OBJECTIVE To determine the mean diameter of the main portal vein (PV) in healthy dogs by use of CT angiography, identify any associations between PV diameter and certain dog characteristics, and validate a clinically valuable ratio for quantifying the size of the PV. ANIMALS 100 dogs with no hepatic, cardiac, or vascular anomalies that underwent abdominal CT angiography. PROCEDURES Diameters of the main PV, abdominal aorta (Ao), and caudal vena cava (CVC) were measured by 2 observers at a defined location on postcontrast CT angiographic images in axial, sagittal, and transverse planes. Dog characteristics were evaluated for associations with PV diameter, and a PV:Ao diameter ratio was calculated. Intraclass correlations were calculated to assess intra- and interobserver agreement in vessel diameter measurements. RESULTS Mean diameter values were 7.9 mm (range, 4.1 to 14.8 mm) for the PV, 8.9 mm (range, 3.7 to 13.7 mm) for the Ao, and 11.4 mm (range, 4.4 to 22.5 mm) for the CVC. The PV:Ao diameter ratio was 0.91 mm. The PV diameter was significantly associated with dog body weight but not with dog age, sex, or neuter status. Intra- and interobserver reliabilities for measurements of all 3 vessels were considered excellent (intraclass correlation coefficients > 0.85). CONCLUSIONS AND CLINICAL RELEVANCE Findings indicated that the PV:Ao diameter ratio was a repeatable measurement that may be useful for evaluating the size of the portal vasculature in dogs and possibly for distinguishing healthy PVs from abnormal PVs in dogs with hepatic vascular anomalies.

The primary objective of this observational study was to examine the association between passive transfer of immunity and growth performance in preweaning calves. A secondary objective was to evaluate the utility of a heart girth tape (HGT) to estimate body weight (BW) in preweaning calves. A total of 142 Holstein calves were enrolled in this study. Blood samples were collected 24 to 48 hours after birth and serum immunoglobulin G (IgG) concentration for each calf was measured by radial immunodiffusion assay. Calf BW was determined at birth, at 21 days, and at weaning using an electronic scale (ES) and HGT. A significant positive association was detected between serum IgG and both BW at 21 days and average daily gain (ADG) from 0 to 21 days of life. Additionally, ADG from 0 to 42 days of life showed a trend toward an improved rate of gain as IgG concentration increased. The Pearson correlation coefficient between BW obtained from ES and HGT was 0.81 at birth, 0.86 at 21 days, and 0.83 at weaning. The mean differences between BW obtained from ES and HGT were -3.1 kg at birth, -3.2 kg at 21 days, and -7.7 kg at weaning. In conclusion, serum IgG concentration in neonatal calves is an important contributing factor for the variation in growth performance of preweaning calves. The HGT can be used to estimate the BW of preweaning calves but has a tendency to overestimate weight, especially at weaning compared to birth and 21 days of age.

OBJECTIVE To determine the correlation between glucose concentrations in serum, plasma, and blood measured by a point-of-care glucometer (POCG) and serum glucose concentration measured by an automated biochemical analyzer (ABA; gold standard). SAMPLE 152 canine and 111 feline blood samples. PROCEDURES For each sample, the glucose concentration in serum, plasma, and blood was measured by a POCG and compared with the ABA-measured glucose concentration by means of the Lin concordance correlation coefficient. Results were summarized by species for all samples and subsets of samples with hyperglycemia (ABA-measured glucose concentration > 112 mg/dL for dogs and > 168 mg/dL for cats) and pronounced hyperglycemia (ABA-measured glucose concentration > 250 mg/dL for both species). The effect of PCV on correlations between POCG and ABA measurements was also assessed. RESULTS Hyperglycemia and pronounced hyperglycemia were identified in 69 and 36 canine samples and 44 and 29 feline samples, respectively. The POCG-measured glucose concentrations in serum, plasma, and blood were strongly and positively correlated with the gold standard concentration. The PCV was positively associated with the correlation between the POCG-measured blood glucose concentration and the gold standard concentration but was not associated with the correlations between the POCG-measured glucose concentrations in serum and plasma and the gold standard concentration. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that POCG-measured glucose concentrations in serum, plasma, and blood were strongly correlated with the ABA-measured serum glucose concentration, even in hyperglycemic samples. Given the time and labor required to harvest serum or plasma from blood samples, we concluded that blood was the preferred sample type for use with this POCG.

OBJECTIVE To radiographically compare patellar ligament length (PLL) in dogs undergoing tibial plateau leveling osteotomy (TPLO) for unilateral cranial cruciate ligament rupture at preoperative, postoperative, and follow-up evaluations. ANIMALS 105 dogs that underwent TPLO for unilateral cranial cruciate ligament rupture at a referral veterinary hospital from October 1, 2008, through November 30, 2017. PROCEDURES Medical records were reviewed to obtain information on dog signalment, surgical procedure, and radiographically measured PLL at preoperative, postoperative, and follow-up evaluations. RESULTS Dogs undergoing TPLO had a shorter PLL at the postoperative and follow-up evaluations, compared with the PLL at the preoperative evaluation. Mean ± SD overall unadjusted PLL decreased significantly by 2.3 ± 3.4% between the preoperative and postoperative evaluation and by 2.8 ± 3.9% between the preoperative and follow-up evaluation. The PLL did not differ significantly between the postoperative and follow-up evaluation; mean PLL decreased by 0.4 ± 3.8% between the postoperative and follow-up evaluation. CONCLUSIONS AND CLINICAL RELEVANCE The PLL was shorter after TPLO in dogs, which was similar to changes observed for humans after high tibial osteotomy procedures. Further evaluation of clinical assessments, joint mobility, ultrasonographic assessments, and kinematic results are needed to determine the relevance of the PLL and whether a decrease in ligament length results in decreased mobility and persistent lameness in dogs, as has been reported for humans.

OBJECTIVE To characterize abdominal lymphatic drainage in cats after thoracic duct ligation (TDL) and cisterna chyli ablation (CCA). ANIMALS 7 purpose-bred research cats. PROCEDURES Baseline CT lymphangiography was performed. A popliteal lymph node was injected with iohexol, and images were acquired at 5-minute intervals for 15 minutes. Cats underwent TDL and CCA; methylene blue was used to aid in identifying lymphatic vessels. The CT lymphangiography was repeated immediately after and 30 days after surgery. All cats were euthanized and necropsied. RESULTS Results of baseline CT lymphangiography were unremarkable for all 7 cats. Only 5 cats completed the study. Leakage of contrast medium at the level of the cisterna chyli was seen on CT lymphangiography images obtained from all cats immediately after surgery. Evaluation of 30-day postoperative CT lymphangiography images revealed small branches entering the caudal vena cava in 2 cats, leakage of contrast medium into the caudal vena cava with no visible branches in 1 cat, and no contrast medium in the caudal vena cava in 2 cats. Contrast medium did not flow beyond the level of the cisterna chyli in any cat. Gross examination during necropsy revealed that all cats had small lymphatic vessels that appeared to connect to local vasculature identified in the region of the cisterna chyli. CONCLUSIONS AND CLINICAL RELEVANCE Abdominal lymphaticovenous anastomoses formed after TDL and CCA in cats. This would support use of these procedures for treatment of cats with idiopathic chylothorax, although additional studies with clinically affected cats are warranted.

OBJECTIVE To describe perfusion and diffusion characteristics of the liver, spleen, and kidneys of healthy adult male cats as determined by morphological, perfusion-weighted, and diffusion-weighted MRI. ANIMALS 12 healthy adult male cats. PROCEDURES Each cat was anesthetized. Morphological, perfusion-weighted, and diffusion-weighted MRI of the cranial aspect of the abdomen was performed. A region of interest (ROI) was established on MRI images for each of the following structures: liver, spleen, cortex and medulla of both kidneys, and skeletal muscle. Signal intensity was determined, and a time-intensity curve was generated for each ROI. The apparent diffusion coefficient (ADC) was calculated for the hepatic and splenic parenchyma and kidneys on diffusion-weighted MRI images. The normalized ADC for the liver was calculated as the ratio of the ADC for the hepatic parenchyma to the ADC for the splenic parenchyma. RESULTS Perfusion-weighted MRI variables differed among the 5 ROIs. Median ADC of the hepatic parenchyma was 1.38 × 10(-3) mm2/s, and mean ± SD normalized ADC for the liver was 1.86 ± 0.18. Median ADC of the renal cortex and renal medulla was 1.65 × 10(-3) mm2/s and 1.93 × 10(-3) mm2/s, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results provided preliminary baseline information about the diffusion and perfusion characteristics of structures in the cranial aspect of the abdomen of healthy adult male cats. Additional studies of cats of different sex and age groups as well as with and without cranial abdominal pathological conditions are necessary to validate and refine these findings.

OBJECTIVE: To assess changes in pupil size and intraocular pressure (IOP) following topical application of a 0.5% tropicamide solution in the eyes of healthy butorphanol-sedated dogs. ANIMALS: 12 healthy adult Beagles. PROCEDURES: In a randomized crossover study consisting of 2 treatment periods with a 1-week washout between periods, dogs received an IM injection of butorphanol (0.2 mg/kg) or an equal volume of sterile saline (0.9% NaCl) solution. For each dog, 1 drop of 0.5% tropicamide ophthalmic solution was topically instilled in one eye and 1 drop of artificial tear solution was topically instilled in the other eye 10 minutes after the IM injection and again 5 minutes later. Extent of sedation, pupil size, and IOP were evaluated from 20 minutes before to 80 minutes after the IM injection and compared among treatment combinations. RESULTS: Butorphanol induced mild (n = 9) or moderate (3) sedation in all dogs and slightly delayed the onset of, but did not prevent, tropicamide-induced mydriasis. Butorphanol caused a significant increase in IOP, which was not exacerbated by tropicamide-induced mydriasis; however, that increase was generally not sufficient to exceed the upper limit of the IOP reference range. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that butorphanol did not prevent tropicamide-induced mydriasis but did increase the IOP in ophthalmologically normal Beagles. Although the butorphanol-induced increase in IOP did not appear clinically relevant for the dogs of this study, that may not be true for dogs with glaucoma, and care should be taken when butorphanol is administered to such dogs.

OBJECTIVE To assess single-day and multiday repeatability of weight distribution (stance) data obtained with a commercial analyzer for dogs with naturally occurring hind limb lameness. ANIMALS 46 dogs (15 and 31 for single-day and multiday trials, respectively).PROCEDURES For single-day trials, 5 to 10 measurements/trial were collected to determine body weight (BW), weight distribution on each limb, and forelimb and hind limb symmetry indices (SIs). The dog was removed from the room and returned immediately; 5 trials were performed. For multiday trials, measurements were performed in the same manner on 2 sequential days. Data were compared among trials (single-day measurements) and between days (multiday measurements). Repeatability (correlation coefficients and Lin concordance correlation coefficients [LCCCs]) and variability (coefficients of variation [CVs]) were assessed. RESULTS In single-day trials, BW (r = 0.999), weight distribution on the lame hind limb (r = 0.915) and contralateral hind limb (r = 0.948), and hind limb SI (r = 0.964) were each significantly correlated among trials. In multiday trials, BW results were similar; weight distribution on the lame hind limb and contralateral hind limb and hind limb SI were each less closely but still significantly correlated between days. The LCCCs were highest for BW, weight distribution on the contralateral hind limb, and hind limb SI in single-day trials and for BW and weight bearing on the contralateral and lame hind limbs in multiday trials. The CVs were lowest for BW and highest for forelimb SI in both trial types. CONCLUSIONS AND CLINICAL RELEVANCE The analyzer used allowed repeatable measurement of BW and weight distribution on the hind limbs of dogs with hind limb lameness. Measurement of forelimb stance variables was not repeatable in this group of dogs.

OBJECTIVE To evaluate agreement of 4 methods (Tikhonov gamma variate adaptive regularization of plasma concentration-time curve fitting applied to technetium Tc 99m diethylenetriamine pentaacetic acid [99mTc-DTPA] plasma clearance [Tk-GV], plasma clearance of exogenous creatinine [CrCL], Gates gamma camera-based measurement method with 99mTc-DTPA renal clearance and dynamic scintigraphy [GTS], and iohexol renal clearance assessed with dynamic CT with Patlak plotting [CT-Pp]) for measuring glomerular filtration rates (GFR) in healthy cats. ANIMALS 7 healthy, laboratory-raised cats. PROCEDURES Each method for measuring GFR was performed twice in 7 cats at 24-day intervals. The Wilcoxon signed-rank sum test was used to compare the results obtained from the 14 studies for each method. Results from the 4 methods were assessed for agreement and correlation. RESULTS The median GFR values were 2.75, 2.83, 3.14, and 4.26 mL/min/kg, for Tk-GV, CT-Pp, plasma CrCL, and GTS, respectively. Analysis with Wilcoxon signed-rank sum tests identified significant pairwise differences between results obtained with the Tk-GV versus the plasma CrCL method, the Tk-GV versus the GTS method, and the plasma CrCL versus the GTS method. The least variable method was Tk-GV, with an SD of 1.27 (mL/min/kg). CONCLUSIONS AND CLINICAL RELEVANCE Findings indicated that Tk-GV yielded GFR measurements comparable with those obtained with CT-Pp, plasma CrCL, and GTS; however, the Tk-GV method yielded the tightest range of results among the methods evaluated.

The degree of analgesia provided by blind techniques for brachial plexus blocks (BPBs) has not been compared in clinical cases undergoing surgery of the thoracic limb. The objective of this study was to evaluate the anesthetic conditions and postoperative analgesia resulting from 3 different BPB local anesthetic techniques in canine patients undergoing such surgery. Twenty-four client-owned dogs received a standardized premedication/induction protocol (hydromorphone and acepromazine/propofol), maintained with isoflurane in oxygen using mechanical ventilation, in a prospective, randomized, blinded clinical trial. Before surgery, dogs received 1 of 3 anatomical BPB techniques: traditional, perpendicular, or axillary, with 0.2 mL/kg body weight (BW) of bupivacaine 0.5%. Cardiorespiratory variables and isoflurane end-tidal concentrations were recorded throughout anesthesia. Scores for anesthetic maintenance (0-best to 4-responsive), recovery quality (0-not responsive to 3-responsive), and Glasgow pain scale were recorded for up to 24 h postoperatively. All dogs recovered uneventfully from anesthesia and no differences in the measured variables or scores were noted among groups, during and after anesthesia. When thoracic limb amputations in each of the 3 groups (n = 9; 4 in traditional, 3 in perpendicular, 2 in axillary) were compared to the other surgical procedures (n = 15); however, scores for anesthetic maintenance were higher [0 (0 to 1) versus 0 (0 to 0); median (interquartile range)], recovery [1 (0 to 2) versus 0 (0 to 0)], and pain [2.4 (2.4 to 3.0) versus 1.6 (1.4 to 2.2)] in the first 3 h post-extubation. Surgery times were also longer with amputations [115 min (100 to 138 min) versus 50 min (41 to 90 min)]. The 3 BPB techniques provided similar anesthesia and postoperative pain scores. Despite higher pain scores in thoracic limb amputations than in less invasive surgeries, the BPB appeared to provide significant comfort.