected vertebrae as well as the extent and density of lung parenchyma were performed with a Digital Imaging and Communications in Medicine (DICOM) viewer. Morphometric and quantitative data were summarized. Results-Separation of individual lung lobes could not be identified, except for the accessory lung lobe. In all alpacas, both lungs extended farther caudally at the medial aspect than at the lateral aspect. The right lung extended farther in both cranial and caudal directions than did the left lung. The branching pattern of the bronchial tree varied only slightly among alpacas and consisted of 1 cranial bronchus and 3 caudal bronchi bilaterally, with a right accessory bronchus. Luminal diameters of first-generation bronchi ranged from 3 to 9 mm. Mean +/- SD parenchymal lung density was −869 +/- 40 Hounsfield units (HU) before contrast injection and −825 +/- 51 HU after contrast injection. Mean difference in diameter between bronchi and associated arteries or veins was 0.8 +/- 0.9 mm. Conclusions and Clinical Relevance-Knowledge of the typical anatomy of the lungs and bronchial tree in healthy alpacas as determined via CT will aid veterinarians in clinical assessment and bronchoscopic evaluation of alpacas.

Objective-To evaluate antinociceptive and selected effects associated with IM administration of xylazine hydrochloride in combination with tiletamine-zolazepam in llamas. Animals-8 adult male llamas. Procedures-Each llama received tiletamine-zolazepam (2 mg/kg) combined with either xylazine (0.1, 0.2, or 0.4 mg/kg) or saline (0.9% NaCl) solution IM (treatments designated as TZ-Xy0.1, TZ-Xy0.2, TZ-Xy0.4, and TZ-Sal, respectively) at 1-week intervals. Selected cardiorespiratory variables were assessed during lateral recumbency and anesthesia, and recovery characteristics were recorded. Duration of antinociception was evaluated by clamping a claw every 5 minutes. Results-Interval between treatment administration and lateral recumbency for TZ-Xy0.4 was shorter than that for TZ-Xy0.1 or TZ-Sal. Mean ± SEM duration of antinociception was longer for TZ-Xy0.4 (51.3 +/- 7. 0 minutes), compared with findings for TZ-Xy0.2 (31.9 +/- 6.0 minutes), TZ-Xy0.1 (8.1 +/- 4.0 minutes), and TZ-Sal (0.6 +/- 0.6 minutes). Interval between treatment administration and standing was longer for TZ-Xy0.4 (112 +/- 9 minutes) than it was for TZ-Xy0.2 (77 +/- 9 minutes) or TZ-Sal (68 +/- 9 minutes). Mean heart and respiratory rates during the first 30 minutes for TZ-Sal exceeded values for the other treatments. Administration of TZ-Xy0.2 and TZ-Xy0.4 resulted in Pao2 < 60 mm Hg at 5 minutes after llamas attained lateral recumbency, and values differed from TZ-Sal findings at 5, 10, and 15 minutes; Paco2 was greater for TZ-Xy0.2 and TZ-Xy0.4 than for TZ-Sal at 5, 10, 15, and 20 minutes. Conclusions and Clinical Relevance—Xylazine (0.2 and 0.4 mg/kg) increased the duration of antinociception in llamas anesthetized with tiletamine-zolazepam.

Objective: To compare pharmacokinetics after IV, IM, and oral administration of a single dose of meloxicam to Hispaniolan Amazon parrots (Amazona ventralis). Animals: 11 healthy parrots. Procedures: Cohorts of 8 of the 11 birds comprised 3 experimental groups for a crossover study. Pharmacokinetics were determined from plasma concentrations measured via high-performance liquid chromatography after IV, IM, and oral administration of meloxicam at a dose of 1 mg/kg. Results: Initial mean ± SD plasma concentration of 17.3 ± 9.0 μg/mL was measured 5 minutes after IV administration, whereas peak mean concentration was 9.3 ± 1.8 μg/mL 15 minutes after IM administration. At 12 hours after administration, mean plasma concentrations for IV (3.7 ± 2.5 μg/mL) and IM (3.5 ± 2.2 μg/mL) administration were similar. Peak mean plasma concentration (3.5 ± 1.2 μg/mL) was detected 6 hours after oral administration. Absolute systemic bioavailability of meloxicam after IM administration was 100% but was lower after oral administration (range, 49% to 75%). Elimination half-lives after IV, IM, and oral administration were similar (15.9 ± 4.4 hours, 15.1 ± 7.7 hours, and 15.8 ± 8.6 hours, respectively). Conclusions and Clinical Relevance: Pharmacokinetic data may provide useful information for use of meloxicam in Hispaniolan Amazon parrots. A mean plasma concentration of 3.5 μg/mL would be expected to provide analgesia in Hispaniolan Amazon parrots; however, individual variation may result in some birds having low plasma meloxicam concentrations after IV, IM, or oral administration. After oral administration, meloxicam concentration slowly reached the target plasma concentration, but that concentration was not sustained in most birds.

Bovine viral diarrhea virus (BVDV) is a widespread bovine pathogen capable of causing disease affecting multiple body systems. Previous studies have shown 2-(2-benzimidazolyl)-5-[4-(2-imidazolino)phenyl]furan dihydrochloride (DB772) effectively prevents BVDV infection in cell culture. The aim of this project was to assess the efficacy of DB772 for the prevention of acute BVDV infection. Four calves seronegative to BVDV were treated with DB772 and another 4 calves were treated with diluent only on the same dosing schedule. Each calf was subsequently challenged intranasally with BVDV. Virus was isolated consistently from untreated calves on days 4 to 8, while treated calves remained negative by virus isolation during this period. Azotemia was exhibited by all treated calves on day 4 resulting in the euthanasia of 1 calf on day 10 and the death of another on day 13. Virus was isolated from the 2 remaining treated calves on day 14 or 21. On day 21, both remaining treated calves and all 4 untreated calves had anti-BVDV antibody titers > 1:2048. This pilot study indicates that DB772 temporarily prevented acute disease due to BVDV, but carries a significant concern of renal toxicity.

Objective-To determine the effect of dexmedetomidine, morphine-lidocaine-ketamine (MLK), and dexmedetomidine-morphine-lidocaine-ketamine (DMLK) constant rate infusions on the minimum alveolar concentration (MAC) of isoflurane and bispectral index (BIS) in dogs. Animals-6 healthy adult dogs. Procedures-Each dog was anesthetized 4 times with a 7-day washout period between anesthetic episodes. During the first anesthetic episode, the MAC of isoflurane (baseline) was established. During the 3 subsequent anesthetic episodes, the MAC of isoflurane was determined following constant rate infusion of dexmedetomidine (0.5 μg/kg/h), MLK (morphine, 0.2 mg/kg/h; lidocaine, 3 mg/kg/h; and ketamine, 0.6 mg/kg/h), or DMLK (dexmedetomidine, 0.5 μg/kg/h; morphine, 0.2 mg/kg/h; lidocaine, 3 mg/kg/h; and ketamine 0.6 mg/kg/h). Among treatments, MAC of isoflurane was compared by means of a Friedman test with Conover posttest comparisons, and heart rate, direct arterial pressures, cardiac output, body temperature, inspired and expired gas concentrations, arterial blood gas values, and BIS were compared with repeated-measures ANOVA and a Dunn test for multiple comparisons. Results-Infusion of dexmedetomidine, MLK, and DMLK decreased the MAC of isoflurane from baseline by 30%, 55%, and 90%, respectively. Mean heart rates during dexmedetomidine and DMLK treatments was lower than that during MLK treatment. Compared with baseline values, mean heart rate decreased for all treatments, arterial pressure increased for the DMLK treatment, cardiac output decreased for the dexmedetomidine treatment, and BIS increased for the MLK and DMLK treatments. Time to extubation and sternal recumbency did not differ among treatments. Conclusions and Clinical Relevance-Infusion of dexmedetomidine, MLK, or DMLK reduced the MAC of isoflurane in dogs.

Objective-To determine whether oxidative stress could be induced in canine chondrocytes in vitro. Sample-Chondrocytes obtained from healthy adult mixed-breed dogs. Procedures-Harvested chondrocytes were maintained at 37°C with 5% CO2 for 24 hours. To assess induction of oxidative stress, 2 stimuli were used: hydrogen peroxide and a combination of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). To determine the effect of hydrogen peroxide, a set of chondrocyte-seeded plates was incubated with control medium alone or hydrogen peroxide (100, 200, or 300μM) for 24 hours. For inhibition of oxidative stress, cells were incubated for 24 hours with N-acetylcysteine (NAC; 10mM) before exposure to hydrogen peroxide. Another set of chondrocyte-seeded plates was incubated with control medium alone or with IL-1β (10 ng/mL) and TNF-α (1 ng/mL) for 24 hours. Supernatants were obtained for measurement of prostaglandin E2 production, and cell lysates were used for measurement of superoxide dismutase (SOD) activity and reduced-glutathione (GSH) concentration. Results-Chondrocytes responded to the oxidative stressor hydrogen peroxide with a decrease in SOD activity and GSH concentration. Exposure to the antioxidant NAC caused an increase in SOD activity in hydrogen peroxide-stressed chondrocytes to a degree comparable with that in chondrocytes not exposed to hydrogen peroxide. Similarly, NAC exposure induced significant increases in GSH concentration. Activation with IL-1β and TNF-α also led to a decrease in SOD activity and increase in prostaglandin E2 production. Conclusions and Clinical Relevance-Canine chondrocytes responded to the oxidative stress caused by exposure to hydrogen peroxide and cytokines. Exposure to oxidative stress inducers could result in perturbation of chondrocyte and cartilage homeostasis and could contribute to the pathophysiology of osteoarthritis. Use of antioxidants, on the other hand, may be helpful in the treatment of arthritic dogs.

Objective: To evaluate the growth kinetics of a strain of Bifidobacterium pseudocatenulatum (BP) on 4 oligo- or polysaccharides and the effect of feeding a selected probiotic-prebiotic combination on intestinal microbiota in cats. Animals: 10 healthy adult cats. Procedures: Growth kinetics of a strain of cat-origin BP (BP-B82) on fructo-oligosaccharides, galacto-oligosaccharides (GOS), lactitol, or pectins was determined, and the combination of GOS and BP-B82 was selected. Cats received supplemental once-daily feeding of 1% GOS–BP-B82 (10(10) CFUs/d) for 15 days; fecal samples were collected for analysis the day before (day 0) and 1 and 10 days after the feeding period (day 16 and 25, respectively). Results: Compared with the prefeeding value, mean fecal ammonia concentration was significantly lower on days 16 and 25 (288 and 281 μmol/g of fecal dry matter [fDM], respectively, vs 353 μmol/g of fDM); fecal acetic acid concentration was higher on day 16 (171 μmol/g of fDM vs 132 μmol/g of fDM). On day 16, fecal concentrations of lactic, n-valeric, and isovaleric acids (3.61, 1.52, and 3.55 μmol/g of fDM, respectively) were significantly lower than on days 0 (5.08, 18.4, and 6.48 μmol/g of fDM, respectively) and 25 (4.24, 17.3, and 6.17 μmol/g of fDM, respectively). A significant increase in fecal bifidobacteria content was observed on days 16 and 25 (7.98 and 7.52 log10 CFUs/g of fDM, respectively), compared with the prefeeding value (5.63 log10 CFUs/g of fDM). Conclusions and Clinical Relevance: Results suggested that feeding 1% GOS–BP-B82 combination had some positive effects on the intestinal microbiota in cats.

Objective—To evaluate effects of quaternary benzo(c)phenanthridine alkaloids (QBAs) against Salmonella spp and determine effects on growth performance, organism shedding, and gastrointestinal tract integrity in pigs inoculated with Salmonella enterica serovar Typhimurium. Sample—36 Salmonella isolates and twenty 5-week-old pigs. Procedures—Minimum inhibitory concentration of QBAs against the Salmonella isolates was determined. Pigs were allocated to 4 groups and inoculated with Salmonella organisms. Pigs received diets supplemented with 1.5 g of QBAs/1,000 kg of feed, 0.75 g of QBAs/1,000 kg of feed, or 59.4 g of chlortetracycline/1,000 kg of feed or a nonsupplemented (control) diet. Pigs were weighed on day 0 and then weekly for 40 days. Fecal samples were collected to quantify Salmonella organisms. Gastrointestinal tract integrity was evaluated by measuring transepithelial resistance. Results—In vitro, 9 of 36 (25%) Salmonella isolates were inhibited at 90 μg of QBAs/mL; all 36 were inhibited at 179 μg of QBAs/mL. Diets containing QBAs significantly decreased Salmonella spp shedding; shedding was lower 40 days after inoculation for pigs fed diets containing QBAs or chlortetracycline than for pigs fed the control diet. Growth performance was similar for pigs fed diets containing QBA or chlortetracycline. Gastrointestinal tract integrity was improved in pigs fed the diet containing 1.5 g of QBAs/1,000 kg of feed. Conclusions and Clinical Relevance—QBAs and chlortetracycline decreased Salmonella spp shedding but did not differ with regard to growth performance. Gastrointestinal tract integrity was better, albeit not significantly, in pigs fed diets containing QBAs. Further investigation into the role of QBAs and their mechanism as an immunomodulator is necessary.