Medical management and positive outcome after prolonged recumbency in a case of equine herpesvirus myeloencephalopathy

A 17-year-old mare presenting with acute fever, weakness and bladder dysfunction was diagnosed with equine herpesvirus myeloencephalopathy (EHM). The mare become transiently recumbent, underwent parenteral fluid therapy, plasma infusion, steroidal/nonsteroidal anti-inflammatory drugs (SAID/NSAIDs) and bladder catheterization. After 10 days the mare was hospitalized. Neurological evaluation revealed ataxia and proprioceptive deficits mainly in the hind limbs. The mare was able to stand but unable to rise from recumbency or walk. Secondary complications included Escherichia coli cystitis, corneal ulcers and pressure sores. A full-body support sling was used for 21 days. Medical treatment included systemic antimicrobials, NSAIDs, gradual discontinuation of SAIDs, parenteral fluid therapy and bladder lavage. The mare tested positive for Varicellovirus equidalpha 1 (EHV-1) DNA in nasal swab and blood samples on day 13 and in urine samples on days 13 and 25 after the onset of fever. Neurological signs improved over a period of 34 days and the mare was discharged with mild hind limb weakness/ataxia. Secondary complications resolved within 2 weeks. At the eight-month follow-up, marked improvement in locomotory function had been achieved.

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.

Evaluation of a smartphone electrocardiograph in healthy foals and comparison to standard base-apex electrocardiography

Smartphone-based technology for ECG recording has recently spread as a complementary tool for electrocardiographic screening and monitoring in adult horses and in other animal species. The present study aimed to assess the feasibility and accuracy of a smartphone-based ECG in healthy foals. This was a prospective observational study (authorization n. 45,865/2016) including 22 foals aged less than 21 days. A reference standard base-apex ECG (rECG) was acquired, and a smartphone ECG (sECG) was recorded immediately after by using a smartphone-based single lead electrocardiograph. All ECG tracings were evaluated in a blind fashion by a single board-certified cardiologist, who judged whether the tracings were acceptable for interpretation and performed ECG measurements and diagnosis. The Spearman correlation coefficient, the Cohen's k test and the Bland-Altman test were used to assess the agreement between sECG and rECG. All sECG tracings were acceptable for interpretation. All foals showed sinus rhythm on both rRCG and sECG tracings, with perfect agreement in heart rate classification (κ = 0.87; p < 0.001). No clinically relevant differences were found in the assessment of waves and intervals duration. Concerning P wave and QRS complex polarity, the percentage of agreement between rECG and sECG was 78% and 83%, respectively. About ECG tracing quality, rECG and sECG showed a substantial agreement (κ = 0.624; p < 0.001). In conclusion, the smartphone-based ECG device tested in the present study recorded good quality single-lead ECG tracings in foals, reliable for heart rate and ECG measurements, but different polarity of P waves and QRS complexes was found in some foals in comparison to rECG.

A Retrospective Study on the Status of Working Equids Admitted to an Equine Clinic in Cairo: Disease Prevalence and Associations between Physical Parameters and Outcome

Working equids are often used to exhaustion, living and dying in conditions below minimal welfare standards. Due to their poor welfare status, euthanasia should be considered in certain conditions. The study aimed to describe the population and the disease frequency of the working equids admitted at an equine clinic in Cairo (i.e., Egypt Equine Aid (EEA)) from 2019 to 2022 and identify possible associations between physical parameters at admission and the outcome. Records of 1360 equids admitted at EEA were reviewed. The majority of the admitted equids were horses (65.6%), followed by donkeys (33%), in particular stallions (68.7%), from 1 to 15 years old (74.8%). Hospitalisation was mainly due to wounds (28.9%), orthopaedic problems (27.4%), colic (8.5%), or infectious diseases (7.4%). The majority of the equids were discharged, but 5.1% died on their own, without human intervention, and 23% were euthanised. Text mining revealed the anamnesis's most frequent words were 'accident', 'lameness', and 'wound'. In addition, owners sometimes reported using inappropriate remedies (e.g., firing) before hospitalisation. Multivariable ordinal regression analysis performed between physical parameters and the outcome (ordered based on severity: discharged, euthanasia, and dead) revealed that sex (male vs. female: OR = 1.33; p < 0.05), colour of the mucous membrane (pathological vs. physiological: OR = 1.72; p < 0.01), and capillary refill time (pathological vs. physiological: OR = 1.42; p = 0.02) increased the likelihood of a non-survival outcome. In conclusion, early euthanasia should be considered for these equids, to minimise prolonged suffering. Moreover, owners' education is recommended to guarantee minimal welfare standards to the working equids.

Identification of asinine gamma herpesviruses in a donkey with interstitial pulmonary fibrosis, pleural effusion and thrombocytopenia

A 23-year-old domestic donkey (Equus asinus) referred for severe respiratory distress due to suspected equine asthma. Ultrasound of the chest revealed bilateral irregular pulmonary consolidation and pleural effusion. Airway endoscopy and tracheal wash cytology showed severe neutrophilic inflammation and bacterial culture was positive for Streptococcus equi subsp. zooepidemicus. Despite aggressive treatment, the donkey died in 48 hours. On post-mortem examination, the lung was whitish, collapsed, and firm, with fibrotic multifocal nodular areas. Pleural effusion and pleuritis were detected. Histologically, the lung architecture was markedly replaced by interstitial fibrosis. The histological features observed were suggestive of a severe chronic fibrosing interstitial pleuropneumonia with type 2 pneumocyte hyperplasia and intralesional syncytial cells. Pulmonary fibrosis was associated with the presence of asinine gammaherpesvirus 2 and 5 infection, confirmed by PCR and sequence analysis. The macroscopic and histological pattern of fibrosis was diffuse and interstitial, and the nodular lesions were consistent with spared lung parenchyma, instead of the canonical nodular distribution of the fibrosis observed in equine multinodular pulmonary fibrosis. Asinine herpesviral pulmonary fibrosis is uncommon, but should be considered by clinicians in the list of differentials in donkeys with chronic respiratory signs.

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.

Survey of horse transportation in Switzerland: practices and issues

INTRODUCTION

This study aimed to describe equine transportation practices and transport-related behavioural and health problems in Switzerland and to identify possible associations between them. An online survey was disseminated to Swiss equine industry members and questioned respondents' details, transport practices (before, during, and after journeys), horse transport-related behavioural (TRPBs) and health problems (TRHPs) experienced in the previous 2 years. The survey generated 441 valid responses, analysed using descriptive statistics and logistic regression models (outcomes: TRPBs, TRHPs, injuries, diarrhea). Respondents were mainly women (79,5 %), younger than 50 years (75 %), and amateurs (80 %). Most of the respondents transported one or two horses (88,7 %), for a short (< 2 hours) journey (75,5 %). Pre-transport practices were performed by 72,1 % of respondents and horses' fitness for travel was assessed in the majority of cases (66,5 %). During the journey, horses were tethered (92,6 %) and monitored (52,7 %). The majority of respondents (74,9 %) assessed also the horses' fitness after travel. TRPBs were reported by 13,4 % of respondents. TRPBs' likelihood increased when the respondents were women, performed pre-transport practices and training for transport, did not assess drinking behaviour and general health before journey, and the horses experienced also TRHPs. TRHPs were reported by 34 % of the respondents and were associated with younger respondents, use of trucks, doing pre-transport practices, wearing protections, not monitoring horses during transport and preexisting TRPBs. Among TRHPs the most frequent were injuries (72,1 %) and diarrhea (41 %). The likelihood of injuries increased with younger respondents, use of trucks, wearing protections, lack of monitoring during transport and TRPBs. While younger respondents, longer journeys, wearing protections, lack of monitoring during transport, measuring rectal temperature after journeys and TRPBs increased the odds of reporting diarrhea. Even though our findings must be interpreted with caution due to survey limitations, considering that the found associations do not always mean causation, they highlight the strengths and weaknesses of transport practices in Switzerland and report evidence to implement current regulations on the protection of horse welfare during transport.

Effects of Transport and Feeding Strategies Before Transportation on Redox Homeostasis and Gastric Ulceration in Horses

Transportation may lead to oxidative stress (OS) and gastric ulceration in horses, and optimal feed management before, or during, transportation is unclear. This study aimed to evaluate the effects of transportation after three different feeding strategies on OS and to explore possible associations between OS and equine gastric ulcer syndrome (EGUS). Twenty-six mares were transported by truck for 12 hours without food or water. Horses were randomly divided into 3 groups; (1) fed 1 hour before departure (BD), (2) fed 6 hours BD, (3) fed 12 hours BD. Clinical examinations and blood collections were performed at approximately 4 hours BD (T0), at unloading (T1), 8 hours (T2) and 60 hours (T3) after unloading. Gastroscopy was conducted prior to departure, and at T1 and T3. Although OS parameters remained in the normal range, transportation was associated with increased reactive oxygen metabolites (ROMS) at unloading (P=0.004), with differences between horses fed 1 hour and 12 hours BD (P < .05). The level of total antioxidant (PTAS) was affected by both transportation and feeding strategy (P = 0.019), with horses fed 1 hour BD demonstrating greater PTAS at T = 0, and a different response in comparison with the other groups and the literature. Nine horses demonstrated clinically significant ulceration of the squamous mucosa at T1 but, although weak correlations were evident between OS parameters and ulcer scores, univariate logistic regression showed no associations. This study suggests that feed management prior to a long journey (12 hours) may affect oxidative balance. Further studies are needed to understand the nexus between feed management before and during transport, transport-related OS and EGUS.

Blood Gas, Acid-Base and Electrolyte Analysis in Healthy Dromedary Camel Calves up to 21 Days of Life

The importance of prompt evaluation and care of the newborn is essential for reducing neonatal mortality, which represents a major cause of loss in camelids. This study investigated the blood gases, acid-base and electrolyte profiles in healthy dromedary calves during the first 3 weeks of life, assessing possible associations with age. Twenty-one dromedary camel calves aged 1 to 21 days were sampled, and venous whole blood analyzed through a VETSTAT® analyzer. The following parameters were measured: sodium (Na⁺), potassium (K⁺), chloride (Cl^-), hydrogen ion concentration (pH), partial pressure carbon dioxide (pCO₂), partial pressure oxygen (pO₂), total hemoglobin concentration (tHb), hemoglobin oxygen saturation (sO₂), total carbon dioxide (tCO₂), bicarbonate (HCO₃^-), base excess (BE) and anion gap (AG). Calves were divided in two groups; younger calves (1-10 d), and older calves (11-21 d). Statistical analysis showed an effect of age, with lower K⁺ (p < 0.001) and higher Na⁺ and Cl^- (p < 0.05) mean concentrations in the younger calves compared to the older ones, and higher pCO₂ and lower sO₂ mean concentrations in the older group. These preliminary results firstly described the blood gas, acid-base and electrolyte profiles in the healthy dromedary calf during the first 3 weeks of age, suggesting an effect of age on some parameters.

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.

Ex vivo ultrasonographic and histological morphometry of small intestinal wall layers in horses

Ultrasonographic morphometry of wall layers is commonly used in veterinary patients with suspected small intestinal disease, however published studies comparing this method with histopathology in horses are limited. This prospective, methods comparison study compared the qualitative and quantitative characteristics of small intestinal wall layers using ex vivo high‐frequency ultrasound versus histopathology in a sample of 16 horses. Transverse section images of duodenum, distal jejunum, and ileum were acquired with a high‐frequency linear transducer (7–15 MHz). Transverse histological cryosections were obtained at the same level. Appearance and measurements of the intestinal wall layers were assessed on the ultrasonographic and histological images. High‐frequency scanning with the probe in close contact with the serosal surface of the equine intestinal wall allowed a clear and detailed definition of wall layers. A hyperechoic line was consistently detected within the tunica muscularis in all the intestinal tracts, corresponding histologically to the interface between its longitudinal and circular muscle layers. The overall trend of the values for wall layers thickness was comparable between ex vivo ultrasonography and histology. However, a poor agreement was found between the two methods for all layers. The ultrasonographic measurements were thicker compared to histological measurements, with the exception of the total wall and the muscular layer thicknesses. These layers were thinner on ultrasonography in the duodenum and in all the intestinal segments, respectively. Findings from the current study can be used as background for future ultrasonographic investigations of small intestinal diseases in horses.

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.

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.

Transabdominal ultrasonographic measurement of caudal vena cava to aorta derived ratios in clinically healthy neonatal foals

Background

Ultrasonographic measurement of the vena cava and aorta (Ao) diameters and their ratios have been suggested to be a reliable way of quantifying hypovolemia.

Objective

To evaluate the feasibility and reliability of an ultrasonographic technique for measurement of Ao and caudal vena cava (CVC) and derived ratios using three different acoustic windows in a population of healthy neonatal foals. Correlation between Ao and CVC measurements and ratios and foals' age or bodyweight were also investigated.

Methods

In 14 healthy foals aged less than 7 days, the diameters of the Ao and of the CVC in long and short axis were measured by two observers from images obtained using three different ultrasonographic imaging planes (left dorsal, left ventral and right views). The Ao and CVC cross‐sectional area and the CVC/Ao diameter and area ratios were calculated. Image quality was subjectively assessed. Intraobserver and interobserver reliabilities for image quality scores and measurements were evaluated between the two observers. Simple linear regression models were used to identify correlations between the CVC/Ao measurements and ratios and the age and bodyweight of the foals.

Results

The left ventral view showed the highest reliability. A correlation between bodyweight and the short axis measurement of the CVC was found (R² = 0.385; p = 0.018). Age was positively correlated with the long axis of measurement of the CVC (R² = 0.426; p = 0.011) and CVC/Ao diameter ratio (R² = 0.625; p = 0.001).

Conclusions

The left ventral view allows the Ao and CVC cross sections to be easily visualized and measured in neonatal foals in right lateral recumbency.

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.

Doppler evaluation of renal resistivity index in healthy conscious horses and donkeys

The renal resistive index (RRI) is used as a measurement of downstream resistance in arteries. The aim of this study was to assess the RRI of the arcuate arteries by pulsed-wave Doppler ultrasonography in healthy conscious horses and donkeys, and to verify any differences related to age, breed, bodyweight (BW) or body condition (BCS). Thirty-three healthy conscious horses and nine donkeys had their systolic and diastolic flow velocities at the level of the arcuate arteries estimated by pulsed-wave Doppler ultrasound, and the RRI was calculated. The relationship of RRI with age, breed (Trotters vs. other breeds), bodyweight (BW), and body condition score (BCS) were evaluated. PW Doppler evaluation of RRI was successfully applied in most of the horses, but to date not in the donkeys. In horses, median RRI values for the right kidney (0.58±0.006) were statistically higher than for the left (0.51±0.006). For the donkeys the values were comparable. There was no significant difference in RRI between horses younger or older than 15 years, and between breeds in horses. No correlation with age, BW or BCS was found in either horses or donkeys.

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.

Feasibility of the echocardiographic subcostal view in newborn foals: two-dimensional and Doppler aortic findings

BACKGROUND

In dogs, due to better alignment with the aortic outflow, the subcostal (SC) transducer site provides greater Doppler-derived velocities than those obtained from the left parasternal view. The feasibility of this imaging approach has never been described in equine echocardiography.

OBJECTIVES

The objective of this study was to evaluate the feasibility of the SC view in newborn foals and compare aortic two-dimensional and Doppler-derived velocity measurements with those of standard parasternal long-axis (LAX) views.

STUDY DESIGN

A prospective observational study.

METHODS

Twenty-three newborn healthy Standardbred and Warmblood foals, aged from 7 h to 6 days, underwent transthoracic two-dimensional (2DE), M-mode and Doppler echocardiography that was performed in lateral recumbency. Right and left parasternal long-axis (R-LAX, L-LAX) and SC views were obtained to perform 2DE and Doppler assessments of the aortic valve (AoV). Aortic diameter at the sinus of Valsalva (AoS D) was measured from R-LAX and SC images. Aortic maximal velocity (AoV Vel_max ), velocity time integral (AoV VTI) and pressure gradient (AoV PG) were obtained by pulsed wave Doppler spectra from SC and L-LAX views.

RESULTS

The SC view was feasible in all foals. No significant difference was found in AoS D between different views (P = 0.06), and no significant correlation was detected for bodyweight (BW). AoV Vel_max , VTI and PG obtained from the SC view were greater than from the L-LAX view (P<0.0001, P = 0.0001 and P<0.0001 respectively), especially in foals with lower BW.

MAIN LIMITATIONS

The order of the transducer site was not randomised among foals, and the observer was not blinded during offline measurement.

CONCLUSIONS

The SC view can be easily obtained in recumbent newborn foals and provides optimal alignment with aortic outflow, leading to more reliable Doppler flow velocity than the conventional L-LAX view. Further investigations of the potential use of this view in Doppler estimation of aortic outflow and cardiac assessment of sick foals are recommended.

Endothelin 1 in healthy foals and in foals affected by neonatal diseases

In newborn babies, endothelin 1 (ET-1), a potent vasoconstrictor, increases during septicemia and severe respiratory syndromes. Because equine neonatal sepsis (ENS) and perinatal asphyxia syndrome (PAS) are major causes of morbidity and mortality in newborn foals and because no information on the concentration of ET-1 in healthy and sick foals has been reported yet, the aims of this study were (1) to define the serum concentration of Big ET-1 in healthy neonatal foals during the first week of age; (2) to preliminarily explore the diagnostic and prognostic role of Big ET-1 during ENS and PAS. Six healthy and 23 sick foals affected by ENS and/or PAS were enrolled in the study. In healthy foals, Big ET-1 concentration increased in the first hours of life until 24 hours after birth, and it remained constant during the first 3 days, then gradually decreased becoming significantly lower from Day 4 onward (P < 0.05). In sick foals, only 26.1% of animals showed higher values of Big ET-1 than controls at admission, and no difference between surviving and nonsurviving foals was found. Because in nonsurviving foals, Big ET-1 remained over the maximum value recorded in clinically healthy horses or, when normal at admission, increased over time; this study suggested that repeated measurement of Big ET-1 during hospitalization may be helpful in monitoring the course of the disease. In conclusion, possible prognostic information may be obtained by repeated analysis of Big ET-1 during hospitalization, but further studies are needed.

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.