The purpose of this study was to determine the impact of a transoral tracheal wash (TOTW) on respiratory mechanics in dogs and to describe the use of a critical care ventilator (CCV) to determine respiratory mechanics. Fourteen client-owned dogs with respiratory diseases were enrolled. Respiratory mechanics, including static compliance (Cstat) and static resistance (Rstat), were determined before and after TOTW. Pre- and post-wash results were compared, with a P-value of < 0.05 considered significant. The mean ± standard deviation (SD) value of Cstat pre-TOTW was 1.59 ± 0.94 mL/cmH2O/kg while the mean ± SD of Cstat post-TOTW was 1.29 ± 0.71 mL/cmH2O/kg (P = 0.045). The median Rstat was not significantly different pre- and post-wash. The transoral tracheal wash altered respiratory mechanics, as observed by a reduction in Cstat, presumably due to airway flooding and collapse. While no long-lasting effects were noted in these clinical patients, this effect should be considered when performing TOTW on dogs with respiratory diseases. Respiratory mechanics testing using a CCV was feasible and may be a useful clinical testing approach.

As little information is available on the reproductive system of guinea fowl (Numida meleagris), a study was conducted on 49 male guinea fowl to document the histological structure and developmental changes in the luminal diameter of the ducts within the excurrent duct system and associated changes in concentrations of testosterone. Age-related changes were analyzed using the Kruskal-Wallis test and medians separated by the Mann-Whitney U-test. Tubuli recti were clearly visible in the guinea fowl and the rete testes were both intracapsular and extracapsular. Regardless of age, the luminal diameter of the proximal ductuli efferentes was the largest, while that of the connecting duct was the smallest. The luminal diameter of all ducts within the epididymal region increased (P < 0.001) monthly until 20 wk of age, and then increased marginally every month thereafter. Peripheral testosterone concentrations also peaked at 20 wk of age and declined thereafter. In adult birds, the ductus deferens enlarged posteriorly, from an average of about 279 μm cranially to 678 μm caudally. Peripheral testosterone concentrations strongly and positively correlated with the luminal diameter of ducts within the excurrent duct system. The pattern of increase in the luminal diameter of all ducts followed the pattern of testosterone secretion in these birds, which indicates that testosterone concentrations may be closely related to the development of the excurrent duct system in male guinea fowl.

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 evaluate effects of blood contamination on dipstick results, specific gravity (SG), and urine protein-to-urine creatinine ratio (UPCR) for urine samples from dogs and cats. SAMPLE Urine samples collected from 279 dogs and 120 cats. PROCEDURES Urine pools were made for each species (dogs [n = 60] and cats [30]). Blood was added to an aliquot of a pool, and serial dilutions were prepared with the remaining urine. Color and dipstick variables were recorded, and SG and UPCR were measured. For cats, 1 set of pools was used; for dogs, 2 sets were used. Comparisons were made between undiluted urine and spiked urine samples for individual colors. Repeated-measures ANOVA on ranks was used to compare dipstick scores and UPCR results; χ2 tests were used to compare proteinuria categorizations (nonproteinuric, borderline, or proteinuric). RESULTS Any blood in the urine resulted in significantly increased dipstick scores for blood. In both species, scores for bilirubin and ketones, pH, and SG were affected by visible blood contamination. No significant difference for the dipstick protein reagent results was evident until a sample was visibly hematuric. The UPCR was significantly increased in dark yellow samples of both species. Proteinuria categorizations differed significantly between undiluted urine and urine of all colors, except light yellow. CONCLUSIONS AND CLINICAL RELEVANCE Any degree of blood contamination affected results of dipstick analysis. Effects depended on urine color and the variable measured. Microscopic blood contamination may affect the UPCR; thus, blood contamination may be a differential diagnosis for proteinuria in yellow urine samples.

OBJECTIVE To identify clinical or clinicopathologic variables that can be used to predict a positive PCR assay result for Anaplasma phagocytophilum infection in equids. ANIMALS 162 equids. PROCEDURES Medical records were reviewed to identify equids that underwent testing for evidence of A phagocytophilum infection by PCR assay between June 1, 2007, and December 31, 2015. For each equid that tested positive (case equid), 2 time-matched equids that tested negative for the organism (control equids) were identified. Data collected included age, sex, breed, geographic location (residence at the time of testing), physical examination findings, and CBC and plasma biochemical analysis results. Potential predictor variables were analyzed by stepwise logistic regression followed by classification and regression tree analysis. Generalized additive models were used to evaluate identified predictors of a positive test result for A phagocytophilum. RESULTS Total lymphocyte count, plasma total bilirubin concentration, plasma sodium concentration, and geographic latitude were linear predictors of a positive PCR assay result for A phagocytophilum. Plasma creatine kinase activity was a nonlinear predictor of a positive result. CONCLUSIONS AND CLINICAL RELEVANCE Assessment of predictors identified in this study may help veterinarians identify equids that could benefit from early treatment for anaplasmosis while definitive test results are pending. This information may also help to prevent unnecessary administration of oxytetracycline to equids that are unlikely to test positive for the disease.

OBJECTIVE To evaluate acute changes of the liver by use of shear wave elastography (SWE) and CT perfusion after radiofrequency ablation (RFA). ANIMALS 7 healthy Beagles. PROCEDURES RFA was performed on the liver (day 0). Stiffness of the ablation lesion, transitional zone, and normal parenchyma were evaluated by use of SWE, and blood flow, blood volume, and arterial liver perfusion of those regions were evaluated by use of CT perfusion on days 0 and 4. All RFA lesions were histologically examined on day 4. RESULTS Examination of the SWE color-coded map distinctly revealed stiffness of the liver tissue, which increased from the normal parenchyma to the transitional zone and then to the ablation zone. For CT perfusion, blood flow, blood volume, and arterial liver perfusion decreased from the transitional zone to the normal parenchyma and then to the ablation zone. Tissue stiffness and CT perfusion variables did not differ significantly between days 0 and 4. Histologic examination revealed central diffuse necrosis and peripheral hyperemia with infiltration of lymphoid cells and macrophages. CONCLUSIONS AND CLINICAL RELEVANCE Coagulation necrosis induced a loss of blood perfusion and caused tissue hardening (stiffness) in the ablation zone. Hyperemic and inflammatory changes of the transitional zone resulted in increased blood perfusion. Acute changes in stiffness and perfusion of liver tissue after RFA could be determined by use of SWE and CT perfusion. These results can be used to predict the clinical efficacy of RFA and to support further studies, including those involving hepatic neoplasia.

OBJECTIVE To determine the influence of various neck positions on cervical vertebral radiographic measurements in horses. ANIMALS 18 client-owned horses examined for lameness but free of cervical disease. PROCEDURES Laterolateral radiographs of the cervical vertebrae from C1 through T1 were acquired for each horse in 3 neck positions (low, neutral, and high). Minimum sagittal diameter, intravertebral sagittal diameter (intra-VSD) ratio, inter-VSD ratio, length of the articular processes joint ratio, vertebral alignment angle, and vertebral fossa angle were measured at each segment in each neck position. Values for the high and low positions were compared with those for the neutral position. RESULTS No significant differences from neutral position values were identified for minimum sagittal diameter, intra-VSD ratio, and vertebral fossa angle as measured in low and high neck positions. Compared with results in the neutral position, the high position resulted in a greater vertebral alignment angle at C3–4 and inter-VSD ratio at C4–5 and a lower length of the articular processes joint ratio at C2–3, C3–4, and C4–5; the low position resulted in a lower vertebral alignment angle at C4–5. However, all observed differences were small. CONCLUSIONS AND CLINICAL RELEVANCE Neck position influenced some radiographic measurements of the cervical vertebrae in horses free of cervical disease. However, because several of these measurements were not or were only minimally affected by neck position, some latitude in neck position may be possible without concern about substantially affecting radiographic measurements in this region.

OBJECTIVE To evaluate the 3-D geometry of canine pelves and to characterize the long-term effects of juvenile pubic symphysiodesis (JPS) on pelvic geometry by comparing the pelvic configuration between littermates that did and did not undergo the procedure. ANIMALS 24 Labrador Retriever, Golden Retriever, or Labrador Retriever–Golden Retriever crossbred service dogs from 13 litters. PROCEDURES At 16 weeks old, puppies with a hip joint distraction index ≥ 0.5 were randomly assigned to undergo thermal JPS (n = 9), mechanical JPS (7), or a sham (control) surgical procedure (8). Ten years later, each dog underwent a CT scan of the pelvic region. Modeling software was used to create 3-D reconstructions from the CT scans, and various pelvic measurements were made and compared among the 3 treatments. RESULTS Compared with the control treatment, thermal and mechanical JPS increased the hemipelvis acetabular angle by 4°, the acetabular angle of lateral opening by 5°, and the orientation of the medial acetabular wall in a transverse plane by 6°, which indicated that JPS increased dorsal femoral head coverage by the acetabulum. Both JPS procedures decreased the pelvic canal area by approximately 20% and acetabular inclination by 6° but did not alter acetabular retroversion. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that thermal and mechanical JPS were equally effective in altering the 3-D pelvic geometry of dogs. These findings may help guide future studies of alternatives for optimizing canine pelvic anatomy to minimize the risk of hip dysplasia and associated osteoarthritis.

Colistin is one of the last-resort antibiotics for the treatment of multidrug-resistant infections in humans, but transmissible colistin-resistance genes have emerged in bacteria from animals. The rapid and sensitive detection among animals of colonization with bacteria carrying these genes is critical in helping to control further spread. Here we describe a method for broth enrichment of colistin-resistant Escherichia coli from animal fecal and cecal samples followed by real-time polymerase chain reaction (PCR) for the simultaneous detection of two of the main colistin-resistance genes, mcr-1 and mcr-2. The PCR uses a single set of nondegenerative primers, and mcr variants can be differentiated by melt-curve analysis. Overnight culture enrichment was effective for amplifying colistin-resistant E. coli, even when initially present in numbers as low as 10 bacteria per gram of sample. The mcr-1 and mcr-2 genes were not found in any of the Ontario swine and poultry samples investigated.

OBJECTIVE To investigate the effect of lipopolysaccharide (LPS) on type VII collagen– cleaving matrix metalloproteinases (MMPs) in the lamellar tissue of extracorporeally perfused equine limbs. SAMPLE 10 right forelimbs and 3 left forelimbs collected from 10 adult horses after slaughter at a licensed abattoir. PROCEDURES Extracorporeal perfusion of the isolated equine limbs was performed for 10 hours under physiologic conditions (control-perfused limbs; n = 5) and with the addition of 80 ng of LPS/L of perfusate (LPS-perfused limbs; 5). Lamellar tissue specimens were then collected from the dorsal aspect of the hooves. Additionally, corresponding control specimens were collected from the 3 nonperfused left forelimbs. Immunohistochemical analysis was performed on paraffin-embedded tissue blocks with antibodies against total (latent and active) MMP-1, MMP-2, MMP-8, and MMP-9 as well as antibody against active MMP-9. Intensity of immunohistochemical staining was scored, and stain distribution in the lamellar tissue was noted. RESULTS Staining intensity of total and active MMP-9 was significantly increased in LPS-perfused versus control-perfused limbs. No such difference was identified for MMP-1, MMP-2, and MMP-8. CONCLUSIONS AND CLINICAL RELEVANCE Of the 4 MMPs that are capable of degrading type VII collagen, MMP-9 was the only one for which production increased in the lamellar tissue of isolated equine limbs perfused with versus without a clinically relevant concentration of LPS. These results suggested that MMP-9 may be involved in initiation of pathological changes in lamellar tissue in endotoxin-induced laminitis, whereas MMP-1, MMP-2, and MMP-8 may be less relevant.