Objective—To assess the microcirculatory effects of IV fluid administration in healthy anesthetized dogs undergoing elective ovariohysterectomy. Animals—49 client-owned dogs. Procedures—Dogs were sedated, and anesthesia was induced with propofol and diazepam and maintained with isoflurane in oxygen. Dogs received lactated Ringer's solution (LRS) IV at rates of 0, 10, or 20 mL/kg/h. Videomicroscopy was used to assess and record effects of LRS administration on microcirculation in the buccal mucosa. Measurements of microcirculatory (total vessel density, proportion of perfused vessels, microcirculatory flow index, and perfused vessel density by vessel size [< 20 μm, ≥ 20 μm, and all diameters]) and other physiologic variables (heart rate, Doppler-measured blood pressure, oxygen saturation as measured by pulse oximetry, capillary refill time, and body temperature) were compared among groups at baseline (immediately after anesthetic induction), 30 and 60 minutes afterward, and overall. Results—Neither the proportion of perfused vessels nor microcirculatory flow index varied among treatment groups at any time point, regardless of vessel size. For vessels < 20 μm in diameter and for all vessels combined, total and perfused vessel density were similar among groups. For vessels ≥ 20 μm in diameter, total vessel density was significantly greater in the 20 mL/kg/h group than in other groups, and perfused vessel density was significantly greater in the 20 mL/kg/h group than in the 0 mL/kg/h group, when all time points were considered. Other physiologic variables were similar among groups. Conclusions and Clinical Relevance—Total and perfused vessel density of vessels ≥ 20 μm in diameter (mostly venules) were greatest in dogs that received 20 mL of LRS/kg/h. Further research is required to evaluate clinical importance of these findings.

Objective—To determine the effect of region of interest (ROI) setting and slice thickness on trabecular bone mineral density (BMD) measured with quantitative CT in dogs. Animals—14 healthy Beagles. Procedures—CT of the lumbar vertebrae and a quantitative CT phantom was performed. The BMD of trabecular bone was measured from L1 to L7 in 2 ways in all dogs. First, sequential 9.6-mm-thick CT images were acquired and then CT images were reconstructed into transverse CT images with slice thicknesses of 2.4, 4.8, and 9.6 mm. The obtained images were analyzed by circular ROI and trace ROI methods. Second, lumbar vertebrae were scanned with the installed quantitative CT protocol with a slice thickness of 10 mm and then the CT images were analyzed by installed automatic BMD software. Results—Interclass correlation coefficients of the automatic software (0.975 to 1.0) and the circular method (0.871 to 0.996) were high, compared with those of the trace method (0.582 to 0.996). The BMD measured with the automatic software was not significantly different from that measured with circular ROI and a slice thickness of 9.6 mm. The BMD measured by use of the circular method was not different according to slice thickness. Conclusions and Clinical Relevance—Results obtained by use of automatic software were similar to those obtained by use of more manual methods. The CT images with thinner slice thickness (2.4 and 4.8 mm) could be used in dogs of toy and small breeds to measure lumbar vertebrae BMD to reduce the limitations of the standard 10-mm slice thickness.

Objective—To develop and assess the short-term feasibility, maintenance, and complications associated with percutaneous endoscopic gastrostomy (PEG) tube placement in standing horses. Animals—6 adult horses. Procedures—Feasibility of the technique was evaluated in 2 horses. In each of 4 other horses, a PEG tube was maintained for 14 days and used to provide fluid requirements during the latter 7 days, before removal. Following air inflation of the stomach, each PEG tube was placed via a left intercostal approach; proper tube location was ascertained by percutaneous ultrasonography and gastroscopy. The horses underwent physical examinations, CBCs, and peritoneal fluid analyses before and at intervals after tube placement. Seven days after tube removal, horses were euthanized and necropsied. Results—Placement of a PEG tube was feasible in all 6 horses. The 4 horses assessed long term tolerated water administration through the PEG tube and remained clinically stable throughout the 21-day experiment. However, during the period PEG tubes were in place, significant increases in some peritoneal and hematologic variables were detected. Postmortem evaluation revealed localized peritonitis in 1 horse and body wall inflammation along the PEG tube tracks in 3 additional horses. Conclusions and Clinical Relevance—Placement and maintenance of a PEG tube were tolerated well by the study horses, although peritoneal and systemic inflammation were detectable. Fluid requirements were adequately met with this technique, which could provide an alternative method for managing chronically dysphagic horses. Nevertheless, further research is warranted to evaluate the feasibility of enteral feeding by use of this approach in horses.

Objective-To investigate age-related and regional differences in estimated metabolite concentrations in the brain of healthy dogs by means of magnetic resonance spectroscopy (MRS). Animals-15 healthy Beagles. Procedures-Dogs were grouped according to age as young (n = 5; all dogs were 2 months old), adult (5; mean age, 4.5 years), or geriatric (5; all dogs were 12 years old). Imaging was performed by use of a 1.5-T MRI system with T1- and T2-weighted spin-echo and fluid-attenuated inversion recovery sequences. Signal intensity measurements for N-acetyl aspartate, creatine, choline, and lactate-alanine (the spectroscopic peaks associated with alanine and lactate could not be reliably differentiated) were determined with MRS, and areas under the spectroscopic peaks (representing concentration estimates) were calculated. Ratios of these metabolite values were compared among age groups and among brain regions with regression analysis. Results-The choline-to-creatine ratio was significantly higher in young dogs, compared with other age groups. The N-acetyl aspartate-to-choline ratio was significantly lower in young dogs and geriatric dogs than in adult dogs. When all age groups were considered, the choline-to-creatine ratio was significantly higher and N-acetyl aspartate-to-choline ratio was significantly lower in the frontal lobe than in all other regions. The N-acetyl aspartate-to-creatine ratio was significantly lower in the cerebellum than in other regions. Conclusions and Clinical Relevance-Metabolite ratios varied significantly among age groups and brain regions in healthy dogs. Future studies should evaluate absolute concentration differences in a larger number of dogs and assess clinical applications in dogs with neurologic diseases.

Objective-To assess effects of body position on direct measurements of intra-abdominal pressure (IAP) and abdominal perfusion pressure (APP) in horses anesthetized with total intravenous anesthesia (TIVA). Animals-9 healthy adult horses. Procedures-Instrumentation in unsedated standing horses involved insertion of an arterial catheter for blood pressure measurements and 3 intraperitoneal cannulas (left flank, right flank, and ventral abdomen) for IAP measurements. Baseline values were measured for heart rate, respiratory rate, systolic arterial blood pressure, mean arterial blood pressure (MAP), diastolic arterial blood pressure, and IAP. Horses were medicated with xylazine, and pressures were measured again. Anesthesia was induced with ketamine-diazepam and maintained with a ketamine-guaifenesin infusion. Horses were positioned twice into left lateral recumbency, right lateral recumbency, or dorsal recumbency. Hemodynamic pressures and accessible abdominal pressures were measured for each recumbency position. The APP was calculated as MAP - IAP. Differences in IAP, MAP, APP and sedation (standing horses) or body position (anesthetized horses) were compared by means of repeated-measures ANOVA or paired t tests. Results-Baseline hemodynamic and IAPs were not different after xylazine administration. Ventral abdomen IAP and MAP were lower for horses in dorsal recumbency than in right or left lateral recumbency. Ventral abdomen APP remained unchanged. For lateral recumbencies, flank IAP was lower and APP was higher than pressure measurements at the same sites during dorsal recumbency. Conclusions and Clinical Relevance-Body position affected IAP and APP in healthy anesthetized horses. These effects should be considered when developing IAP acquisition methods for use in horses with abdominal disease.

Susceptibility results for Pasteurella multocida and Streptococcus suis isolated from swine clinical samples were obtained from January 1998 to October 2010 from the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, and used to describe variation in antimicrobial resistance (AMR) to 4 drugs of importance in the Ontario swine industry: ampicillin, tetracycline, tiamulin, and trimethoprim–sulfamethoxazole. Four temporal data-analysis options were used: visualization of trends in 12-month rolling averages, logistic-regression modeling, temporal-scan statistics, and a scan with the “What’s strange about recent events?” (WSARE) algorithm. The AMR trends varied among the antimicrobial drugs for a single pathogen and between pathogens for a single antimicrobial, suggesting that pathogen-specific AMR surveillance may be preferable to indicator data. The 4 methods provided complementary and, at times, redundant results. The most appropriate combination of analysis methods for surveillance using these data included temporal-scan statistics with a visualization method (rolling-average or predicted-probability plots following logistic-regression models). The WSARE algorithm provided interesting results for quality control and has the potential to detect new resistance patterns; however, missing data created problems for displaying the results in a way that would be meaningful to all surveillance stakeholders.

Objective—To evaluate the efficacy and effects of labeling equine umbilical cord blood (UCB)– and bone marrow (BM)–derived multipotent mesenchymal stromal cells (MSCs) with an ultrasmall uperparamagnetic iron oxide (SPIO) contrast agent and the detection of labeled MSCs by use of MRI. Sample—UCB MSCs from placental tissues of 5 foals and BM MSCs from 5 horses. Procedures—UCB and BM MSC cultures were seeded in duplicate (5,000 cells/cm2). One duplicate was incubated with SPIO (50 μg/mL); the other was processed identically, but without SPIO. Mesenchymal stromal cells were expanded in triplicates for 5 passages and assessed for viability and proliferative capacity, labeling efficacy, and labeled cell proportion. For MRI detection, 5 × 106 labeled BM MSCs from passage 1 or 2 were injected into a collagenase-induced superficial digital flexor tendon defect of an equine cadaveric forelimb from 2 horses. Results—For passages 1, 2, and 3, labeling efficacy and cell proportion for UCB MSCs (99.6% [range, 98.8% to 99.9%], 16.6% [range, 6.5% to 36.1%], and 1.0% [range, 0.4% to 2.8%], respectively) were significantly higher than for BM MSCs (99.2% [range, 97.8% to 99.7%], 4.5% [range, 1.6% to 11.8%], and 0.2% [range, 0.1% to 0.6%], respectively). Labeling was not detectable after passage 3. Viability of MSCs was not affected, but cell doubling time increased in labeled MSCs, compared with that of unlabeled MSCs. On MRI 3-D T2*-weighted fast gradient echo sequences, decreased signal intensity was observed for BM passage 1 MSCs. Conclusions and Clinical Relevance—Equine UCB and BM MSCs were labeled with SPIO at high efficiencies.

Objective—To determine pharmacokinetics of marbofloxacin in water buffalo calves (Bubalus bubalis) after multiple SC administrations and to assess differences in regimen efficacy. Animals—18 healthy buffalo calves. Procedures—Calves (n = 6 calves/group) were assigned to receive marbofloxacin SC in the neck at 1 of 3 dosages (2 mg/kg, q 24 h for 6 days [regimen 1]; 4 mg/kg, q 48 h for 6 days [regimen 2]; and 4 mg/kg, q 24 h for 3 days [regimen 3]). Serum marbofloxacin concentrations were analyzed. Efficacy predictors were estimated on the basis of minimum inhibitory concentration and mutant prevention concentration reported for Pasteurella multocida and Mannheimia haemolytica. Results—Mean ± SD area under the concentration-time curve was 5.92 ± 0.40 μg•h/mL for regimen 1, which differed significantly from that for regimens 2 (14.26 ± 0.92 μg•h/mL) and 3 (14.17 ± 0.51 μg•h/mL). Mean residence time and mean elimination half-life for regimen 2 (9.93 ± 0.20 hours and 8.77 ± 0.71 hours) both differed significantly from those for regimens 1 (721 ± 0.11 hours and 5.71 ± 0.38 hours) and 3 (759 ± 0.13 hours and 737 ± 1.19 hours). Values obtained from indices for P multocida and M haemolytica had an excessively wide range because of the various degrees of antimicrobial susceptibility (low, medium, and high) of the strains. Conclusions and Clinical Relevance—Regimen 3 had the most favorable indices, and it would be conducive for owner compliance and require less handling of animals.

Objective—To compare the anesthetic efficacy and adverse effects associated with peribulbar injection of ropivacaine (1% solution) performed with and without ultrasound guidance (UG) in dogs. Animals—15 dogs without ophthalmologic abnormalities. Procedures—Each dog was sedated and anesthetized. A peribulbar injection of ropivacaine (1% solution; 0.3 mL/kg) was performed with UG in 1 eye and without UG in the contralateral eye (control). For each eye, the intraocular pressure (IOP) immediately after eye centralization and number of punctures were recorded; ophthalmic complications, postinjection corneal sensitivity (determined by Cochet-Bonnet esthesiometry), durations of the sensory and motor blockades (the latter determined as the interval to restoration of the vestibuloocular reflex, pupillary light reflex, and conjugate eye movement), and blockade quality were assessed in both eyes following anesthetic recovery. Results—Needle placement was fully visualized in 8 of the 15 eyes injected with UG. For eyes injected with or without UG, there was no difference with regard to the number of punctures, postinjection corneal sensitivity, and sensory or motor blockade duration and quality; however, restoration of conjugate eye movement occurred later in control eyes. For eyes injected with UG, mean IOP was 18.6 mm Hg, compared with 23.3 mm Hg for control eyes. Incidence of subconjunctival hemorrhage was higher for control eyes; severity of chemosis and hyperemia varied over time within both groups of eyes. Conclusion and Clinical Relevance—In dogs, peribulbar injection of ropivacaine with UG is feasible in dogs and provides effective sensory and motor blockades similar to those achieved with conventional techniques.

Objective—To evaluate whether the application of steam to a variety of surface types in a veterinary hospital would effectively reduce the number of bacteria. Sample—5 surface types.Procedures—Steam was applied as a surface treatment for disinfection to 18 test sites of 5 surface types in a veterinary hospital. A pretreatment sample was obtained by collection of a swab specimen from the left side of each defined test surface. Steam disinfection was performed on the right side of each test surface, and a posttreatment sample was then collected in the same manner from the treated (right) side of each test surface. Total bacteria for pretreatment and posttreatment samples were quantified by heterotrophic plate counts and for Staphylococcus aureus, Pseudomonas spp, and total coliforms by counts on selective media. Results—Significant reductions were observed in heterotrophic plate counts after steam application to dog runs and dog kennel floors. A significant reduction in counts of Pseudomonas spp was observed after steam application to tub sinks. Bacterial counts were reduced, but not significantly, on most other test surfaces that had adequate pretreatment counts for quantification. Conclusions and Clinical Relevance—Development of health-care–associated infections is of increasing concern in human and veterinary medicine. The application of steam significantly reduced bacterial numbers on a variety of surfaces within a veterinary facility. Steam disinfection may prove to be an alternative or adjunct to chemical disinfection within veterinary practices.