Evaluation of Brix Refractometry for the Estimation of Colostrum Quality in Jennies

Immunity transfer in mule foals fed with good IgG quality colostrum

While the passive transfer of immunity in horse and donkey foals has been extensively studied, there is limited information for mule foals. Immunoglobulin type G (IgG) and serum total protein concentration (TP) were assessed at different sampling times to evaluate the correlation between serum radial immunodiffusion (SRID) with electrophoresis, refractometry, and dry chemistry analyzer (Biuret), and to estimate serum IgG concentrations using serum TP in mule foals. We analyzed a total of 30 samples collected at birth, and at 6, 12, 24, and 48 h of life from 6 mule foals by SRID, electrophoresis TP, biuret TP, and refractometry TP. The SRID IgG concentration significantly increased from birth until T6 (p < 0.001). Serum TP analyzed with refractometry revealed differences between T0 and T12, T24 and T48 (p < 0.05), while a significant difference was observed with the biuret method between T0 and all the other sampling times (p < 0.001). A strong correlation was found between IgG SRID and biuret TP (r = 0.69, p < 0.001), and a good correlation existed between IgG SRID, refractometry TP, and electrophoresis TP (r = 0.44, p < 0.01 and r = 0.39, p < 0.05, respectively). All methods can be used to estimate the passive transfer of immunity in mule foals. TP refractometry and biuret TP values can be used to determine serum IgG concentrations in the blood of mule foals on their first day of life through the application of a specific equation.

Characterization of lyophilized equine colostrum

Foals require maternal colostrum in the first hours of life to prevent failure of transfer of passive immunity (FTIP). Innovative storage methods such as lyophilization may enable conservation of colostrum immunoglobulins by a differentiated process of dehydration. The current study aimed to compare the quality of equine colostrum after freezing and after the lyophilization process. Thirty-one pregnant Quarter Horse mares were used. The IgG concentration of frozen and lyophilized colostrum was determined by simple radial immunodiffusion (SRID) and Brix refractometry. The physical-chemical composition (pH, total protein (TP), fat, lactose, salts, total solids (TS), and density) of the samples was evaluated and the lyophilized colostrum reconstitution test was performed. There were no significant differences (P > 0.05) in the variables IgG, fat, lactose, salts, TS, density, and pH between samples measured before and after lyophilization. There was a significant difference (P < 0.05) between the Brix average and the TP of the frozen and lyophilized colostrum samples. Lyophilization resulted in a small reduction (6.55%) in the IgG concentration measured by SRID. A strong positive correlation was observed between colostrum density and IgG concentration by SRID (r = 0.76) and between Brix and IgG concentration by SRID (r = 0.77). In the reconstitution test, the lyophilized colostrum was easily rehydrated in water, with full dilution, and remained stable. Lyophilization could be an alternative for the conservation of mare colostrum, since it is a very efficient process for retaining the physicochemical characteristics of the product, with minimal loss, particularly of IgG.

Apgar Score, Clinical, Hemato-Biochemical, and Venous Blood Gas Parameters in a Cohort of Newborn Mule Foals: Preliminary Data

The study aimed to assess Apgar scores and collect data on clinical, hemato-biochemical, and venous blood gas parameters in seven mules during their first 48 hours of life. Apgar scores, heart rate (HR), respiratory rate (RR), body temperature (BT), body weight (BW), time to achieve sternal recumbency, stand, nurse, and pass meconium were recorded. Blood samples were collected at birth (T0), 6 (T6), 12 (T12), 24 (T24), 48 (T48) hours of life. Data distribution was verified and differences in laboratory parameters over time assessed. One foal had an Apgar score of 6/8, thus excluded from the statistical analysis. Three foals had an Apgar score of 7/8, three had a score of 8/8. All foals showed suckling reflex within 20 minutes and raised the head within 1 minute; six foals reached sternal recumbency within 2 minutes. Times to stand and nurse were 38.7 ± 13.4 and 72.3 ± 30.5 minutes, respectively. Five foals passed meconium spontaneously in 416.3 ± 401.8 minutes. The mean HR, RR, and BT values were 92 ± 16.1 bpm, 50.2 ± 5.9 bpm, and 37.6 ± 0.3°C, respectively. Creatinine and lactate decreased from birth to 48 hours. Blood glucose increased from 12 hours. Mg increased from 12 to 24 hours. Compared to horses and donkeys, mules showed an intermediate BW, shorter time to stand and nurse, longer time to pass meconium, intermediate HR and lower RR. Compared to donkey mules showed lower BT. Other dissimilarities from the parental species were found in laboratory parameters. Our findings emphasize the need for reference ranges for a comprehensive evaluation of newborn mules.

Changes in serum total protein and immunoglobulin G concentrations and Brix percentages in neonatal Arabian foals from birth up to 21 days of age

The aim of this study was to evaluate changes in the serum immunoglobulin G (IgG) and serum total protein (STP) concentrations and serum Brix percentages of neonatal Arabian foals during first 3 weeks of life. Blood samples were collected from 12 apparently healthy foals by jugular venipuncture at birth and at 12-hours, 24-hours, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15 and 21 days of age. Serum IgG and STP concentrations and Brix percentages were measured by the radial immunodiffusion assay, and digital STP and Brix refractometers, respectively. Based on the serum IgG concentrations measured at 24 h, two foals were diagnosed with failure of transfer of passive immunity (FTPI). While IgG concentrations were determined using the data of foals with adequate transfer of passive immunity, other calculations were made using the data of all foals. The mean IgG concentration of the foals increased from birth (<200 mg/dl) to 12 (2068.5 mg/dl) and 24 h (2184.7 mg/dl), and progressively decreased up to 21 days of age (1318.5 mg/dl). The serum IgG concentrations at 12 h were highly correlated with each of the IgG concentrations measured over the 21-day period. The serum IgG and STP concentrations and Brix percentages of the foals diagnosed with FTPI at 12 h did not reach the adequate strata over time. These results suggest that foals can be reliably tested for passive immunity status at 12 h after birth.

Evaluation of refractometry methods for estimating passive immunity status in neonatal foals

The objective of this cross-sectional study was to determine the accuracy of the digital Brix and serum total protein (TP) refractometers for estimating different passive immunity status in neonatal foals. In total, 18- to 40-h old purebred Arabian foals (n = 185) were used. Serum TP concentrations, total solid percentages and IgG concentrations were measured with a digital serum TP refractometer, digital Brix refractometer and the gold standard radial immunodiffusion (RID) assay, respectively. Correlation coefficients were calculated between the refractometer and RID assay results. A receiver operating characteristic analysis was used to select the optimal cut-offs for both refractometers. Test performance and agreement were evaluated using diagnostic test characteristics at optimal thresholds and areas under the ROC curve, and by calculating Cohen's kappa coefficient. The sensitivity and specificity of the digital Brix refractometer at optimal cut-offs (≤7.8%, ≤7.9%, ≤8.2%, ≤8.3%, ≤9.0%) were 100 and 69.3%; 100% and 68.5%; 70.5% and 71.0%; 88.3% and 85.5%; 88.1% and 76% to estimate RID-IgG of <400 mg/dL, <800 mg/dL, <1500 mg/dL, <2500 mg/dL and < 3000 mg/dL, respectively. The sensitivity and specificity of the digital serum TP refractometer at optimal cut-off (≤4.6 g/dL, ≤4.6 g/dL, ≤4.8 g/dL, ≤5.0 g/dL, ≤5.4 g/dL) were 100 and 69.3%; 100% and 72.8%; 90% and 72.8%; 72.9% and 83.9%; 84.4% and 88% to estimate RID-IgG of <400 mg/dL, <800 mg/dL, <1500 mg/dL, <2500 mg/dL and < 3000 mg/dL, respectively. In conclusion, the refractometers showed a good potential as screening tools for the estimation of different IgG concentrations in neonatal foals.

Ultrasonography Evaluation of Umbilical Structures in Clinically Healthy Donkey Foals during the First Week of Life

The umbilicus is a potential access-point for pathogens in equine foal, causing umbilical infections and potentially life-threating illness. Early diagnosis based on ultrasonographic appearance and measurement is crucial to avoid severe complications and promptly implement appropriate therapy. This study ultrasonographically evaluates the umbilical remnants of donkey foals, in the first week of life. Fifteen healthy donkey foals were included in the study. The umbilical vein, arteries and urachus ultrasounds were performed at 24 h, 3 and 7 days of life, using a portable ultrasound machine and a 5-7.5 MHz multifrequency linear probe. The Kruskal-Wallis test and Dunn's multiple comparisons test were applied to verify differences in relation to time for all the umbilical remnants measured. Statistical significance was set at p < 0.05. No statistical differences were observed in relation to time regarding umbilical remnant measurements. A correlation was found between body weight and the left artery at T0. The regression of the umbilical remnant during the first week of life was slower compared with what was reported in equine foals but was comparable with the results on calves. Thus, the different regression timing needs be considered when evaluating donkey foals with umbilical remnant diseases within the first week of life.

Evaluation of Different Methods to Estimate the Transfer of Immunity in Donkey Foals Fed with Colostrum of Good IgG Quality: A Preliminary Study

Simple Summary

Little is known about the passive transfer of immunity in donkey foals and about the different types of analysis that can be performed to assess it. The aims of the present study were to evaluate the correlation between IgG Serum Radial Immunodiffusion, Electrophoresis Gamma Globulins, Electrophoresis Total Protein and the Serum Total Protein analyzed by Refractometry and by Dry Chemistry Analyzer (Biuret) and to estimate serum IgG concentrations using Serum TP. IgG Serum Radial Immunodiffusion showed a good correlation with Electrophoresis Gamma Globulins and a high correlation with Total Protein Electrophoresis, Biuret and Refractometry. All the tests performed may be a useful to estimate the serum IgG in donkey foals’ blood in the first day of life using a specific equation.

Abstract

The aims of the present study were to evaluate the correlation between IgG Serum Radial Immunodiffusion (SRID), Electrophoresis Gamma Globulins (EGG), Electrophoresis Total Protein (ETP) and the serum total protein (TP) analyzed by refractometry and by a dry chemistry analyzer (Biuret) and to estimate serum IgG concentrations using serum TP. A total of 36 samples collected at four different times (birth, 6, 12, 24 h after birth) from nine Amiata donkey foals were evaluated with SRID, EGG, ETP, serum TP Biuret and refractometry. SRID IgG concentration increased significantly over time until T12. Serum TP analyzed with refractometry, electrophoresis and Biuret showed a statistically significant difference between T0 and T6 vs. T12 and T24. A good or strong correlation was found between different tests performed. Equations to quantify serum IgG were created and can be used for estimating the donkey foals’ serum IgG in the first day of life. Serum TP refractometry showed a high correlation with SRID IgG (0.91) which may be a particularly useful and economic instrument to estimate the transfer of immunity in donkey foals during the first day of life. Further studies evaluating a high number of animals are needed in order to set specific cut-off values.