New strategies to classify canine pleural effusions and the diagnostic value of acute phase proteins, amylase, and adenosine deaminase in pleural exudates.

BACKGROUND: In dogs, simplified Light's criteria can discriminate transudates from exudates. Other tests used in human medicine are pleural effusion cholesterol (CHOLPE) and butyrylcholinesterase [BChEPE], the pleural effusion/serum ratio of these analytes (CHOLratio and BChEratio), and the serum albumin minus pleural effusion albumin gradient (SEAG). OBJECTIVES: We aimed to assess the diagnostic accuracies of different biomarkers in dogs with pleural effusion in differentiating exudates from transudates. Secondarily, we evaluated the potential diagnostic utility of pleural effusion acute phase proteins, amylase, and adenosine deaminase in discriminating causes of exudative effusions. METHODS: Cross-sectional study including 68 client-owned dogs with pleural effusion. RESULTS: There were 48 exudates (10 septic, 16 neoplastic, 9 hemorrhagic, and 13 classified as other exudates) and 20 transudates. All the variables analyzed, except SEAG, were significantly different between exudates and transudates. Using the cut-off values adopted in human literature, accuracies for CHOLPE, CHOLratio, BChEPE, and BChEratio were between 82.35% and 85.29%; all values were significantly lower compared with the previously published simplified Light's criteria accuracy (i.e., 98%, p < .001 for all comparisons). We found the accuracy of the simplified Light's criteria to be similar to what has been previously reported (95.59%, p = .238). Paraoxonase-1 (PON-1PE) activity and the pleural effusion/serum paraoxonase-1 ratio (PON-1ratio) were significantly lower in exudative neoplastic effusions than in exudative hemorrhagic (p = .004 and p = .001) and septic (p = .004 and p < .001) effusions. CONCLUSION: Simplified Light's criteria were the best method for discriminating transudates from exudates, and a low PON-1PE activity and PON-1ratio in exudative effusions may suggest an underlying neoplasia.

Changes in cortisol, cortisone and 11ß-hydroxysteroid dehydrogenase type II activity in saliva during pregnancy and lactation in sows.

The activity of the enzyme 11ß-hydroxysteroid dehydrogenase type II (11ß-HSD type II), which can be estimated by the combined measurement of cortisol and cortisone, is gaining importance as a marker for the assessment of stress in pigs. The aim of this study was to investigate the activity of this enzyme and the salivary concentrations of cortisol and cortisone in pigs during pregnancy, farrowing and lactation and to compare it with other stress-related biomarkers such as Chromogranin A (CgA), S100A12 and alpha-amylase. Salivary cortisone concentrations and 11ß-HSD type II activity decreased after farrowing, while cortisol concentrations increased. Enzyme activity did not show significant correlations with any of the other stress-related biomarkers measured in this study. Overall, the results of this report indicate a different regulation of 11ß-HSD type II activity and of cortisol and cortisone during pregnancy and lactation, which should be considered when evaluating these analytes in saliva during these periods.

Salivary oxytocin changes and effect of the season in sows kept in different farrowing systems: Farrowing crate and farrowing pen with temporary crating.

Alternative farrowing systems that have been developed in recent years could have a positive effect on the welfare of sows during farrowing and lactation. Oxytocin measurements in saliva may provide information about positive animal welfare status. The purpose of this study was to evaluate the changes in salivary oxytocin concentrations in sows during the lactation period in three different farrowing systems and in two different seasons. Crossbred Duroc sows (n = 34, average parity = 3.6 ± 1.80) were housed in conventional farrowing crates (FC) (n = 10) or in farrowing pens with temporary crating (TC), including SWAP (n = 12) and JFL15 (n = 12) in two different seasons: summer and winter. Saliva samples were collected for six days during lactation: days 2, 4, 12, 23, 25 (i.e., 1-day post-weaning) and 26 (i.e., 2-day post-weaning) after farrowing. Moreover, behavioral data from sows was recorded on days 2, 4, 12 and 23 after farrowing, using a 30-s scan sampling method for 3 min per pen to record the behaviors which were assessed by the same observer. The results showed that the salivary oxytocin concentrations were 472.5 pg/mL and 399.4 pg/mL higher in both TC (SWAP and JLF15, respectively) than in the FC in early-lactation period, and these differences were more pronounced in summer and at the end of lactation in winter. In terms of behavior, higher number of mother-young interactions were observed in TC than FC in early- and mid-lactation period. In conclusion, TC is associated to a higher salivary oxytocin concentration that could indicated an increased mother-young interaction, although oxytocin concentration can be influenced by other factors, such as season or day of lactation.

Changes in biomarkers of the redox status in whole blood and red blood cell lysates in canine hypothyroidism.

Hypothyroidism is the most commonly diagnosed endocrine disease in dogs. The objective of this study was to evaluate the changes in the redox status in canine hypothyroidism using whole blood (WB) and red blood cell (RBCs) lysates. For this purpose, a panel of five antioxidants and five oxidants biomarkers was measured in WB and RBCs lysates of 30 dogs with hypothyroidism, 26 dogs with non-thyroidal illnesses and 15 healthy dogs. The antioxidants measured were cupric reducing antioxidant capacity (CUPRAC), ferric reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), thiol and paraoxonase type-1 (PON-1). Oxidants measured include the total oxidant status (TOS), peroxide-activity (POX-Act), reactive oxygen-derived metabolites (d-ROMs), advanced oxidation protein products (AOPP) and thiobarbituric acid reactive substances (TBARS). WB showed a significant decrease of the antioxidants CUPRAC, TEAC and thiol, and also an increase in TBARS and a decrease in AOPP in dogs with hypothyroidism compared to healthy dogs. Meanwhile, RBCs lysates showed a significant increase in FRAP and PON-1 in dogs with hypothyroidism. The changes in the redox biomarkers in this study show that WB in canine hypothyroidism had a higher number of changes in biomarkers of the redox status than RBCs lysates, making it a promising sample type for the evaluation of the redox status in this disease. In addition, WB is easier and simpler to process than RBCs lysates and unlike serum, it does not have any hemolysis interference.

Validation of assays for measurement of oxidant compounds in saliva of pigs: Thiobarbituric acid reactive substances (TBARS), carbonyl, and reactive oxygen species (ROS).

Thiobarbituric acid reactive substances (TBARS), carbonyls and reactive oxygen species (ROS) are oxidant compounds that can provide useful information on the oxidative status. Pigs can be affected by oxidative stress in different situations including physiological conditions such as lactation and also in different diseases, and the measurement of these three analytes in saliva could be potentially useful as biomarkers of the redox status in this species. Assays for the measurement of TBARS and carbonyls by spectrophotometry and ROS by luminol-based chemiluminescence in pigs' saliva were analytically validated and were applied in saliva of pigs after an in vitro incubation with different doses of ascorbic acid (AA). All the assays showed a satisfactory analytical precision and accuracy. The 240 h-incubation of saliva samples with 60 mM of AA induced to an increased TBARS and carbonyls production. TBARS, carbonyls and ROS can be estimated in saliva of pigs by the assays validated in this report. In addition, these assays can detect changes in the concentration of these analytes associated to incubation of saliva samples with AA.

Measurement of haptoglobin in saliva of cows: Validation of an assay and a pilot study of its potential application.

In recent years, the use of saliva as a matrix for the measurement of biomarkers of health and welfare is gaining importance due to its non-invasive collection. Haptoglobin (Hp) is an acute-phase protein involved in the inflammatory response and changes in its concentration can provide information about the health status of the animals. This study aimed to develop and validate an assay based on luminescent amplification (AlphaLISA technology) for the measurement of Hp in bovine saliva and to study the possible changes in different inflammatory situations such as peripartum period and lameness. The assay proved to be accurate, reliable, and sensitive for the measurement of Hp in cow saliva (coefficient of variation (CV) 7.57%; coefficient of determination (R2) 0.992; recovery test 105.15%; lower limit of quantification (LLQ) 7.9 ng/ml). Significant differences were observed between Hp levels in saliva of cows before (13 days before) and after (7 and 20 days after) calving and at the moment of calving (p < 0.0001), and between lame and healthy cows (p < 0.008). In conclusion, this assay can detect Hp in a precise, sensitive, and accurate way in saliva of cows. Future studies with a larger population and different disease conditions should be conducted to determine the potential of Hp as an inflammatory biomarker in cow saliva.

Diagnostic performance of glycated haemoglobin (HbA1c) for diabetes mellitus in dogs.

The objective of this study was to determine the diagnostic performance of glycated haemoglobin (HbA1c) for canine diabetes mellitus (DM) and compare it with that of serum fructosamine. Aliquots of blood samples collected for diagnostic purposes from adult dogs were used. HbA1c was measured using a previously validated capillary electrophoresis assay. The dogs were allocated into four groups: (1) DM; (2) hyperadrenocorticism (HAC); (3) long-term corticosteroid therapy (CST); and (4) various chronic diseases (VD). In total, 88 dogs were included as follows: DM (n = 11), HAC (n = 10), CST (n = 14), and VD (n = 53). Fructosamine was measured in all four groups as follows: DM (n = 6), HAC (n = 7), CST (n = 9), and VD (n = 42). Median (range) serum glucose concentration was higher (P < 0.001) in the DM group (22.8 mmol/L; range, 15.6-29.3 mmol/L) compared to HAC (5.9 mmol/L; range, 4.2-6.8 mmol/L), CST (5.6 mmol/L; range, 4.3-23.3 mmol/L), and VD (5.5 mmol/L; range, 4.1-9.4 mmol/L) groups. Mean (± standard deviation) HbA1c was higher (P < 0.001) in the DM group (6.3% ± 1.5%) compared to HAC (1.9% ± 0.5%), CST (1.7% ± 0.5%), and VD (1.9% ± 0.5%) groups. All diabetic dogs and none of the other dogs had HbA1c levels above the cut-off value for DM (3.3%), indicating an accuracy of 100% in diagnosing DM. Significant differences (P < 0.01) were observed in median fructosamine between the DM group (389 µmol/L; range, 348-865 µmol/L) and the HAC (306 µmol/L; range, 167-348 µmol/L) and the VD (316 µmol/L; range, 189-500 µmol/L) groups. Fructosamine had an accuracy of 84.4% for the diagnosis of DM. When used for the diagnosis of canine DM, HbA1c measured with this specific assay had excellent diagnostic accuracy and was superior to serum fructosamine.

Using integrated wildlife monitoring to prevent future pandemics through one health approach.

In the One Health context, Integrated Wildlife Monitoring (IWM) merges wildlife health monitoring (WHM) and host community monitoring to early detect emerging infections, record changes in disease dynamics, and assess the impact of interventions in complex multi-host and multi-pathogen networks. This study reports the deployment and results obtained from a nationwide IWM pilot test in eleven sites representing the habitat diversity of mainland Spain. In each study site, camera-trap networks and sampling of indicator species for antibody and biomarker analysis were used to generate information. The results allowed identifying differences in biodiversity and host community characteristics among the study sites, with a range of 8 to 19 relevant host species per point. The Eurasian wild boar (Sus scrofa) was the most connected and central species of the host communities, becoming a key target indicator species for IWM. A negative relationship between biodiversity and disease risk was detected, with a lower number and prevalence of circulating pathogens in the sites with more species in the community and larger network size. However, this overall trend was modified by specific host-community and environmental factors, such as the relative index of wild boar - red deer interactions or the proximity to urban habitats, suggesting that human-driven imbalances may favour pathogen circulation. The effort of incorporating wildlife population monitoring into the currently applied WHM programs to achieve effective IWM was also evaluated, allowing to identify population monitoring as the most time-consuming component, which should be improved in the future. This first nationwide application of IWM allowed to detect drivers and hotspots for disease transmission risk among wildlife, domestic animals, and humans, as well as identifying key target indicator species for monitoring. Moreover, anthropogenic effects such as artificially high wildlife densities and urbanisation were identified as risk factors for disease prevalence and interspecific transmission.

Automated assays for trace elements and ferritin measurement in saliva of pigs: Analytical validation and a pilot application to evaluate different iron status.

The aim of this study was to validate automated methods to measure iron (Fe), zinc (Zn), copper (Cu) and ferritin in pig saliva samples. A complete analytical validation was performed of all assays. In addition, these methods were applied to saliva of Fe supplemented (n = 22) and non-supplemented (n = 20) piglets. All assays were able to measure these biomarkers in pig saliva with adequate precision, accuracy and high sensitivity and, in case of trace elements without needing a deproteinization pre-process. The group of piglets supplemented with Fe presented significantly higher levels of ferritin and Zn in saliva. In conclusion, the automated assays evaluated were able to measure Fe, Zn, Cu and ferritin in saliva of pigs, and in case of trace elements, they have the advantage of not needing a deproteinization pre-treatment and thus these analytes can be measured in a simple and fast manner.

Changes in salivary analytes in cows due to the in vitro presence of feed.

BACKGROUND: The effect in a sialochemistry profile of the presence of usually available feed in dairy cows was evaluated by an in vitro experiment. For this purpose, a pooled clean saliva from five healthy dairy cows was incubated five times with a standard feed based on a total mixed ration (F), wheat hay (H), and grass (G). The salivary panel was integrated by biomarkers of stress (cortisol -sCor-, salivary alpha-amylase -sAA-, butyrylcholinesterase -BChE-, total esterase -TEA-, and lipase -Lip-), immunity (adenosine deaminase -ADA-), oxidative status (Trolox equivalent antioxidant capacity -TEAC-, the ferric reducing ability of saliva -FRAS-, the cupric reducing antioxidant capacity -CUPRAC-, uric acid, and advanced oxidation protein products -AOPP-), and enzymes, proteins, and minerals of general metabolism and markers of liver, muscle, and renal damage (aspartate aminotransferase -AST-, alanine aminotransferase -ALP-, γ-glutamyl transferase -gGT-, lactate dehydrogenase -LDH-, creatine kinase -CK-, creatinine, urea, triglycerides, glucose, lactate, total protein, phosphorus, and total calcium). RESULTS: Most of the evaluated analytes showed a coefficient of variations (CV) higher than 15% and/or significant changes compared with the clean saliva when feed was present. Some analytes, such as the oxidative status biomarkers (CV > 80%), AST (CV > 60%), or glucose (CV > 100%), showed significant changes with all the feed types tested. Others showed significant differences only with certain types of feed, such as LDH with F (CV > 60%) or triglycerides with F (CV > 100%) and H (CV > 95%). However, sCor or gGT remained unchanged (CV < 15%, P > 0.05) in all the treatments. CONCLUSIONS: The presence of feed can produce changes in most of the analytes measured in cows' saliva, being of high importance to consider this factor when saliva is used as a sample to avoid errors in the interpretation of the results.

Biomarkers of sepsis in pigs, horses and cattle: from acute phase proteins to procalcitonin.

Sepsis is a complex clinical syndrome triggered by an inflammatory host response to an infection. It is usually complicated to detect and diagnose, and has severe consequences in human and veterinary health, especially when treatment is not started early. Therefore, efforts to detect sepsis accurately are needed. In addition, its proper diagnosis could reduce the misuse of antibiotics, which is essential fighting against antimicrobial resistance. This case is a particular issue in farm animals, as antibiotics have been traditionally given massively, but now they are becoming increasingly restricted. When sepsis is suspected in animals, the most frequently used biomarkers are acute phase proteins such as C-reactive protein, serum amyloid A and haptoglobin, but their concentrations can increase in other inflammatory conditions. In human patients, the most promising biomarkers to detect sepsis are currently procalcitonin and presepsin, and there is a wide range of other biomarkers under study. However, there is little information on the application of these biomarkers in veterinary species. This review aims to describe the general concepts of sepsis and the current knowledge about the biomarkers of sepsis in pigs, horses, and cattle and to discuss possible advances in the field.

Basics for the potential use of saliva to evaluate stress, inflammation, immune system, and redox homeostasis in pigs.

The use of saliva as a biological sample has many advantages, being especially relevant in pigs where the blood collection is highly stressful and painful, both for the animal and the staff in charge of the sampling. Currently one of the main uses of saliva is for diagnosis and detection of infectious diseases, but the saliva can also be used to measure biomarkers that can provide information of stress, inflammation, immune response and redox homeostasis. This review will be focused on the analytes that can be used for such evaluations. Emphasis will be given in providing data of practical use about their physiological basis, how they can be measured, and their interpretation. In addition, some general rules regarding sampling and saliva storage are provided and the concept of sialochemistry will be addressed. There is still a need for more data and knowledge for most of these biomarkers to optimize their use, application, and interpretation. However, this review provides updated data to illustrate that besides the detection of pathogens in saliva, additional interesting applicative information regarding pigs´ welfare and health can be obtained from this fluid. Information that can potentially be applied to other animal species as well as to humans.

Insulin in the saliva of pigs: Validation of an automated assay and changes at different physiological conditions.

This study aimed to evaluate whether insulin could be measured in the saliva of pigs and if its concentration changes in some physiological conditions. For this purpose, a validation of an automated heterologous immunoassay for measuring insulin in the saliva of pigs was performed. In addition, the possible changes of salivary insulin concentration in sows after food intake and during gestation and lactation were studied. The evaluated immunoassay was able to detect insulin in the saliva of pigs in a precise and accurate way when species-specific calibrators were used. There was no correlation in insulin concentrations between serum and saliva. Insulin concentrations showed a significant increase in the saliva of sows after feeding. Sows at farrowing and lactation presented higher salivary insulin levels as compared with those in gestation. In conclusion, the results showed that insulin could be measured in the saliva of pigs, and changes in its concentration can be detected due to food intake and different physiological conditions.

Changes in saliva proteins in cows with mastitis: A proteomic approach.

This study aimed to evaluate the possible saliva proteome changes in cows with mastitis using a Tandem Mass Tags (TMT) proteomics approach. For this purpose, the salivary proteomes from healthy cows and cows with mastitis were analysed, and their serum proteomes were also studied for comparative purposes. A total of eight saliva and serum paired samples for each group were used for the proteomic study, and eight additional samples for each group were analysed in the analytical and overlap performance studies. In saliva samples, 2192 proteins were identified, being sixty-three differentially modulated in mastitis. In serum, 1299 proteins were identified, being twenty-nine differentially modulated in mastitis. Gamma glutamyl transferase (γGT) in saliva and serum amyloid A (SAA) were validated by commercially available automated assays. In conclusion, there are changes in protein expression and metabolic pathways in saliva and serum proteomes of cows with mastitis, showing different response patterns but complementary information.

Changes in saliva analytes during pregnancy, farrowing and lactation in sows: A sialochemistry approach.

Salivary biomarkers were studied in 17 healthy Large White sows from early gestation to the end of lactation. Saliva samples were obtained at 34 ± 3 days from insemination (G30), 24 ± 4 days before farrowing (G90), within the first 24 h after farrowing (L1) and at the end of a lactation period of 21 days (L21). The measurements in saliva included stress-related biomarkers (cortisol, chromogranin A, α-amylase, butyrylcholinesterase [BChE] and lipase [Lip]), inflammatory biomarkers (adenosine deaminase isoenzymes 1 [ADA1] and 2 [ADA2], and haptoglobin [Hp]) and oxidative stress biomarkers (cupric reducing antioxidant capacity, trolox equivalent antioxidant capacity, ferric reducing ability, uric acid, advanced oxidation protein products [AOPP] and hydrogen peroxide [H2O2]), as well as routine biochemistry analytes (aspartate aminotransferase [AST], alkaline phosphatase [ALP], γ-glutamine transferase [GGT], lactate dehydrogenase [LDH], creatine kinase [CK], urea, creatinine, triglycerides, lactate, calcium and phosphorus). The main changes were observed at farrowing, with increases in biomarkers of stress (cortisol and BChE), inflammation (ADA isoenzymes and Hp) and oxidative stress (AOPP and H2O2), as well as muscle and hepatic enzymes (CK, AST, ALP, GGT and LDH). Lactate and triglycerides increased at the end of gestation and remained at high concentrations until the end of lactation. Lip was higher in gestation than at lactation. Thus, changes in biomarkers of stress, immune function, oxidative stress, hepatic and muscle integrity, and energy mobilization occur in sow saliva during pregnancy, farrowing and lactation. These changes, caused by physiological conditions, should be taken into consideration when these biomarkers are used for the evaluation of sow health and welfare.

Changes in saliva biomarkers during a standardized increasing intensity field exercise test in endurance horses.

Salivary biomarkers could be useful to evaluate stress, fitness level, and skeletal muscle damage associated to exercise in horses in an easy and non-painful way. Therefore, this study aims to evaluate if cortisol in saliva (sCor), salivary alpha-amylase (sAMY) and butyrylcholinesterase (sBChE) and lactate (sLA) and creatine kinase (sCK) in saliva of horses can show changes during a standardized exercise test, and if they are related to heart rate variability (HRV) parameters related to sympathetic and parasympathetic tone, fitness level or skeletal muscle damage. For this purpose, ten endurance horses were submitted to a standardized exercise test in field conditions. Saliva and blood were obtained at basal time (TB), after the seven bouts of velocity (T + 01 to T + 07), and 5, 15, 30, and 45 min later (T + 5, T + 15, T + 30, and T + 45). Five endurance horses in resting condition (control group) were also enrolled. HRV and fitness level parameters, and plasma CK as a marker of muscle damage were also evaluated. Salivaryalpha-amylase increased at T + 30 (P = 0.03), sBChE at T + 5 (P = 008), and sCK at T + 07 (P = 0.009) after the exercise test, with significant differences between the exercise and control groups' results. The sCor did not show significant changes during the exercise test in the exercise group but higher concentration compared to the control horses (P < 0.001) were observed. sCor, sAMY, sBChE, and sCK showed a positive correlation (r values between 0.47 and 0.64) with the sympathetic tone and a negative correlation (r values between -0.37 and -0.56) with the parasympathetic tone. In conclusion, sAMY, sBChE, and sCK showed significant increases in ten endurance horses after an increasing intensity velocity exercise. Values of sCor, sAMY, sBChE, and sCK were associated with HRV, which is used to evaluate stress, and therefore, they could be potentially used to assess the exercise-related stress after a physical effort.

Nasal secretory protein changes following intravenous choline administration in calves with experimentally induced endotoxaemia.

Nasal secretory fluid proteomes (NSPs) can provide valuable information about the physiopathology and prognosis of respiratory tract diseases. This study aimed to determine changes in NSP by using proteomics in calves treated with lipopolysaccharide (LPS) or LPS + choline. Healthy calves (n = 10) were treated with LPS (2 µg/kg/iv). Five minutes after LPS injection, the calves received a second iv injection with saline (n = 5, LPS + saline group) or saline containing 1 mg/kg choline (n = 5, LPS + choline group). Nasal secretions were collected before (baseline), at 1 h and 24 h after the treatments and analysed using label-free liquid chromatography-tandem mass spectrometry (LCMS/MS). Differentially expressed proteins (>1.2-fold-change) were identified at the different time points in each group. A total of 52 proteins were up- and 46 were downregulated at 1 h and 24 h in the LPS + saline group. The upregulated proteins that showed the highest changes after LPS administration were small ubiquitin-related modifier-3 (SUMO3) and glutathione peroxidase-1 (GPX1), whereas the most downregulated protein was E3 ubiquitin-protein ligase (TRIM17). Treatment with choline reduced the number of upregulated (32 proteins) and downregulated proteins (33 proteins) in the NSPs induced by LPS. It can be concluded that the proteome composition of nasal fluid in calves changes after LPS, reflecting different pathways, such as the activation of the immunological response, oxidative stress, ubiquitin pathway, and SUMOylation. Choline treatment alters the NSP response to LPS.

Effect of reduction and alkylation treatment in three different assays used for the measurement of oxytocin in saliva of pigs.

Oxytocin is a hormone that is increasingly being used for welfare evaluation in animals. Although several types of samples have been used for oxytocin measurement, saliva can be a suitable option for pigs producing less stress than blood sampling. In this study, 3 different methods for oxytocin measurements, 2 based on alphaLISA technology (one with a monoclonal and other with a polyclonal antibody) and one commercially available kit, were compared in saliva of pigs. These methods were used in saliva samples obtained from female pigs at 3 different days during gestation and lactation, with and without a reduction/alkylation (R/A), which is a procedure for breaking the links between oxytocin and proteins of the sample. The assays showed a different behavior after the R/A procedure, with no significant changes in the oxytocin results in case of the alphaLISA monoclonal method, a significant decrease with the alphaLISA polyclonal method, and a significant increase with the commercial kit. Although all assays showed a similar tendency in detecting the changes in oxytocin during gestation and lactation, they showed changes of different magnitude and statistical signification. This report indicates that different assays can measure different forms of oxytocin present in saliva and can have a different behavior after R/A of the sample and when are used to measure oxytocin in gestation and lactation.

Measurement of cortisol, cortisone and 11ß-hydroxysteroid dehydrogenase type 2 activity in hair of sows during different phases of the reproductive cycle.

Two sensitive assays based on AlphaLISA technology were developed and validated for the measurement of cortisol and cortisone in hair of pigs, that also enabled estimation of 11ß-hydroxysteroid dehydrogenase type 2 activity. These assays were applied to hair samples from sows (n = 32) collected at 5 days before, and at 23 and 59 after farrowing, in reproductive cycles in two different periods: spring-summer (n = 16) and winter-spring (n = 16). The assays were precise (imprecision <12%) and accurate (recovery range, 80-115%) for cortisol and cortisone determination. Hair cortisone concentrations and the cortisone/cortisol ratio (an estimate of 11ß-hydroxysteroid dehydrogenase isoenzyme type 2 activity) increased after farrowing more than cortisol, being these changes of higher magnitude during periods of higher atmospheric temperature. The measurement of hair cortisone concentrations and estimations of the activity of the 11ß-hydroxysteroid dehydrogenase isoenzyme type 2, measured by the assays developed in this study, are complementary biomarkers to hair cortisol, and can increase at periods associated with stress, such as farrowing and lactation, especially at high atmospheric temperatures. .