Immunologic Profiles of Peripheral Blood Leukocytes and Serum Immunoglobulin G Concentrations in Perinatal Mares and Neonatal Foals (Heavy Draft Horse)

Neonatal and maternal upregulation of antileukoproteinase in horses

Introduction

The end of gestation, ensuing parturition, and the neonatal period represent highly dynamic phases for immunological changes in both mother and offspring. The regulation of innate immune cells at the maternal-fetal interface during late term pregnancy, after birth, and during microbial colonization of the neonatal gut and other mucosal surfaces, is crucial for controlling inflammation and maintaining homeostasis. Innate immune cells and mucosal epithelial cells express antileukoproteinase (SLPI), which has anti-inflammatory and anti-protease activity that can regulate cellular activation.

Methods

Here, we developed and validated new monoclonal antibodies (mAbs) to characterize SLPI for the first time in horses. Peripheral blood and mucosal samples were collected from healthy adults horses and a cohort of mares and their foals directly following parturition to assess this crucial stage.

Results

First, we defined the cell types producing SLPI in peripheral blood by flow cytometry, highlighting the neutrophils and a subset of the CD14+ monocytes as SLPI secreting immune cells. A fluorescent bead-based assay was developed with the new SLPI mAbs and used to establish baseline concentrations for secreted SLPI in serum and secretion samples from mucosal surfaces, including saliva, nasal secretion, colostrum, and milk. This demonstrated constitutive secretion of SLPI in a variety of equine tissues, including high colostrum concentrations. Using immunofluorescence, we identified production of SLPI in mucosal tissue. Finally, longitudinal sampling of clinically healthy mares and foals allowed monitoring of serum SLPI concentrations. In neonates and postpartum mares, SLPI peaked on the day of parturition, with mares returning to the adult normal within a week and foals maintaining significantly higher SLPI secretion until three months of age.

Conclusion

This demonstrated a physiological systemic change in SLPI in both mares and their foals, particularly at the time around birth, likely contributing to the regulation of innate immune responses during this critical period.

Circulating endocrine, metabolic, and haematologic indices during the peripartum period of Darehshori mares

The characteristics associated with equine peripartum period are different from those of other periods. Information concerning the values and dynamic changes of circulating peripartum endocrine, metabolic, and haematologic indices may improve the understanding of the whole body haemostatic patterns which lead to parturition, lactogenesis, and estrus in the horse. The present study aimed to evaluate these changes around parturition in Darehshori breed. For this purpose, blood sampling was performed on six clinically healthy Darehshori mares (10 years old) about one week prior to parturition, three days following parturition, at the beginning of estrus, and one week after estrus. Circula­ting values ​​of glucose, estrogen, progesterone, cortisol, T3, T4, TG, cholesterol, HDL, LDL, VLDL, RBC, HGB, HCT, MCV, MCH, MCHC, WBC, neutrophil, lymphocyte, and PLT were assessed in all samples. Progesterone concentrations were minimum before parturition and increased significantly one week after foaling heat (P=0.035). Cortisol level was significantly higher during foaling heat compared with other periods (P=0.029). T4 levels significantly increased from pre- to post-partum periods (P=0.001), but T3 showed increased and decreased values during the study period. All serum lipid profile parameters were significantly reduced from pre to postpartum period (P<0.05). Haematological parameters in mares significantly changed during the peripartum period (P<0.05). Based on the results, the metabolic, haematological, endocrinological, and stress indices in Darehshori mares were found to change around parturition and the first estrus. These changes were largely dependent on hormonal mechanisms related to pregnancy and parturition occurring in normal mares.

Serum Chemistry and Hematology Changes in Neonatal Stock-Type Foals During the First 72 Hours of Life

Limited research has characterized blood chemistry in healthy stock-type foals. Our objectives were to determine foal serum chemistry and hematology changes during the first 72 hours postnatal and compare these with adult horse reference ranges. Over 3 foaling seasons, serum chemistry and hematology were determined for 16 healthy stock-type foals born to similarly managed mares. Blood was collected at 0 hours (before nursing but after standing, within 85 minutes of birth) and 6, 12, 24, 48, and 72 hours after initial sampling. Data were analyzed with sampling hour, year, and their interaction as fixed effects. Serum glucose and triglyceride concentrations increased (P < .001) from 0 to 24 hours. Triglycerides increased (P < .001) and glucose decreased (P = .01) between 24 to 48 hours. Serum nonesterified fatty acids increased (P = .04) from 0 to 6 hours and decreased (P ≤ .01) from 6 to 24 hours. Serum urea nitrogen increased (P < .001) between 0 and 6 hours and decreased (P < .001) from 12 to 72 hours. Serum total protein and globulin concentrations increased (P < .001) from 0 to 12 hours, albumin decreased (P ≤ .01) from 0 to 24, and creatinine decreased (P ≤ .02) from 0 to 72 hours. Hour also affected (P ≤ .03) electrolytes, metabolic enzymes, and all hematological components except for mean corpuscular hemoglobin (P = .77). These data demonstrate dynamic blood biochemical and hematological changes throughout the first 72 hours in foals, suggesting that sampling time should be considered when evaluating individual neonates.

Hematological and biochemical profiles of Mangalarga Marchador mares in the transition period bred on pasture

ABSTRACT The present study aimed to evaluate the effects of the transition period on hematological and biochemical constituents in Mangalarga Marchador mares. Forty-eight mares were used to form a maintenance group (MG) and transition group (TG), formed by pregnant mares and, after delivery, infants. Blood samples were collected at the following times: T-60 (60 d pre-delivery), T-30 (30 d pre-delivery), T-15 (15 d pre-delivery), T0 (first 6h post-delivery), T15 (15 d post-delivery), T30 (30 d post-delivery), and T60 (60 d post-delivery). The TG had lower values (P< 0.05) of red blood cells, hematocrit and hemoglobin at T0, T15, T30 and T60 times than MG. The mean corpuscular volume was lower in MG (P< 0.05) than in TG (T0, T15, T30 and T60) and mean corpuscular hemoglobin concentration was higher (P< 0.05) in MG than in TG (T15, T30 and T60). On the other hand, the diameter distribution of red blood cells presented a lower value (P< 0.05) in MG than in TG (T15 and T30). Mares in transition period presented regenerative anemia. The results demonstrate physiological metabolic variations of different intensities during pregnancy, delivery and early lactation.

Haematological profile in foals during the first year of life

Foals' haematological values change constantly during their first year of life. The use of updated age-based reference intervals (RIs) is imperative for providing accurate diagnosis and optimum care for sick foals. The authors' objective was to provide updated RIs for 13 haematological values in 2, 7, 14, 30, 90, 180 and 365-day-old foals and to investigate the changes over time in each measured value. Venous blood was collected at those ages from clinically healthy foals. Thirteen haematological values were analysed. The 95% RIs were reported using a bootstrapping method. Differences over time were examined using Friedman test. RIs for each of the measured values were calculated. Results showed noticeable trends in changes over time in several values. Nevertheless, white blood cell counts significantly increased between day 2 and day 90 (P=0.011) while lymphocyte counts increased from day 2 up to day 180 (P=0.033). The mean corpuscular haemoglobin and mean corpuscular volume (P=0.011) significantly decreased between day 2 and day 90. Normal haematological values in foals not only differ from those in adult horses but also change throughout the first year of life; thus, it is critical that clinicians use age-based RIs when treating sick foals.

Comparison of the reliability of snap foal Ig test, Gamma-Check E test, refractometry and electrophoresis for determining the immune status of newborn foals in the first hours of life

Twenty-eight warmblood mares were monitored during their late pregnancy in the Teaching Hospital of Ghent University. The reliability of two commercial assays (enzyme immunoassay and glutaraldehyde coagulation test) used for determining the IgG concentrations of their newborn foals was tested. Mammary secretions were examined at the time of foaling (T₀), and then 4 (T₁) and 8 (T₂) hours after foaling by refractometry and electrophoresis. The foals' blood IgG levels were measured at T₁ and T₂ as a routine clinical diagnostic examination using two different commercial test kits (SNAP Foal Ig and Gamma-Check E) and T₀, T₁ and T₂ samples were stored (at -18 °C) for immunoglobulin (Ig) determination by electrophoresis. Differences between the results of refractometry and electrophoresis occurred in 27.8% of the colostrum analyses. Some serum IgG could be detected immediately post partum (T₀) in 75% of the foals, and 42.82% of the newborn foals acquired a serum concentration of more than 800 mg/dl IgG within 8 h of birth. Compared to the electrophoresis, the glutaraldehyde test scored better (85%) than the enzyme immunoassay (74%), although both are accurate and safe to use since they clearly distinguish between safe and unsafe IgG concentrations.

Leukocyte modifications during the first month after foaling in mares and their newborn foals

During early post-partum period both neonatal foals and peripartum mares are most susceptible to diseases. The aim of this study was to establish physiologic modifications of leukogram during the first month after foaling in mares and their newborn foals. To this end blood samples were collected from nine mares and nine foals (T0-T10), every three days from the 1st day until the 30th day after foaling. Samples were analysed for white blood cell (WBC) count and differential leucocyte counts. Two-way repeated measure analysis of variance (ANOVA) showed, in postpartum mares WBC showed significant higher values at T0 (9.02±0.76) in respect to other time points, and at T2 (8.08±0.53) and T3 (7.92±0.59) compared to T1 (6.98±0.43), whereas in foals lower WBC values at T0 (6.11±0.49) compared to other experimental periods except T1 (6.90±0.94), and at T1 compared to T8 (7.95±0.61) and T10 (7.90±0.36) were observed. The differential leucocyte counts showed significant modifications in the percentage of neutrophils (π<0.001) and lymphocytes (p<0.001) both in postpartum mares and in foals during the experimental period. Furthermore ANOVA showed significant differences between postpartum mares and foals (P<0.01) in all studied parameters, and between postpartum mares and control mares in WBC and neutrophils values. The obtained results provide suitable information about the influence of foaling on leukogram of periparturient mares and reveal WBC dynamics in newborn foals during the first month post-partum.

Physiological adjustments of haematological profile during the last trimester of pregnancy and the early post partum period in mares

The aim of the study was to assess changes in some haematological parameters of periparturient mares from the last three months of pregnancy until the third week after foaling. The study was carried out on 15 healthy pregnant mares (Group A) and 7 healthy non-pregnant non-lactating mares (Group B). Blood samples were collected by jugular venipuncture into EDTA tubes and tested for Haematocrit (Hct), Red Blood Cell (RBC), Haemoglobin (Hb), Platelets (Plt) and White Blood Cell (WBC). Peripheral blood smears were also performed to assess changes in the leucocyte differential count. Group A showed a progressive reduction in Hct and Hb levels over the experimental period, whereas Plt and WBC (P<0.05) peaked at parturition. Among WBC, neutrophils increased until parturition when lymphocytes reached the lowest values. The statistical analysis also revealed significant interactions time × pregnancy on Hb (P<0.001), WBC (P<0.001), neutrophils (P<0.001) and lymphocytes (P<0.001). Analysing the last trimester of pregnancy and the first post partum period the present study provides suitable information about the influence of peripartum on mares' haematological parameters.

Hemostatic profile during late pregnancy and early postpartum period in mares

Hemostasis is a physiological process that prevents excessive blood loss and represents a protective mechanism at the time of delivery. Peripartum hemorrhage is a recurring hazardous condition to mare's health; therefore, we aimed to study mares' hemostatic profile to investigate whether physiological adjustments occur during late pregnancy and early postpartum. Fifteen pregnant mares have been monitored from the 34th week of pregnancy until the third week after foaling. Fifteen nonpregnant mares were used as control group. Jugular blood samples were analyzed for platelet count (Plt), prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen (Fb). Platelet count showed significant changes at foaling (P < 0.05) and a negative correlation (r = -0.968; P = 0.032) with postpartum. Prothrombin time changed (P < 0.05) showing a significant correlation (r = 0.675; P = 0.016) with late pregnancy. Fibrinogen concentrations changed throughout the experimental period (P < 0.0001). The linear regression model revealed a positive correlation (r = 0.9210; P < 0.0001) between Fb and late pregnancy and a negative correlation (r = -0.9583; P = 0.042) between Fb and early postpartum. The shortening in PT recorded in the imminence of parturition along with the increase in Plt and Fb at foaling might reflect a physiological hypercoagulable state that constrains excessive bleeding, enhancing mares' odds of surviving. Our research improves the knowledge about blood coagulation in periparturient mares providing specific information on routine coagulation tests that may support in monitoring mare's hemostatic profile during late pregnancy and early postpartum.