Objective: To evaluate the use of retrospectively ECG-gated, contrast-enhanced, multi-detector row computed tomography (MDCT) for assessment of left ventricular function in dogs and to compare the results with those obtained by use of 2-D and M-mode echocardiographc techniques. Animals: 10 healthy Beagles. Procedures: Dogs underwent MDCT (performed by use of a 64-detector row CT system) and echocardiography under general anesthesia. Left ventricular end-systolic volume (ESV), end-diastolic volume (EDV), and ejection fraction (EF) were determined in MDCT-generated multiplanar reformatted images by use of Simpson and biplane area-length calculation methods. Results were compared with left ventricular ESV, EDV, and EF determined in echocardiographc images by use of Teichholz and bullet method calculations. Results were evaluated via Deming regression analysis and Pearson correlation tests. Bland-Altman analysis was used to assess limits of agreement and systematic errors between the 2 methods. Results: Mean values for EDV and ESV determined by use of MDCT were highly correlated with those determined by use of echocardiography, regardless of the calculation methods compared (r = 0.91 to 0.96); volumes determined by use of MDCT appeared to be higher than those determined by use of echocardiography, although most differences were nonsignificant. Mean EF determined by use of MDCT with the Simpson calculation method was highly correlated with that determined by use of echocardiography with bullet method calculations (r = 0.90). Conclusions and Clinical Relevance: Results suggested that assessment of left ventricular volume and function in dogs is feasible with MDCT. To estimate left ventricular EF with MDCT. use of the Simpson calculation method is advised.

The aim of this study was to describe early infections with porcine circovirus type 2 (PCV2) in naturally infected piglets and the piglets' serologic profiles. A total of 20 sows (15 PCV2-vaccinated and 5 unvaccinated) and 100 newborn piglets were studied. Colostrum and serum of the sows and serum of the presuckling piglets were obtained on the day of parturition. Milk samples were collected on day 20 postpartum. Blood samples were taken and the piglets weighed on days 1, 20, 42, 63, and 84 postpartum. Colostrum and milk were evaluated for infectious PCV2 and for PCV2 total antibody (TA), neutralizing antibody (NA), and IgA. Serum samples were evaluated for PCV2 TA, NA, IgA, IgM, and DNA. The sows had high levels of TA and NA in serum and colostrum; however, 11 and 5, respectively, of the 20 colostrum and milk samples contained infectious PCV2. In the serum, PCV2 DNA and IgM were detected in 17 and 5, respectively, of the 20 sows. Nine piglets were born with PCV2 antibodies, which indicates in utero transmission of PCV2 after the period of immunocompetence (> 70 d of gestation). On day 1 postpartum, PCV2 DNA was detected in 29 of the 100 serum samples from the piglets. There was no difference between the weights of viremic and nonviremic piglets throughout the study. In conclusion, even on farms with sows that have high PCV2 antibody titers, vertical transmission of PCV2 may occur, resulting in piglet infection.

Encephalomyocarditis virus (EMCV) can infect many host species and cause acute myocarditis and sudden death in preweaned piglets. In this study, an EMCV strain (NJ08) was isolated from newborn pigs with clinical signs on a pig farm in mideastern China. It was identified by indirect immunofluorescence assay and reverse-transcription polymerase chain reaction. Experiments showed that the isolate could cause severe clinical symptoms and pathological changes in mice but no obvious clinical and pathological changes in commercial piglets. Complete genomic sequencing showed that the NJ08 strain was 78.3% to 100% identical with other isolates in regions coding for various proteins. Phylogenetic analysis showed that the NJ08 isolate belonged to subgroup Ia. This study confirmed that an EMCV isolate from pigs could be fatal to mice and provided new epidemiologic data on EMCV in China.

Objective: To determine whether an applanation tonometer and rebound tonometer can be used to detect similar intraocular pressure (IOP) measurements in eyes of dogs undergoing phacoemulsification. Animals: 24 dogs (40 eyes) undergoing elective phacoemulsification. Procedures: IOP measurements were obtained from each eye by use of both the rebound tonometer and applanation tonometer. Central corneal thickness was measured by use of an ultrasonic pachymeter 3 hours before surgery and 2 and 24 hours after surgery. Statistical analysis was performed by use of paired t tests. Results: Mean ± SD IOP 3 hours before surgery, 2 hours after surgery, and 24 hours after surgery was 11.9 ± 4.7 mm Hg, 15.5 ± 11.7 mm Hg, and 10.9 ± 6.7 mm Hg, respectively, as measured with the rebound tonometer and 12.2 ± 5.3 mm Hg, 15.7 ± 12.5 mm Hg, and 12.4 ± 5.4 mm Hg, respectively, as measured with the applanation tonometer. Measured IOP did not differ significantly between the 2 tonometers 3 hours before surgery and 2 hours after surgery, but measured IOP differed significantly between the tonometers 24 hours after surgery. Conclusions and Clinical Relevance: Use of a rebound tonometer underestimated IOP, relative to results for use of an applanation tonometer, by 1.65 mm Hg in eyes 24 hours after phacoemulsification. Caution should be used when IOP measurements obtained with a rebound tonometer are in the high part of the reference range, and verification of these values with an applanation tonometer would be advised.

Objective: To identify housing- and exercise-related risk factors associated with the development of hip dysplasia (HD) as determined by radiographic evaluation in Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds in Norway. Animals: 501 client-owned dogs from 103 litters. Procedures: Dogs were assessed from birth until official radiographic screening for HD at 12 (Labrador Retriever [n = 133] and Irish Wolfhound [63]) or 18 (Newfoundland [125] and Leonberger [180]) months of age. Information regarding housing and exercise conditions during the preweaning and postweaning periods was obtained with questionnaires. Multivariable random effects logistic regression models were used to identify housing- and exercise-related risk factors associated with the development of radiographically detectable HD. Results: Puppies walking on stairs from birth to 3 months of age had an increased risk of developing HD. Factors associated with a decreased risk of developing HD included off-leash exercise from birth to 3 months of age, birth during the spring and summer, and birth on a farm. Significant clustering of dogs with HD was detected within litters. Conclusions and Clinical Relevance: Results indicated that puppies ≤ 3 months old should not be allowed access to stairs, but should be allowed outdoor exercise on soft ground in moderately rough terrain to decrease the risk for developing radiographically detectable HD. These findings could be used as practical recommendations for the prevention of HD in Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds.

Objective: To evaluate the components of canine whole blood samples that contribute to results of thromboelastometry (TEM). Animals: 127 healthy dogs.Procedures: For each dog, a blood sample was collected from a jugular vein into tubes containing no anticoagulant, EDTA, or citrate anticoagulant. Citrated whole blood samples underwent TEM with tissue factor and TEM with ellagic acid. Indicators of RBC mass and platelet concentration were evaluated, and plasma coagulation tests were performed; data obtained were compared with results of TEM. For technical reasons, samples were not available from all dogs for all tests. Results: Coagulation time was correlated with concentrations of primarily extrinsic pathway coagulation factors for TEM with tissue factor and with most factors via TEM with ellagic acid. Clot formation time, α angle, and maximum clot firmness were highly correlated with fibrinogen and platelet concentrations and some individual factor concentrations. Sample Hct was strongly correlated with most measured variables; low Hct was associated with relative hypercoagulability, and high Hct was associated with relative hypocoagulability. Conclusions and Clinical Relevance: For TEM of canine blood samples, coagulation time was primarily a function of coagulation factor concentrations, whereas other variables were dependent on platelet and fibrinogen concentrations. Sample Hct strongly influenced the results of TEM, likely because RBCs act as a diluent for plasma coagulation factors. Thromboelastometry appeared to be affected by abnormalities of coagulation factors, platelet concentrations, and RBC mass. In samples from anemic patients, results of TEM indicative of hypercoagulability may be artifactual because of low RBC mass.

Objective: To determine between-pony and within-pony variations and interobserver and intraobserver agreements of a technique for measurement of flow-mediated vasodilation (FMD) in healthy ponies Animals: 6 healthy pony mares (weight range, 236 to 406 kg; body condition score range, 3/9 to 7/9; age range, 14 to 25 years). Procedures: In each pony, the left median artery was occluded with a blood pressure cuff (inflated to > 300 mm Hg for 5 minutes). Two-dimensional ultrasonographic images of the artery were recorded for 30 seconds before cuff inflation and for 2 minutes after cuff deflation. Maximum luminal diameters of arteries were compared with their baseline diameters to calculate FMD (relative percentage increase in luminal size). Images were obtained from 6 ponies 1 time and from 1 pony 6 times. Independent analysis of images was performed by 2 investigators, 1 of whom analyzed images on 2 occasions. Results: Mean ± SD FMD in 6 ponies (1 time) was 12.57 ± 4.28% and in 1 pony (6 times) was 7.30 ± 2.11%. Between-pony and within-pony coefficients of variation were 34.09% and 28.84%, respectively. Interobserver agreement was fair (intraclass correlation coefficient, 0.47); intraobserver agreement was poor (intraclass correlation coefficient, 0.30). Conclusions and Clinical Relevance: FMD was identified and measured in ponies. Measurement of FMD is used to assess endothelial function in humans and has been investigated in dogs. Measurement of FMD in ponies appeared to be feasible and could be used to assess endothelial function (to determine predisposition for development of laminitis or cardiovascular diseases).

Objective: To evaluate onset of protection induced by modified-live virus (MLV) bovine viral diarrhea virus (BVDV) vaccine administered 7, 5, or 3 days before inoculation with type 1b BVDV (strain NY-1). Animals: 40 calves. Procedures: Calves were assigned to 4 groups: an unvaccinated control group or groups vaccinated with MLV vaccine containing BVDV types 1a and 2 at 7, 5, or 3 days, before inoculation with NY-1 BVDV. Blood samples were collected for leukocyte counts, serum virus neutralization, and virus isolation (VI); nasal swab specimens (NSSs) were obtained for VI, and rectal temperatures were monitored for 14 days after inoculation. Results: No significant differences in leukocyte counts or rectal temperatures were detected after BVDV inoculation in vaccinated calves. Vaccinated calves had reduced viremia and viral shedding after inoculation, compared with results for unvaccinated calves. On day 5 after inoculation, a higher proportion of calves vaccinated 3 days before inoculation had positive VI from NSSs, compared with NSS VI results for calves vaccinated 5 and 7 days before inoculation. Unvaccinated calves had leukopenia on days 3, 5, and 6 and had higher rectal temperatures on days 7 and 8 after inoculation, compared with temperatures before inoculation. All unvaccinated calves had ≥ 1 positive VI result from NSSs 3 to 11 days after inoculation, and 4 became viremic. Conclusions and Clinical Relevance: MLV BVDV vaccine prevented fever, viremia, and leukopenia in calves challenge inoculated with NY-1 BVDV. A high proportion of calves vaccinated 3 days before inoculation shed BVDV after inoculation.

Objective: To determine the pharmacokinetics of dexmedetomidine administered as a short-duration IV infusion in isoflurane-anesthetized cats. Animals: 6 healthy adult domestic female cats. Procedures: Dexmedetomidine hydrochloride was injected IV (10 μg/kg over 5 minutes [rate, 2 μg/kg/min]) in isoflurane-anesthetized cats. Blood samples were obtained immediately prior to and at 1, 2, 5, 6, 7, 10, 15, 30, 60, 90, 120, 240, and 480 minutes following the start of the IV infusion. Collected blood samples were transferred to tubes containing EDTA, immediately placed on ice, and then centrifuged at 3,901 × g for 10 minutes at 4°C. The plasma was harvested and stored at −20°C until analyzed. Plasma dexmedetomidine concentrations were determined by means of liquid chromatography–mass spectrometry. Dexmedetomidine plasma concentration-time data were fitted to compartmental models. Results: A 2-compartment model with input in and elimination from the central compartment best described the disposition of dexmedetomidine administered via short-duration IV infusion in isoflurane-anesthetized cats. Weighted mean ± SEM apparent volume of distribution of the central compartment and apparent volume of distribution at steady-state were 402 ± 47 mL/kg and 1,701 ± 200 mL/kg, respectively; clearance and terminal half-life (harmonic mean ± jackknife pseudo-SD) were 6.3 ± 2.8 mL/min/kg and 198 ± 75 minutes, respectively. The area under the plasma concentration curve and maximal plasma concentration were 1,061 ± 292 min•ng/mL and 17.6 ± 1.8 ng/mL, respectively. Conclusions and Clinical Relevance: Disposition of dexmedetomidine administered via short-duration IV infusion in isoflurane-anesthetized cats was characterized by a moderate clearance and a long terminal half-life.

Objective-To investigate the ability of ABT-116 (a proprietary antagonist of transient receptor potential vanilloid type 1) administered at 2 doses to attenuate lameness in dogs with experimentally induced urate synovitis. Animals-8 purpose-bred mixed-breed dogs. Procedures-n a 4-way crossover study, dogs orally received each of low-dose ABT-116 treatment (LDA; 10 mg/kg), high-dose ABT-116 treatment (HDA; 30 mg/kg), firocoxib (5 mg/kg), and no treatment (nontreatment) once a day for 2 days, in a randomly assigned order. Synovitis was induced on the second day of each treatment period by intra-articular injection of either stifle joint with sodium urate, alternating between joints for each treatment period, beginning with the left stifle joint. Ground reaction forces, clinical lameness scores, and rectal temperature were assessed before the injection (baseline) and at various points afterward. Results-Lameness scores at the 2-, 6-, and 12-hour assessment points were higher than baseline scores for HDA and nontreatment, whereas scores at the 2- and 6-hour points were higher than baseline scores for LDA. For firocoxib, there was no difference from baseline scores in lameness scores at any point. Compared with baseline values, peak vertical force and vertical impulse were lower at 2 and 6 hours for HDA and nontreatment and at 2 hours for LDA. No changes in these values were evident for firocoxib. The HDA or LDA resulted in higher rectal temperatures than did treatment with firocoxib or nothing, but those temperatures did not differ among treatments. Conclusions and Clinical Relevance-HDA had no apparent effect on sodium urate–induced lameness; LDA did attenuate the lameness but not as completely as firocoxib treatment. High rectal temperature is an adverse effect of oral ABT-116 administration that may be of clinical concern.