Porcine reproductive and respiratory syndrome virus (PRRSV) can be difficult to manage in commercial settings. A novel type I PRRSV vaccinal strain (94881) was evaluated for safety and efficacy/onset of immunity (OOI) in piglets. In 2 experiments, groups of piglets were vaccinated intramuscularly (IM) at approximately 14 d of age with a maximum-range commercial dose, an overdose, or a placebo in experiment 1 and either a minimum-range commercial dose or a placebo in experiment 2. The piglets in experiment 1 were evaluated for local and systemic reactions from days -2 through 14 after vaccination. The piglets in experiment 2 were challenged with a virulent heterologous type I PRRSV isolate 14 d after vaccination and observed once daily for general health from days -1 through 12 after vaccination and once daily for clinical signs associated with challenge from days 13 through 24 after vaccination. The average daily weight gain (ADWG) and the results of serologic and viremia testing were evaluated in experiments 1 and 2. Lung lesion scores and results of testing for PRRSV in lung tissue were evaluated in experiment 2. In experiment 1 the vaccine was shown to be safe, as there were no relevant differences between the vaccinated piglets and the piglets given a placebo. In experiment 2 the vaccine's efficacy, with an OOI of 14 d after vaccination, was established, as the vaccinated and challenged piglets exhibited significantly lower lung lesion scores, viremia, viral load in lung tissue, and total clinical sign scores, along with a significantly greater ADWG, compared with the placebo-vaccinated and challenged piglets.

OBJECTIVE To analyze the effects of vertical force peak (VFP) of repition within trials and between trial sessions in horses with naturally occurring appendicular lameness. ANIMALS 20 lame horses acclimated to trotting over a force plate. PROCEDURES Kinetic gait data were collected by use of a force plate regarding affected and contralateral limbs of lame horses that completed 5 valid repetitions in each of 5 sessions performed at 0, 3, 6, 12, and 24 hours, constituting 1 trial/horse. Data were compared within and among repetitions and sessions, and factors influencing VFP values were identified. RESULTS VFP values differed for lame limbs after 3 valid repetitions were performed within a session and when the interval between sessions was 3 hours. Direction of change reflected less lameness (greater VFP). Lamer horses (≥ grade 4/5) had this finding to a greater degree than did less lame horses. Results were similar for contralateral limbs regarding valid repetitions within a session; however, VFP decreased when the interval between sessions exceeded 6 hours. The coefficient of variation for VFP was ≤ 8% within sessions and ≤ 6% between sessions. The asymmetry index for VFP did not change throughout the study. CONCLUSIONS AND CLINICAL RELEVANCE Lameness profiles obtained through kinetic gait analysis of horses with naturally occurring lameness were most accurate when valid repetitions were limited to 3 and the interval between sessions within a trial was > 3 hours. Findings suggested that natural lameness may be as suitable as experimentally induced lameness for lameness research involving horses.

OBJECTIVE To evaluate the efficacy of IV administration of a product containing hyaluronan, sodium chondroitin sulfate, and N-acetyl-d-glucosamine for prevention or treatment of osteoarthritis in horses. ANIMALS 32 healthy 2- to 5-year-old horses. PROCEDURES The study involved 2 portions. To evaluate prophylactic efficacy of the test product, horses received 5 mL of the product (n = 8) or saline (0.9% NaCl) solution (8; placebo) IV every fifth day, starting on day 0 (when osteoarthritis was induced in the middle carpal joint of 1 forelimb) and ending on day 70. To evaluate treatment efficacy, horses received either the product or placebo (n = 8/treatment) on days 16, 23, 30, 37, and 44 after osteoarthritis induction. Clinical, diagnostic imaging, synovial fluid, gross anatomic, and histologic evaluations and other tests were performed. Results of each study portion were compared between treatment groups. RESULTS Limb flexion and radiographic findings were significantly worse for horses that received the test product in the prophylactic efficacy portion than for placebo-treated horses or product-treated horses in the treatment efficacy portion. In the prophylactic efficacy portion, significantly less articular cartilage erosion was identified in product-treated versus placebo-treated horses. In the treatment efficacy portion, joints of product-treated horses had a greater degree of bone edema identified via MRI than did joints of placebo-treated horses but fewer microscopic articular cartilage abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that caution should be used when administering the evaluated product IV to horses, particularly when administering it prophylactically, as it may have no benefit or may even cause harm.

OBJECTIVE To characterize the extent and location of atelectasis in healthy anesthetized dogs positioned in lateral recumbency and to determine whether repositioning dogs in sternal recumbency would resolve atelectasis. ANIMALS 6 healthy adult Beagles. PROCEDURES Each dog was anesthetized and underwent a CT examination twice with a 2-week interval between examinations. Once anesthetized, each dog was positioned in sternal recumbency, and a breath-hold helical transverse thoracic CT scan was acquired. The dog was then positioned in lateral recumbency for 30 minutes, and images were obtained at 5 preselected sites at 3, 8, 13, 20, and 30 minutes after repositioning (phase 1). Then, the dog was repositioned in sternal recumbency, and CT images were obtained at the 5 preselected sites at 5, 10, and 20 minutes after repositioning (phase 2). The protocol for the second examination was the same as the first except the dog was positioned in the opposite lateral recumbency during phase 1. The attenuation and cross-sectional area of the lung lobes at the preselected sites were measured and compared over time. RESULTS Lateral recumbency did not cause atelectasis in any of the dogs. Patchy areas of abnormally increased attenuation were infrequently detected in the left cranial lung lobe when dogs were positioned in left lateral recumbency, and those areas failed to resolve when dogs were positioned in sternal recumbency. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent of lung attenuation changes was minimal in healthy anesthetized Beagles positioned in lateral recumbency and should not preclude CT examination.

OBJECTIVE To evaluate effects of simultaneous intra-articular and IV injection of autologous adipose-derived stromal vascular fraction (SVF) and platelet-rich plasma (PRP) to dogs with osteoarthritis of the hip joints. ANIMALS 22 client-owned dogs (12 placebo-treated [control] dogs and 10 treated dogs). PROCEDURES Dogs with osteoarthritis of the hip joints that caused signs of lameness or discomfort were characterized on the basis of results of orthopedic examination, goniometry, lameness score, the Canine Brief Pain Inventory (CBPI), a visual analogue scale, and results obtained by use of a pressure-sensing walkway at week 0 (baseline). Dogs received a simultaneous intraarticular and IV injection of SVF and PRP or a placebo. Dogs were examined again 4, 8, 12, and 24 weeks after injection. RESULTS CBPI scores were significantly lower for the treatment group at week 24, compared with scores for the control group. Mean visual analogue scale score for the treatment group was significantly higher at week 0 than at weeks 4, 8, or 24. Dogs with baseline peak vertical force (PVF) in the lowest 25th percentile were compared, and the treatment group had a significantly higher PVF than did the control group. After the SVF-PRP injection, fewer dogs in the treated group than in the control group had lameness confirmed during examination. CONCLUSIONS AND CLINICAL RELEVANCE For dogs with osteoarthritis of the hip joints treated with SVF and PRP, improvements in CBPI and PVF were evident at some time points, compared with results for the control group.

OBJECTIVE To determine effects of catheter shape, interelectrode spacing (IS), and electrode size (ES) on pacing threshold (PT), extraneous muscular stimulation (EMS), and zone of capture (ZOC) for dogs undergoing transesophageal atrial pacing (TAP). ANIMALS 10 purpose-bred dogs without cardiac conduction disturbances. PROCEDURES 7 configurations for TAP catheters were tested in each dog to evaluate effects of catheter shape (curved or straight), IS (5, 15, and 25 mm), and ES (2, 4, and 6 mm). Each catheter was passed into the esophagus to a location aboral to the heart and slowly withdrawn until atrial pacing was achieved. Then, catheters were withdrawn in 5-mm increments until pacing could not be achieved. Outcomes measured at each pacing site included PT, degree of EMS, and ZOC. RESULTS There was a significantly lower PT, wider ZOC, and less EMS for the curved catheter than for the straight catheter. An ES of 6 mm induced significantly more EMS than was induced by an ES of 2 or 4 mm. An IS of 5 mm induced significantly less EMS and a significantly narrower ZOC but required a significantly higher PT, compared with results for an ES of 15 or 25 mm. Additionally, there was a significant direct correlation between IS and ZOC. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a curved catheter with multiple 4-mm electrodes that provides for variable IS would be ideal for TAP in dogs. IMPACT FOR HUMAN MEDICINE TAP catheters currently used in human medicine are straight. The PT in humans may potentially be reduced with curved catheters.

OBJECTIVE To develop a device intended for gradual venous occlusion over 4 to 6 weeks. SAMPLE Silicone tubing filled with various inorganic salt and polyacrylic acid (PAA) formulations and mounted within a polypropylene or polyether ether ketone (PEEK) outer ring. PROCEDURES 15 polypropylene prototype rings were initially filled with 1 of 5 formulations and placed in PBSS. In a second test, 10 polypropylene and 7 PEEK prototype rings were filled with 1 formulation and placed in PBSS. In a third test, 2 formulations were loaded into 6 PEEK rings each, placed in physiologic solution, and incubated. In all tests, ring luminal diameter, outer diameter, and luminal area were measured over 6 weeks. RESULTS In the first test, 2 formulations had the greatest changes in luminal area and diameter, and 1 of those had a greater linear swell rate than the other had. In the second test, 6 of 7 PEEK rings and 6 of 10 polypropylene rings closed to a luminal diamater < 1 mm within 6 weeks. Polypropylene rings had a greater increase in outer diameter than did PEEK rings between 4.5 and 6 weeks. In the third test, 11 of 12 PEEK rings gradually closed to a luminal diameter < 1 mm within 6 weeks. CONCLUSIONS AND CLINICAL RELEVANCE A PAA and inorganic salt formulation in a prototype silicone and polymer ring resulted in gradual occlusion over 4 to 6 weeks in vitro. Prototype PEEK rings provided more reliable closure than did polypropylene rings.

OBJECTIVE To determine the effect of repeated gas sterilization on rate of closure of ameroid ring constrictors in vitro. SAMPLE Twenty-four 3.5-mm ameroid ring constrictors. PROCEDURES Ameroid ring constrictors were allocated to 1 of 4 treatment groups (6/group) to undergo gas sterilization 0, 1, 5, or 10 times. After sterilization, constrictors were incubated in canine plasma at a protein concentration of 3 g/dL for 27 days. A digital camera was used to obtain images of the constrictors prior to and at various points during incubation, and lumen diameter was measured. RESULTS Mean ± SD percentage of lumen closure for all groups of ameroid ring constrictors combined was 85.2 ± 1.6% at day 0 (prior to plasma incubation) and 95.4 ± 0.8% at day 27. Mean lumen area was 3.64 ± 0.43 mm2 (95% confidence interval, 2.67 to 4.77 mm2) at day 0 and 1.32 ± 0.25 mm2 (95% confidence interval, 0.76 to 2.04 mm2) at day 27. None of the ameroid ring constrictors had closed completely by day 27. CONCLUSIONS AND CLINICAL RELEVANCE Overall closure rates for ameroid ring constrictors appeared to be unaffected by repeated gas sterilization up to 10 times. Findings suggested that veterinary surgeons can resterilize ameroid ring constrictors up to 10 times with confidence that ring properties would remain suitable for clinical use.

OBJECTIVE To compare blood pressure measured noninvasively with an oscillometric device that involved use of a novel conical cuff and a traditional cylindrical blood pressure cuff. ANIMALS 17 adult hound-type dogs. PROCEDURES Dogs were anesthetized, and a 20-gauge, 1.5-inch catheter was inserted in the median sacral artery. The catheter was attached to a pressure transducer via fluid-filled noncompliant tubing, and direct blood pressure was recorded with a multifunction monitor. A specially fabricated conical cuff was placed on the antebrachium. Four sets of direct and indirect blood pressure measurements were simultaneously collected every 2 minutes. Four sets of measurements were then obtained by use of a cylindrical cuff. RESULTS The cylindrical cuff met American College of Veterinary Internal Medicine consensus guidelines for validation of indirect blood pressure measurements for mean arterial blood pressure (MAP), systolic arterial blood pressure (SAP), and diastolic arterial blood pressure (DAP). The conical cuff met the consensus guidelines for difference of paired measurements, SD, and percentages of measurements within 10 and 20 mm Hg of the value for the reference method, but it failed a correlation analysis. In addition, although bias for the conical cuff was less than that for the cylindrical cuff for SAP, MAP, and DAP measurements, the limits of agreement for the conical cuff were wider than those for the cylindrical cuff for SAP and MAP measurements. CONCLUSIONS AND CLINICAL RELEVANCE On the basis of results of this study, use of a conical cuff for oscillometric blood pressure measurement cannot be recommended.

OBJECTIVE To investigate the effects of isoflurane anesthesia administered at 2 multiples of the minimum alveolar concentration (MAC) on tissue perfusion in dogs. ANIMALS 8 healthy young adult Beagles. PROCEDURES A randomized crossover design was used. Dogs were anesthetized with isoflurane at 1.5 or 2.0 times the MAC for 2 hours, a 7-day washout period was provided, and dogs were reanesthetized with the alternate treatment. Various physiologic variables were monitored before anesthesia (baseline), at 20-minute intervals during anesthesia, and after anesthetic recovery. Variable values were compared between MAC multiples by means of repeated-measures ANOVA, with the Tukey test used for multiple comparisons. RESULTS During anesthesia, mean arterial blood pressure, cardiac output, and mixed venous oxygen saturation were significantly greater when isoflurane was administered at 1.5 versus 2.0 times the MAC. Cardiac output gradually increased during anesthesia at 1.5 times but not at 2.0 times the MAC. Arterial blood lactate concentration did not differ between MAC multiples at any point; however, this concentration decreased with increasing anesthetic duration at both MAC multiples. Oxygen delivery differed between MAC multiples, and oxygen consumption differed from baseline during anesthesia at 2.0 times the MAC. Oxygen extraction was higher at 2.0 versus 1.5 times the MAC. Heart rate differed between MAC multiples only after anesthetic recovery. CONCLUSIONS AND CLINICAL RELEVANCE Isoflurane anesthesia impaired tissue perfusion in dogs, but these changes would not be clinically relevant with oxygen delivery at 100%. Peripheral tissue perfusion was maintained or improved with time.