Newborn Foals Research Articles

108 Early colostrum uptake by the newborn requires prepartum initiation of lactogenesis in ungulate species - Sponsored by EAAP

Abstract Due to anatomical characteristics of ungulate placenta types, immunoglobulins (IG) cannot be transferred via the placenta from the maternal to the fetal circulation during pregnancy. Therefore, passive immunization of the newborn ungulate immediately after birth is crucial for its survival. Colostrum, the first milk produced contains immunoglobulins (IG) as well as greater concentrations of several nutrients and bioactive components to provide specific immunity for the first weeks of life as well as an activation of the digestive tract and metabolism through colostral hormones, growth factors, vitamins, and special nutrients such as oligosaccharides. The uptake of colostrum by newborn calves, piglets, or foals within the first few hours after birth requires the availability of colostrum in a sufficiently liquid form. The formation of pre-colostrum starts days or even weeks before parturition, which allows concentrations of IG and other factors far beyond the concentrations in maternal blood circulation. Pre-colostrum components are partially secreted into the alveolar lumen and partially stored in the lactocytes of the mammary gland. These secretions are characterized by increased viscosity and density, which are difficult to harvest by the newborn. Through lactogenesis the secretion of milk components such as lactose is initiated, which causes a considerable water influx into the mammary secretion through an osmotic gradient between maternal blood and mammary secretion. The typical high concentrations of gestagens, mostly progesterone, inhibit the initiation of lactogenesis during pregnancy. A declining gestagen activity is the key signal to initiate a lactogenic prolactin increase and hence milk secretion. Mechanisms and timing of gestagen withdrawal differ considerably among mammalian species. Most species initiate both parturition and lactation through luteolysis (cattle, goat, pig, cat, dog, rabbit, mouse rat). In some species the placenta takes over the main portion of gestagen production (human, sheep, horse). In human, IG are transferred to the fetus during pregnancy, and the start of colostrum secretion only several days after parturition is no problem. In sheep and horses, gestagen secretion during late pregnancy is provided by the placenta. Both of these species are ungulates, and a delayed start of lactogenesis would be critical for the survival of the newborn. Therefore, the placental steroid secretion is subject to characteristic changes in both species towards the end of pregnancy to allow a timely availability of colostrum immediately after birth. At the end of pregnancy, the placenta of sheep produces estrogens at the expense of progesterone, and in horses the less potent dihydroprogesterone is produced instead of progesterone. A considerable variation in the resulting colostrum composition is likely due to the existing wide range of the interval between the commencement of lactogenesis and parturition or due to local regulatory effects at the level of individual glands.

Effects of maternal dietary supplementation with antioxidants on clinical status of mares and their foal

BackgroundThe peripartum period constitutes a delicate physiological moment in mares showing a transient state of oxidative stress. Diet supplementation with antioxidants during pregnancy in women appears to have a beneficial effect on mother and neonate health. The aim of this work was to evaluate the effects of diet supplementation with a commercial product containing a mix of antioxidants (Oxyliver®, Candioli) on the length of gestation, weight, and haemato-biochemical parameters in Italian Salernitano mares and their newborn foals. Eight late-term pregnant mares were randomly divided into two groups: Antiox group receiving 30 g/day of antioxidants, and Car group receiving the same amount of carrot powder, from 290 to 320 days of gestation. The following parameters were evaluated in mares: weight, colostrum composition, haemato-biochemical parameters, progesterone, and cortisol blood concentrations, along with blood oxidant/antioxidant status. Assessments were conducted at specific time points: immediately before the start of diet supplementation (T0), 15 days after (T1), at the end of diet supplementation (T2), within 8 h after parturition (T3), and 10 days post-partum (T4). Foal parameters such as weight, haemato-biochemical values, cortisol concentration, and blood oxidative stress variables were assessed within 8 h of birth (TF0) and at 10 days of age (TF1).ResultsPregnancy was shorter in the Antiox group (P < 0.05) compared with the Car group; the foals’ weight increase of group Antiox (40%) was higher (P < 0.05) compared to those of the Car group (28.6%). The colostrum of the Antiox group exhibited higher levels of Brix, total solids, protein, nonfat solids, casein, urea, density, free fatty acids, and glucose, while lower levels of fat and lactose were observed compared to the Car group (P < 0.05). Mares’ serum albumin at T1 and T3, creatinine, glucose, total proteins, total bilirubin, AST, and ALT at T3 were lower in Antiox than in the Car group. No significant differences were found in foals.ConclusionsWhile the limited sample size and the potential variability of evaluated parameters, the observed outcomes suggest that Oxyliver® supplementation in mares might safely decrease gestation length and enhance liver function, thus potentially improving colostrum quality and offspring development.

Endothelial glycocalyx degradation in critically ill foals.

Endothelial glycocalyx (EG) degradation occurs in septic humans and EG products can be used as biomarkers of endothelial injury. Information about EG biomarkers and their association with disease severity is lacking in hospitalized foals. Measure serum syndecan-1 (SDC-1), heparan sulfate (HS), angiopoietin-2 (ANG-2), aldosterone (ALD), and plasma atrial natriuretic peptide (ANP) concentrations and to determine their association with disease severity and death in hospitalized foals. Ninety foals ≤3 days old. Prospective, multicenter, longitudinal study. Foals were categorized into hospitalized (n = 74; 55 septic; 19 sick nonseptic) and 16 healthy foals. Serum ([SDC-1], [HS], [ANG-2], [ALD]) and plasma (ANP) were measured over 72 hours using immunoassays. Serum ([SDC-1], [HS], [ANG-2], [ALD]) and plasma (ANP) were significantly higher in hospitalized and septic than healthy foals (P < .05). Serum (ANG-2) and plasma (ANP) were significantly higher in hospitalized nonsurvivors than in survivors (P < .05). On admission, hospitalized foals with serum (HS) > 58.7 ng/mL had higher odds of nonsurvival (odds ratio [OR] = 6.1; 95% confidence interval [CI] = 1.02-36.7). Plasma (ANP) >11.5 pg/mL was associated with the likelihood of nonsurvival in hospitalized foals (OR = 7.2; 95% CI = 1.4-37.4; P < .05). Septic foals with serum (ANG-2) >1018 pg/mL on admission had higher odds of nonsurvival (OR = 6.5; 95% CI =1.2-36.6; P < .05). Critical illness in newborn foals is associated with EG degradation and injury, and these biomarkers are related to the severity of disease on admission and the outcome of sick foals.

Skin derived branched‐chain fatty acids in fetal horse gut

AbstractBranched‐chain fatty acids (BCFAs) are mostly saturated fatty acids with a methyl branch at the penultimate or antepenultimate position to the CH3 end. Very‐long‐chain BCFAs (C ≥ 20) are uniquely found in surface lipids. Human and California sea lion (Zalophus californianus) are the only two species that possess vernix at birth, and vernix particles carry loads of BCFA to the gut, potentially influencing the establishment of the first microbiota. Horse (Equus caballus) contains high levels of BCFA in its surface lipids, and the current study aims to investigate if BCFA are components of a neonatal foal's gut. Electron ionization tandem mass spectrometry was used to distinguish iso‐ and anteiso‐form of BCFA from straight‐chain fatty acids. Abundant very‐long‐chain iso‐BCFA, mainly even‐numbered iso‐20:0, iso‐22:0, iso‐24:0, and iso‐26:0 were found in horse meconium but not in their manure collected a few months later. There are little differences in BCFA types and concentrations between foal manure and adult manure. Moderate to high levels of very‐long‐chain anteiso‐BCFA were also found. Comparisons of horse meconium BCFA to horse skin cholesterol ester BCFA content and to meconium from human and sea lion suggest its skin derived origin. The study expands our knowledge on the gut nutritional environment of a newborn horse, and further study is needed to establish the relationship between gut BCFA and microbiota composition in the first few hours of life.Practical Applications: Branched‐chain fatty acids (BCFA) are bioactive compounds found in vernix caseosa, the lipid‐laden material covering the surface of a newborn baby. BCFA also reaches high concentrations from the third trimester of gestation until birth. However, the exact functionality and mechanisms of BCFA in the surface and gut of a fetus remain unclear. The current study aims to clarify the lipid conditions in the gut of newborn foals and to identify the associations between BCFA in the gut and on the skin at a critical point when the horse's microbiota establishes itself. The findings of the current study lay a path for studying the physiological functions of BCFA in horse models, potentially accelerating research related to BCFA.

Ultrasound findings in 34 newborn foals with uroperitoneum.

Uroperitoneum is a typical disease of the newborn foal, which occurs rarely but regularly. Ultrasonography is considered the most important imaging method for diagnosing this disease. Thus far, only one older case series comprising 31 foals suffering from uroperitoneum has systematically listed results of ultrasound examinations. This paper presents the findings of an ultrasonographic examination of 34 foals with uroperitoneum in order to inform future interpretation of ultrasonographic data in suspected uroperitoneum cases. Ultrasonographic data of 34 neonatal foals up to the age of 14 days diagnosed with uroperitoneum between 2006 and 2022 were analysed. Most foals demonstrated highly increased levels of free (97%), anechogenic (91%) fluid in the abdomen. Although the urinary bladder was frequently visible (50%), bladder wall discontinuity was only occasionally detectable (18%). Transabdominal ultrasonography has proved to be a very reliable imaging method for diagnosing suspected uroperitoneum. It is recommended that it be used in every case of suspected uroperitoneum in order to exclude differential diagnoses.

МОРФОЛОГИЯ ПРОВИЗОРНЫХ ОРГАНОВ ЛОШАДИ ВО ВЗАИМОСВЯЗИ С ЖИЗНЕСПОСОБНОСТЬЮ НОВОРОЖДЕННЫХ ЖЕРЕБЯТ

The aim of the study is to identify the morphofunctional features of the fetal part of the equine placenta in relation to prenatal growth and development of newborn foals. The fetal parts of the placentas of the most viable foals of the first subtype have a maximum weight of (8.02 ± 0.24) kg, area of (14287.48 ± 311.72) cm2, length of the umbilical cord of (57.68 ± 0.75) cm, thickness of (3.76 ± 0.07) cm. The diameter of the arteries and veins in the umbilical cord is almost the same – 11–12 mm, their lumen is strongly narrowed, the thickness of the wall of the umbilical arteries and vein is also equal to (5–6 mm). The thickness of the chorion reaches (8.00 ± 0.91) mm, the number of villi per 1 cm2 of the chorion is (41.80 ± 1.56) pcs., the thickness of the allantoamnion is (6.20 ± 0.58) mm, and the diameter of the vessels is from 4 to 6 mm, their number on the allantoamnion section of 100 cm2 is 5–10. The weight of the fetal parts of the placentas of less viable foals of the second subtype is (5.93 ± 0.24) kg, the area is (10854.92 ± 407.67) cm2, the length of the umbilical cord is (60.00 ± 0.84) cm, the diameter is (3.62 ± 0.06) cm. The diameter of the vein in the umbilical cord is slightly larger (12 mm) than the arteries (11 and 8 mm). The thickness of the chorion decreases to 4–6 mm (5.20 ± 0.37) mm, the number of villi per 1 cm2 of the chorion is 38.40 ± 1.17, there are areas in which the height and density of the villi are even smaller. The thickness of the allantoamnion is (4.06 ± 0.45) mm, and the diameter of the vessels is from 4 to 6 mm, from 3 to 7 vessels are found in an area of 100 cm2 of the allantoamnion. The weight of the fetal parts of the placentas of the third subtype of the least viable foals is significantly (by 37.37 %) lower than the first, as is the area, the length of the umbilical cord is (57.20 ± 0.66) cm, the diameter is (3.44 ± 0.05) cm. The diameter of the vein in the umbilical cord is slightly smaller (9 mm) than the arteries (12 and 11 mm). The chorion is unevenly covered with small, slightly branching villi, not shiny, its thickness reaches (2.84 ± 0.07) mm, and the number of villi per 1 cm2 is from 20 to 40. The diameter of the walls of the allantoamnion vessels decreases and is no more than 3.5 mm at most, their number is from 3 to 5 per 100 cm2.

Serum activities of complement 1q and antibodies to the virulence-associated protein A are lower in foals that develop rhodococcal pneumonia.

To determine the effects of transfusion of Rhodococcus equi hyperimmune plasma (REHIP) on serum concentrations of complement component 1q (C1q) and to examine the association of serum C1q and anti-rhodococcal antibodies of newborn foals with subsequent development of rhodococcal pneumonia. Foals (n = 205) from 2 Thoroughbred breeding farms in New York transfused with REHIP between January 1, 2022, and December 1, 2022. Blood was collected immediately before transfusion with REHIP and again from the contralateral vein immediately after transfusion. Foals were followed through weaning for clinical and ultrasonographic evidence of rhodococcal pneumonia. Serum samples were tested by ELISA for concentrations of C1q and for activity of IgG1 and IgG4/7 recognizing the virulence-associated protein A (VapA) of R equi. Logistic regression analysis was used to determine the association between rhodococcal pneumonia and levels of C1q and anti-VapA IgG1 and IgG4/7. REHIP significantly decreased C1q concentrations immediately after transfusion. Accounting for effects of farm and birth month, estimated odds of pneumonia were 2.1-fold (P = .0330) higher for foals with pretransfusion C1q concentrations less than or equal to the population median and 3.3-fold (P = .0051) higher for foals with posttransfusion IgG1 activity in the lower quartile. Both C1q and IgG appear to contribute to protection against R equi, and IgG1 appears to be especially important. Increasing IgG1 concentrations targeting rhodococcal proteins in REHIP or serum of foals might improve protection against R equi foal pneumonia.

Hematological profile of healthy Thoroughbred foals from birth to one month of age in Trinidad, West Indies.

This study aimed to develop a sound database for the hematological reference intervals of thoroughbred foals in Trinidad, West Indies from birth to 1 month of age. 89 foals. Whole blood samples were taken from 89 foals throughout Trinidad at approximately 1 day, 1 week, and 1 month of age. These foals were examined to be classified as healthy or free from disease. Complete blood count (CBC), microscopic analysis of blood smears, and conventional PCR for Theileria equi and Babesia caballi were performed. Of the 89 foals, 67 were deemed healthy and suitable for establishing reference intervals. Foals in this study had lower mean hemoglobin and hematocrit values for all 3 times of sampling when compared to their North American counterparts. Age had a significant effect on hemoglobin, hematocrit, white blood cell (WBC), neutrophil, and platelet counts of the foals from birth to 1 month of age. Variations in reference intervals can occur due to differences in demographic, physiological, and environmental factors such as age, gender, breed, and geographical location. Given the changes in the hematological values over time, this study provides clinicians with valuable information that can be used to monitor the health status of newborn foals and detect disease conditions.

Plasma melatonin concentration during the early post-partum period in Thoroughbred mares and their foals.

The authors aimed to determine the plasma melatonin concentration in mares and their new-born foals in the early post-partum period. Blood samples were collected from the jugular vein of 53 mare-foal pairs within twelve hours after parturition. Plasma melatonin levels were measured by ELISA. The melatonin concentration, adjusted for the moment of parturition using a generalised linear model, was34.58 pg mL-1 in mares. It was significantly lower (27.63 pg mL-1) in the new-born foals. However, the melatonin concentration declined differently by the end of the twelve hours, it decreased less in theoffspring than in the mothers. An artificial light supplementation at the end of gestation reduced the melatonin concentration both in mares and their foals by about 10 pg mL-1, compared to the controls. An elevated melatonin production may be related to preparation of mares for parturition and ensures the chances of survival of offspring, therefore the melatonin may reach its peak at the moment of foalingregardless of its actual time. The effect of low melatonin concentration in new-born foals might be associated with the foal's health and subsequent performance. The need to monitor the melatonin concentration in the offspring justifies further studies.

Effects of Lactobacillus rhamnosus Supplementation on Growth Performance, Immune Function, and Antioxidant Capacity of Newborn Foals.

This study aimed to explore the effects of Lactobacillus rhamnosus GG (LGG) supplementation on the growth performance, immune function, and antioxidant capacity of foals. Fifteen newborn foals with similar birth weight (51.67 ± 6.07 kg) and good health were randomly assigned to three groups: control group and test groups I and II, which were supplemented with 5.0 × 109 CFU/day and 1.0 × 1010 CFU/day LGG, respectively, for 150 days. LGG intake increased the daily body height (P < .01) and weight (P < .01) gain of foals aged 120 to 150 days. The foals' IgA (P < .05) and IgG (P < .01) plasma levels increased at 30 and 150 days, respectively, and IL-6 plasma level increased at 90 days (P < .01). Plasma total antioxidant capacity level was significantly higher in test group I than in the control and test group II at 30 days (P < .01), whereas glutathione peroxidase level was significantly higher in test group II than in the control and test group I at 30 days (P < .01). Both test groups had significantly higher superoxide dismutase level than the control group (P < .01) and significantly decreased malondialdehyde plasma level at 90 and 150 days (P < .05). Overall, our findings indicate that dietary supplementation of LGG can improve the growth performance, immune function, and antioxidant capacity of newborn foals.

Evaluation of glutaraldehyde coagulation test and colostrum BRIX refractometer compared with SNAP foal IgG test in neonatal foals.

Prompt diagnosis of passive transfer failure in the neonatal period is important for early treatment. To compare the diagnostic performance of serum glutaraldehyde coagulation test (GCT) and colostrum BRIX% for failure to transfer passive immunity (FTPI) diagnosis with the results of SNAP foal test and to evaluate the results of serum GCT and colostrum BRIX% measurements in foals with diarrhoea in the 0-1 month period. In vitro experiments. Excess serum and colostrum (n: 298) from samples collected from newborn foals and their dams for clinical purposes were used. Foals were classified as FTPI positive (IgG < 8 g/L) or negative (IgG ≥ 8 g/L) using the SNAP foal test. We compared the sensitivity and specificity of serum GCT and colostrum BRIX % for diagnosing FTPI in all foals and in the sub-group of foals which developed diarrhoea within the first month of life was noted. The relationships between the results of the serum GCT and colostrum BRIX% and diarrhoea in foals with and without FTPI were evaluated. Serum GCT and colostrum BRIX % were statistically significantly different (p < 0.05) between the foals without FTPI and with FTPI classified according to the SNAP test. Using a cut-off value for serum GCT of >10, sensitivity was 100% (95% CI 92.9%-100%) and specificity 100% (98.3%-100%) while with a cut-off value of ≤24, with colostrum BRIX% of ≤24 sensitivity was 92% (80.9%-97.8%), and specificity was 98% (95.3-99.3). In the sub-group of foals without FTPI using a colostrum BRIX% cut-off value of ≤26 the sensitivity for prediction of diarrhoea in the 0-1 month period was only 72.4% (52.8-87.3, p < 0.001) with specificity 54.3% (47.6-61.1) but the test performance was not robust (ROC AUC 0.61). The number of repeated measurements in the evaluation of serum GCT, and colostrum BRIX% was low. More clinical problems could be examined. The serum GCT, and colostrum BRIX%, both economical and practical to use in the field, gave results comparable with the SNAP foal IgG test. The ability to accurately predict diarrhoea in the first month of life with these tests was limited.

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.

Studies of colostrum and milk composition and quality of Gidran mares

Foals are born with intact but weakly functioning immune systems. Colostrum provides special immunoglobulins, which are essential for the development of passive immunity. The newborn foal is entirely dependent on antibodies from colostrum for protection against infection during the early neonatal period, meaning that after foaling, in a short time, they need to pick up a sufficient amount of colostrum in proper quality. The quantity and quality of colostrum cannot be influenced although it is well known that well-fed mares in good health typically produce enough antibody-rich colostrum for their newborn foals, the quality of colostrum can be determined by several methods. In 2022, I examined the gestation and lactation of 9 Gidran mares at Kismacs Experimental Station of Animal Husbandry of the University of Debrecen. I used a BRIX refractometer for measuring the colostrum IgG level, and a Lactoscan MCC Combo milk analyser for testing colostrum and milk.

Development of a chronic focal equine arteritis virus infection of a male reproductive tract cell line

Equine arteritis virus (EAV) is an Alphaarterivirus (family Arteriviridae, order Nidovirales) that frequently causes an influenza-like illness in adult horses, but can also cause the abortions in mares and death of newborn foals. Once primary infection has been established, EAV can persist in the reproductive tract of some stallions. However, the mechanisms enabling this persistence, which depends on testosterone, remain largely unknown. We aimed to establish an in vitro model of non-cytopathic EAV infection to study viral persistence. In this work, we infected several cell lines originating from the male reproductive tract of different species. EAV infection was fully cytopathic for 92BR (donkey cells) and DDT1 MF-2 (hamster cells) cells, and less cytopathic for PC-3 cells (human cells); ST cells (porcine cells) seemed to eliminate the virus; LNCaP (human cells) and GC-1 spg (murine cells) cells were not permissive to EAV infection; finally, TM3 cells (murine cells) were permissive to EAV infection without any overt cytopathic effects. Infected TM3 cells can be maintained at least 7 days in culture without any subculture. They can also be subcultured over 39 days (subculturing them at 1:2 the first time at 5 dpi and then every 2–3 days), but in this case, the percentage of infected cells remains low. Infected TM3 cells may therefore provide a new model to study the host-pathogen interactions and to help determine the mechanisms involved in EAV persistence in stallion reproductive tract.

Characterization of lyophilized equine colostrum

Colostrum is the first milk secretion at birth and is indispensable for the equine newborn. In addition to being the only natural source of immunoglobulins (Igs) available, it has excellent nutritional importance in helping the gastrointestinal system's maturation. Thus, foals need to ingest maternal colostrum in the first hours of life to acquire immunity so that failure of passive transfer of immunity (FPTI) does not occur. The quality of the colostrum supplied to the animals must be evaluated, and innovation in its storage methods would greatly benefit management. Lyophilization is a differentiated process of dehydration that retains a large concentration of colostrum immunoglobulins. The only lyophilized colostrum for foals is based on bovine colostrum) This study aimed to compare the IgG concentration and the physicochemical characteristics of frozen equine colostrum after the lyophilization process. Thirty-one pregnant mares were used. Colostrum samples were collected manually from both mammary glands immediately after delivery. The udder was cleaned with 70% alcohol solution to avoid sample contamination. About 20 mL of colostrum were collected, and the first two jets were discarded. The IgG concentration of frozen and lyophilized colostrum was determined by the Simple Radial Immunodiffusion method (IDRS) and also, indirectly, by Brix refractometry. The samples' physical-chemical composition (pH, total protein (TP),fat, lactose, salts, total solids (TS), and density) was evaluated,and the lyophilized colostrum reconstitution test was performed. The ways of preserving colostrum were compared using a t-test at 5% probability. Pearson correlations were utilized between variables with Sisvar®, version 5.7 statistical software. No significant differences were seen in the measurements of IgG, fat, lactose, salts, TS, density, and pH before and after lyophilization. No difference was seen in the IgG concentration measured by IDRS (frozen 30.5 g/L vs lyophilized 28.5 g/L). A strong positive correlation was observed between colostrum density and IgG concentration by IDRS (r = 0.76) and between Brix and IgG concentration by IDRS (r= 0.77). In the reconstitution test, lyophilized colostrum was efficiently rehydrated in water, with total dilution, and remained stable. The results suggest that lyophilization can be an alternative for conservation of colostrum from mares, because it is a very efficient process for the retention of the physicochemical characteristics of the product, with no significant loss of IgG concentration. In addition, it is easy to reconstitute, can be preserved for a long period without the need for refrigeration and easily transported. This research should be expanded to make an innovative equine product available. This will facilitate the management of newborn foals and help to reduce the rates of failure of passive immunity transfer.

Effect of plasma transfusion on serum amyloid A concentration in healthy neonatal foals and foals with failure of transfer of passive immunity.

Anecdotal evidence suggests plasma transfusions increase serum amyloid A (SAA) concentrations in healthy neonatal foals making this marker of inflammation inappropriate for therapeutic decision making in such animals. Administration of hyperimmune fresh frozen plasma (FFP) increases SAA concentration in healthy foals and in foals with failure of transfer of passive immunity (FTPI). Eighty-six healthy foals. Prospective cohort study. Foals <24 hours of age receiving plasma transfusion for treatment of FTPI (serum immunoglobulin G [IgG] concentrations <8g/L; n=17) or as a preventative measure for Rhodococcus equi infection (IgG >8g/L; n=33) were enrolled. A healthy nontransfused group of foals (IgG >8g/L; n=21) also was included. SerumamyloidA concentration was determined before (t0h) and after (t24h) administration of FFP. Changes in blood SAA concentration were assessed using linear regression models. No statistical differences were found in SAA concentration at t0h or t24h among the 3 groups (P > .05, for all comparisons). The variation in SAA concentration before (t0h) and after (t24h) plasma transfusion showed that administration of FFP was not associated with the changes in SAA concentration (P > .05). An association between SAA concentration at t0h and at 24 hours (P < .05) was identified, where foals with higher SAA concentration at t0h also had higher SAA concentration at t24h. Administration of FFP to newborn foals was not associated with changes in SAA concentration.

Pathological Features and Genomic Characterization of an Actinobacillus equuli subsp. equuli Bearing Unique Virulence-Associated Genes from an Adult Horse with Pleuropneumonia

Actinobacillus equuli subsp. equuli is the etiological agent of sleepy foal disease, an acute form of fatal septicemia in newborn foals. A. equuli is commonly found in the mucous membranes of healthy horses' respiratory and alimentary tracts and rarely causes disease in adult horses. In this study, we report a case of a 22-year-old American Paint gelding presenting clinical signs associated with an atypical pattern of pleuropneumonia subjected to necropsy. The gross and histopathological examinations revealed a unilateral fibrinosuppurative and hemorrhagic pleuropneumonia with an infrequent parenchymal distribution and heavy isolation of A. equuli. The whole genome sequence analysis indicated that the isolate shared 95.9% homology with the only other complete genome of A. equuli subsp. equuli available in GenBank. Seven virulence-associated genes specific to the isolate were identified and categorized as iron acquisition proteins, lipopolysaccharides (LPS), and capsule polysaccharides. Moreover, four genes (glf, wbaP, glycosyltransferase family 2 protein, and apxIB) shared higher amino acid similarity with the invasive Actinobacillus spp. than the reference A. equuli subsp. equuli genome. Availability of the whole genome sequence will allow a better characterization of virulence determinants of A. equuli subsp. equuli, which remain largely elusive.

Assessment and management of the neonatal foal

Background: Neonatal care can seem daunting to the equine veterinary practitioner, particularly in practices without a high stud medicine caseload, meaning visits to newborn foals are infrequent. Deciding when to refer and when field treatment is likely to be adequate can be difficult. Clinical signs of disease can be subtle and deterioration rapid. Accurate assessment and early recognition of problems are crucial in successful treatment, as is education of owners about when to seek veterinary intervention.Aim of the article: This article provides practical guidelines on how to accurately assess the newborn foal in the field within the first 24 hours of life, including common early warning signs, and when referral should be advised.

Assessment of the microvascular perfusion using sidestream dark‐field imaging in healthy newborn foals

Different methods to measure tissue perfusion are available in equine neonatology, but they are not representative of microvascular derangements. To evaluate the feasibility of the sidestream dark-field (SDF) capillaroscopy to visualize the capillary microvasculature in conscious newborn foals, the differences between two imaging sites and times of measurements, and the measurements' reproducibility. Seventeen healthy newborn foals were enrolled. Three sites at the upper and lower lip mucosa were assessed by SDF, using a hand-held capiscope, at 24 h and at 4-5 days after birth. Videos were assessed independently by two observers for quality and for semiquantitative calculation of microvascular parameters, including vascular density (VD), microvascular flow index (MFI), proportion of perfused vessels (PPV), and functional capillary density (FCD). Data were analyzed using unpaired and paired Student's T-tests to assess differences between sites and time-points. Bland-Altman plots and intraclass correlation coefficient (ICC) were used to assess measurement reproducibility. Differences were found between the upper and the lower lip for VD at both 24 h and 4-5 days, and for FCD at 24 h, and between the two time-points for PPV at the lower lip. ICC for measurement reproducibility was good for all parameters (0.64-0.79) for the lower lip, and was good for VD and FCD (0,76-0,79) and fair to moderate for MFI and PPV (0.31-0.41) for the upper lip. Measurement of the capillary microvasculature is feasible in the conscious newborn foal. The lower lip has the best measurement reproducibility. Further investigations are warranted in cardiovascularly compromised cases, particularly in septic foals.

The fecal bacterial microbiota of healthy and sick newborn foals

The fecal bacterial microbiota of normal foals and foals with enterocolitis has been characterized using next-generation sequencing technology; however, there are no reports investigating the gut microbiota in foals hospitalized for other perinatal diseases. To describe and compare the fecal bacterial microbiota in healthy and sick foals using next-generation sequencing techniques. Hospitalized (17) and healthy foals (21). Case-control study. Fecal samples were collected from healthy and sick foals on admission. Sick foals were further divided into sick nonseptic (SNS, n=9) and septic (n=8) foals. After extraction of DNA, the V4 region of the 16 S rRNA gene was amplified using a PCR assay, and the final product was sequenced with an Illumina MiSeq. Diversity was significantly lower in healthy than sick foals (P < .05). The bacterial membership (Jaccard index) and structure (Yue & Clayton index) of the fecal microbiota of healthy, septic, and SNS foals were similar (AMOVA, P > .05). Bacterial membership (AMOVA, P=.06) and structure (AMOVA, P=.33) were not different between healthy and sick foals. Enterobacteriaceae, Enterococcus, and Streptococcus were among the 5 more abundant taxa identified in both groups. Higher fecal microbiota diversity in sick than healthy foals might suggest a high exposure to environmental microorganisms or an unstable colonic microbiota. The presence of microorganisms causing bacteremia in foals in a high relative abundance in the feces of foals suggests the intestine might play an essential role in the causation of bacteremia in foals.