Retrospective analysis of factors associated with umbilical diseases in foals

In neonatal foals, umbilical remnants can be affected by infectious and non-infectious diseases. This study aimed to retrospectively evaluate historical, management and clinical factors that may be related to the occurrence of umbilical remnant diseases. Clinical reports of foals born or hospitalized within 24 h of life during the 2017-2021 foaling seasons were reviewed. Forty/183 foals (21.9 %) developed umbilical remnant diseases (URD group), while 143/183 foals (78.1 %) had normal umbilical remnants (NUR group). In the URD group, 24/40 (60 %) had a patent urachus, 16/40 (40 %) omphalo-arteritis, 4/40 (10 %) omphalo-phlebitis, 10/40 (25 %) urachitis, 9/40 (22.5 %) abscess, 3/40 (7.5 %) periumbilical hematoma and 12/40 (30 %) more than one condition. URD frequency was higher in foals hospitalized after birth than in those born at the hospital (17/46 vs 23/137; P = 0.0068), lower in those that had access to the paddock before three days of life (p = 0.0426) and higher in recumbent foals (P = 0.0001). URD occurred more frequently after dystocia (P = 0.0068), prolonged stage II parturition (19±20.51 min vs 13±6.41 in NUR group; P = 0.0279), traction at parturition (P = 0.0005), and in foals with lower APGAR scores (8±1.72 vs 9±0.86 in NUR; P = 0.0063). Sepsis (P = 0.0245), neonatal encephalopathy (P = 0.0014), meconium retention (P = 0.0241) and congenital flexural limb deformities (P = 0.0049) were the most common associated diseases. Umbilical cord (UC) coiling, abnormal UC rupture, umbilical hemorrhage and increased umbilical stump volume occurred more frequently in URD than in NUR group (P = 0.0329, P = 0.0191, P = 0.0007 and P < 0.00001, respectively). Recognition of the identified predisposing historical, management and clinical factors should prompt careful umbilical remnant monitoring in neonatal foals.

Hematological reference intervals in newborn dromedary calves in the first week after birth: Age and sex-related variations

The establishment of hematological reference intervals (RIs) is an important tool to assess the health status of animals and to evaluate the impact of diseases at individual and population levels. Nowadays, specific RIs of hematological parameters in newborn dromedary camel calves at birth and during the first week after birth, are lacking. Therefore, RIs for the hematological variables from a complete blood cell count were established in 47 healthy newborn dromedary calves (18 females and 29 males). Blood samples were collected within 2 h after birth (d0), at 24 h (d1), at 3 (d3) and 7 days (d7) after birth, and analyzed within 24 h. The RIs were described based on the 95% confidence interval, and possible differences among mean values due to age (sampling time) and sex were investigated. Statistical analysis showed that age affected all the hematological variables except MCV, MCH, and MCHC, indicating that the adaptational process to the extrauterine life continues for several days after birth; sex affected most of the hematological variables, with higher RBC and PLT count, HGB, PCV, neutrophil population and neutrophil:lymphocyte ratio at d7 in females compared to males. These findings suggest possible sex-based differences in the physiological maturation mechanisms and deserves further investigations. To the best of the authors' knowledge, this is the first report of hematological RIs for newborn dromedary calves at birth up to 7 days of age; the RIs registered in the present study in newborns differ from those reported in adult dromedaries in literature, thus confirming the need for the adoption of separated reference ranges according to age also in the dromedary camel, as previously reported for other species.

Could assisted reproductive techniques affect equine fetal membranes and neonatal outcome?

Embryo transfer (ET) and intracytoplasmic sperm injection (ICSI) are widely used in equine species, but their effects on fetal adnexa and neonates have not been investigated yet. The aim of this study was to retrospectively evaluate whether pregnancies obtained by ET or ICSI could be associated with the presence of macroscopic alterations of fetal membranes (FM) and umbilical cord (UC) and if the use of these techniques could influence neonatal outcome. Sixty-six light breed mares hospitalized at the Veterinary Teaching Hospital, University of Bologna, for attending delivery were included in the study. Mares were divided into Artificial Insemination (AI; 32/66 mares, 48 %), Embryo Transfer (ET; 12/66 mares, 18.2 %) and Intracytoplasmic Sperm Injection (ICSI; 22/66 mares, 33 %) groups. All the medical reports of mares and their foals were reviewed and data about mare, pregnancy, foaling, fetal membranes, umbilical cord and foal were recorded. The occurrence of dystocia resulted statistically different between AI group and ICSI group (p = 0.0066), and between AI group and ET group (p = 0.044). Macroscopic examination of FM revealed alterations in 30/66 mares (46 %): 8/32 in AI (25 %), 7/12 in ET (58 %) and 15/22 in ICSI (68 %) with significant lower incidence in AI compared to ET (p = 0.04) and ICSI (p = 0.002) groups. Alterations reported were chorionic villi hypoplasia, chorioallantois edema, allantois cysts, necrotic areas and greenish-grey concretions. Total length of UC resulted significantly shorter in ICSI group (49 ± 9 cm; p < 0.03) compared to AI (60 ± 17 cm) and ET (59 ± 15 cm). However, there were no differences in the incidence of foals' diseases at birth and in foals' survival among groups (p > 0.05). The results demonstrate that transfer of in vivo or in vitro produced embryos may lead to alterations of placental development, as observed in other species, without being associated with a higher incidence of neonatal morbidity and mortality. Further studies about trophoblast development, FM histological evaluation, and placental gene expression should be carried out to clarify the mechanisms underlying the placental alterations.

Management of uroperitoneum through combination of conservative and surgical treatments in two colts

Background

Ruptures of the urinary bladder and urachus are the most frequent cause of uroperitoneum in foals. Surgical correction is often the first treatment choice, however, nonsurgical methods, such as urine removal via urinary catheters and abdominal drains, have been successfully performed in foals.

Case Description

Two foals were referred to the Equine Perinatology Unit for suspicion of uroperitoneum. The diagnosis was confirmed by hematobiochemical and ultrasound examinations, thus cystorrhaphy and cystoplasty were attempted. Surgeons found a lesion in the dorsocranial margin of the bladder (Case 1) and a tear in the pelvic urethra (Case 2); in the first case, the defect was routinely repaired, while the last lesion was impossible to repair due to its localization. A urinary catheter was left in place in both cases. Uroperitoneum recurred 72 hours after the surgery in both foals: a second surgical correction was not recommended due to the localization of the tears and conservative treatment, with the placement of a 32F chest tube in the most ventral part of the abdomen, was preferred. Abdominal drains were removed 5-7 days after surgery, while urinary catheters were left in place for up to 7-8 days. Colts' conditions improved during hospitalizations. Two months after bladder surgery, Case 1 was euthanized due to multiple adhesions between the small intestine and the abdominal wall. Case 2 was still alive one year postoperatively.

Conclusion

Although it cannot be considered the first choice for the treatment of uroperitoneum in the foal, nonsurgical treatment was successful in both cases in the short-term follow-up. However, the prognosis should be cautious due to the risk of long-term complications. Conservative management may be used to manage bladder/urethral tears that cannot be solved by surgery.

Corneal Ulcers in Critically Ill Foals in Intensive Care: Case Series of Standard Treatment and Corneal Cross-Linking

Riboflavin/UV-A corneal cross-linking (CXL) has been applied to treat corneal ulcers in adult horses, but its use in critically ill neonatal foals has not been described. Five cases of hospitalized, critically ill neonatal foals that were in intensive care with corneal ulcers, the ophthalmic treatment, and their outcome up to 1 year are described. A single treatment of CXL phototherapy was performed in three of five foals (five eyes). The application of a riboflavin ophthalmic solution for 20 minutes was followed by the UV-A light irradiation at 30 mW/cm2 for 3 minutes. Topical antibiotic administration was withdrawn after CXL. Two other foals received standard treatment. Descriptions of ocular lesions, fluorescein staining, and photographic documentation were recorded. The visual outcome, corneal transparency, and aesthetics, as well as healing time were evaluated in the follow-up. The frequency of topical medication considerably decreased in cases treated with CXL. Corneal opacity and pain decreased within 3 days following CXL. In the foals treated with CXL, the ulcers healed (fluorescein stain negative) in 24, 28, and 35 days after the onset of clinical signs and 10, 15, and 21, after CXL. No fibrosis or corneal scars were found in the cases treated with CXL. The two standard treatment cases healed after 26 and 36 days respectively. Corneal cross-linking may be an additional or alternative treatment of corneal ulcers in critically ill neonatal foals and may reduce the use of antibiotics.

Gross and histological examination of Wharton's Jelly in the equine umbilical cord

Wharton's jelly (WJ) is fundamental for the well-being of the fetus, binding to the umbilical vessels and protecting them from twisting and compression. Gross and microscopic studies have been undertaken on the umbilical cord (UC) of human placentae in both normal and high-risk pregnancies, however there is limited research on equine UC. The aim of this study was to describe microscopically and immunohistochemically the equine UC in normal pregnancies, with particular attention to WJ. Forty-seven healthy mares, with no complications during pregnancy, admitted to the hospital for attending delivery were enrolled. Clinical data was collected at foaling on foal health and placental characteristics. UC samples were collected from three sites (amniotic, allantoic and in the region of vein anastomosis) for histology. The thickness of different layers of arteries and veins and WJ in different UC portions were measured (μm). Wharton's Jelly was weighted (g) and its sections were stained with Masson's trichrome, orcein technique and silver impregnation. Immunohistochemistry was undertaken using antibodies raised-against collagen type I, V, VI and fibrillin. Forty-seven UCs, from 19 colt and 28 filly foals, were analyzed for WJ weight and 8/47 UCs were examined histologically. Warton's jelly was only found in the amniotic portion of the UC closest to the foal's abdomen. The weight of WJ (4.0 ± 3.3 g) did not vary between colts and fillies and it was not correlated with any of the clinical or UC parameters measured. The tunica media of arteries and veins was thicker in the amniotic portion of the UC, as described in human UCs in late pregnancy. This finding could be an adaptation to aid in resisting compression because of fetal movements and UC twisting. The umbilical vein was thicker than the umbilical arteries in the tunica media and tunica adventitia in the sections examined throughout the length of the cord. This preliminary study describes gross and histological WJ's structure in the equine species. However, further studies are required to better characterize UC's changes throughout pregnancy and in the presence of mare's or fetal disease.

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

BACKGROUND

Different methods to measure tissue perfusion are available in equine neonatology, but they are not representative of microvascular derangements.

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

High-Risk Pregnancy Is Associated With Increased Alpha-Fetoprotein Concentrations in the Amniotic Fluid and Foal Plasma

This study aimed to determine alpha-fetoprotein (AFP) concentrations in amniotic fluid, plasma of mares and respective foals: carrying normal pregnancies and delivering healthy foals (n = 20; Group 1); carrying apparently normal pregnancies and delivering sick foals (n = 15; Group 2); carrying high-risk pregnancies and delivering sick foals (n = 14; Group 3). High-risk pregnancy was defined by a history of premature udder development/lactation or increased of the combined thickness of the uterus and placenta, or vulvar discharge and/or mares' systemic illness. Sick foals were affected by neonatal encephalopathy, sepsis, prematurity/dysmaturity, or hypoxic-ischemic encephalopathy. Based on histological examination of the chorioallantois, AFP trend was analyzed in pregnancies with pathologic (PFM) and normal fetal membranes (NFM). Concentrations of AFP were measured using a commercially available immunoassay previously validated for horses. Mares' plasma AFP did not change during the last 15-20 days of pregnancy in the three groups, and there was no difference among them. Amniotic fluid AFP was higher in Group 3 (P = .014). Foals' plasma AFP concentration was higher from birth to 72hours in foals of Group 2 and 3 than in healthy ones, and foals of Group 3 had the highest value. The strong association (r = 0.84; P < .0001) between AFP in amniotic fluid and foals' plasma at birth is likely due to the presence of AFP in fetal urine. AFP was higher in pregnancy with PFM than with NFM in mare's plasma at admission (P = .031), amniotic fluid (P = .004), foal's plasma at birth (P = .002), at 24 (P = .005) and at 72 hours of life (P = .004). AFP is higher in pregnancy with histopathological lesions of the chorioallantois providing the evidence of the differences between pregnancy with a normal placental barrier and the more compromised ones. The increased AFP concentration in the amniotic fluid and plasma of high-risk foals suggests upregulation.

Study on NGF and VEGF during the Equine Perinatal Period-Part 1: Healthy Foals Born from Normal Pregnancy and Parturition

The importance of trophic factors, such as nerve growth factor (NGF), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) during the perinatal period, is now emerging. Through their functional activities of neurogenesis and angiogenesis, they play a key role in the final maturation of the nervous and vascular systems. The present study aims to: (i) evaluate the NGF and VEGF levels obtained at parturition from the mare, foal and umbilical cord vein plasma, as well as in amniotic fluid; (ii) evaluate NGF and VEGF content in the plasma of healthy foals during the first 72 h of life (T0, T24 and T72); (iii) evaluate NGF and VEGF levels at parturition in relation to the selected mares’ and foals’ clinical parameters; (iv) evaluate the relationship between the two trophic factors and the thyroid hormone levels (TT3 and TT4) in the first 72 h of life; (v) assess mRNA expression of NGF, VEGF and BDNF and their cell surface receptors in the placenta. Fourteen Standardbred healthy foals born from mares with normal pregnancies and parturitions were included in the study. The dosage of NGF and VEGF levels was performed using commercial ELISA kits, whereas NGF, VEGF and BDNF placental gene expression was performed using semi-quantitative real-time PCR. In foal plasma, both NGF and VEGF levels decreased significantly over time, from T0 to T24 (p = 0.0066 for NGF; p < 0.0001 for VEGF) and from T0 to T72 (p = 0.0179 for NGF; p = 0.0016 for VEGF). In foal serum, TT3 levels increased significantly over time from T0 to T24 (p = 0.0058) and from T0 to T72 (p = 0.0013), whereas TT4 levels decreased significantly over time from T0 to T24 (p = 0.0201) and from T0 to T72 (p < 0.0001). A positive correlation was found in the levels of NGF and VEGF in foal plasma at each time point (p = 0.0115; r = 0.2862). A positive correlation was found between NGF levels in the foal plasma at T0 and lactate (p = 0.0359; r = 0.5634) as well as between VEGF levels in the foal plasma at T0 and creatine kinase (p = 0.0459; r = 0.5407). VEGF was expressed in all fetal membranes, whereas NGF and its receptors were not expressed in the amnion. The close relationship between the two trophic factors in foal plasma over time and their fine expression in placental tissues appear to be key regulators of fetal development and adaptation to extra-uterine life.

Dystocia in the Standardbred Mare: A Retrospective Study from 2004 to 2020

Dystocia as a prolonged stage II parturition (>30 min) was associated with a higher risk of complications. The hypothesis of the study was that any type of dystocia could affect the foal’s health, even when the stage II was <30 min. Clinical reports on 222 Standardbred mares and their foals hospitalized at the Veterinary Teaching Hospital of the University of Bologna from 2004 to 2020 were reviewed. Mares were divided into the Eutocia Group (165, eutocic delivery) and the Dystocia Group (57, dystocic delivery). The incidence of dystocia was 4.9%. Stage II was longer in the Dystocia Group (median 20 min) than in the Eutocia Group (median 12 min). All occurrences of dystocia were retrospectively classified into three categories of severity: mild, moderate and severe dystocia. The occurrence of postpartum complications in mares and neonatal diseases and failure of passive transfer of immunity in foals was higher in the Dystocia Group. Foal venous lactatemia and serum creatine kinase were significantly higher in the Dystocia Group (median 3.9 mmol/L; 262 UI/L respectively) than in the Eutocia Group (median 3.1 mmol/L; 187 UI/L respectively). The APGAR score was lower in the Dystocia Group (median 8) than in the Eutocia Group (median 10) and significantly lower in severe dystocia (median 3). The duration of stage II should not be considered the only parameter of dystocia in mares: even a rapid resolution of dystocia could pose health risks to the foal and the mare.

Development of a Composite Pain Scale in Foals: A Pilot Study

Prompt pain management is crucial in horses; however, tools to assess pain are limited. This study aimed to develop and pilot a composite scale for pain estimation in foals. The “Foal Composite Pain Scale” (FCPS) was developed based on literature and authors’ expertise. The FCPS consisted of 11 facial expressions, 4 behavioural items, and 5 physical items. Thirty-five pain-free foals (Control Group) and 15 foals experiencing pain (Pain Group) were used. Foals were video-recorded at different time points: the Control Group only at inclusion (C), while the Pain Group at inclusion (T1), after an analgesic treatment (T2), and at recovery (T3). Physical items were also recorded at the same time points. Videos were scored twice by five trained observers, blinded to group and time points, to calculate inter- and intra-observer reliability of each scale item. Fleiss’ kappa values ranged from moderate to almost perfect for the majority of the items, while the intraclass correlation coefficient was excellent (ICC = 0.923). The consistency of FCPS was also excellent (Cronbach’s alpha = 0.842). A cut-off ≥ 7 indicated the presence of pain. The Pain Group scores were significantly higher (p < 0.001) than the Control Group and decreased over time (T1, T2 > T3; p = 0.001). Overall, FCPS seems clinically applicable to quantify pain and improve the judgment of the quality of life in foals, but it needs modifications based on these preliminary findings. Consequently, further studies on a larger sample size are needed to test the feasibility and validity of the refined FCPS.

Morphological study of equine amniotic compartment

Exfoliative cytology of human amniotic fluid (AF) has been extensively studied since 1940s, but no data exist in equine species. The AF compartment represents the environment in which the foetus grows and matures, and its composition changes, reflecting foetal well-being and development. The aim of this study was to describe for the first time the morphology of equine AF cells and amniotic membrane (AM) with light microscopy (LM) and transmission electron microscopy (TEM). AF was collected at parturition within 5 min after the appearance of the AM with a 60 mL syringe from 34 mares and samples of AM were collected from a subset of 7 mares with normal pregnancy hospitalized for attended parturition. For LM observation, a sample of cytocentrifuged fresh AF was stained with May-Grünwald Giemsa and AM sections were stained with H-E. For TEM observation, AF and AM were fixed, embedded in epoxy resins, then sectioned and stained with uranyl acetate and lead citrate solutions. Nucleated and anucleated squamous cells with basophilic cytoplasm, intensely basophilic cornified cells, polymorphonuclear cells, and clusters of eosinophilic amorphous substance were observed. Cells presumably derived from tracheal epithelium and small round nucleated cells with eosinophilic cytoplasm presumably derived from amniotic or urinary epithelium were occasionally found. Lamellar body-like structures (LBs) were present in some epithelial cells. In AM, epithelial, basal and mesenchymal layers were clearly visible with both techniques as previously described. Epithelial cells had several cytoplasmic vacuolization and microvilli were present on apical surface. The connective tissue presented fibroblasts, mesenchymal and rare polymorphonuclear cells, surrounded by abundant extracellular matrix, with distribution of collagen fibres. This is the first report about equine amniotic compartment description by LM and TEM. As recently reported in human medicine, the AM could be a second potential source of pulmonary surfactant, given the finding of LBs inside the cells which could have the same function as in humans. Further studies in samples collected at different gestational ages could increase the knowledge of AF cells and their modification during pregnancy, as well as a better comprehension of the role of AM as a secondary source of pulmonary surfactant in the horse. The diagnostic evaluation of AF cellular composition in high-risk pregnancies may also be investigated.

Changes in the Fecal Microbiota Associated with a Broad-Spectrum Antimicrobial Administration in Hospitalized Neonatal Foals with Probiotics Supplementation

Simple Summary

Post-antibiotic intestinal dysbiosis leads to an overall reduction in bacterial and functional diversity, along with a minor resistance against pathogens. The study aimed to determine the changes on the fecal microbiota in hospitalized neonatal foals administered with broad-spectrum antimicrobials and supplemented probiotics. Fecal samples were collected at hospital admission, at the end of the antimicrobial treatment and at discharge. Seven foals treated with intravenous ampicillin and aminoglycosides for a mean of seven days were included. The results suggest that the fecal microbiota of neonatal foals rapidly returns to a high diversity after treatment. While the findings need to be confirmed in a larger population, the study suggests that in foals, the effect of antimicrobials may be strongly influenced by the changes that occur over time in the developing gut microbiota. Of note, the findings are influenced by the use of probiotics, and whether the changes would be consistent in antimicrobial-administered but not supplemented foals remains to be elucidated.

Abstract

There is a wide array of evidence across species that exposure to antibiotics is associated with dysbiosis, and due to their widespread use, this also raises concerns also in medicine. The study aimed to determine the changes on the fecal microbiota in hospitalized neonatal foals administered with broad-spectrum antimicrobials and supplemented probiotics. Fecal samples were collected at hospital admission (Ta), at the end of the antimicrobial treatment (Te) and at discharge (Td). Feces were analysed by next-generation sequencing of the 16S rRNA gene on Illumina MiSeq. Seven foals treated with IV ampicillin and amikacin/gentamicin were included. The mean age at Ta was 19 h, the mean treatment length was 7 days and the mean time between Te and Td was 4.3 days. Seven phyla were identified: Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, Proteobacteria, TM7 and Verrucomicrobia. At Ta, Firmicutes (48.19%) and Proteobacteria (31.56%) were dominant. The alpha diversity decreased from Ta to Te, but it was the highest at Td. The beta diversity was higher at Ta than at Te and higher at Td than at Te. An increase in Akkermansia over time was detected. The results suggest that the intestinal microbiota of neonatal foals rapidly returns to a high diversity after treatment. It is possible that in foals, the effect of antimicrobials is strongly influenced or overshadowed by the time-dependent changes in the developing gut microbiota.

The first case of Tyzzer's disease in a young foal in Italy: a case report

Seizures, coma and death rapidly appeared after admission in a one ‑month‑old foal with a history of lethargy, fever and anorexia. Severe icterus and necrotizing hepatitis were observed at necropsy. Clinical signs, laboratory and postmortem findings were compatible with a suspect of clostridial hepatitis. Tyzzer’s disease was confirmed by the presence of organisms morphologically consistent with Clostridium piliforme in the hepatocytes at the margins of multiple areas of hepatic necrosis. To the authors’ knowledge, this is the first reported case of clostridial hepatitis caused by Clostridium piliforme in a horse in Italy.

Adrenal Gland Ultrasonographic Measurements and Plasma Hormone Concentrations in Clinically Healthy Newborn Thoroughbred and Standardbred Foals

Simple Summary

The hypothalamic–pituitary–adrenal axis regulates many physiologic and metabolic functions and plays a central role in the inflammatory response to illness. Clinically, hypothalamic–pituitary–adrenal axis function can be evaluated by combined assessment of adrenal hormones, adrenocorticotropin plasma concentrations and ultrasonographic examination of the adrenal glands in other species. Multiple individual variables have been demonstrated to affect ultrasonographic measurements of adrenal glands in several species. Ultrasonographic measurements of the adrenal glands and plasma concentration of adrenocorticotropin, cortisol, dehydroepiandrosterone, progesterone, aldosterone and adrenocorticotropin/adrenal hormone ratios were assessed and compared between Thoroughbred and Standardbred healthy neonatal foals. The effect of age, weight and sex on ultrasonographic measurements of the adrenal glands was also investigated. The width of whole adrenal glands and the medulla differed significantly between Thoroughbreds and Standardbreds. Cortisol and adrenocorticotropin were, respectively, higher and lower in Thoroughbreds than in Standardbreds. The cortisol/dehydroepiandrosterone ratio was higher in Thoroughbreds than in Standardbreds. The results of this study provide reference ranges for healthy neonatal Thoroughbred and Standardbred foals and suggest the presence of breed-related differences in ultrasonographic measurements, plasmatic cortisol and adrenocorticotropin concentrations. The higher cortisol/dehydroepiandrosterone ratio of Thoroughbred foals may suggest a different response to stress and environmental stimulation between the two breeds.

Abstract

Adrenal hormones, ACTH plasma concentrations and the ultrasonographic evaluation of the adrenal glands are considered complementary in clinical evaluations of the hypothalamic–pituitary–adrenal (HPA) axis function in several species. In dogs, age, size and weight have a significant effect on the ultrasonographic size of the adrenal glands. In neonatal foals, ultrasonographic evaluation and measurements of the adrenal glands have been demonstrated to be reliable; however, the effect of individual variables on ultrasonographic features has not been investigated, and the clinical usefulness of adrenal gland ultrasonography is still not known. The aims of this study were: (i) to provide and compare adrenal glands ultrasound measurements in healthy newborn Thoroughbred and Standardbred foals, and assess any effect of age, weight and sex on them; (ii) to assess and compare ACTH and steroid hormone concentrations in healthy neonatal foals of the two breeds. Venous blood samples and ultrasonographic images of the adrenal glands were collected from 10 healthy neonatal Thoroughbred and 10 healthy neonatal Standardbred foals. Ultrasonographic measurements of the adrenal glands were obtained and adrenocorticotropin (ACTH), cortisol, dehydroepiandrosterone (DHEA), progesterone (P4) and aldosterone plasma concentrations were assessed. The ACTH/cortisol, ACTH/progesterone, ACTH/aldosterone, ACTH/DHEA and cortisol/DHEA ratios were calculated. A significant positive correlation was found between the height of the right adrenal gland and the foal’s weight; the width of the right and left adrenal gland and the medulla was significantly lower in Thoroughbreds than in Standardbreds. Cortisol and ACTH plasma concentrations were significantly higher and lower, respectively, in Thoroughbreds compared with Standardbreds. The cortisol/DHEA ratio was significantly higher in Thoroughbreds. This study provides reference ranges for neonatal Thoroughbred and Standardbred foals, and suggests the presence of breed-related differences in ultrasonographic adrenal gland measurements, plasmatic cortisol and ACTH concentrations. The higher cortisol/DHEA ratio detected in Thoroughbred foals could suggest a different response to environmental stimulation in the two breeds.

Activities of matrix metalloproteinase-2 and -9 in amniotic fluid at parturition in mares with normal and high-risk pregnancy

The matrix metalloproteinases (MMPs) are a family of enzymes involved in extracellular matrix remodeling. MMPs are secreted in a latent form and activated by local and infiltrating cells. MMP-2 and -9 are the most studied in reproduction and have been detected in bovine, ovine, equine and human placenta. There is only one study on MMPs in the equine amniotic fluid (AF) reporting a decrease in the activity of MMP-2 in case of premature delivery. The aim of this study was focused on MMP-2 and -9 activity in AF collected at parturition from mares with normal or high-risk pregnancy. High-risk pregnancy was defined as a history of premature udder development/lactation, increase of combined thickness of the uterus and placenta, vulvar discharge and/or mare's systemic illness. The diagnosis of placental insufficiency was confirmed retrospectively after macroscopic and histopatologic examination of the placenta. AF was collected by needle puncture of the amnion within 5 min after its appearance through the vulva. The activity of MMP-2 and -9 was analyzed by in-gel zymography allowing the evaluation of both latent and active forms. Twenty mares with normal pregnancy (group 1) and 8 mares with high-risk pregnancy (group 2) were included. All mares in group 2 had a high-risk pregnancy with a diagnosis of placental insufficiency associated with placental villous hypoplasia, placentitis or placental edema. The bands relative to latent and active forms of MMP-2 were clearly visible in both groups and the activity of latent (P = 0.010) and active (P = 0.004) forms was lower in the AF samples of group 2. The band of the latent form of MMP-9 was visible in 17/20 samples of group 1, while it was completely absent in all samples of group 2. In contrast, the band of the active form was clearly visible and with a greater activity in AF samples of group 2 (P = 0.002). Placental dysfunction seems to induce a lower MMP-2 activity and a higher MMP-9 activity through the release of pro-inflammatory cytokines. Because fetal pulmonary secretions are a likely source of gelatinases in AF during late gestation, the increased MMP-9 activity could be related to fetal distress. These data provide a starting point to better understand the role of MMPs in equine pregnancy, although it should be confirmed in a larger and more homogeneous population of mares with high-risk pregnancy.

Epidemiologic case investigation on the zoonotic transmission of Staphylococcus aureus infection from goat to veterinarians

Staphylococcus aureus infection led to a case of goat abortion, and four veterinarians contracted S. aureus infection from the goat during and after the abortion. Three veterinarians assisted a doe during the dystocic delivery of a dead foetus. Seventy-two hours after the dystocia, which ended with the goat's death, the veterinarians who assisted during the kidding and the veterinarian who performed the necropsy showed the presence of multiple, isolated, painful pustules 1-5 mm in diameter located along their forearms and knees. S. aureus was isolated from the pustules of the veterinarians, the placenta and uterus of the goat, the organs (brain, thymus gland, abomasum, liver and spleen) of the foetus, the scrotum and eye swabs of the buck, and mammary pustules of another goat from the same herd. Histological analysis revealed purulent metritis and inflammation of the placental cotyledons. Additional investigations eliminated the chances of other infections. S. aureus isolates recovered from the veterinarians, goats, foetus and buck were sensitive to the tested anti-microbials and did not encode staphylococcal enterotoxin genes (sea, ser, sep, see, seg and sei). The isolates were closely related, as indicated by the results of Fourier-transform infrared spectroscopy and comparative whole-genome sequencing analysis. The results of this study clearly support the hypothesis that an episode of professional zoonosis was caused by S. aureus infection during the abortion and also highlight the need for bacterial subtyping in epidemiological surveys.

Rhabdomyolysis and Acute Renal Failure Associated with Oxytetracycline Administration in Two Neonatal Foals Affected by Flexural Limb Deformity

Oxytetracycline (OTC) administration has become a frequent practice in equine neonatology for the treatment of flexural limb deformity. The cause of this condition remains unclear but clinical studies revealed that following IV administration of OTC a relaxation of the metacarpophalangeal joint occurs in foals affected by flexural deformity. Studies concluded that OTC administration in neonatal foals did not adversely affect the kidneys. Other adverse effects of OTC have never been reported. This report presents two cases with different outcomes of 3-day-old foals which presented acute collapse and progressive depression after OTC administration. The clinical aspects, the increased activity of serum enzymes indicative of muscular damage, the presence of myoglobin in urine were clear diagnostic indicators of severe rhabdomyolysis, and the gross and histological findings confirmed a myopathy associated with renal damage in one case. Adverse effects on the musculoskeletal and urinary systems in healthy foals were first reported and were probably associated with multiple doses administered to foals less than 24–48 h old and/or at dosing intervals less than 24–48 h. The risk of development of rhabdomyolysis and nephrotoxicity in neonatal foals treated with OTC for flexural deformity from now on should be considered.

Ultrasonographic measurement of the adrenal gland in neonatal foals: reliability of the technique and assessment of variation in healthy foals during the first five days of life

BACKGROUND

Adrenal gland ultrasonographic measurements are useful in clinical evaluation of patients with adrenal dysfunction in several species. In human healthy neonates, the ultrasonographic size of the adrenal glands decreases during the first days of life. Ultrasonography of adrenal glands was demonstrated to be feasible in neonatal foals. The aims of this study were to describe a technique for ultrasonographic measurement of adrenal gland size to test its reliability in neonatal foals, and to assess any variation of ultrasonographic measurements during the first five days of life in healthy foals.

METHODS

First, measurements of the adrenal glands were retrospectively obtained by three observers in 26 adrenal gland images of 13 healthy and sick neonatal foals. The interobserver and intraobserver agreement were tested. Later, adrenal gland ultrasonographic images and measurements were acquired by one operator in 11 healthy neonatal foals at one, three and five days of life and differences among the measurements obtained at the different time points were assessed.

RESULTS

Interobserver agreement ranged from fair to excellent (0.48-0.92), except for cortex width (<0.4); intraobserver agreement ranged from good to excellent (0.52-0.98). No significant differences were found among the measurements obtained at one, three and five days of life.

CONCLUSION

Adrenal glands ultrasonographic measurements can be obtained consistently in equine neonates, and in contrast to people they do not vary during the first five days of life in healthy foals.

Venous blood gas parameters, electrolytes, glucose and lactate concentration in sick neonatal foals: Direct venipuncture versus push-pull technique

BACKGROUND

Blood collection by indwelling intravenous catheter (IVC) avoids repeated venipuncture, which could cause thrombophlebitis risk, anxiety and pain in patients.

OBJECTIVES

To compare blood gas parameters, electrolytes, glucose, lactate and haematocrit concentration obtained from venous blood samples collected via a jugular IVC by push-pull (PP) technique to those obtained by venipuncture in hospitalised foals, at the time of catheter placement (T0) and 24 hours after the beginning of intravenous therapy (T24).

STUDY DESIGN

Prospective observational study.

METHODS

Paired blood samples were drawn from hospitalised foals at T0 and T24. In each foal, one venous blood sample was collected via IVC by the following PP technique: 2.4 mL of blood was aspirated and immediately reinfused through the catheter three times consecutively, then 1 mL of blood was collected using a 1 mL heparinised syringe. Thereafter, another sample was collected by direct venipuncture of the contralateral jugular vein, with an identical 1 mL heparinised syringe, with a 1-inch, 20-G needle. All samples were analysed with an automated blood gas analyser within 10 minutes of collection. The agreement between the two techniques was assessed by Bland-Altman analysis and intraclass correlation coefficient (ICC).

RESULTS

The level of agreement of blood gas values obtained by the two different techniques was high with very small bias and clinically acceptable ICC (>0.907 at T0; >0.794 at T24) for all variables, except for haematocrit (bias -3.52 at T0; -2.44 at T24) and PvO₂ at T0 and T24 (ICC 0.669 and 0.733, respectively).

MAIN LIMITATIONS

Potential sub-clinical catheter-related complications were not investigated by ultrasound or bacterial culture of the catheter; short duration of the study.

CONCLUSIONS

PP technique appears to be acceptable for collection of blood samples for venous blood gas parameters, as well as electrolytes, glucose and lactate in sick neonatal foals.

Peripartum findings and blood gas analysis in newborn foals born after spontaneous or induced parturition

Induction of parturition in horses is still not well accepted due to the potential peripartum complications for mares and newborn foals. We assessed differences after spontaneous and induced parturition with low doses of oxytocin (OX) in 1) incidence of peripartum complications in mares; 2) viability, behavioral, physical, and venous blood gas analyses in foals. In this study 61 mares were included; 45/61 were enrolled in the spontaneous foaling group (SF) and 16/61 in the induced foaling group (IF). In the IF group, when the calcium in mammary secretion reached concentrations of ≥250 ppm, mares received a single injection of 2.5 IU of oxytocin IV once a day until foaling. Mares' breed, age, parity, gestational and stage II length, and peripartum complications were recorded. Foal maturity, vital (Apgar score), behavioral and physical parameters were assessed at birth, and the foal clinical condition was monitored for one week. A jugular venous blood sample was collected at birth for blood gas analysis, acid-base status, and lactate assessment. The median gestational length was within the reference interval in all the mares included and did not differ between the two groups. No statistical differences in the II stage length nor in incidence of peripartum complications were observed between the two groups. All the foals were born alive and showed no signs of prematurity/dysmaturity. No statistical differences were found in foal viability between the two groups. Time to stand and nurse from the mare, and body temperature were significantly higher in the IF compared to the SF group. Venous blood pH, SO₂% and BE were lower, while pCO₂ and lactate were higher in the IF than in the SF group. All the foals in both groups remained clinically healthy during the observation period. In conclusion, at term induction of parturition with a low dose of oxytocin does not have adverse effects on peripartum in mares. Our findings suggest that at term induced foals suffer slightly greater, but not clinically significant, hypoxia, hypercapnia and acidosis than spontaneously delivered foals.

The First Case of Botulism in a Donkey

Botulism, a severe neuroparalytic disease that can affect humans, all warm-blooded animals, and some fishes, is caused by exotoxins produced by ubiquitous, obligate anaerobic, spore-forming bacteria belonging to the genus Clostridium and named botulinum neurotoxin (BoNT)-producing clostridia. This report presents the case of a 3-year-old donkey mare referred for progressive and worsening dysphagia of four days’ duration. Her voluntary effort in eating and drinking was conserved, and she was able to slow chew without swallowing. A complete neurological examination was performed, and botulism was strongly suspected. The ability to swallow feed and water returned on the tenth day of hospitalization and improved progressively. The jenny was discharged from the hospital after fifteen days. During the hospitalization, the Italian National Reference Centre for Botulism confirmed the diagnosis: mare’s feces were positive for BoNT/B and Clostridium botulinum type B.

Molecular Detection of Bovine Papillomavirus DNA in the Placenta and Blood of Healthy Mares and Respective Foals

Despite the characteristic species specificity of Papillomaviruses (PVs), the bovine papillomavirus (BPV) types 1, 2, and-more rarely-13, can cross-infect equids, where they are involved in the pathogenesis of sarcoid neoplasms. Sarcoids are locally invasive fibroblastic skin tumors that represent the most common skin neoplasms in horses worldwide. The transmission mechanism of BPV is still controversial in horses. Thus far, direct and indirect routes have been implicated, while vertical transmission has been suggested after the detection of viral DNA in the semen of healthy stallions. Testing of the blood and placenta of non-sarcoid baring mares and their respective foals revealed that the equine placenta can harbor BPV DNA, leading us to speculate a possible prenatal vertical DNA transmission in equids.

Heterologous Wharton's Jelly Derived Mesenchymal Stem Cells Application on a Large Chronic Skin Wound in a 6-Month-Old Filly

A complex feedback of growth factors, secreted by a variety of cell types, is responsible for the mediation of skin healing. Despite the recent advances in wound healing management, this fails up to 50% and skin wounds can still be considered one of the main causes of morbidity, both in human and veterinary medicine. Regenerative medicine, involving mesenchymal stromal cells (MSCs), is nowadays a promising solution for skin wound healing. Indeed, MSCs are involved in the modulation of the inflammatory local response and cell replacing, by a paracrine mode of action. Local application of equine umbilical cord Wharton's jelly MSCs (WJMSCS) was carried out in a 6-months-old filly with a non-healing skin wound. Heterologous WJMSCs were applied four times using a carboxymethylcellulose (CMC) gel, produced dissolving CMC in autologous plasma. At first application the mean wound area was 7.28 ± 0.2 cm². Four days after the last application of WJMSCs, the mean wound area was 1.90 ± 0.03 cm², and the wound regression rate was +74%. No local or systemic side effects were registered after WJMSCs application and no evident exuberant scar was observed after wound healing. At discharge, the mean wound area was 0.38 ± 0.01 cm² and the total regression rate was +80%. Five days later, the wound was completely healed. In the present clinical case report, the use of WJMSCs led to promising clinical results, paving the way for possible future applications in the treatment of chronic wounds in horses.

A regression model including fetal orbit measurements to predict parturition in Standardbred mares with normal pregnancy

In the mare, foaling is a critical unpredictable event due to a wide range of gestational length and the absence of clear signs of impending parturition. To predict foaling, pH, inversion sodium potassium and increase of calcium concentration in mammary secretions are used. The aim of this study was to find how many days are left until parturition knowing mare's age (A) and parity (P) combined with ultrasonographic measurements of the fetal orbit in Standardbred mares with normal pregnancy. Eighty healthy Standardbred mares with normal pregnancy were hospitalized for attended delivery. Information about mare's age, parity and breeding date were recorded at admission. Transrectal ultrasonography were routinely performed at admission and every 10 days until parturition using a B-mode real time portable unit equipped with a 5-7.5 MHz linear transducer. The images of the fetal orbit were acquired when cornea, anterior and posterior chamber, vitreous body, lens and optic nerve were visible. Longitudinal diameter (LD) was considered as the distance between the two ocular poles, within the vitreous body; transverse diameter (TD), perpendicular to LD and bisecting the lens, was measured as the distance between cornea and retina. At delivery, length of pregnancy and gestational age at each exam were registered. For each ultrasound examination, days before parturition (DBP) were calculated. Seventy-eight Standardbred mares with normal pregnancies were included in the study. Mares' mean age was 9 ± 5 years old (range 4-20 years) and mean gestation length was 341 ± 7 days (range 327-366 days). Thirty-three mares were primiparous and 45 mares were multiparous. Data were analyzed using a regression tree: P, A, LD and TD were used as covariates. DBP was used as the variable of interest. Nine terminal nodes were identified based on the selected covariates. The first split is produced by the TD: fetuses with TD greater or equal than 2.97 cm are further split according to LD, with a threshold of 3.28 cm. The next split is dictated by A; after a further split on LD, the first terminal node is built, containing 34 fetuses with average DBP equal to 10 days. If the A is ≥ 9.5 years a further split is on P: when mares are multiparous, the TD built two different nodes. Since prediction of mare's foaling date is an important factor in stud farm management, the regression model developed may help the veterinarian to estimate the DBP in Standardbred mares with normal pregnancy.

Early colonisation and temporal dynamics of the gut microbial ecosystem in Standardbred foals

BACKGROUND

Even if horses strictly depend on the gut microbiota for energy homeostasis, only a few molecular studies have focused on its characterisation and none on the perinatal gut microbial colonisation process.

OBJECTIVES

To explore the perinatal colonisation process of the foal gut microbial ecosystem and the temporal dynamics of the ecosystem assembly during the first days of life.

STUDY DESIGN

Longitudinal study.

METHODS

Thirteen Standardbred mare-foal pairs were included in the study. For each pair, at delivery we collected the mare amniotic fluid, faeces and colostrum, and the foal meconium. Milk samples and faeces of both mare and foal were also taken longitudinally, until day 10 post-partum. Samples were analysed by means of next-generation sequencing of the 16S rRNA gene on Illumina MiSeq.

RESULTS

Our findings suggest that microbial components derived from the mare symbiont communities establishes in the foal gut since fetal life. After birth, an external transmission route of mare microorganisms takes place. This involves a rapid and dynamic process of assembling the mature foal gut microbiome, in which the founder microbial species are derived from both the milk and the gut microbial ecosystems of the mare.

MAIN LIMITATIONS

The inability to discriminate between live and dead cells, the possible presence of contaminating bacteria in low biomass samples (e.g. meconium and amniotic fluid), the limits of the phylogenetic assignment down to species level, and the presence of unassigned operational taxonomic units.

CONCLUSIONS

Our data highlight the importance of mare microbiomes as a key factor for the establishment of the gut microbial ecosystem of the foal.

Cytokine levels in colostrum and in foals' serum pre- and post-suckling

The purpose of this study is to investigate the presence of IL-4, IL-8, IL-13 and IFN-γ in equine colostrum and in foals' serum. Samples were obtained from 14 mares and their healthy foals. Soon after parturition, 10ml of colostrum was collected, filtered, centrifuged and frozen until assayed. Blood samples were obtained from each foal at birth (TO) and again after 24h (T24), after which they were frozen until assayed. Serum IgG was measured at 24h of age with an immunoturbidimetric quantitative method. Cytokine concentration was determined using commercially available ELISA tests. Statistical analyses revealed a significant difference in serum concentration of IL-4 at T0 and at T24 (p<0.05) and a significant correlation between the serum IL-4 at T24 and colostral IL-4. These results suggest the absorption of IL-4 from colostrum. The presence of IL-8 in the pre-suckle foal's serum may be due to an endogenous production. With the exception of two samples, there was no IL-13 detected in the foals' serum at birth and remained undetectable in 8/14 samples after 24h. This cytokine was also undetectable in four colostrum samples, where its concentration showed a wide range and a high standard deviation. IFN-γ was present in both the colostrum and in the foals serum at birth.

Time-dependent changes and prognostic value of lactatemia during the first 24 h of life in brachycephalic newborn dogs

Blood lactate concentration is known to be a good prognostic indicator associated with the severity of illness and the patient's outcome both in human and veterinary medicine. It also plays a significant role in the assessment of the newborn, being a good indicator of fetal hypoxia and the ideal predictor of morbidity at term in babies. In veterinary neonatal medicine, hyperlactatemia is considered a valid prognostic marker in critically ill foals; moreover, blood lactate measurement has been proposed for the evaluation of newborn viability and the assessment of fetal distress during delivery in dogs. Unfortunately, only a few studies have been published concerning the canine species. The present work examines 67 brachycephalic newborn dogs and their mothers, with the aim to evaluate the time-dependent changes of blood lactate and glucose concentration during the first 24 h after vaginal or caesarean delivery both in puppies and bitches. To our knowledge, this is the first published study examining the time-dependent changes of these parameters in the bitch after parturition. Within the studied population of puppies, non-surviving was significantly associated with a higher lactatemia and a lower APGAR score. Blood lactate was high at birth then progressively decreased during the first 24 h of life and a lack of normalization of blood lactate levels within this time interval was suggestive for a poor prognosis for the newborn dogs; moreover, the decrease appeared to be slower after vaginal delivery. Lactatemia also showed a positive correlation with glycemia at birth. Concerning the bitches examined, blood lactate was found to be significantly higher after vaginal delivery than after caesarean section; the normalization occurred within 24 h after parturition. Blood glucose level was significantly higher at 2 h from delivery both in the group of bitches submitted to caesarean section and in those undergoing natural whelping but no statistical correlation was found between maternal glycemia and lactatemia. The results of the present study highlighted that the monitoring of lactatemia during the first 24 h of life, in association with the assessment of the APGAR score at birth, can be an useful prognostic tool helping to identify the most severely distressed puppies and to provide them an adequate support.

97 PRELIMINARY DESCRIPTIVE STUDY OF EQUINE PLACENTA GENERATED AFTER TRANSFER OF IN VIVO- AND IN VITRO-PRODUCED EMBRYOS

Placental changes associated with artificial reproductive technologies have been described in several species, but little information is available in horses. Joy et al. (2012) reported that human placentas from intracytoplasmic sperm injection derived embryos were heavier and thicker than those produced after natural conception. Despite the most growing interest and efficiency of artificial reproductive technologies in equine species, only recently, Pozor et al. (2016) described placental abnormalities in pregnancies generated by somatic cell NT, but there are no studies on equine placenta generated by intracytoplasmic sperm injection and traditional embryo transfer. In the present preliminary study, macroscopic differences of placentas generated after transfer of in vitro- or in vivo-produced embryos were registered. Twelve Standardbred recipient mares with pregnancy generated after transfer of in vivo-derived (Group 1) and in vitro-derived (Group 2) embryos were enrolled; 10 Standardbred mares with pregnancy derived by traditional AI were included as control (Group 3). All pregnancies were physiological, and newborn foals were healthy. Mare age, parity, length of pregnancy, gross evaluation and weight of placenta, total length of umbilical cord (UC), length of UC, number of UC coils, foal sex, and weight at birth were registered. Collected data are listed in Table 1 and are expressed as mean ± standard deviation. Differences between groups were evaluated by 1-way ANOVA, and the difference in proportion of overweight placentas was evaluated with the Fisher test. The gross evaluation of placenta revealed 8/12 placentas (2/4 Group 1; 6/8 Group 2) were heavier than 11% (Madigan, 1997) due to oedema of the chorioallantois. No overweight placentas were registered in Group 3. In Group 1, 1/4 placentas had villous hypoplasia, and in Group 2, 1/8 placentas had cystic pouches on the UC. There were no significant differences among groups. However, the proportion of overweight placentas between Group 2 (6/8) and Group 3 (0/10) approached significance (P = 0.06). Although preliminary, the results of the present study suggest that production of equine embryos in vitro may lead to alterations in placental development. Several studies in cattle and sheep have suggested that alterations in the placentas of pregnancies derived from in vitro-produced embryos are related to effects of culture on epigenetic regulation. Less is known in the horse about the effects of in vitro embryo production on placental development; thus, further research in this area is necessary. Table 1. Characteristics of full-term placentas derived from AI or embryo transfer with in vivo- and in vitro-produced embryos

Total plasma magnesium in healthy and critically ill foals

Abnormalities in total Mg (tMg) concentration in plasma and/or serum are common in critically ill humans, and the association with increased mortality has been documented in several clinical studies in adults and newborns with hypoxic-ischemic encephalopathy. Abnormalities in tMg were studied in hospitalized dogs, cats, and adult horses. Newborn foals were scarcely studied with regard to Mg concentration. The aims of the present study were: (1) to compare two analytical methods for the determination of tMg in plasma: the automated colorimetric method and the atomic absorption spectrometry; (2) to measure plasma tMg in healthy foals during the first 72 hours after birth and in sick foals during the first 72 hours of hospitalization; (3) to compare total plasma Mg concentration among healthy foals, foals affected by perinatal asphyxia syndrome (PAS), prematurity and/or dismaturity, and sepsis; (4) to evaluate tMg plasma concentration in surviving and non-surviving foals. One hundred seventeen foals were included in the study: 20 healthy and 97 sick foals. The automated method used in clinical practice probably overestimates plasma tMg. Due to its higher sensitivity and specificity, the atomic absorption spectrometry should be considered the method of choice from an analytical point of view, but requires an instrumentation not easily available in any laboratory and specific technical skills and competencies. Plasma tMg in healthy foals were included in the range 0.52 to 1.01 mmol/L and did not show any time-dependent change during the first 72 hours of life. In sick foals, tMg evaluated at T0 was statistically higher than tMg measured at subsequent times. Foals affected by PAS had a tMg at T0 significantly higher (P < 0.01) than healthy, septic, and premature and/or dysmature foals. The t test found significantly higher (P < 0.01) plasma tMg measured at T0 in non-surviving than in surviving foals. Plasma tMg could be a useful parameter for the diagnosis of PAS and the formulation of the prognosis in critically ill foals.

Expression of interleukin-1β, interleukin-8, and interferon-γ in blood samples obtained from healthy and sick neonatal foals

OBJECTIVE

To evaluate and compare the gene expression of interleukin(IL)-1β, IL-8, and interferon-γ during the first 72 hours after birth in healthy foals and during the first 72 hours after hospitalization in sick neonatal foals and investigate correlations of clinicopathologic variables with cytokine expressions in healthy and sick neonatal foals.

ANIMALS

33 foals < 7 days old (10 healthy foals, 7 foals with sepsis, 6 foals with peripartum asphyxia syndrome, and 12 foals with other diseases [2 with failure of passive transfer of immunity only were not further evaluated]).

PROCEDURES

A blood sample (15 mL) was collected from each foal immediately after birth or hospital admission (0 hours) and at 24 and 72 hours later. Clinicopathologic variables were evaluated, and cytokine gene expression in WBCs was measured with an absolute quantitative real-time reverse transcriptase PCR assay.

RESULTS

At all time points, gene expression of interferon-γ was low in all groups. No time-dependent changes in cytokine expressions were detected in healthy or sick foals. Foals with sepsis had significantly higher IL-1β gene expression than did healthy foals, foals with peripartum asphyxia syndrome, or foals with other diseases. At 0 hours, IL-1β expression was correlated with plasma fibrinogen concentration in healthy foals and with the neutrophil-to-lymphocyte ratio in foals with sepsis; IL-8 expression was correlated with monocyte count in foals with sepsis and with arterial pH, plasma fibrinogen concentration, and plasma lactate concentration in foals with peripartum asphyxia syndrome.

CONCLUSIONS AND CLINICAL RELEVANCE

Data have suggested that evaluation of IL-1β expression in sick neonatal foals could help identify those with sepsis.

Evaluation of lung maturity by amniotic fluid analysis in equine neonate

The aim of this study was to gather useful new data for evaluation of lung maturity in the neonatal foal. Because equine neonatal intensive therapy is very expensive, a precocious diagnosis could help to express a prognosis and to offer a respiratory support early after birth, increasing the survival rate and reducing complications. Amniotic fluid was collected at parturition on n=18 mares. Lamellar bodies were isolated in the amniotic fluid and measured with transmission electron microscopy (TEM). Furthermore two tests on amniotic fluid that are commonly used in humane medicine were utilized: lecithin/sphingomyelin ratio (L/S) and lamellar body count (LBC). L/S ratio was determined using thin layer chromatography (TLC) and, for the first time in equine amniotic fluid, with high performance liquid chromatography (HPLC). LBC was performed with an automated blood cell counter. The mean of the L/S ratio obtained in mature foals was 2.5 with TLC and 2.7 with HPLC. The mean LBC in the same group was 48x10(3)/microL. The Spearman's Rank correlation test found a significant correlation between TLC and Apgar score (R=0.66, p<0.01), between TLC and cord pH (R=0.65, p<0.05), between HPLC and Apgar score (R=0.63, p<0.01) and between cord pH and Apgar score (R=0.82, p<0.01). The Student's t-test did not found a significant difference between L/S ratio performed with TLC and with HPLC. These methods may be useful for evaluation of lung maturity in the equine species, but further studies on a large number of mature and premature foals are necessary to establish equine pulmonary maturity standards.