Total plasma magnesium in healthy and critically ill foals

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

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

Study on NGF and VEGF during the Equine Perinatal Period-Part 2: Foals Affected by Neonatal Encephalopathy

Neonatal Encephalopathy (NE) may be caused by hypoxic ischemic insults or inflammatory insults and modified by innate protective or excitatory mechanisms. Understanding the underlying pathophysiology is important in formulating a rational approach to diagnosis. The preliminary aim was to clinically characterize a population of foals spontaneously affected by NE. The study aimed to: (i) evaluate nerve growth factor (NGF) and vascular endothelial growth factor (VEGF) levels in plasma samples obtained in the affected population at parturition from the mare’s jugular vein, umbilical cord vein and foal’s jugular vein, as well as in amniotic fluid; (ii) evaluate the NGF and VEGF content in the plasma of foals affected by NE during the first 72 h of life/hospitalization; (iii) evaluate NGF and VEGF levels at birth/admission in relation to selected mare’s and foal’s clinical parameters; (iv) evaluate the relationship between the two trophic factors and thyroid hormone levels (TT3 and TT4) in the first 72 h of life/hospitalization; and (v) assess the mRNA expression of NGF, VEGF and brain-derived neurotrophic factor (BDNF), and their cell surface receptors, in the placenta of mares that delivered foals affected by NE. Thirteen affected foals born from mares hospitalized for peripartum monitoring (group NE) and twenty affected foals hospitalized after birth (group exNE) were included in the study. Dosage of NGF and VEGF levels was performed using commercial ELISA kits, whereas NGF, VEGF, and BDNF placental gene expression was performed using a semi-quantitative real-time PCR. In group NE, NGF levels decreased significantly from T0 to T24 (p = 0.0447) and VEGF levels decreased significantly from T0 to T72 (p = 0.0234), whereas in group exNE, only NGF levels decreased significantly from T0 to T24 (p = 0.0304). Compared to healthy foals, a significant reduction of TT3 levels was observed in both NE (T24, p = 0.0066; T72 p = 0.0003) and exNE (T0, p = 0.0082; T24, p < 0.0001; T72, p < 0.0001) groups, whereas a significant reduction of TT4 levels was observed only in exNE group (T0, p = 0.0003; T24, p = 0.0010; T72, p = 0.0110). In group NE, NGF levels were positively correlated with both TT3 (p = 0.0475; r = 0.3424) and TT4 levels (p = 0.0063; r = 0.4589). In the placenta, a reduced expression of NGF in the allantois (p = 0.0033) and a reduced expression of BDNF in the amnion (p = 0.0498) were observed. The less pronounced decrease of the two trophic factors compared to healthy foals, their relationship with thyroid hormones over time, and the reduced expression of NGF and BDNF in placental tissues of mares that delivered affected foals, could be key regulators in the mechanisms of equine NE.

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.

Equine Neonatal Encephalopathy: Facts, Evidence, and Opinions

Neonatal encephalopathy (NE) and neonatal maladjustment syndrome (NMS) are terms used for newborn foals that develop noninfectious neurologic signs in the immediate postpartum period. Cerebral ischemia, hypoxia, and inflammation leading to neuronal and glial dysfunction and excitotoxicity are considered key mechanisms behind NE/NMS. Attention has been placed on endocrine and paracrine factors that alter brain cell function. Abnormal steroid concentrations (progestogens, neurosteroids) have been measured in critically ill and NE foals. In addition to supportive treatment, antimicrobials should be considered. Controversies regarding the pathophysiology, diagnosis, and treatment of NE and NMS will remain until controlled mechanistic and therapeutic studies are conducted.

Hematological and biochemical indicators of maturity in foals and their relation to the placental features

ABSTRACT: Newborn’s health is directly related to gestational conditions and placental efficiency. The aims of this study were: (1) To evaluate hematological and biochemical parameters of foals born from mares with placentitis at birth and at 24h of age, (2) to verify if placental pathology had any influence on neonatal maturity degree through hematological and biochemical response of those foals. According to placental findings (control and placentitis) and neonatal maturity degree (mature and immature), foals were divided into three groups: (1) Control group (n=22), foals born from mares with placentitis and classified as (2) Mature (n=26), and (3) Immature (n=10). The hematocrit and plasma concentration of fibrinogen, total plasma protein, white blood cells count, lactate, glucose, creatinine, urea, albumin, bilirubin, triglyceride, cholesterol, calcium, phosphorus, magnesium, aspartate aminotransferase (AST), creatine kinase (CK), alkaline phosphatase (ALP), and gamma-glutamyltransferase (GGT) were measured. Placental features were significantly different between neonatal maturity degree (P=0.001). Mares that had acute placentitis foaled more immature neonates (n=8/10; 80%). Concentrations of fibrinogen (P=0.003), creatinine (P=0.021), total cholesterol (P=0.014), AST (P=0.001), GGT (P=0.002), total (P=0.001) and unconjugated bilirubin (P=0.010) were higher at birth in the Immature group, whereas albumin levels were lower (P=0.002). Foals born from mares with placentitis presented hyperlactatemia at 24h of age (P=0.002). Acute placentitis had an influence on the neonatal maturity, allowing an accelerated but incomplete fetal maturation. The monitoring of lactate, fibrinogen, creatinine, bilirubin, cholesterol, albumin, AST, and GGT levels, associated with clinical, physical, and behavior evaluation may contribute as indicators of neonatal maturity.