Pre-analytical factors affecting the results of laboratory blood analyses in farm animal veterinary diagnostics

Analytical and Clinical Interference of Sample Hemolysis in Evaluating Blood Biochemical and Endocrine Parameters in Cows

Hemolysis is a common cause of errors in laboratory tests as it affects blood parameters and leads to a positive or negative bias. This study aims to examine the relationship between the level of hemolysis (expressed as cell-free hemoglobin concentration, g/L) and the variability of metabolic and endocrine parameters and to determine the threshold level of hemolysis that causes an analytically and clinically significant bias for the twenty most frequently examined blood parameters in cows. Paired blood samples of 10 mL each were obtained from 30 cows. One was subjected to mechanical trauma and plasma was extracted directly from the other. Hemolyzed and non-hemolyzed samples from the same animal were mixed to obtain final samples with cell-free hemoglobin concentrations of 0, 1, 2, 4, 6, 8, and 10 g/L. Metabolic and endocrine parameters were measured in the samples and their deviation and the linear equation between the level of hemolysis and the deviation were determined. The following threshold values of hemolysis were determined, which correspond to the acceptable analytical (lower value) and clinical (upper value) levels of parameter variability: BHB 0.96 and 4.81; NEFA 0.39 and 3.31; GLU 0.38 and 3.90; ALB 1.12 and 6.11; TPROT 1.40 and 6.80; UREA 6.62 and 20.1; TBIL 0.75 and 5.65; AST 0.11 and 2.18; GGT 1.71 and 8.90, LDH 0.01 and 0.11, ALP 0.97 and 2.95; TGC 1.56 and 15.5; CHOL 1.29 and 8.56; Ca 5.68 and 25.7; P 0.57 and 8.43; Mg 1.10 and 8.47; INS 1.15 and 3.89; T3 8.19 and 15.6; T4 8.97 and 18.5; and CORT 2.78 and 11.22 g/L cell-free hemoglobin. Three decision levels are available for each metabolic and endocrine parameter: if hemolysis is below the lower (analytical) threshold value, results can be reported without restriction; if hemolysis is between the lower and upper thresholds, the results can be issued with guidance in the form of corrective linear equations; and if hemolysis is above the upper (clinical) threshold, the results and sample must be discarded. This method contributes to an optimal approach to hemolysis interference with metabolic profile parameters in blood samples from cows.

Anaemia in South American camelids - an overview of clinical and laboratory diagnostics

South American camelids (SACs) play an increasing role in veterinary care in Europe. Many alpacas or llamas presented to veterinarians suffer from anaemia, regularly with a packed cell volume (PCV) below 0.10 l/l, which is a life-threatening condition for the animals. This review article presents clinical and laboratory diagnostic tools for the diagnosis of anaemia in SACs. Clinical identification of anaemic animals can be performed by assessing the FAMACHA© score and the Body Condition Score (BCS), since anaemia in alpacas and llamas correlates with pale mucous membranes and a lowered BCS. Haematological examination of a blood sample can provide a more differentiated diagnosis of anaemia in SACs. A common finding is regenerative anaemia with an increased number of reticulocytes that is often caused by blood loss due to Haemonchus contortus. Changes in a blood smear from an alpaca or llama with regenerative anaemia may include normoblasts (nucleated red blood cells), anisocytosis, poikilocytosis, polychromasia, Howell-Jolly bodies or basophilic stippling. Furthermore, non-regenerative anaemia, often caused by trace element deficiency or cachexia, can also occur.

New Perspectives In The Objective Evaluation Of Animal Welfare, With Focus On The Domestic Pig

Animal welfare can be viewed as the result of integrating repeated affective evaluations of success in coping with environmental challenges, i.e., subjective challenge adequacy.  The present work summarizes why established physiological and behavioral welfare parameters are inadequate to assess challenge adequacy. Behavioral tests based on the mood-congruent judgment effect and physiologic parameters based on components of the somatotropic axis are proposed as an alternative. Here, the judgment bias measures an animal's subjective confidence to cope successfully with a challenge, which is in turn modulated by the animal's previous experience. The somatotropic axis incorporates the insulin-like growth factor (IGF) and its binding proteins (IGFBP), which are involved in the regulation of metabolism and growth. First results indicate that in particular IGF-1 and IGFBP-3 react with higher latency and higher inertness to short-term stressful events than established physiological stress parameters. Before these indicators can be utilized for overall welfare assessment, further validation studies are necessary that provide more insights into how repeatable the measurements are under different conditions and which other factors may confound the measures.

Full genotype characterization of Brazilian canine G3P[3] strains during a 10-year survey (2012-2021) of rotavirus infection in domestic dogs and cats

There is a dearth of information on the molecular epidemiology of rotaviruses in pets in Brazil. The aim of this study was to monitor rotavirus infections in household dogs and cats, determine full-genotype constellations, and obtain data on evolutionary relationships. Between 2012 and 2021, 600 fecal samples from dogs and cats (516 and 84, respectively) were collected at small animal clinics in São Paulo state, Brazil. Rotavirus screening was conducted using ELISA, PAGE, RT-PCR, sequencing, and phylogenetic analysis. Rotavirus type A (RVA) was detected in 0.5% (3/600) of the animals. No non-RVA types were detected. The three canine RVA strains were found to have a novel genetic constellation, G3-P[3] -I2-R3-C2-M3-A9-N2-T3-E3-H6, which has never been reported in dogs. As expected, all of the viral genes, except those encoding NSP2 and VP7, were closely related to the corresponding genes from canine, feline, and canine-like-human RVA strains. A novel N2 (NSP2) lineage was identified, grouping together Brazilian canine, human, rat and bovine strains, suggesting that genetic reassortment had occurred. Uruguayan G3 strains obtained from sewage contained VP7 genes that were phylogenetically close to those of the Brazilian canine strains, which suggests that these strains are widely distributed in pet populations in South American countries. For the NSP2 (I2), NSP3 (T3), NSP4 (E3), NSP5 (H6), VP1 (R3), VP3 (M3), and VP6 (I2) segments, phylogenetic analysis revealed possibly new lineages. The epidemiological and genetic data presented here point out the necessity for collaborative efforts to implement the One Health strategy in the field of RVA research and to provide an updated understanding of RVA strains circulating canines in Brazil.

Rules of thumb to obtain, isolate, and preserve porcine peripheral blood mononuclear cells

One of the most used biospecimens in immunology are peripheral blood mononuclear cells (PBMC). PBMC are particularly useful when evaluating immunity through responses of circulating B- and T-cells, during an infection, or after a vaccination. While several reviews and research papers have been published aiming to point out critical steps when sampling, isolating, and cryopreserving human PBMC -or even analyzing any parameter before sampling that could impair the immune assays' outcomes-, there are almost no publications in swine research dealing with these topics. As it has been demonstrated, several factors, such as stress, circadian rhythmicity, or the anticoagulant used have serious negative impact, not only on the separation performance of PBMC, but also on the ulterior immune assays. The present review aims to discuss studies carried out in humans that could shed some light for swine research. When possible, publications in pigs are also discussed. The main goal of the review is to encourage swine researchers to standardize protocols to obtain, manage and preserve porcine PBMC, as well as to minimize, or at least to consider, the bias that some parameters might induce in their studies before, during and after isolating PBMC.

Effects of spray-dried bovine plasma protein in milk replacers fed at a high plane of nutrition on performance, intestinal permeability, and morbidity of Holstein calves

Spray-dried plasma protein (SDP) has been shown to improve growth and intestinal function in young calves when included in milk replacers (MR) fed at conventional rates. Use of an SDP and wheat protein blend to replace a portion of whey protein has been shown to perform similarly to using an all-whey protein control MR. However, a trend in the dairy industry is to feed calves for greater rates of growth during the preweaning period. The purpose of this study was to determine the effects of increasing amounts of SDP inclusion in MR on growth and health of calves fed at a high plane of nutrition. Young (<7 d) Holstein calves were offered starter and assigned to 1 of 5 MR treatments: an all-milk protein (whey) control MR (0SDP, n = 26) or MR containing 5% SDP (5SDP, n = 20), 7.5% SDP (7.5SDP, n = 14), 10% SDP (10SDP, n = 20), or 12% of an approximate 1:1 SDP plus wheat protein blend (PW, n = 17). All MR were formulated to contain 26% CP and 16% fat and were fed at a maximum rate of 1 kg of powder (as fed) from d 8 to 36. Amounts of MR powder were decreased by 25%/wk from d 37 to weaning at d 57. Thereafter, calves were provided only starter feed until the end of the study at d 63. On d 4, 15, 36, and 57, intestinal permeability was assessed via oral administration of lactulose and d-mannitol followed by analysis of lactulose and mannitol in blood at 60 min after administration. Increasing SDP led to a small linear decrease in MR consumed. There was a tendency for a positive linear relationship between increasing SDP and average daily gain of body weight, and SDP had mixed effects on body frame variables. Increasing SDP tended to increase fecal scores and increased the amount of fluid therapy given. Diet had no effect on intestinal permeability. Increasing SDP led to an increase in serum total cholesterol and serum urea N and tended to have a quadratic effect on serum glucose concentration on d 36. Calves fed PW tended to have increased withers height, increased intestinal permeability on d 36, and an increased likelihood of being medicated for any reason or being medicated for respiratory illness, but growth and health were not different from the control diet otherwise. Feeding PW led to an increase in serum total cholesterol and tended to lead to increased serum glucose concentration on d 36. Results of this study indicate that SDP can be included at up to 10% as fed in the MR of calves fed at a high plane of nutrition (1 kg/d of MR powder, as fed) with improvements in average daily gain. Additionally, a 1:1 SDP plus wheat protein blend can be used at 12% inclusion with no difference in most health and growth parameters.

Hematologic and biochemical reference intervals for 1-month-old specific-pathogen-free Landrace pigs

BACKGROUND

Hematologic and biochemical reference intervals (RIs) provide valuable data for the nutritional status and clinical diagnosis of animals. However, the specific hematologic and biochemical RIs for specific-pathogen-free (SPF) Landrace pigs has not been determined.

OBJECTIVE

The present study was designed to establish the hematologic and biochemical RIs for SPF 1-month-old Landrace pigs.

METHODS

Blood samples were collected from the jugular vein of 105 SPF 1-month-old Landrace pigs (50 males and 55 females), and complete blood counts and biochemical examinations were performed. The mean, RI, and 90% confidence interval were calculated for each variable, and gender differences were analyzed.

RESULTS

Reference intervals for SPF 1-month-old Landrace pigs were generated. The results revealed that there was generally no significant difference between male and female hematologic and serum biochemical variables (P > .05). However, a significant difference was noted in serum triglyceride concentrations between male and female pigs (P < .05).

CONCLUSIONS

This study provides hematologic and biochemical RIs for SPF 1-month-old Landrace pigs and provides basic data for the research and application of SPF Landrace pigs as a laboratory animal.

Measurement of serum zinc concentration in ruminants: a comparison of results from standard serum and specific trace element collection tubes

Aims: To evaluate agreement between the concentration of Zn in serum from samples collected from cattle and sheep into standard collection tubes for serum and from samples collected into tubes developed for trace element measurement. Methods: Eighty-eight animals (78 cattle and 10 sheep) on eight farms had paired blood samples collected into standard serum and trace element vacutainers. The paired samples were submitted the same day to the laboratory to be tested for the concentration of Zn in serum using atomic absorption spectrophotometry. The agreement between the paired results was then assessed using limits of agreement analysis. On one farm an additional 10 pairs of samples was taken from the same animals; this second set of paired samples was refrigerated for 48 hours prior to laboratory submission to identify the impact of delaying submission on the apparent concentration of Zn in serum. Results: The limits of agreement analysis found no evidence of a systematic difference between Zn concentrations in serum collected into standard serum tubes and into trace element tubes as neither the intercept nor the slope on the mean-difference plot were significantly different from zero. The SD of the difference between results increased as the concentration of Zn increased, so at the lowest Zn concentration reported in this study (6.9 μmol/L) the limits of agreement were ±1.07 μmol/L, while at the highest (23.5 μmol/L) they were ±3.39 μmol/L. Refrigerating the sample (as whole blood) for 48 hours prior to submission increased the apparent concentration of Zn in serum in both standard serum tubes and trace element tubes by 1.3 μmol/L (95% CI = 0.75-1.85). Conclusions: There was no evidence that the concentration of Zn in serum from standard serum tubes were artificially elevated. In contrast, delaying sample submission by 48 hours did elevate Zn concentrations. Clinical relevance: While these data apply only to the batch of vacutainers used in this study, there is unlikely to be much between batch variation in the potential for contamination. Thus these results suggest that monitoring zinc status in ruminants, by measuring the concentration of Zn in serum from samples collected into standard serum tubes does not result in clinically relevant alterations in Zn concentration compared to using specific trace element tubes. However delaying submission to the laboratory may result in significantly elevated concentrations of Zn in serum so should be avoided.

Towards the quantitative characterisation of piglets' robustness to weaning: a modelling approach

Weaning is a critical transition phase in swine production in which piglets must cope with different stressors that may affect their health. During this period, the prophylactic use of antibiotics is still frequent to limit piglet morbidity, which raises both economic and public health concerns such as the appearance of antimicrobial-resistant microbes. With the interest of developing tools for assisting health and management decisions around weaning, it is key to provide robustness indexes that inform on the animals' capacity to endure the challenges associated with weaning. This work aimed at developing a modelling approach for facilitating the quantification of piglet resilience to weaning. A total of 325 Large White pigs weaned at 28 days of age were monitored and further housed and fed conventionally during the post-weaning period without antibiotic administration. Body weight and diarrhoea scores were recorded before and after weaning, and blood was sampled at weaning and 1 week later for collecting haematological data. A dynamic model was constructed based on the Gompertz-Makeham law to describe live weight trajectories during the first 75 days after weaning, following the rationale that the animal response is partitioned in two time windows (a perturbation and a recovery window). Model calibration was performed for each animal. Our results show that the transition time between the two time windows, as well as the weight trajectories are characteristic for each individual. The model captured the weight dynamics of animals at different degrees of perturbation, with an average coefficient of determination of 0.99, and a concordance correlation coefficient of 0.99. The utility of the model is that it provides biologically meaningful parameters that inform on the amplitude and length of perturbation, and the rate of animal recovery. Our rationale is that the dynamics of weight inform on the capability of the animal to cope with the weaning disturbance. Indeed, there were significant correlations between model parameters and individual diarrhoea scores and haematological traits. Overall, the parameters of our model can be useful for constructing weaning robustness indexes by using exclusively the growth curves. We foresee that this modelling approach will provide a step forward in the quantitative characterisation of robustness.

Hematologic reference intervals of Danish sows at mid-gestation

Hematologic reference intervals are useful tools for interpretation of laboratory results in swine practice and research. Until now, there were no hematologic reference intervals established for gestating Danish sows and those established in other countries are either out-dated, produced using very few sows or incomplete with few variables. In the past few decades there have been significant increases in litter size due to breeding, as well as the development of new analytical procedures for hematology and statistical procedures for calculating reference intervals. Therefore, hematologic reference intervals representing current pig production and technology are greatly needed. The main objective of this study was to provide updated and complete hematologic reference intervals for Danish sows at mid-gestation. Blood samples were collected at mid-gestation from 248 sows belonging to five commercial herds in Denmark and the samples were analysed for several hematologic variables using the Advia 2120i Hematology System. The reference intervals were calculated according to the guidelines of American Society for Veterinary Clinical Pathology. The reference interval for hemoglobin concentration was 103.1-145.0 g/L. For red blood cells, hematocrit and mean corpuscular volume, the 95% reference intervals were 4.98-7.50 × 10¹²/L, 0.32-0.47 L/L, 57.0-69.3 fL, respectively. The reference intervals established in this study are different from those previously reported in the literature. These reference intervals add to the current knowledge and will be useful in the prevention, diagnosis and treatment of several disease conditions in gestating sow populations.

Technical pre-analytical effects on the clinical biochemistry of Atlantic salmon (Salmo salar L.)

Clinical biochemistry has long been utilized in human and veterinary medicine as a vital diagnostic tool, but despite occasional studies showing its usefulness in monitoring health status in Atlantic salmon (Salmo salar L.), it has not yet been widely utilized within the aquaculture industry. This is due, in part, to a lack of an agreed protocol for collection and processing of blood prior to analysis. Moreover, while the analytical phase of clinical biochemistry is well controlled, there is a growing understanding that technical pre-analytical variables can influence analyte concentrations or activities. In addition, post-analytical interpretation of treatment effects is variable in the literature, thus making the true effect of sample treatment hard to evaluate. Therefore, a number of pre-analytical treatments have been investigated to examine their effect on analyte concentrations and activities. In addition, reference ranges for salmon plasma biochemical analytes have been established to inform veterinary practitioners and the aquaculture industry of the importance of clinical biochemistry in health and disease monitoring. Furthermore, a standardized protocol for blood collection has been proposed.

The preanalytic phase in veterinary clinical pathology

This article presents the general causes of preanalytic variability with a few examples showing specialists and practitioners that special and improved care should be given to this too often neglected phase. The preanalytic phase of clinical pathology includes all the steps from specimen collection to analysis. It is the phase where most laboratory errors occur in human, and probably also in veterinary clinical pathology. Numerous causes may affect the validity of the results, including technical factors, such as the choice of anticoagulant, the blood vessel sampled, and the duration and conditions of specimen handling. While the latter factors can be defined, influence of biologic and physiologic factors such as feeding and fasting, stress, and biologic and endocrine rhythms can often not be controlled. Nevertheless, as many factors as possible should at least be documented. The importance of the preanalytic phase is often not given the necessary attention, although the validity of the results and consequent clinical decision making and medical management of animal patients would likely be improved if the quality of specimens submitted to the laboratory was optimized.

Variation of serum selenium concentrations in German sheep flocks and implications for herd health management consultancy

Background

This study was performed to demonstrate the widespread distribution and severity of selenium (Se) deficiency in sheep flocks and to evaluate the impact of influencing factors. In 150 flocks, ten serum samples of adult ewes were analysed for Se concentration. The farmers were interviewed concerning flock size, provision of mineral supplement, predominant form of husbandry (stationary fenced pasture/transhumance), predominant form of water provision (tap water/well/surface water) and predominant soil (sandy, silty/loamy, clay) in the area. The location of the flock was recorded as well as the production stage/season at the time of sampling. Intra-group variation and the validity to analyse pooled samples were tested.

Results

Pools of five samples correlated well with the mean of individually analysed samples. The intra-group range of serum Se concentration varied enormously (mean 45.4 ± 18.8 μg Se/l). About 60% of the flocks showed mean serum Se concentrations below 80 μg/l, 37.4% were below 60 μg Se/l, representing a Se deficient stage. Using mineral supplement in general was no key factor for Se status. Stationary flocks on fenced pasture had constantly higher mean serum Se concentrations during breeding (outdoors, August-November), lambing (mainly indoors, December-March) and lactation (outdoors, April-July), whereas flocks practising transhumance had significantly lower Se status, except during lambing. There was no significant correlation between the soil type and the Se status, but flocks in Southern Germany tend to show a lower Se status compared to Central and Northern Germany. Increasing flock size was associated with lower mean serum Se concentrations. In stationary flocks only, the use of surface water was accompanied by significantly lower Se status.

Conclusion

Se deficiency is widespread in German sheep flocks. More than one third of the flocks showed Se deficiency, indicating the need to optimise the nutritional management. Factors raising suspicion of Se deficiency are large flocks, transhumance during lactation and the breeding season as well as surface water provision in stationary flocks.