Objective—To develop a standardized meal challenge test by assessing associations between food-withheld preprandial (ie, fasting) and postprandial triglyceride concentrations, determining the most appropriate sampling time to detect the peak concentration (highest postprandial concentration), and estimating reference intervals for fasting and postprandial concentrations in healthy dogs.
Animals—12 lean healthy mixed-breed dogs.
Procedures—Dogs were fed a dry commercially available diet (fat, 31% metabolizable energy) for 3 weeks. After food was withheld for 23 to 24 hours, plasma triglyceride concentrations were measured 1 and 0.083 hours before and 1, 2, 3, 4, 5, 6, 9, and 12 hours after feeding of a standardized challenge meal (median amount eaten, 63 kcal/kg [127 kcal/kg0.75]). Correlation and agreement between concentrations at peak and other time points were assessed by use of correlation coefficients and Bland-Altman limits of agreement. Reference intervals were calculated by use of a robust method.
Results—Fasting and peak triglyceride concentrations were not closely associated. The highest concentration among samples obtained 2, 5, and 6 hours after meal consumption had closest agreement with peak concentration. In 5 of 12 dogs, concentrations 12 hours after eating were still significantly above baseline concentration (mean of each dog's fasting concentrations).
Conclusions and Clinical Relevance—Fasting triglyceride concentration could not be used to accurately predict peak concentration. When estimating peak concentration, multiple samples should be collected 2, 5, and 6 hours after consumption of a standardized meal. Food may need to be withheld for > 12 hours when assessing fasting concentrations in healthy dogs.
Objective—To evaluate changes in stability of haptoglobin and C-reactive protein (CRP) concentrations caused by freezing of saliva and meat juice samples.
Animals—16 specific-pathogen-free pigs and 16 pigs with clinical signs of disease.
Procedures—Saliva and diaphragmatic muscle were collected immediately before and after slaughter, respectively. Haptoglobin and CRP concentrations of pooled samples were measured before storage (day 0) and after 7, 15, 30, 60, 120, 210, and 365 days of storage at −20°C and after repeated freezing-thawing cycles (up to 7 times). In a second experiment, addition of a protease-inhibitor cocktail to saliva and storage of saliva samples at −80°C for up to 30 days were assessed for effects on CRP concentrations.
Results—Haptoglobin concentrations in saliva did not change for up to 120 days in samples stored at −20°C, but longer storage times and multiple freezing-thawing cycles increased haptoglobin concentrations. Salivary CRP concentrations decreased significantly after 7 days of storage at −20°C, and addition of a protease-inhibitor cocktail did not improve CRP stability. Lower temperatures limited salivary CRP degradation. In meat juice, haptoglobin and CRP concentrations were stable at −20°C up to 210 days.
Conclusions and Clinical Relevance—Acute-phase protein measurements in saliva should be performed as soon as possible after sample collection. When this is not possible, storage temperature of −80°C is recommended. Acute-phase protein concentrations appeared to be more stable in meat juice samples than in saliva samples. Saliva and meat juice could be used as alternatives to serum for haptoglobin and CRP analysis.
Objective—To assess the usefulness and reliability of a milk-flow measurement technique and the values obtained in unobstructed teats and teats with teat canal stenosis in dairy cows.
Animals—16 Holstein cows.
Procedures—Teats were assessed via hand milking and classified as unobstructed or partially obstructed. Partially obstructed teats were further categorized according to the anatomic location of the obstruction via ultrasonography into teat canal obstruction (TCO) and obstruction at the proximal portion of the teat canal (Fürstenberg rosette obstruction [FRO]) The milk-flow characteristics of the teat canal were assessed by measuring the intracisternal pressure at the start (PSL) and at cessation (PCL) of leakage of an infused solution.
Results—The PSL and PCL values among unobstructed teats were not significantly different between lactating and nonlactating cows nor among quarters. In assessment of test-retest intrarater reliability, a high degree of correlation was detected for PSL (correlation coefficient, 0.94; 95% confidence interval, 0.90 to 0.96) and PCL (correlation coefficient, 0.92; 95% confidence interval, 0.86 to 0.95). Teats with TCO and FRO had higher PSL and PCL values, compared with unobstructed teats. Teats with FRO had significantly higher PSL but lower PCL than teats with TCO.
Conclusions and Clinical Relevance—Results indicated the usefulness and reliability of the technique in assessing the milk-flow characteristics of the teat canal. The milk-flow pattern of teats with teat canal stenosis varies depending on the location of obstruction. This technique may be a valuable tool in evaluating the effectiveness of teat canal surgery. (Am J Vet Res 2010;71:1123-1126)
Objective—To evaluate a 3-D kinematic model of the hind limb developed by use of a joint coordinate system in dogs.
Animals—6 clinically normal adult mixed-breed dogs.
Procedures—17 retroreflective markers were affixed to the skin on the right hind limb of each dog. Eight infrared cameras were arranged around a gait platform to record marker locations as dogs were recorded moving through the calibrated space 5 times during a walk and trot at velocities of 0.9 to 1.2 m/s and 1.7 to 2.1 m/s, respectively. Local and global coordinate systems were established, and a segmental rigid-body model of the canine hind limb was produced. Dynamic 3-D joint kinematic measurements were collected for the hip, stifle, and tarsal joints.
Results—Sagittal (flexion-extension), transverse (internal-external rotation), and frontal (abduction-adduction) plane kinematic measurements were acquired during each trial for the hip, stifle, and tarsal joints.
Conclusions and Clinical Relevance—The joint coordinate system allowed acquisition of 3-D kinematic measurements of the hip, stifle, and tarsal joints of the canine hind limb. Methods were described to model 3-D joint motion of the canine hind limb. (Am J Vet Res 2010;71:1118-1122)
Objective—To establish a protocol to collect temporal-spatial gait analysis variables by use of a portable walkway system in Labrador Retrievers at a walk and to determine reference values.
Animals—56 healthy Labrador Retrievers.
Procedures—6 passes across the walkway (3 passes in each direction) were recorded. Inclusion criteria for a pass were that the dog was at a walk (velocity, 60.0 to 90.0 cm/s) and had minimal head turning. The first 3 passes that met the inclusion criteria were analyzed for each dog.
Results—Mean stride length was 88.4 cm. Mean stance time (ST) of forelimbs and hind limbs was 0.62 and 0.56 seconds, respectively. Mean stance time percentage (ST%; proportion of stance time to total gait cycle time) for forelimbs and hind limbs was 55.6% and 50.2%, respectively. Mean total pressure index (TPI) of forelimbs and hind limbs was 27.1 and 17.4, respectively. Mean number of sensors (NS) activated by each paw strike of forelimbs and hind limbs was 17 and 13, respectively. Mean forelimb-to-hind limb symmetry ratios were 1.11 (ST), 1.10 (ST%), 1.62 (TPI), and 1.37 (NS). Symmetry ratios for left limbs to right limbs, left forelimb to right forelimb, and left hind limb to right hind limb were 1.00.
Conclusions and Clinical Relevance—A protocol for collection of temporal-spatial gait analysis variables with a portable walkway system in Labrador Retrievers at a walk was developed, and reference values for variables and symmetry ratios were reported. Further research will determine the extent to which symmetry ratios differ in dogs with orthopedic disorders. (Am J Vet Res 2010;71:997–1002)
Objective—To determine fluid retention, glomerular filtration rate, and urine output in dogs anesthetized for a surgical orthopedic procedure.
Animals—23 dogs treated with a tibial plateau leveling osteotomy.
Procedures—12 dogs were used as a control group. Cardiac output was measured in 5 dogs, and 6 dogs received carprofen for at least 14 days. Dogs received oxymorphone, atropine, propofol, and isoflurane for anesthesia (duration, 4 hours). Urine and blood samples were obtained for analysis every 30 minutes. Lactated Ringer's solution was administered at 10 mL/kg/h. Urine output was measured and glomerular filtration rate was estimated. Fluid retention was measured by use of body weight, fluid balance, and bioimpedance spectroscopy.
Results—No difference was found among control, cardiac output, or carprofen groups, so data were combined. Median urine output and glomerular filtration rate were 0.46 mL/kg/h and 1.84 mL/kg/min. Dogs retained a large amount of fluids during anesthesia, as indicated by increased body weight, positive fluid balance, increased total body water volume, and increased extracellular fluid volume. The PCV, total protein concentration, and esophageal temperature decreased in a linear manner.
Conclusions and Clinical Relevance—Dogs anesthetized for a tibial plateau leveling osteotomy retained a large amount of fluids, had low urinary output, and had decreased PCV, total protein concentration, and esophageal temperature. Evaluation of urine output alone in anesthetized dogs may not be an adequate indicator of fluid balance.
Objective—To assess performance of a portable bioimpedance monitor for measurement of body composition in dogs.
Animals—24 client-owned dogs.
Procedures—Percentage body fat was measured via dual-energy x-ray absorptiometry (DEXA) and with a portable bioimpedance monitor, and body condition score (BCS) was measured by use of a 9-integer scale.
Results—Although the precision of the bioimpedance monitor was good, this varied among dogs. Body position (standing vs sternal) had no effect on bioimpedance results. There was a significant association between results determined via DEXA and bioimpedance, but this association was weaker than between DEXA and BCS. When agreement was assessed via Bland-Altman plot, the bioimpedance monitor under- and overestimated values at high and low body fat percentages, respectively. In 9 dogs, body fat measurements were taken before and after weight loss to determine the proportional loss of tissue mass during weight management. There was a significant difference in the estimated percentage of weight lost as fat between the DEXA and bioimpedance methods.
Conclusions and Clinical Relevance—Although percentage body fat measured by use of a portable bioimpedance monitor correlated well with values determined via DEXA, the imprecision and inaccuracy in dogs with high percentage body fat could make the monitor inappropriate for clinical practice.
Objective—To evaluate postmortem surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomies.
Animals—10 healthy mixed-breed male dogs.
Procedures—Dogs were anesthetized, and 5 surgical techniques (pretied suture loop, energy-based sealer-divider, harmonic scalpel, suction with clip application, or suction with use of a thoracoabdominal stapler) were used to perform 5 partial liver lobectomies in each dog. Dogs were euthanatized, and the portal vein and hepatic artery were cannulated and perfused with a modified kidney perfusion machine (pulsatile flow for arterial perfusion and nonpulsatile flow for portal perfusion). Lobectomy sites were inspected for leakage of perfusate, and time until detection of leakage was recorded. The techniques in each dog were ranked on the basis of time until leakage. Time until leakage and rankings for each surgical technique were analyzed by use of an ANOVA.
Results—Leakage of perfusate was recorded in 44 lobes at supraphysiologic pressures. Of the 6 lobes without leakage, a pretied suture loop procedure was performed in 5 and a harmonic scalpel procedure was performed in 1. Time until leakage and the ranking differed significantly between the pretied suture loop and the other techniques. Time until leakage and ranking did not differ significantly among the other techniques.
Conclusions and Clinical Relevance—Time until leakage of perfusate was greater for the pretied suture loop technique than for the other techniques, and that technique did not fail in 5 of 10 lobes. However, all techniques appeared to be safe for clinical use.
Procedures—A CGMS was placed and used to obtain calculated glucose measurements before, during, and after anesthesia in each dog. Periodically, CGMS measurements were compared with concurrent measurements of glucose concentration in peripheral venous blood obtained with a portable chemistry analyzer (PCA).
Results—CGMS-calculated glucose measurements were significantly different from PCA blood glucose measurements during most of the anesthetic period. The CGMS values differed from PCA values by > 20% in 54 of 126 (42.9%) paired measurements obtained during the anesthetic period. Hypoglycemia was evident in CGMS measurements 25 of 126 (19.8%) times during anesthesia. By comparison, only 1 incident of hypoglycemia was detected with the PCA during the same period.
Conclusions and Clinical Relevance—Use of the CGMS for routine monitoring of interstitial glucose concentration as an indicator of blood glucose concentration during anesthesia cannot be recommended. Additional investigation is necessary to elucidate the cause of discrepancy between CGMS results and PCA data during anesthesia.
Objective—To determine the spatiotemporal gait characteristics and associated covariates of clinically normal dogs and dogs with spinal cord disease.
Animals—42 clinically normal dogs and 24 dogs with myelopathy at spinal cord segment T3-L3.
Procedures—Gait was analyzed for velocity, stride length, stride time, stance time, and swing time and compared between groups with consideration of covariates, including height, weight, velocity, sex, and age.
Results—By use of multivariate regression, dogs with neurologic signs, compared with clinically normal dogs, had decreased stride time, stance time, and stride length in the forelimbs and increased swing time in the hind limbs.
Conclusions and Clinical Relevance—Use of spatiotemporal gait characteristics appears to have potential for use as an outcome measure for dogs with neurologic disease.