Objective: To determine the pharmacokinetics of ciprofloxacin in dogs, including oral absorption following administration of generic ciprofloxacin tablets. Animals: 6 healthy Beagles. Procedures: In a crossover study design, ciprofloxacin was administered as a generic tablet (250 mg, PO; mean dose, 23 mg/kg) and solution (10 mg/kg, IV) to 6 dogs. In a separate experiment, 4 of the dogs received ciprofloxacin solution (10 mg/mL) PO via stomach tube (total dose, 250 mg). Blood samples were collected before (time 0) and for 24 hours after each dose. Plasma concentrations were analyzed with high-pressure liquid chromatography. Pharmacokinetic analysis was performed by means of compartmental modeling. Results: When ciprofloxacin was administered as tablets PO, peak plasma concentration was 4.4 μg/mL (coefficient of variation [CV], 55.9%), terminal half-life (t1/2) was 2.6 hours (CV, 10.8%), area under the time-concentration curve was 22.5 μg•h/mL (CV, 62.3%), and systemic absorption was 58.4% (CV, 45.4%). For the dose administered IV, t1/2 was 3.7 hours (CV, 52.3%), clearance was 0.588 L/kg/h (CV, 33.9%), and volume of distribution was 2.39 L/kg (CV, 23.7%). After PO administration as a solution versus IV administration, plasma concentrations were more uniform and consistent among dogs, with absorption of 71% (CV, 7.3%), t1/2 of 3.1 hours (CV, 18.6%), and peak plasma concentration of 4.67 μg/mL (CV, 17.6%). Conclusions and Clinical Relevance: Inconsistent oral absorption of ciprofloxacin in some dogs may be formulation dependent and affected by tablet dissolution in the small intestine. Because of the wide range in oral absorption of tablets, the dose needed to reach the pharmacokinetic-pharmacodynamic target concentration in this study ranged from 12 to 52 mg/kg (CV, 102%), with a mean dose of 25 mg/kg, once daily, for bacteria with a minimum inhibitory concentration ≤ 0.25 μg/mL.

The objective of this study was to evaluate the effect of a single joint lavage with 7.2% or 15% hypertonic saline solutions (HSS) on the tarsocrural joints of healthy calves. The tarsi of 10 calves were randomly lavaged with 7.2% HSS, 15% HSS, or isotonic saline. Synovial fluid samples were collected aseptically on days 1 (before joint lavage), 2, 3, 4, and 8 for complete cytological analysis. Lameness, joint swelling, and pain were recorded daily. Calves were euthanized on day 8 for gross and histological analyses of synovial membranes and articular cartilage. Synovitis was evaluated using a scoring system reflecting inflammatory changes in synovial membranes. Joints irrigated with HSS were more distended and painful compared with isotonic control joints. Swelling decreased consistently in the joints lavaged with 7.2% HSS, whereas it remained unchanged in joints lavaged with 15% HSS. Slight to moderate lameness was observed in the joints lavaged with 15% HSS. In comparison to isotonic saline joints, total protein concentration was significantly increased on day 2 and 3 for the joints lavaged with 7.2% HSS (P ≤ 0.01) and on days 2, 3, and 4 in the joints lavaged with 15% HSS (P ≤ 0.0006). Gross and histological findings revealed that synovitis was more severe in the joints lavaged with 15% HSS but variable in the joints lavaged with 7.2% HSS. No significant differences were observed for the articular cartilage. Fifteen percent HSS is not recommended for joint lavage. Although irrigation with 7.2% HSS may induce a variable synovitis, it was found appropriate for joint lavage. Its effects on septic joints remain undetermined.

Objective: To assess long-term effects and risk factors for the efficacy of hyperimmunization protocols against infectious bovine rhinotracheitis (IBR) during a longitudinal field study of dairy and dairy-beef mixed farms. Animals: Approximately 7,700 cows from 72 farms. Procedures: Farms were assigned to 3 treatment groups (hyperimmunization groups [HIGs] 1 and 2, which were hyperimmunized with glycoprotein E [gE]–deleted marker vaccines, and a nonintervention group [NIG]). Cattle in HIG 1 were initially vaccinated with an attenuated vaccine, whereas cattle in HIG 2 were initially vaccinated with an inactivated-virus vaccine. Cattle in both HIGs received booster inoculations with inactivated-virus vaccines at 6-month intervals. The risk for gE seroconversion was compared among experimental groups via a shared frailty model with a piecewise constant baseline risk to correct for seasonal and secular effects. Results: Risk for gE seroconversion significantly decreased over time for the HIGs, compared with the NIG. Seasonal changes in the risk of gE seroconversion were detected, with a higher risk during winter periods, compared with grazing periods. No significant difference was detected between HIGs 1 and 2. The only significant risk factor was the number of buildings for cattle on a farm; the higher the number of buildings, the lower the risk for gE seroconversion. Prevalence of IBR decreased over time in both HIGs but remained constant or increased in the NIG. Conclusions and Clinical Relevance: Hyperimmunization via repeated administration of attenuated and inactivated-virus gE-deleted marker vaccines as well as inactivated-virus vaccines may provide a method for control of IBR.

Objective: To determine whether incubation of cruciate ligament cells with acetylsalicylic acid, carprofen, meloxicam, or robenacoxib provides protection against apoptosis induced by sodium nitroprusside (SNP). Sample: Explants of cranial (CCL) and caudal (CaCL) cruciate ligaments from eight 1-day-old Beagles. Procedures: Primary cultures of CCL and CaCL cells were created via enzymatic dissociation of cruciate explants. Purified cell cultures were incubated for 2 hours without (controls) or with 1 of 3 concentrations of 1 of 4 NSAIDs (10, 100, or 200 μg of acetylsalicylic acid/mL; 0.1, 1, or 10 μg of carprofen/mL; 0.1, 1, or 10 μg of meloxicam/mL; or 0.1, 1, or 10 μg of robenacoxib/mL) and subsequently incubated for 18 hours with 1 of 3 concentrations of SNP in an attempt to induce mild, moderate, or severe cytotoxic effects. Cell viability and apoptosis were analyzed via a cell proliferation assay and flow cytometry, respectively. Prostaglandin E2 concentrations were measured via an ELISA. Results: Cytoprotective effects of NSAIDs were dependent on the extent of SNP-induced apoptosis and were greatest in CCL and CaCL cell cultures with moderate SNP-induced cytotoxic effects. Preincubation with an NSAID improved cell viability by 15% to 45% when CCL and CaCL cells were subsequently incubated with SNP. Carprofen (10 μg/mL) had the greatest cytoprotective effects for CCL and CaCL cells. Incubation with NSAIDs resulted in a nonsignificant decrease in PGE2 production from SNP-damaged cells. Conclusions and Clinical Relevance: Results indicated that carprofen, meloxicam, and robenacoxib may reduce apoptosis in cells originating from canine cruciate ligaments.

Objective: To investigate contrast-enhanced ultrasonography as a minimally invasive method for the subjective and quantitative assessment of pancreatic and duodenal perfusion in healthy adult dogs, with reference to perfusion in adjacent liver tissue. Animals: 8 clinically normal adult dogs. Procedures: Contrast-enhanced ultrasonograms of the right pancreatic limb, proximal portion of the descending duodenum, and adjacent liver were acquired after IV administration of a microbubble contrast medium. Following subjective evaluation, quantitative time-intensity curves were generated from regions of interest in the pancreas, duodenum, and liver. Five contrast medium characteristics representing perfusion parameters were determined for each organ and used for statistical analysis: interval to arrival, inflow rate, peak intensity (PI), time of peak intensity (TPI), and outflow rate. Results: Significant associations between pancreatic and duodenal values were found for interval to contrast medium arrival, PI, TPI, and outflow rate. Pancreatic and duodenal inflow rates were not correlated. Inflow and outflow rates were significantly faster and TPI significantly shorter for the pancreas and duodenum, compared with values for the liver. There was no significant difference among all 3 organs for interval to arrival and PI of contrast medium. Subjective evaluation findings corresponded to quantitative analysis results. Conclusions and Clinical Relevance: Results suggested that contrast-enhanced ultrasonography may be a useful, minimally invasive method for evaluating pancreatic and duodenal perfusion in dogs. The data from healthy dogs reported here could aid in the assessment of pancreatic and duodenal conditions and their response to medical treatment.

Objective: To compare the axial stiffness, maximum axial displacement, and ring deformation during axial loading of single complete and incomplete circular (ring) external skeletal fixator constructs. Sample: 32 groups of single ring constructs (5 constructs/group). Procedures: Single ring constructs assembled with 2 divergent 1.6-mm-diameter Kirschner wires were used to stabilize a 60-mm-long segment of 16-mm-diameter acetyl resin rod. Construct variables included ring type (complete or incomplete), ring diameter (50, 66, 84, or 118 mm), and fixation wire tension (0, 30, 60, or 90 kg). Axial loading was performed with a materials testing system. Construct secant stiffness and maximum displacement were calculated from the load-displacement curves generated for each construct. Ring deformation was calculated by comparing ring diameter during and after construct loading to ring diameter prior to testing. Results: Complete ring constructs had greater axial stiffness than did the 66-, 84-, and 118-mm-diameter incomplete ring constructs. As fixation wire tension increased, construct stiffness increased in the 66-, 84-, and 118-mm-diameter incomplete ring constructs. Maximum axial displacement decreased with increasing fixation wire tension, and complete ring constructs allowed less displacement than did incomplete ring constructs. Incomplete rings were deformed by wire tensioning and construct loading. Conclusions and Clinical Relevance: Mechanical performance of the 66-, 84-, and 118-mm-diameter incomplete ring constructs improved when wire tension was applied, but these constructs were not as stiff as and allowed greater displacement than did complete ring constructs of comparable diameter. For clinical practice, tensioning the wires placed on 84- and 118-mm-diameter incomplete rings to 60 kg is recommended.

Objective: To determine whether body lean angle could be predicted from circle radius and speed in horses during lunging and whether an increase in that angle would decrease the degree of movement symmetry (MS). Animals: 11 medium- to high-level dressage horses in competition training. Procedures: Body lean angle, head MS, and trunk MS were quantified during trotting while horses were instrumented with a 5-sensor global positioning system–enhanced inertial sensor system and lunged on a soft surface. Speed and circle radius were varied and used to calculate predicted body lean angle. Agreement between observed and predicted values was assessed, and the association between lean angle and MS was determined via least squares linear regression. Results: 162 trials totaling 3,368 strides (mean, 21 strides/trial) representing trotting speeds of 1.5 to 4.7 m/s and circle radii of 1.8 to 11.2 m were conducted in both lunging directions. Differences between observed and predicted lean angles were small (mean ± SD difference, −1.2 ± 2.4°) but significantly greater for circling to the right versus left. Movement symmetry values had a larger spread for the head than for the pelvis, and values of all but 1 MS variable changed with body lean angle. Conclusions and Clinical Relevance: Body lean angle agreed well with predictions from gravitational and centripetal forces, but differences observed between lunging directions emphasize the need to investigate other factors that might influence this variable. For a fair comparison of MS between directions, body lean angle needs to be controlled for or corrected with the regression equations. Whether the regression equations need to be adapted for lame horses requires additional investigation.

Objective: To determine MRI characteristics of the skulls and brains of sheep with chronic cerebral coenurosis (CC) caused by naturally acquired Taenia multiceps infection. Animals: 33 sheep with CC and 10 healthy control sheep. Procedures: Sheep underwent MRI of the head. Volumes of the cranial cavity and rostral and caudal fossas of the cranial cavity were determined. For CC-affected sheep, the number, location, and volume of T multiceps cysts were determined and the percentage volumes of cysts in the cranial cavity and rostral and caudal fossas of the cranial cavity were calculated. Focal and diffuse abnormalities of cranial bones in CC-affected sheep were identified. Brain edema and hemorrhage and signs of increased cranial pressure (ICP) in MRI images were determined. Results: Volumes of the cranial cavity and rostral and caudal fossas of the cranial cavity were significantly larger for CC-affected sheep versus healthy control sheep. Total volumes of cysts ranged from 4.40% to 46.93% in cranial cavities of sheep, 4.12% to 51.53% in rostral fossas of cranial cavities of sheep, and 15.24% to 68.30% in caudal fossas of cranial cavities of sheep. Moderate to severe diffuse cranial bone abnormalities and signs of increased ICP in MRI images were detected in 21 and 24 sheep, respectively, and were positively correlated with cyst volumes. Conclusions and Clinical Relevance: Results suggested that cranial cavity volume and morphological abnormalities can be detected in sheep with CC. These changes may reflect abnormalities in ossification of the cranial bones secondary to chronically increased ICP caused by development of T multiceps cysts.

Objective: To identify gait characteristics during trotting on a treadmill in nonlame Labrador Retrievers presumed predisposed or not predisposed to cranial cruciate ligament disease (CCLD). Animals: Clinically normal Labrador Retrievers presumed predisposed (n = 10) or not predisposed (7) to CCLD. Procedures: The right hind limb of each dog was classified by use of a predictive score equation that combined tibial plateau angle and femoral anteversion angle as presumed predisposed (high score [> −1.5]) or not predisposed (low score [≤ −1.5]) to CCLD. Tarsal joint, stifle joint, and hip joint kinematics, net moments, and powers were computed. Results: The stifle joint was held at a greater degree of flexion in limbs presumed predisposed to CCLD (130.9° vs 139.3°). More power was generated by muscles acting on the stifle joint in the early stance phase of limbs presumed to be predisposed to CCLD (2.93 vs 1.64 W/kg). The tarsal joint did not reach the same degree of extension in limbs presumed predisposed to CCLD, compared with that in limbs presumed not predisposed to CCLD (179.0° vs 161.0°). Velocity, stance time, vertical and craniocaudal forces, angular velocities, and net joint muscle moments did not differ between groups. Conclusions and Clinical Relevance: Gait mechanics of dogs with high (> −1.5) and low (≤ −1.5) tibial plateau angle and femoral anteversion angle scores were characterized on a treadmill, which may help in the identification of dogs predisposed to CCLD.

Objective: To investigate the influence of dietary supplementation with l-carnitine on metabolic rate, fatty acid oxidation, weight loss, and lean body mass (LBM) in overweight cats undergoing rapid weight reduction. Animals: 32 healthy adult neutered colony-housed cats. Procedures: Cats fattened through unrestricted ingestion of an energy-dense diet for 6 months were randomly assigned to 4 groups and fed a weight reduction diet supplemented with 0 (control), 50, 100, or 150 μg of carnitine/g of diet (unrestricted for 1 month, then restricted). Measurements included resting energy expenditure, respiratory quotient, daily energy expenditure, LBM, and fatty acid oxidation. Following weight loss, cats were allowed unrestricted feeding of the energy-dense diet to investigate weight gain after test diet cessation. Results: Median weekly weight loss in all groups was ≥ 1.3%, with no difference among groups in overall or cumulative percentage weight loss. During restricted feeding, the resting energy expenditure-to-LBM ratio was significantly higher in cats that received l-carnitine than in those that received the control diet. Respiratory quotient was significantly lower in each cat that received l-carnitine on day 42, compared with the value before the diet began, and in all cats that received l-carnitine, compared with the control group throughout restricted feeding. A significant increase in palmitate flux rate in cats fed the diet with 150 μg of carnitine/g relative to the flux rate in the control group on day 42 corresponded to significantly increased stoichiometric fat oxidation in the l-carnitine diet group (> 62% vs 14% for the control group). Weight gain (as high as 28%) was evident within 35 days after unrestricted feeding was reintroduced. Conclusions and Clinical Relevance: Dietary l-carnitine supplementation appeared to have a metabolic effect in overweight cats undergoing rapid weight loss that facilitated fatty acid oxidation.