Breed‐specific variation of hematologic and biochemical analytes in healthy adult Bernese Mountain dogs

Background: Hematology and serum biochemistry reference intervals in dogs may be affected by internal factors, such as breed and age, and external factors, such as the environment, diet, and lifestyle. In humans, it is well established that geographic origin and age may have an impact on reference intervals and, therefore, more specific reference intervals are sought for subpopulations. Objective: The objective of this study was to validate and transfer standard laboratory reference intervals for healthy Bernese Mountain dogs and to create new intervals for analytes where the established laboratory reference intervals were rejected. Methods: The procedure was performed using the human Clinical and Laboratory Standards Institute‐approved model modified for veterinary use. Thirty‐two dogs were included in the study using a direct a priori method, as recommended. Results: While 23 of the standard laboratory reference intervals were readily validated, 7 of the analytes (eosinophils, MCHC, alkaline phosphatase [ALP], γ‐glutamyltransferase, total bilirubin, amylase, and cholesterol) required new reference intervals according to the standard. These were calculated using the robust method. In particular, the new reference range for ALP was wide compared with the established laboratory reference interval. No clinical causes were found for differences in the results of these analytes. Conclusion: We found significant differences in 7 hematologic and serum biochemical analytes for which a breed‐specific variation appears to be the most plausible explanation. Breed‐specific reference intervals for Bernese Mountain dogs will help avoid misinterpretation of laboratory results in the diagnostic process.     

Malignant histiocytosis in Bernese Mountain dogs

Malignant histiocytosis was diagnosed in 10 male and 1 female Bernese Mountain Dogs. Nine of these dogs were closely related. The disease was characterized by a rapidly progressive and inevitably fatal course. Clinical signs varied, but lethargy, anorexia, weight loss, and respiratory and CNS abnormalities predominated. The lungs were the primary site of tumor involvement in 10 dogs. The eleventh dog had lymphadenopathy and severe anemia. Metastatic lesions were detected in all dogs. Anaplastic pulmonary carcinoma was diagnosed originally in 6 of the 11 cases, but this diagnosis was changed to malignant histiocytosis after electron microscopic examination of tissues and immunohistochemical identification of histiocytic markers in the tumor cells.     

Study on biological variation of haemostatic parameters in clinically healthy dogs

Thromboelastography (TEG) may be a valuable supplement to the coagulation assays activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin time (TT), fibrinogen, antithrombin (AT) and D-Dimer currently used in most clinical pathology laboratories. Allowable imprecision and bias reference limits for analytical tests can be calculated based on measurements of biological variation. No studies to date have examined the effect of biological variation on these haemostasis parameters in the same group of dogs. Plasma samples were collected after a set protocol once weekly for five consecutive weeks from eight healthy dogs (four males and four females) and stored at -80 degrees C until analysis. Randomized duplicate coagulation tests and TEG analyses were performed on all plasma samples within one run. The data were analyzed for outliers and subsequently subjected to nested analysis of variance to obtain the coefficient of analytical, intra-individual and inter-individual variation. From these objective analytical performance standards for imprecision, critical difference, total error and the index of individuality were calculated to assess the utility of conventional population-based reference ranges. All the clotting times (aPTT, PT and TT), fibrinogen, AT and D-Dimer showed a degree of individuality, which may make the use of population-based reference ranges alone an insensitive interpretation criterion, whereas a population-based reference interval seems to be sensitive for interpreting all TEG parameters. Analytical performance standards for imprecision were only met for one of the coagulation assays, whereas all TEG parameters except the alpha angle, alpha achieved this analytical goal.     

Complement C3 in Bernese Mountain dogs

Background: Previous research suggests that low serum concentrations of the third component of complement (C3) are associated with both the susceptibility to infectious agents such as Borrelia burgdorferi and the development of glomerular disease. We hypothesized that low levels of C3 are associated with the coincident occurrence of B. burgdorferi infection and glomerulonephritis in Bernese Mountain dogs. Objectives: The aims of this study were to evaluate the serum concentration of C3 in Bernese Mountain dogs with and without antibodies against B. burgdorferi and to compare this concentration with that of healthy control dogs. Methods: Eighty‐three clinically healthy Bernese Mountain dogs and 46 control dogs were included. Antibodies against B. burgdorferi were determined using an ELISA with a whole cell sonicate as antigen. Results were confirmed using Western blot. C3 was measured using a single radial immunodiffusion test. Results were reported as the percentage concentration of C3 compared with that in pooled preserved canine serum (100% C3 concentration). Results: Median C3 concentration was 128.5% in Bernese Mountain dogs with antibodies against B. burgdorferi, 133.5% in B. burgdorferi‐negative Bernese Mountain dogs, 87.8% in positive control dogs, and 102.2% in negative control dogs. Within Bernese Mountain and control groups, C3 was lower in dogs with antibodies against B. burgdorferi compared with those without. Percentage concentration of C3 was higher in healthy Bernese Mountain dogs compared with control dogs. Conclusion: Low C3 concentration is not an explanation for the high prevalence of B. burgdorferi infections and glomerular disease in Bernese Mountain dogs.     

The presence of antiphospholipid antibodies in healthy Bernese Mountain Dogs

Background

The role of antiphospholipid antibodies in the prolonged activated partial thromboplastin time (aPTT) previously identified in healthy Bernese Mountain Dogs remains unknown. In people, an isolated prolonged aPTT without evidence of bleeding might be because of a thrombophilic condition caused by antiphospholipid antibodies.

Objective

To examine if prolonged aPTT in healthy Bernese Mountain Dogs is because of antiphospholipid antibodies.

Animals

Twenty‐two healthy Bernese Mountain Dogs and 10 healthy adult dogs of various breeds.

Methods

Prospective case control study. Healthy Bernese Moutain Dogs were examined twice over 6 months. Dogs were investigated for the presence of lupus anticoagulants and anticardiolipin (aCL) antibodies by the use of multiple aPTT tests with low and high lupus anticoagulant sensitivities, a mixing study, and an ELISA test for aCL antibody optical density to detect solid phase antiphospholipid antibodies.

Results

In all, 15 of 22 healthy Bernese Mountain Dogs were positive for lupus anticoagulants. The Bernese Mountain Dogs had markedly higher levels of aCL antibodies compared with the control dogs (P = .006). In all, 7 of 21 of the Bernese Mountain Dogs were positive for both lupus anticoagulants and aCL antibodies, whereas 4 of 21 Bernese Mountain Dogs were negative for both.

Conclusions and Clinical Importance

Lupus anticoagulants and aCL antibodies could be the cause of prolonged aPTT in healthy Bernese Mountain Dogs. The importance of the antiphospholipid antibodies in the dogs remains unknown.     

Breed‐associated variability in serum biochemical analytes in four large‐breed dogs

Background: Genetic background can influence the expected values of hematologic and serum biochemical analytes in domestic animal species. Objective: The purpose of this study was to determine if there are breed‐related differences in serum biochemical variables in healthy purebred dogs of 4 breeds and to develop appropriate reference intervals. Methods: Alaskan Malamutes (n=59), Siberian Huskies (n=78), Golden Retrievers (n=90), and English Setters (n=77) were included in the study. The dogs had a median age of 42 months (range 10–112 months) and each breed included a mix of intact and neutered dogs of both sexes. Serum biochemical profiles (Olympus AU400e) were performed along with physical examinations, CBCs, and urinalyses to ensure dogs were clinically healthy. Differences in the values of biochemical analytes were assessed nonparametrically and reference intervals for all breeds combined were calculated as the central 95% percentile. Results: Significant differences were observed between breeds for all serum biochemical analytes except alkaline phosphatase, glucose, and chloride. The analyte ranges had a large degree of overlap between the different breeds. Conclusions: Although many statistically significant breed‐related differences in serum biochemical values were observed, the differences were small and unlikely to have clinical relevance or impact medical decision making.     

Association of urine protein excretion and infection with Borrelia burgdorferi sensu lato in Bernese Mountain dogs

Bernese Mountain dogs (BMDs) are prone to develop a familial glomerulonephropathy and a pathogenic role of Borrelia burgdorferi sensu lato in this disease has been suspected. Glomerular disease in many affected dogs is clinically inapparent and proteinuria is found incidentally. In this study, urine protein excretion was evaluated in 122 clinically healthy BMDs and 55 controls. The seroprevalence of B. burgdorferi in BMDs was 57%, compared to 16% in controls. There were no significant differences in the occurrence of positive dipstick results, microalbuminuria, urine protein-to-urine creatinine ratio or abnormal urine protein pattern (determined by sodium dodecyl sulphate agarose gel electrophoresis) between BMDs and controls and BMDs with and without antibodies against B. burgdorferi. It was concluded that antibodies against B. burgdorferi are not associated with proteinuria as an early sign of renal disease in BMDs.     

Transthoracic echocardiography in Estrela Mountain dogs: reference values for the breed

Of 100 Estrela Mountain dogs, 74 were examined to obtain echocardiographic reference values for the breed. The influence of bodyweight, age and sex on different echocardiographic parameters was studied using either analysis of variance or regression analysis. Statistically significant differences were found between sex and heart rate as well as interventricular septal thickness at end-systole and left ventricular internal dimension at end-diastole. A statistically significant linear correlation was also found between several parameters and (1) age (mean arterial pressure, left ventricular internal dimension at end-systole, fractional shortening, circularity index in systole, aortic valve velocity time integral, pulmonic valve velocity time integral and mitral valve E wave peak velocity), (2) weight (left ventricular posterior wall thickness at end-diastole and end-systole, end-diastolic volume index, left atrium diameter, aortic valve peak velocity and mitral valve E wave deceleration time), (3) sex and age (left ventricle end-diastolic volume), and (4) sex and weight (aortic root diameter and pulmonic valve peak velocity). Reference values for the breed are presented, as well as dispersion graphics for selected parameters, based on a regression equation.     

Genetic variation and genetic trends in hip and elbow dysplasia in Swedish Rottweiler and Bernese Mountain Dog

The aim of this study was to estimate genetic parameters and genetic trends for hip (HD) and elbow dysplasia (ED) in Swedish Rottweiler (RW) and Bernese Mountain Dog (BMD). Analyses were based on screening results of hip status for 14 693 RW and 8221 BMD and elbow status for 11 891 RW and 7963 BMD, as well as pedigree data for 16 614 RW and 9835 BMD, recorded by the Swedish Kennel Club. Components of (co)variance and breeding values were obtained with a mixed linear animal model. The model included the fixed effects of sex, birth month, age at screening and a combined random effect of clinic and year of examination. The need to include genetic groups for phantom parents in the model was evaluated by comparison of two different models: with and without genetic groups. Estimated heritabilities for HD and ED were between 0.34 and 0.42. The genetic correlation between the traits was weak and positive for RW (r_g = 0.23 ± 0.05) and not different from zero for BMD (r_g = 0.06 ± 0.06). F‐statistics of the genetic group effects were not significant, implying that genetic groups do not need to be included in the model. Genetic trends indicated a genetic improvement in both traits. However, a faster genetic progress is expected if selection is based on predicted breeding values rather than phenotype. Based on the results, a statistical model for routine prediction of breeding values for HD and ED in Swedish dogs was suggested.     

Effects of haemolysis, lipaemia and bilirubinaemia on prothrombin time, activated partial thromboplastin time and thrombin time in plasma samples from healthy dogs

Interferences caused by haemolysis, lipaemia and bilirubinaemia on prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT in normal canine plasma samples were studied using commercially available reagents and a steel ball coagulometer. Haemolysis significantly interfered with APTT (P = 0.0076) and TT (P = 0.0292). Regression analysis showed that TT was significantly shortened as haemoglobin concentrations increased. Lipaemia increased as demonstrated by regression analysis. Bilirubin significantly interfered with PT (P=0.0003) and APTT (P=0.002). Although statistically significant, none of the differences found were of clinical relevance.     

Doppler-derived deformation imaging in unsedated healthy adult dogs

Objectives

To evaluate feasibility, repeatability and reproducibility (R&R) of Doppler-derived deformation imaging (DI) in healthy adult dogs.

Animals, materials and methods

Forty-nine dogs underwent physical examination, ECG, blood pressure measurement and echocardiography. Doppler-derived DI parameters obtained from six selected Regions of Interest (ROI) within the left ventricle (LV) were: strain (S), systolic strain rate (SSR), strain rate E wave (SRE), and strain rate A wave (SRA). The averages of the six ROIs were calculated and labeled avS, avSSR, avSRE, and avSRA. Randomly selected dogs underwent two echocardiographic studies to evaluate intraoperator (n = 14) and interoperator (n = 17) variability.

Results

DI data were obtained in 87.2% of dogs and 77.2% of ROIs. Compared to controls, avSSR was significantly reduced in Doberman Pinchers (DP) and it was increased in dogs <30 kg, compared to dogs >30 kg. The intraoperator Coefficient of Variability (CV) for some ROIs was greater than 15% but for averaged measurements it was ≤ 5.0%. Interoperator CV varied widely but were all <15% for avSSR, avS, and avSRA.

Conclusions

The CV for Doppler-derived DI varied widely. Averaging values from multiple ROIs improved R&R. DI may help elucidate differences in LV mechanics between canine breeds.     

Sleeping respiratory rates in apparently healthy adult dogs

Respiratory rate monitoring of cardiac patients is recommended by many cardiologists. However, little objective data exist about respiratory rates in apparently healthy dogs when collected in the home environment. We measured sleeping respiratory rates (SRR) in apparently healthy dogs and compared sleeping and resting respiratory rates (RRR) with a cross-sectional prospective study. Participants collected 12-14 one-minute SRR over a period ranging from 1 week to 2 months on 114 privately owned adult dogs. Selected participants simultaneously collected RRR. Mean within-dog average SRR (SRR(mean)) was 13breaths per minute (breaths/min). No dog had SRR(mean) >23 breaths/min; three dogs had instantaneous SRR measurements >30 breaths/min. Dogs had higher RRR(mean) (19 breaths/min) than SRR(mean) (15 breaths/min) (P<0.05). Canine SRR(mean) was unaffected by age, bodyweight or geographic location. Data acquisition was considered relatively simple by most participants. This study shows that apparently healthy adult dogs generally have SRR(mean) <30 breaths/min and rarely exceed this rate at any time.     

Blood-to-saliva glucose time lag in sedated healthy dogs

The management of diabetes mellitus mandates measurement of blood glucose. Saliva offers an alternative to blood sampling, but measurement of the salivary glucose concentration is difficult, and the blood-to-saliva glucose time lag is uncertain. We aimed to determine the serum–saliva glucose time lag in the saliva of healthy dogs. The combined duct of the mandibular and sublingual salivary glands of 6 dogs was cannulated to collect saliva and prevent glucose degradation by oral bacteria. Following a 0.25 g/kg IV bolus of dextrose, paired serum–saliva samples were collected at baseline and in twelve 5-min blocks over 60 min. Serum and salivary glucose levels were analyzed with a linear mixed model for repeated measures with a compound symmetry error structure. Mean (±SD) saliva production was 10.3 ± 2.9 µL/kg/min, and the area under the curve (AUC_glucose)_saliva/serum ratio was 0.006, which highlights the magnitude of the large difference in glucose concentration between the 2 compartments. The serum–saliva glucose time lag was 30–40 min.     

Phenotypic and genetic evaluation of elbow dysplasia in Dutch Labrador Retrievers, Golden Retrievers, and Bernese Mountain dogs

Canine elbow dysplasia encompasses four developmental diseases: ununited anconeal process, osteochondrosis of the medial part of the humeral condyle, fragmented medial coronoid process (FCP), and incongruity of the elbow joint. Four radiographic views per joint were used to evaluate 2693 Labrador Retrievers (LRs), 1213 Golden Retrievers (GRs), and 974 Bernese Mountain Dogs (BMDs) for the presence of elbow dysplasia between 2002 and 2009 in the Netherlands. The views were also graded for signs of osteoarthritis and sclerosis. FCP was diagnosed most frequently in LRs, GRs and BMDs, with an incidence of 6%, 5%, and 15%, and a heritability of 0.17, 0.24, and 0.06, respectively. Heritabilities were estimated using a sire model and all available ancestors. Sclerosis at the base of the medial coronoid process was the radiographic sign most strongly correlated with FCP (r=0.95, 0.92, and 0.95 in LRs, GRs and BMDs, respectively). The sex of the dog was significantly correlated with the presence of osteoarthritis in LRs, but not in GRs and BMDs. Male LRs were 1.7-fold more frequently, but not more severely, affected by osteoarthritis than female dogs. Age at radiographic examination was significantly associated with osteoarthritis in all three breeds. The heritability estimates in Retrievers were high enough to warrant including FCP findings in the breeding policy, but until the biomechanical and genetic background of elbow dysplasia are better understood, correct phenotyping with a sensitive technique is essential.     

One-stage prothrombin time, activated partial thromboplastin time, thrombin time, fibrin degradation product concentration, and antithrombin activity in healthy adult alpacas

Background: Alpacas are increasingly presented to veterinarians for evaluation and care. Reports of alpaca reference intervals for one‐stage prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), concentration of fibrin degradation products (FDP), and antithrombin (AT) activities are scarce or nonexistent. Objective: The aim of this study was to determine values for blood coagulation times (PT, aPTT, and TT), FDP concentrations, and AT activities in healthy adult alpacas. Methods: Of blood samples collected from 35 clinically healthy adult alpacas via jugular venipuncture and placed into sodium citrate and FDP tubes, 29 samples were assayable for coagulation testing. PT, aPTT, and TT were determined by physical (mechanical) clot detection; AT activity was determined using a thrombin‐specific chromogenic substrate end‐point assay; and FDP concentrations were determined by the slide agglutination method. Results: Median values and ranges (minimum–maximum) were determined for PT (8.7 seconds, 6.6–11.2 seconds), aPTT (17.3 seconds, 11.9–22.5 seconds), TT (10.2 seconds, 5.4–16.0 seconds), and AT activity (123.3%, 104.8–144.2%). The mean concentration of FDP was <8 μg/mL. Conclusion: These values for coagulation times, FDP concentration, and AT activity will provide a useful starting point in the diagnostic evaluation of ill adult alpacas.     

An evaluation of activated coagulation time in warfarin-intoxicated dogs

Activated coagulation time, one stage prothrombin time and activated partial thromboplastin time were compared in warfarin-intoxicated dogs. All coagulation tests were significantly prolonged on the third and fourth days following intoxication. Coagulation assays of all dogs except one returned to preintoxication values one day following vitamin K therapy. Significant correlation was found between all coagulation tests in the intoxicated group. Activated coagulation time may provide a useful coagulation screening test to veterinarians with limited laboratory capabilities.