Reference intervals and age-related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

Neonatal Clinical Assessment of the Puppy and Kitten: How to Identify Newborns at Risk?

Neonatal puppies and kittens have physiological and anatomical characteristics that differ from those of adult animals, which impacts the interpretation of physical examination and complementary tests. The veterinarian must be familiar with the clinical, laboratory, and imaging aspects observed in neonates. It is necessary to thoroughly evaluate the litter and the mother to notice the most subtle signs of illness and advise the owner to constantly monitor the newborns, quickly sending them to specialized care. This review describes how to perform clinical assessments of newborns systematically and recognize clinical signs of neonatal changes or affections in puppies and kittens.

Canine pulmonary clearance during feto-neonatal transition according to the type of delivery

The success of immediate adaptation to extrauterine life depends on appropriate lung function, however, elective cesarean section can increase the risk of respiratory distress as a result of reduced pulmonary fluid absorption. This study aimed to evaluate the influence of birth mode on pulmonary clearance and respiratory performance of canine neonates in the transition period. For this purpose, 37 neonates were selected according to the obstetric condition: Vaginal Eutocia (n = 17) and Elective C-section (n = 20). Neonates were evaluated for neonatal vitality score, as well as evaluation of heart and respiratory rates, body temperature and body weight, venous hemogasometric evaluation, blood lactate and glucose, pulse oximetry and radiographic evaluation during the first 24 h of life. Additionally, amniotic fluid electrolyte composition of each puppy was evaluated. There was no influence of the type of delivery on electrolyte composition of canine amniotic fluid and neonatal pulmonary liquid content, analyzed by thoracic X-Rays. On the other hand, elective cesarean section delayed pulmonary adaptation, resulting in hypoxemia and less efficient compensatory response to acid-base imbalance and thermoregulation. In conclusion, elective c-section does not delay pulmonary clearance, whilst alters pulmonary adaptation by less efficient gas exchange and lower oxygenation, hindering the compensatory response to acid-base imbalance during the fetal-neonatal transition in dogs.

Preliminary research on tailored fluid therapy in pigs: comparing customized ionic solutions with Hartmann's solution

BACKGROUND

Fluid therapy in veterinary medicine is pivotal for treating various conditions in pigs; however, standard solutions, such as Hartmann's solution, may not optimally align with pig physiology. This study explored the development and efficacy of a customized fluid therapy tailored to the ionic concentrations of pig blood, aiming to enhance treatment outcomes and safety in both healthy and diseased pigs.

RESULTS

The study involved two experiments: the first to assess the safety and stability of customized fluids in healthy pigs, and the second to evaluate the efficacy in pigs with clinical symptoms of dehydration. In healthy pigs, the administration of customized fluids showed no adverse effects, with slight alterations observed in pO2, hematocrit, and glucose levels in some groups. In symptomatic pigs, the customized fluid group did not show any improvement in clinical symptoms, with no significant changes in blood chemistry or metabolite levels compared to controls. The customized fluid group showed a mild increase in some values after administration, yet within normal physiological ranges. The study reported no significant improvements in clinical or dehydration status, attributing the observed variations in blood test results to the limited sample size and anaesthesia effects rather than fluid characteristics.

CONCLUSIONS

Customized fluid therapy, tailored to mimic the ionic concentrations of pig blood, appears to be a safe and potentially more effective alternative to conventional solutions such as Hartmann's solution for treating pigs under various health conditions. Further research with larger sample sizes and controlled conditions is recommended to validate these findings and to explore the full potential of customized fluid therapy in veterinary practice.

Serum symmetric dimethylarginine in older dogs: Reference interval and comparison of a gold standard method with the ELISA

BACKGROUND

Serum symmetric dimethylarginine (SDMA) is used to screen for renal dysfunction in dogs. The gold standard technique for measuring SDMA, liquid chromatography-tandem mass spectrometry (LC-MS/MS) is not widely available. Age-specific reference intervals for SDMA in older dogs are lacking.

OBJECTIVES

Prospective study in older dogs to validate a commercially available LC-MS/MS method for SDMA, compare SDMA concentrations with concentrations measured using ELISA and obtain a reference interval (RI) for older dogs using both methods.

ANIMALS

Client-owned older dogs undergoing health screening.

METHODS

The LC-MS/MS method was analytically validated (limit of detection, precision, and linearity). Serum was sent cooled overnight for ELISA or was frozen at -80°C until batch analysis using LC-MS/MS. Results of LC-MS/MS and ELISA were compared and RIs for older dogs were calculated according to international guidelines.

RESULTS

The LC-MS/MS method showed good linearity (r2  = .99) and precision (coefficient of variation <10%), with a laboratory RI between 8.0 and 14.0 μg/dL. Paired measurements were available from 118 different dogs. Median SDMA concentration were 9.4 (range, 5.0-21.2) using LC-MS/MS and 12.0 (range, 5.0-22.0) μg/dL using ELISA. Both methods significantly differed with a mean difference of 2.2 μg/dL. The RI for older dogs for LC-MS/MS was 4.4-15.0 μg/dL, and for ELISA was 6.4-17.4 μg/dL.

CONCLUSIONS AND CLINICAL IMPORTANCE

The ELISA provided significantly higher SDMA concentrations compared to the validated LC-MS/MS method, indicating the need for device- or assay-specific RI. The obtained age-specific RI for SDMA is considerably higher in older dogs compared to the general laboratory RI.

Comparison of preoperative to postoperative blood glucose in puppies undergoing elective surgical neutering

The objective of this study was to determine if overnight fasting is associated with hypoglycemia in puppies undergoing elective surgical neutering. One hundred seventy-one apparently healthy puppies between the age of 2 and 6 months presented for elective surgical neutering. Owners were instructed to withhold food from puppies after midnight the night before surgery; water was to be freely available. Blood samples were collected pre- and postoperatively to determine blood glucose, packed cell volume (PCV), and serum total protein (TP). Pre- and postoperative data were compared with a paired Wilcoxon test (paired samples). Hypoglycemia was defined as glucose <4.2mmol/L (76mg/dL) for pediatric puppies ≤16 weeks of age (n = 116), and <3.6mmol/L (65mg/dL) for juvenile puppies >16 weeks of age (n = 55). Blood glucose significantly increased after surgery from median 8.8mmol/L (interquartile range [IQR], 1.7mmol/L; range, 4.9-12.3mmol/L) to a median 9.7mmol/L (IQR, 1.8mmol/L; range, 5.4-14.7mmol/L; P <0.0001). Preoperative median PCV was 35% (IQR, 6.5%; range, 26-53%) and TP was 58g/L (IQR, 6g/L; range, 44-82g/L). Preoperative values were significantly higher than postoperative values for PCV (median, 31%; IQR, 4%; range, 24-43%) and TP (median, 55g/L; IQR, 7g/L; range, 40-76g/L; P<0.0001). No puppy developed hypoglycemia and no adverse events were observed or reported. Overnight fasting did not result in pre- or postoperative hypoglycemia in studied puppies undergoing elective neutering.

Age, breed, sex and diet influence serum metabolite profiles of 2000 pet dogs

As an individual's metabolism reflects health and disease states well, metabolomics holds a vast potential in biomedical applications. However, normal physiological factors, such as age, can also influence metabolism, challenging the establishment of disease-specific metabolic aberrations. Here, we examined how physiological and diet-related factors drive variance in the metabolism of healthy pet dogs. We analysed 2068 serum samples using a canine nuclear magnetic resonance (NMR) spectroscopy-based metabolomics platform. With generalized linear models, we discovered that age, breed, sex, sterilization, diet type and fasting time significantly affected the canine metabolite profiles. Especially, breed and age caused considerable variation in the metabolite concentrations, and breeds with very different body conformations systematically differed in several lipid measurands. Our results enhance the understanding how normal physiological factors influence canine metabolism, aid accurate interpretation of the NMR results, and suggest the NMR platform might be applied in identifying aberrations in nutrient absorption and metabolism.

Age, breed, sex and diet influence serum metabolite profiles of 2000 pet dogs

As an individual's metabolism reflects health and disease states well, metabolomics holds a vast potential in biomedical applications. However, normal physiological factors, such as age, can also influence metabolism, challenging the establishment of disease-specific metabolic aberrations. Here, we examined how physiological and diet-related factors drive variance in the metabolism of healthy pet dogs. We analysed 2068 serum samples using a canine nuclear magnetic resonance (NMR) spectroscopy-based metabolomics platform. With generalized linear models, we discovered that age, breed, sex, sterilization, diet type and fasting time significantly affected the canine metabolite profiles. Especially, breed and age caused considerable variation in the metabolite concentrations, and breeds with very different body conformations systematically differed in several lipid measurands. Our results enhance the understanding how normal physiological factors influence canine metabolism, aid accurate interpretation of the NMR results, and suggest the NMR platform might be applied in identifying aberrations in nutrient absorption and metabolism.

Subjective assessment of frequency distribution histograms and consequences on reference interval accuracy for small sample sizes: A computer-simulated study

BACKGROUND

Inaccuracy in estimating reference intervals (RIs) is a problem with small sample sizes.

OBJECTIVES

This study aimed to identify the most accurate statistical methods to estimate RIs based on sample size and population distribution shape. We also studied the accuracy of sample frequency distribution histograms to retrieve the original population distribution and compared strategies based on the histogram and goodness-of-fit test.

METHODS

The statistical methods that best enhanced accuracy were determined for various sample sizes (n = 20-60) and population distributions (Gaussian, log-normal, and left-skewed) were determined by repeated-measures ANOVA and posthoc analyses. Frequency distribution histograms were built from 900 samples of five different sizes randomly extracted from six simulated populations. Three reviewers classified the population distributions from visual assessments of a sample histogram, and the classification error rate was calculated. RI accuracy was compared among the strategies based on the histograms and goodness-of-fit tests.

RESULTS

The parametric, nonparametric, and robust methods enhanced lower reference limit estimation accuracy for Gaussian, log-normal, and left-skewed distributions, respectively. The parametric, nonparametric bootstrap, and nonparametric methods enhanced the upper limit estimation accuracy for Gaussian, log-normal, and left-skewed distributions, respectively. Regardless of sample size, sample histogram assessments properly classified the original population distribution 71% to 93.9% of the time, depending on the reviewers. In this study, the strategy based on histograms assessed by the statistician was significantly more precise and accurate than the strategy based on the goodness-of-fit test (P < 0.001).

CONCLUSIONS

A strategy based on histograms might enhance the accuracy of RI estimations. However, relevant inter-reviewer variations in histogram interpretation were detected. Factors affecting inter-reviewer variations should be further explored.

Effect of age, sex, and body size on the blood biochemistry and physiological constants of dogs from 4 wk. to > 52 wk. of age

BACKGROUND

Blood biochemistry and reference intervals help to differentiate between healthy and ill dogs as well as to provide information for the prognosis, evaluation, and monitoring; however, these intervals are often obtained from adult animals. It is essential to understand that puppies and adults are physiologically different, which justifies the need to obtain age-specific biochemical reference intervals. The aim of this research was to assess the potential effect of age, sex, body size, and their interaction on routine biochemical analytes and physiological constants (body temperature, heart rate, and respiratory rate). To carry out the research, we selected 197 healthy dogs of both sexes and different body sizes (small, medium and large) classified by age: group I (4-8 wk), group II (9-24 wk), group III (25-52 wk), and group IV (> 52 wk). The biochemical analysis included the measurement of the enzymatic activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and the concentrations of cholesterol, triglycerides, total proteins, albumin, globulins, glucose, urea, and creatinine. Statistical analyses used analysis of variance (ANOVA) and a general linear model (GLM), which allows the comparison of multiple factors at two or more levels (p < 0.05).

RESULTS

The results of this study showed that ALT, total protein, albumin, globulin, urea, creatinine, and body temperature levels were lower in puppies than in adult dogs of group IV (p < 0.05), while the enzymatic activity of ALP, LDH, glucose concentration, and heart rate were higher. Whereas sex, body size and the interaction did not show a significant effect (p > 0.05).

CONCLUSIONS

Some biochemical components are influenced by age. For this reason, this manuscript contributes with additional data for the clinical interpretation of blood biochemical results in puppies.

Reference interval estimation of small sample sizes: A methodologic comparison using a computer-simulation study

BACKGROUND

According to the ASVCP and other guidelines, samples should comprise at least 120 individuals for reference interval (RI) estimation. Unfortunately, this minimum sample size is difficult to achieve in veterinary medicine. Several statistical methods are described to determine RIs from small sample sizes, but it is unclear which method provides the best accuracy.

OBJECTIVES

This study aimed to compare statistical strategies for estimating RIs and determine which strategy best enhances accuracy when the sample size is between 20 and 120.

METHODS

Different sample size groups (n = 120, 100, 80, 60, 40, and 20) were randomly selected 50 times from simulated Gaussian, log-normal, and left-skewed populations of 5000 total values. RIs were calculated using seven different statistical strategies comprising robust, parametric, nonparametric, and bootstrap methods, alone or in combination. RI accuracy was compared among these strategies at each sample size. The strategy that was significantly more accurate than others in the largest number of comparisons was considered as the one that best-enhanced RI accuracy.

RESULTS

The strategies that best-enhanced RI accuracy included using the parametric method when the Shapiro-Wilk P > 0.2 and, otherwise, using the nonparametric method to determine the upper and lower RI limits when there were between 60 and 100 reference individuals, and finding the lower RI limit when there were 40 reference individuals. The Box-Cox transformation parametric method best-enhanced RI accuracy of the upper RI limit when there were 40 reference individuals, and the nonparametric method best-enhanced RI accuracy of both RI limits when there were 20 reference individuals.

CONCLUSIONS

Using the parametric method when the Shapiro-Wilk P > 0.2, and the nonparametric method in other instances, will likely enhance RI accuracy when there are between 40 and 100 reference individuals. For smaller samples, the nonparametric method might be preferred.

Myoclonus and hypercalcemia in a dog with poorly differentiated lymphoproliferative neoplasia

A 1‐year, 8‐month‐old Rhodesian Ridgeback was presented with obtundation, ambulatory tetraparesis, and myoclonus. Initial clinical findings included ionized hypercalcemia with an apparent marked increase in parathyroid hormone, thrombocytopenia, and nonregenerative anemia. Low numbers of circulating atypical cells were noted on blood film evaluation. Brain magnetic resonance imaging identified an extra‐axial contrast enhancing subtentorial lesion, and cerebrospinal fluid (CSF) analysis documented a marked atypical lymphocytic pleocytosis. Flow cytometry performed on the CSF demonstrated expression of only CD45, CD90, and MHC class II, with Pax5 positivity on subsequent immunohistochemistry. The final diagnosis was of B‐cell lymphoblastic lymphoma or acute leukemia, given the distribution of disease and the presence of significant bone marrow infiltration alongside an aggressive clinical course. The unusual immunophenotype of the neoplastic cells and hypercalcemia presented antemortem diagnostic challenges, highlighting the need for a multidisciplinary approach and caution in the interpretation of clinical abnormalities in cases with multiple comorbidities.

Perinatal veterinary medicine-related evaluation in hematological and serum biochemical profiles of experimental beagles throughout pregnancy and parturition

BACKGROUND

The aims of this study were (a) to ascertain age-related changes in the reference values in hematological and serum biochemical examinations of beagles, and (b) to clarify the changes in these findings, including acute phase proteins and oxidative stress, throughout pregnancy and after parturition.

METHODS

Clinicopathological parameters were measured in young beagles at 6, 9 and 12 months and in adult beagles aged from 24 to 60 months. Likewise, pregnant beagles were investigated throughout the pregnancy and after parturition.

RESULTS

Apparent age-related changes were found in erythrocytic parameters during the growth and development of beagles. Most of the parameters (total protein, albumin, blood urea nitrogen, creatinine, urate, alkaline phosphatase (ALP) and creatine kinase (CK) exhibited age-dependent transitions. White cell count significantly increased after 30 days of pregnancy. The values of erythrocytic parameters moderately decreased during the second half of the pregnancy. Triglycerides, total cholesterol, free cholesterol and phospholipid concentrations increased in the mid- and late stages of pregnancy. ALP, lactate dehydrogenase, CK and cholinesterase activities markedly increased during pregnancy and/or after parturition. C-reactive protein (CRP) concentrations gradually increased and reached a maximum after 30-40 days of pregnancy. Serum amyloid A (SAA) levels markedly increased at 30 days of pregnancy before subsiding, and then increased again 3 days after parturition. Reactive oxygen metabolites (d-ROMs) showed significant increases after 30 and 40 days of pregnancy.

CONCLUSIONS

Reference values for hematological and serum biochemical examinations should be used for health evaluation of dogs, taking sex, age and the stage of pregnancy into consideration. Measurements of CRP, SAA and d-ROM levels are also useful for assessing maternal conditions in mid-pregnancy.

Development of a Multivariate Predictive Model to Estimate Ionized Calcium Concentration from Serum Biochemical Profile Results in Dogs

BACKGROUND

Ionized calcium concentration is the gold standard to assess calcium status in dogs, but measurement is not always available.

OBJECTIVES

(1) To predict ionized calcium concentration from biochemical results and compare the diagnostic performance of predicted ionized calcium concentration (piCa) to those of total calcium concentration (tCa) and 2 corrected tCa formulas; and (2) to study the relationship between biochemical results and variation of measured ionized calcium concentration (miCa).

ANIMALS

A total of 1,719 dogs with both miCa and biochemical profile results available.

METHODS

Cross-sectional study. Using 1,200 dogs, piCa was determined using a multivariate adaptive regression splines model. Its accuracy and performance were tested on the remaining 519 dogs.

RESULTS

The final model included creatinine, albumin, tCa, phosphorus, sodium, potassium, chloride, alkaline phosphatase, triglycerides, and age, with tCa, albumin, and chloride having the highest impact on miCa variation. Measured ionized calcium concentration was better correlated with piCa than with tCa and corrected tCa and had higher overall diagnostic accuracy to diagnose hypocalcemia and hypercalcemia, but not significantly for hypercalcemia. For hypercalcemia, piCa was as sensitive (64%) but more specific (99.6%) than tCa and corrected tCa. For hypocalcemia, piCa was more sensitive (21.8%) and as specific (98.4%) as tCa. Positive and negative predictive values of piCa were high for both hypercalcemia (90% and 98%, respectively) and hypocalcemia (70.8% and 87.7%, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Predicted ionized calcium concentration can be obtained from readily available biochemical and patient results and seems more useful than tCa and corrected tCa to assess calcium disorders in dogs when miCa is unavailable. Validation on external data, however, is warranted.

Severe hyperkalemia presenting with wide-complex tachycardia in a puppy with acute kidney injury secondary to leptospirosis

OBJECTIVE

To describe a case of hyperkalemia coinciding with wide-complex tachycardia (WCT) in a dog with acute kidney injury secondary to leptospirosis infection.

CASE SUMMARY

An 11-week-old Golden Retriever-Standard Poodle cross puppy was referred for acute kidney injury and hepatopathy. WCT coinciding with marked hyperkalemia was identified on presentation. Tachycardia persisted until resolution of hyperkalemia.

NEW OR UNIQUE INFORMATION PROVIDED

To our knowledge, this is the first report of severe hyperkalemia presenting with WCT in a dog. Hyperkalemia should be considered a differential for WCT in dogs.

Reference intervals for hematology, serum biochemistry, and basic clinical findings in free-ranging Chinese Pangolin (Manis pentadactyla) from Taiwan

BACKGROUND

There are 8 species of Pangolins found in Asia and Africa. Among them, the Chinese Pangolin (Manis pentadactyla) is an endangered insectivorous mammal found only in Asia. Hematology and serum chemistry reference intervals are critical for evaluating an animal's well-being and can be useful for clinical diagnostic purposes. Currently, there are no such reference intervals available for any Pangolin species.

OBJECTIVE

The purpose of the present study was to establish reference intervals for hematology and serum biochemical analytes, and some basic clinical findings, in Chinese Pangolins.

METHODS

Reference intervals for the hematology and serum chemistry variables, and basic clinical findings (body weight, heart rate, body temperature, blood oxygen saturation) were collected from 100 clinically healthy Chinese Pangolins (51 males and 49 females) using parametric and nonparametric percentile methods. In addition, seasonal, age-related, and sexual differences for all variables were statistically analyzed.

RESULTS

No significant differences in the reference intervals were found between males and females, except for body weight. However, significant seasonal differences were observed for heart rate, body temperature, serum ALT and lipase activities, and phosphate concentrations. The variables, which were significantly different between adult and sub-adult Pangolins were heart rate, MCH, creatinine, total protein, phosphate, glucose, and potassium concentration, and amylase activity. Seasonal and age group differences should be taken into consideration when using these reference intervals.

CONCLUSIONS

The findings from the present study represent a valuable resource for assessing the health of Chinese Pangolins, and contribute toward the conservation of this endangered mammal.