OBJECTIVE To develop contact time (ConT) and withers height-normalized relative ConT (ConT*) for force platform gait analysis of dogs. ANIMALS 29 healthy client-owned dogs. PROCEDURES Height at the most dorsal aspect of the shoulders (withers) was measured with a framing square. Dogs were trotted across a force platform at their preferred velocity with controlled acceleration (± 0.5 m/s2). Ranges of ConT and ConT* centered on the population mean ConT were created. Variance effects on ground reaction forces (GRFs) for 4 thoracic limb and 4 pelvic limb ConT and associated ConT* ranges were examined. Efficiency of trial capture and effects of velocity ranges on GRF variance were determined. RESULTS Individual dogs had the greatest effect on GRF variance for thoracic and pelvic limbs. Narrow ConT and ConT* ranges had few significant effects on GRFs but were inefficient at capturing trials. The ConT ranges of 0.22 to 0.29 seconds and 0.19 to 0.25 seconds for thoracic and pelvic limbs, respectively, provided the most efficient rates of trial capture with the fewest significant effects on GRFs. Compared with ConT and ConT* ranges, relative velocity ranges had higher efficiency and smaller GRF variance effects. CONCLUSIONS AND CLINICAL RELEVANCE Dogs of various morphologies have differing limb velocities. Use of ConT as a surrogate for limb velocity may improve GRF data quality. We identified ConT and ConT* ranges associated with low GRF variance. However, relative velocity ranges captured data more efficiently. Efficient capture of data may help avoid worsening of lameness during gait analysis of dogs.

OBJECTIVE To assess the effect of low-level laser therapy (LLLT) on markers of synovial inflammation and signs of pain, function, bone healing, and osteoarthritis following tibial plateau leveling osteotomy (TPLO) in dogs with spontaneous cranial cruciate ligament rupture (CCLR). ANIMALS 12 client-owned dogs with unilateral CCLR. PROCEDURES All dogs were instrumented with an accelerometer for 2 weeks before and 8 weeks after TPLO. Dogs were randomly assigned to receive LLLT (radiant exposure, 1.5 to 2.25 J/cm2; n = 6) or a control (red light; 6) treatment immediately before and at predetermined times for 8 weeks after TPLO. Owners completed a Canine Brief Pain Inventory weekly for 8 weeks after surgery. Each dog underwent a recheck appointment, which included physical and orthopedic examinations, force plate analysis, radiography and synoviocentesis of the affected joint, and evaluation of lameness and signs of pain, at 2, 4, and 8 weeks after surgery. Select markers of inflammation were quantified in synovial fluid samples. Variables were compared between the 2 groups. RESULTS For the control group, mean ground reaction forces were greater at 2 and 4 weeks after TPLO and owner-assigned pain scores were lower during weeks 1 through 5 after TPLO, compared with corresponding values for the LLLT group. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the LLLT protocol used had no beneficial effects on signs of pain or pelvic limb function following TPLO. Further research is necessary to evaluate the effects of LLLT and to determine the optimum LLLT protocol for dogs with CCLR.

OBJECTIVE To determine whether addition of epinephrine to a lidocaine solution would prolong and potentiate the efficacy of a palmar digital nerve block (PDNB) in horses. ANIMALS 6 adult horses with naturally occurring forefoot lameness. PROCEDURES Initially, a PDNB with a 2% lidocaine solution was performed on the affected foot of each horse. Three days later, the PDNB was repeated with a 1% lidocaine solution or a 1% lidocaine solution containing epinephrine (dilution, 1:200,000). After another 3-day washout period, the PDNB was repeated with the treatment opposite that administered for the second PDNB. Gait was analyzed with a computerized lameness analysis system and heart rate and extent of skin sensation between the heel bulbs of the blocked foot were evaluated at predetermined times for 2 hours after each PDNB. RESULTS Efficacy and duration of the PDNB did not differ significantly between the 2% and 1% lidocaine treatments. The addition of epinephrine to the 1% lidocaine solution improved the efficacy and prolonged the duration of the PDNB. It also resulted in a positive correlation between skin desensitization and amelioration of lameness. Median heart rate remained unchanged throughout the observation period for all 3 treatments. No adverse effects associated with the PDNBs were observed. CONCLUSIONS AND CLINICAL RELEVANCE Addition of epinephrine (dilution, 1:200,000) to a 1% lidocaine solution improved the efficacy and prolonged the duration of a PDNB in horses with naturally occurring lameness and might be clinically useful for lameness evaluations and standing surgery of the forefoot of horses.

OBJECTIVE To evaluate 3 contrast medium infusion (CMI) protocols for CT angiography (CTA) and measurement of major artery diameters in African grey parrots (Psittacus erithacus). ANIMALS 9 African grey parrots with no detectable cardiovascular disease. PROCEDURES Each bird was anesthetized and underwent placement of an IV catheter in the left basilic vein and 16-slice CTA scanning (started at peak aortic enhancement) with each of 3 CMI protocols at ≥ 1-month intervals. Protocol 1 involved catheter flushing with saline (0.9% NaCl) solution and IV infusion of iopamidol (2 mL) followed by saline solution (0.2 mL; total infused volume, 5 mL). Protocol 2 involved IV infusion of iopamidol (2 mL) followed by saline solution (0.4 mL; total infused volume, 2.4 mL). Protocol 3 involved catheter flushing with saline solution and IV administration of iopamidol (2 mL; total infused volume, 4.8 mL). The diameters of 6 major arteries were measured by 2 observers, and intra- and interobserver agreement, time-enhancement variables, and patient factors affecting contrast medium enhancement were assessed. RESULTS Among the 3 CMI protocols, CTA-derived arterial diameters differed significantly. Measurements obtained with protocol 2 were significantly larger than those obtained with the other protocols. Uniformity of the time-enhancement variables differed among CMI protocols. Patient factors had nonsignificant effects on contrast medium enhancement. CONCLUSIONS AND CLINICAL RELEVANCE Of the CMI protocols assessed, a 2-phase CMI protocol with a post-CMI saline solution flush was the most reliable for CTA-derived measurements of the major thoracic and abdominal arteries in African grey parrots. However, further technique modification is needed.

OBJECTIVE To investigate water intake and urine measures in healthy cats provided free-choice access to a nutrient-enriched water with (NWP) or without (NW) added poultry flavoring offered at 3 different volumes in addition to tap water (TW). ANIMALS 36 domestic shorthair cats. PROCEDURES Control group cats (n = 4) received dry food with TW ad libitum throughout the study. Cats of the NW and NWP groups (n = 16/group) received the same food with TW only (period 1; 7 days) followed by TW and the assigned treatment ad libitum at 1X, 1.5X, and 2X the volume of TW consumed in period 1 during periods 2 (17 days), 3 (10 days), and 4 (10 days), respectively. Liquid consumption, food intake, and total water intake (from all sources) were measured; urine collected over 48 hours in each period was measured, and urine specific gravity (USG) was determined. Data were analyzed with mixed-effects models. RESULTS TW and food calorie intake were similar among groups in period 1; TW consumption by control cats did not differ during the study. Liquid consumed by drinking increased 18%, 57%, and 96% for the NWP group in periods 2, 3, and 4, respectively, with increases of 25% and 44% for the NW group in periods 3 and 4, respectively, compared with period 1 values for the same groups. Increased urine output and decreased USG were significantly associated with period and treatment. CONCLUSIONS AND CLINICAL RELEVANCE Increasing the volumes of NW or NWP offered to healthy cats led to increased free liquid consumption and was associated with greater urine output and dilution as measured by USG. Studies are warranted to determine whether these treatments provide health benefits for cats in need of greater water consumption.

OBJECTIVE To compare the effects of MK-467 and hyoscine butylbromide on detomidine hydrochloride–induced cardiorespiratory and gastrointestinal changes in horses. ANIMALS 6 healthy adult horses. PROCEDURES Horses received detomidine hydrochloride (20 μg/kg, IV), followed 10 minutes later by MK-467 hydrochloride (150 μg/kg; DET-MK), hyoscine butylbromide (0.2 mg/kg; DET-HYO), or saline (0.9% NaCl) solution (DET-S), IV, in a Latin square design. Heart rate, respiratory rate, rectal temperature, arterial and venous blood pressures, and cardiac output were measured; blood gases and arterial plasma drug concentrations were analyzed; selected cardiopulmonary variables were calculated; and sedation and gastrointestinal borborygmi were scored at predetermined time points. Differences among treatments or within treatments over time were analyzed statistically. RESULTS With DET-MK, detomidine-induced hypertension and bradycardia were reversed shortly after MK-467 injection. Marked tachycardia and hypertension were observed with DET-HYO. Mean heart rate and mean arterial blood pressure differed significantly among all treatments from 15 to 35 and 15 to 40 minutes after detomidine injection, respectively. Cardiac output was greater with DET-MK and DET-HYO than with DET-S 15 minutes after detomidine injection, but left ventricular workload was significantly higher with DET-HYO. Borborygmus score, reduced with all treatments, was most rapidly restored with DET-MK. Sedation scores and pharmacokinetic parameters of detomidine did not differ between DET-S and DET-MK. CONCLUSIONS AND CLINICAL RELEVANCE MK-467 reversed or attenuated cardiovascular and gastrointestinal effects of detomidine without notable adverse effects or alterations in detomidine-induced sedation in horses. Further research is needed to determine whether these advantages are found in clinical patients and to assess whether the drug influences analgesic effects of detomidine.

OBJECTIVE To evaluate in vitro phagocytosis and bactericidal activity of circulating blood neutrophils in horses with severe equine asthma and control horses and to determine whether circulating blood neutrophils in horses with severe equine asthma have an increase in expression of the proinflammatory cytokine tumor necrosis factor (TNF)-α and the chemokine interleukin (IL)-8 and a decrease in expression of the anti-inflammatory cytokine IL-10 in response to bacteria. ANIMALS 6 horses with severe equine asthma and 6 control horses. PROCEDURES Circulating blood neutrophils were isolated from horses with severe equine asthma and control horses. Phagocytosis was evaluated by use of flow cytometry. Bactericidal activity of circulating blood neutrophils was assessed by use of Streptococcus equi and Streptococcus zooepidemicus as targets, whereas the cytokine mRNA response was assessed by use of a quantitative PCR assay. RESULTS Circulating blood neutrophils from horses with severe equine asthma had significantly lower bactericidal activity toward S zooepidemicus but not toward S equi, compared with results for control horses. Phagocytosis and mRNA expression of TNF-α, IL-8, and IL-10 were not different between groups. CONCLUSIONS AND CLINICAL RELEVANCE Impairment of bactericidal activity of circulating blood neutrophils in horses with severe equine asthma could contribute to an increased susceptibility to infections.

Clinically healthy pigs used in research are assumed to have normal cardiac structure and function. Subclinical cardiac abnormalities may adversely affect the responses being measured in these experiments. The gross and histologic lesions observed in hearts collected from a Canadian abattoir between 2012 and 2015 indicated an unexpectedly high prevalence of cardiac abnormalities: 75% (297/396) of the hearts examined had such lesions. The ratios of total heart weight to body weight and of right ventricle weight to body weight were significantly greater for the hearts with lesions than for the hearts with no lesions, which suggests that cardiac remodeling, particularly hypertrophy, had occurred. The large percentage of hearts with cardiac remodeling from asymptomatic market pigs demonstrates an increased probability that subclinical cardiac abnormalities may exist in research pigs, especially those accessed through commercial channels. Researchers should be aware of this likelihood if subclinical cardiac abnormalities could adversely affect their experimental findings.

OBJECTIVE To characterize delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) features of healthy hyaline cartilage of the distal interphalangeal joint (DIPJ) of horses, to determine whether dGEMRIC can be used to differentiate various stages of naturally occurring osteoarthritis of the DIPJ, and to correlate relaxation times determined by dGEMRIC with the glycosaminoglycan concentration, water content, and macroscopic and histologic findings of hyaline cartilage of DIPJs with and without osteoarthritis. SAMPLE 1 cadaveric forelimb DIPJ from each of 12 adult warmblood horses. PROCEDURES T1-weighted cartilage relaxation times were obtained for predetermined sites of the DIPJ before (T1preGd) and after (T1postGd) intra-articular gadolinium administration. Corresponding cartilage sites underwent macroscopic, histologic, and immunohistochemical evaluation, and cartilage glycosaminoglycan concentration and water content were determined. Median T1preGd and T1postGd were correlated with macroscopic, histologic, and biochemical data. Mixed generalized linear models were created to evaluate the effects of cartilage site, articular surface, and macroscopic and histologic scores on relaxation times. RESULTS 122 cartilage specimens were analyzed. Median T1postGd was lower than the median T1preGd for normal and diseased cartilage. Both T1preGd and T1postGd were correlated with macroscopic and histologic scores, whereby T1preGd increased and T1postGd decreased as osteoarthritis progressed. There was topographic variation of T1preGd and T1postGd within the DIPJ. Cartilage glycosaminoglycan concentration and water content were significantly correlated with T1preGd and macroscopic and histologic scores but were not correlated with T1postGd. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dGEMRIC relaxation times varied for DIPJs with various degrees of osteoarthritis. These findings may help facilitate early detection of osteoarthritis.

OBJECTIVE To quantitatively measure the amount of pressure induced at the calcaneus and cranial tibial surface of dogs by use of 2 cast configurations. ANIMALS 13 client- or student-owned dogs. PROCEDURES Pressure sensors were placed over the calcaneus and cranial tibial surface. Dogs then were fitted with a fiberglass cast on a pelvic limb extending from the digits to the stifle joint (tall cast). Pressure induced over the calcaneus and proximal edge of the cast at the level of the cranial tibial surface was simultaneously recorded during ambulation. Subsequently, the cast was shortened to end immediately proximal to the calcaneus (short cast), and data acquisition was repeated. Pressure at the level of the calcaneus and cranial tibial surface for both cast configurations was compared by use of paired t tests. RESULTS The short cast created significantly greater peak pressure at the level of the calcaneus (mean ± SD, 0.2 ± 0.07 MPa), compared with peak pressure created by the tall cast (0.1 ± 0.06 MPa). Mean pressure at the proximal cranial edge of the cast was significantly greater for the short cast (0.2 ± 0.06 MPa) than for the tall cast (0.04 ± 0.03 MPa). CONCLUSIONS AND CLINICAL RELEVANCE A cast extended to the level of the proximal portion of the tibia caused less pressure at the level of the calcaneus and the proximal cranial edge of the cast. Reducing the amount of pressure at these locations may minimize the potential for pressure sores and other soft tissue injuries.