The objective of this study was to explore the mathematical relationships between independent variables (patient morphometrics and treadmill speed) and dependent variables (accelerometer or pedometer output) when evaluating data from accelerometers and pedometers in dogs. Twenty dogs took part in 3 randomized activities, consisting of exercise on a treadmill at 1.0, 1.5, and 2.0 m/s for a total distance of 1 km at each speed. Dogs simultaneously wore both an accelerometer and a pedometer. Statistical analysis used multiple regression models to discover the relationships between independent and dependent variables. A formula was developed to predict the distance traveled by a dog based on its morphometrics and activity monitor output. Shoulder height had stronger correlations to accelerometer and pedometer outputs than other morphometric variables. As shoulder height increased, all accelerometer and pedometer outputs decreased. As treadmill speed increased, both accelerometer and pedometer step counts decreased, while accelerometer activity counts increased. According to a formula derived to predict the total distance traveled using patient shoulder height and accelerometer or pedometer output, pedometer steps were the most accurate predictor of distance traveled. Accelerometer steps were less accurate when using the same model. Accelerometer activity counts did not reveal a meaningful predictive formula. The results of this study indicate that patient morphometrics and treadmill speed (as a measure of intensity) influenced accelerometer and pedometer data. The pedometer data more precisely and accurately estimated the distance traveled based on step counts and patient shoulder height. In normal dogs, accelerometer and pedometer steps may reasonably estimate distance traveled.

OBJECTIVE To describe the pharmacokinetics of morphine, lidocaine, and ketamine associated with IV administration of a constant rate infusion (CRI) of a morphine-lidocaine-ketamine (MLK) combination to calves undergoing umbilical herniorrhaphy. ANIMALS 20 weaned Holstein calves with umbilical hernias. PROCEDURES Calves were randomly assigned to receive a CRI of an MLK solution (0.11 mL/kg/h; morphine, 4.8 μg/kg/h; lidocaine, 2.1 mg/kg/h; and ketamine, 0.42 mg/kg/h) for 24 hours (MLK group) or 2 doses of flunixin meglumine (1.1 mg/kg, IV, q 24 h) and a CRI of saline (0.9% NaCl) solution (0.11 mL/kg/h) for 24 hours (control group). For all calves, the CRI was begun after anesthesia induction. Blood samples were obtained immediately before and at predetermined times for 120 hours after initiation of the assigned treatment. Noncompartmental analysis was used to estimate pharmacokinetic parameters for the MLK group. RESULTS During the CRI, steady-state serum concentrations were achieved for lidocaine and ketamine, but not morphine. Mean terminal half-life was 4.1, 0.98, and 1.55 hours and area under the concentration-time curve was 41, 14,494, and 7,426 h•μg/mL for morphine, lidocaine, and ketamine, respectively. After the CRI, the mean serum drug concentration at steady state was 6.3, 616.7, and 328 ng/mL for morphine, lidocaine, and ketamine, respectively. CONCLUSIONS AND CLINICAL RELEVANCE During the CRI of the MLK solution, steady-state serum concentrations were achieved for lidocaine and ketamine, but not morphine, likely owing to the fairly long half-life of morphine. Kinetic analyses of MLK infusions in cattle are necessary to establish optimal dosing protocols.

OBJECTIVE To characterize the patterns associated with Lorenz plots (LPs) or Poincaré plots derived from the Holter recordings of dogs with various cardiac rhythms. ANIMALS 77 dogs with 24-hour Holter recordings. PROCEDURES A 1-hour period from the Holter recordings from each of 20 dogs without arrhythmias and from each of 57 dogs with arrhythmias (10 each with supraventricular premature complexes, complex supraventricular ectopy, ventricular premature complexes, complex ventricular ectopy, and atrial fibrillation, and 7 with high-grade second-degree atrioventricular block) were used to generate the LPs. Patterns depicted in the LPs were described. RESULTS Arrhythmia-free Holter recordings yielded LPs with a Y-shaped pattern and variable silent zones. Recordings with single premature complexes yielded LPs with double side and triple side lobes. Complex ectopy was denoted by dots clustered in the lower left corner of the LPs. The LPs of recordings with atrial fibrillation had fan patterns consistent with a nonlinear relationship between atrial electrical impulses and atrioventricular nodal conduction. The recordings with atrioventricular block yielded LPs with island patterns consistent with variable atrioventricular nodal conduction. CONCLUSIONS AND CLINICAL RELEVANCE Distinct LP patterns were identified for common cardiac rhythms of dogs, supportive of nonrandom mechanisms as the cause of most rhythms. Visual interpretation of an LP generated from a Holter recording may aid in determining the arrhythmia type and understanding the arrhythmia's mechanism in dogs and other species.

This study investigated oxidative stress biomarkers at 3 different oxygen concentrations in dogs under general anesthesia to determine whether high-concentration oxygen increases oxidative stress. Six healthy beagles were randomly assigned to receive 3 anesthesia protocols (inhalation of 40%, 60%, and 100% oxygen) during 3 hours of general anesthesia with sevoflurane, with at least one week in between each protocol. For each experiment, blood samples were collected at 0, 3, 6, and 24 hours after inhalation of oxygen. Derivatives of reactive oxygen metabolites, biochemical antioxidant potential, superoxide dismutase, and 8-hydroxydeoxyguanosine in the blood did not significantly differ among the 3 groups at any time point. This study is the first comparing high concentrations of oxygen with low concentrations of oxygen for anesthesia in dogs. According to our findings, 100% oxygen may not alter the oxidative stress level in dogs during general anesthesia with sevoflurane for 3 hours.

OBJECTIVE To evaluate the thermal antinociceptive effects of hydromorphone hydrochloride after IM administration to orange-winged Amazon parrots (Amazona amazonica). ANIMALS 8 healthy adult parrots (4 males and 4 females). PROCEDURES In a randomized crossover study, each bird received hydromorphone (0.1, 1, and 2 mg/kg) and saline (0.9% NaCl) solution (1 mL/kg; control) IM, with a 7-day interval between treatments. Each bird was assigned an agitation-sedation score, and the thermal foot withdrawal threshold (TFWT) was measured at predetermined times before and after treatment administration. Adverse effects were also monitored. The TFWT, agitation-sedation score, and proportion of birds that developed adverse effects were compared among treatments over time. RESULTS Compared with the mean TFWT for the control treatment, the mean TFWT was significantly increased at 0.5, 1.5, and 3 hours and 1.5, 3, and 6 hours after administration of the 1- and 2-mg/kg hydromorphone doses, respectively. Significant agitation was observed at 0.5, 1.5, and 3 hours after administration of the 1 - and 2-mg/kg hydromorphone doses. Other adverse effects observed after administration of the 1- and 2-mg/kg doses included miosis, ataxia, and nausea-like behavior (opening the beak and moving the tongue back and forth). CONCLUSIONS AND CLINICAL RELEVANCE Although the 1- and 2-mg/kg hydromorphone doses appeared to have antinociceptive effects, they also caused agitation, signs of nausea, and ataxia. Further research is necessary to evaluate administration of lower doses of hydromorphone and other types of stimulation to better elucidate the analgesic and adverse effects of the drug in psittacine species.

There is evidence that perfusing the heart with a heart and lung machine is less injurious than cross-clamping the aorta and administering cardioplegia during cardiac surgery. Although mitral valve replacement has been carried out without aortic cross-clamping and cardioplegia, it has been stated that cross-clamping is necessary in order to maintain visualization and a motionless surgical field for mitral valve repair. The purpose of this study was to determine the surgical feasibility of mitral valve repair without cross-clamping the aorta and using cardioplegia. Our hypothesis was that a completely bloodless and motion-free field would not be necessary to carry out mitral valve repair with annuloplasty and synthetic chordae tendineae sutures. Papillary muscles, chordae tendineae, annulus, and mitral valve leaflets were all readily visualized. Chordae tendineae sutures were used and annuloplasty was conducted without visual obstruction or motion interference. Our results show that mitral valve repair is feasible without cross-clamping the aorta and using cardioplegia.

OBJECTIVE To establish a method for evaluation of the efficacy of a classical swine fever virus (CSFV) subunit vaccine in rabbits as determined via humoral immune responses to the virus. ANIMALS 40 specific pathogen–free rabbits. PROCEDURES Rabbits were randomly assigned to 4 groups (10 rabbits/group) for SC injection of 0.05, 0.1, and 0.2 mL of a CSFV subunit E2 vaccine (representing 1.15, 2.3, or 4.6 μg of E2 protein/dose, respectively) or saline (0.9% NaCl) solution. Blood samples were collected 21 days after vaccination for measurement of the antibody response against CSFV via ELISA and virus neutralization methods. On the same day, the CSFV Chinese (C) strain was injected into an ear vein. Vaccine efficacy was determined by monitoring of rabbits for pyrexia for 4 days and measurement of viral copies in spleen lysates at the end of the study. Reproducibility of the antibody response was tested with 2 other batches of the vaccine at the minimum immunization dose identified for the initially tested batch. RESULTS The E2 protein dose of the initially tested vaccine was positively correlated with the antibody response and protection rate in rabbits. The identified minimum immunization dose per rabbit was 0.1 mL, representing an E2 protein content of approximately 2.3 μg, and reproducibility of the antibody response to vaccination with the 2 other batches at this dose was good. CONCLUSIONS AND CLINICAL RELEVANCE A method was established in rabbits for evaluation of the efficacy of a CSFV subunit vaccine that could help in the optimization of later large-scale vaccine production and quality control processes as well as in the clinical application of the vaccine.

OBJECTIVE To determine the pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica). ANIMALS 12 adult orange-winged Amazon parrots (6 males and 6 females). PROCEDURES A single dose of amantadine was orally administered to 6 birds at 5 mg/kg (n = 2), 10 mg/kg (2), and 20 mg/kg (2) in a preliminary trial. On the basis of the results, a single dose of amantadine (10 mg/kg, PO) was administered to 6 other birds. Two months later, multiple doses of amantadine (5 mg/kg, PO, q 24 h for 7 days) were administered to 8 birds. Heart rate, respiratory rate, behavior, and urofeces were monitored. Plasma concentrations of amantadine were measured via tandem liquid chromatography–mass spectrometry. Pharmacokinetic parameter estimates were determined via noncompartmental analysis. RESULTS Mean ± SD maximum plasma concentration, time to maximum plasma concentration, half-life, and area under the concentration-versus-time curve from the last dose to infinity were 1,174 ± 186 ng/mL, 3.8 ± 1.8 hours, 23.2 ± 2.9 hours, and 38.6 ± 7.4 μg·h/mL, respectively, after a single dose and 1,185 ± 270 ng/mL, 3.0 ± 2.4 hours, 21.5 ± 5.3 hours, and 26.3 ± 5.7 μg·h/mL, respectively, at steady state after multiple doses. No adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Once-daily oral administration of amantadine at 5 mg/kg to orange-winged Amazon parrots maintained plasma concentrations above those considered to be therapeutic in dogs. Further studies evaluating safety and efficacy of amantadine in orange-winged Amazon parrots are warranted.

OBJECTIVE To compare a ventral and a left lateral endoscopic approach to coelioscopy in bearded dragons (Pogona vitticeps). ANIMALS 18 adult bearded dragons. PROCEDURES In a randomized crossover design involving 2 surgical approaches, anesthetized bearded dragons first underwent coelioscopy with a ventral approach (left lateral of midline next to the umbilicus; animal positioned in dorsal recumbency) or left lateral approach (intercostal; animal positioned in right lateral recumbency) and then with the alternate approach. A 2.7-mm × 18-cm, 30° oblique telescope with a 4.8-mm operating sheath and CO2 insufflation at 2 to 5 mm Hg were used. Ease of entry into the coelom and ease of visual examination of visceral structures were scored. RESULTS Both approaches were straightforward, with the left lateral approach requiring significantly more time than the ventral approach. Scores for ease of visual examination for the heart, lungs, liver, stomach, intestines, pancreas, gallbladder, left kidney, gonads, and fat body were good to excellent. Visual examination of the spleen and adrenal glands was difficult in most animals via either approach. The left kidney, testis, and vas deferens were easier to see with the left lateral approach, whereas the pancreas in females and gallbladder in both sexes were easier to see with the ventral approach. All bearded dragons recovered without complications from the procedures, except for one with nephritis, renal gout, and hepatic necrosis. CONCLUSIONS AND CLINICAL RELEVANCE Both coelioscopy approaches could be safely and effectively used in bearded dragons. Choice of approach should be based on the coelomic structures requiring evaluation.

OBJECTIVE To determine whether a customized unilateral intervertebral anchored fusion device combined with (vs without) an intervertebral spacer would increase the stability of the L1-L2 motion segment following complete intervertebral diskectomy in canine cadaveric specimens. SAMPLE Vertebral columns from T13 through L3 harvested from 16 skeletally mature Beagles without thoracolumbar disease. PROCEDURES Complete diskectomy of the L1-2 disk was performed in each specimen. Unilateral stabilization of the L1-L2 motion segment was performed with the first of 2 implants: a unilateral intervertebral anchored fusion device that consisted of a locking compression plate with or without an intervertebral spacer. The resulting construct was biomechanically tested; then, the first implant was removed, and the second implant was applied to the contralateral side and tested. Range of motion in flexion and extension, lateral bending, and torsion was compared among intact specimens (prior to diskectomy) and constructs. RESULTS Compared with intact specimens, constructs stabilized with either implant were as stable in flexion and extension, significantly more stable in lateral bending, and significantly less stable in axial rotation. Constructs stabilized with the fusion device plus intervertebral spacer were significantly stiffer in lateral bending than those stabilized with the fusion device alone. No significant differences in flexion and extension and rotation were noted between implants. CONCLUSIONS AND CLINICAL RELEVANCE Findings did not support the use of this customized unilateral intervertebral anchored fusion device with an intervertebral spacer to improve unilateral stabilization of the L1-L2 motion segment after complete L1-2 diskectomy in dogs.