Causes of equine perinatal mortality

Evaluating smartphone-based optical readouts for immunoassays in human and veterinary healthcare: A comparative study

Recent advances have significantly enhanced the use of smartphone devices for medical diagnostics. This study uses high-resolution cameras in mobile devices to capture and process bioassay images, enabling the quantification of diverse biomarkers across a range of diagnostic tests conducted on 96-well microplates. The study evaluates the effectiveness of this technology through protein quantification techniques and immunoassays that generate colorimetric responses at specific wavelengths. It includes the assessment of bicinchoninic acid and Bradford protein quantification methods, alongside a conventional immunoassay for detecting mare antibodies in colostrum to monitor foal immunodeficiencies. Further application involves the readout of magneto-actuated immunoassays aimed at quantifying bacteria. The results obtained from benchtop spectrophotometry at 595, 562, and 450 nm are compared with those acquired using a smartphone, which identified color intensities in shades of blue, purple, and yellow. This comparison yields promising correlations for the samples tested, suggesting a high degree of accuracy in the smartphone capability to analyze bioassay outcomes. The analysis via smartphone is facilitated by a specific app, which processes the images captured by the phone camera to quantify color intensities corresponding to different biomarker concentrations. Detection limits of 12.3 and 22.8 μg mL-1 for the bicinchoninic acid assay and 36.7 and 45.4 μg mL-1 for the Bradford are obtained for protein quantification using the spectrophotometer and the smartphone app, respectively. For mare's antibodies in colostrum, the values are 1.14 and 1.72 ng mL-1, while the detection of E. coli is performed at 2.0 x 104 and 2.9 × 104 CFU mL-1, respectively. This approach offers further advantages, including wide availability, cost-effectiveness, portability, compared to traditional and expensive benchtop instruments.

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.

Equine Placentitis in Mares Induces the Secretion of Pro-Inflammatory Cytokine eIL-1β and the Active Extracellular Matrix Metalloproteinase (MMP)-9

Equine placentitis is characterized by infection and inflammation of the placenta. Different biomarkers associated with this inflammatory response have been evaluated in experimentally induced equine placentitis, but not in pregnant mares with spontaneous placentitis. The aim of the current study was to determine the concentration of eIL-1β and the activity of proMMP-2 and proMMP-9 in the serum of healthy mares and mares with placentitis on days 240 and 320 of gestation to explore whether these biomarkers are associated with equine maternal placentitis and/or with the birth of an infected or inviable foals. Serum samples were collected from sixteen pregnant English Thoroughbred mares, retrospectively classified as follows: (1) healthy mares with full-term gestation; and (2) mares with ultrasonographic signs of placentitis. The health of each foal was examined at birth, and it was decided to classify the cases into four groups: (1) healthy mares delivering a healthy foals (HM-HF, n = 6); (2) mares with USP delivering a healthy foal (USP-HF, n = 3); (3) mares with USP delivering a live septic foal (USP-LSeF, n = 4); and (4) mares with USP delivering a dead foal (USP-DF, n = 3). eIL-1β was quantified by ELISA, and proMMP-2 and proMMP-9 activity by gelatin zymography electrophoresis. In healthy mares, the serum concentrations of eIL-1β underwent a significant 16.5-fold increase from day 240 to day 320 of gestation. Although similar results were found in the mares with ultrasonographic signs of placentitis that delivered a healthy foal, those delivering a live septic or nonviable foal exhibited much higher concentrations of eIL-1β. proMMP-2 and proMMP-9 activity was not associated with maternal placentitis, foal infection, or death. Hence, the presence of placentitis severe enough to affect the health of the foal can be confirmed or discarded by determining the eIL-1β concentration in mares that have shown ultrasonographic signs of placentitis.

Equine abortion and stillbirth in California: a review of 1,774 cases received at a diagnostic laboratory, 1990-2022

Reproductive failure represents an important cause of economic loss for the equine industry. We reviewed the cases of equine abortion and stillbirth submitted to the California Animal Health and Food Safety Laboratory System, University of California-Davis from 1990 to 2022. A total of 1,774 cases were reviewed. A confirmed cause of abortion was determined in 29.2% of the cases. Abortion or stillbirth was attributed to infectious agents in 18.7% of the cases, with Streptococcus spp., equine herpesvirus 1, and Leptospira spp. being the most prevalent. Noninfectious causes of abortion were established in 10.5% of the cases, with umbilical cord torsion being the most common. In 70.8% of the cases, a definitive cause of abortion could not be established. Our study demonstrated the difficulties in establishing an etiologic diagnosis, even when following a standard diagnostic work-up. New diagnostic approaches are needed to improve the likelihood of reaching a final diagnosis in cases of equine abortion and stillbirth.

Pregnancy and parturition in dromedary camels III. Incidence, timing and factors affecting abortions and perinatal mortality under intensive management

In this study, the incidence, timing and risk factors associated with abortion and perinatal mortality (PM) were described in dromedary camels under intensive management. In addition, overall pregnancy losses were also summarized and weekly risk of pregnancy wastage was determined throughout gestation. Data were collected over 11 breeding seasons from September 2006 through June 2017 at the world's largest camel dairy farm. A total of 229 abortions were observed (5.05%) out of 4533 pregnancies after 60 days (d) of gestation. Most abortions were singleton (n = 199, 86.9%), but twin abortions were also recorded in 30 cases (13.1%). Abortions showed a pronounced seasonal distribution, with a peak in August. The age category (P < 0.01), breed or ecotype of the female (P < 0.05) and bull influenced the occurrence of singleton abortions. Dromedaries with twins tended to abort earlier than those with a singleton fetus (median = 232.5 d vs. 257 d, P = 0.053). Perinatal mortality was observed in 174 cases (3.84%) out of 4533 pregnancies after 60 d of gestation. The condition included the premature birth of non-viable calves after shorter than normal gestation (330-350 d, n = 26, 14.9%), the birth of well-developed but dead calves after normal gestation length (n = 120, 69.0%) and neonates that died within 48 h after delivery (n = 28, 16.1%). The frequency distribution of PM was parallel with that of parturitions. The most important predisposing factor for PM was difficult calving. Thirty-nine percent (68 out of 174) of these losses were associated with dystocia. In addition, age category (P < 0.05) and parity of the female (P < 0.01), month of delivery (P < 0.05) and breeding season (P < 0.05) also affected the incidence of PM. The cause of 60 cases of PM (1.4% of all deliveries) could not be determined and was considered idiopathic. In conclusion, one-third of total pregnancy losses occurred during mid to late gestation. Approximately 10% of pregnancies after Day 60 failed, and 90% resulted in the birth of a live calf that survived beyond 48 h. More than half of these pregnancy losses were abortions before 330 d of gestation, and approximately 40% were classified as PM. The weekly mean risk of pregnancy loss after 100 d of gestation remained only a fraction of that observed during the first 2-3 months.

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.

Evaluation of Optical Refractometer for Assessing Failure of Transfer of Passive Immunity in Foals

The aim of the present study is to evaluate the correlation between the total protein measured by an optical refractometer and the concentration of IgG by radial immunodiffusion (RID) to determine the performance of the optical refractometer to diagnose the failure of passive transfer of immunity (FPTI) in 12-hour-old foals. Blood was collected from foals (n = 30) 12 hours after birth. A study was carried out to measure the serum IgG concentration by RID test and measure total protein (TP) by optical refractometer. The correlation coefficient was measured between the TP concentration and the IgG-RID. Correlation was made between the IgG-IDR levels of colostrum in mares and the IgG-IDR concentration of the plasma of the foals. A ROC curve was made to identify the ideal cutoff point, in addition to the tests for sensitivity and specificity. The area under the curve (AUC) was calculated. The IgG concentration by RID was positively correlated with a refractometer. Colostrum IgG concentration by RID was moderately correlated with foal plasma IgG-RID concentration. In the ROC curve, AUC was 0.931, and the cutoff point found was ≤5,7 g/dL as the most optimal combination, with 100% sensitivity and 73.3% specificity. Thus, it can be concluded that the total protein concentration by refractometer shows effective utility in the evaluation of FPTI in foals since they are highly sensitive, associated with a low cost, easy to handle, and easily carried out in the field.