Study points to blood biomarkers for diagnosing sick foals

A new Journal of Veterinary Internal Medicine study is adding objective laboratory data to one of equine neonatology’s more difficult diagnostic problems: telling neonatal maladjustment syndrome apart from other serious illnesses in newborn foals. Researchers at North Carolina State University reported that several neuroproteins and neurosteroids differed between healthy foals, foals with neonatal maladjustment syndrome, and foals hospitalized for other diseases, supporting their potential use as diagnostic biomarkers of brain injury and neurologic dysfunction. (pubmed.ncbi.nlm.nih.gov)

That matters because neonatal maladjustment syndrome, sometimes also called neonatal encephalopathy, remains a clinical diagnosis with a broad differential list. Signs can include abnormal behavior, poor nursing, altered awareness, and failure to bond normally, but similar presentations can also be seen with sepsis, prematurity, dysmaturity, and perinatal hypoxic injury. Prior work in foals has also pointed to persistent neurosteroids after birth as one possible contributor to the syndrome’s pathophysiology, which helped set the stage for this biomarker-focused study. (pmc.ncbi.nlm.nih.gov)

In the prospective longitudinal study, investigators measured serum brain-derived neurotrophic factor, serum S100B, plasma glial fibrillary acidic protein, and the neurosteroids progesterone and 17α-hydroxyprogesterone at admission and again during the first two days of hospitalization. According to the published report, biomarker patterns differed by foal group over time, with significant group-by-time interaction reported for GFAP. The authors concluded that the analytes were associated with neonatal maladjustment syndrome and could have diagnostic value, while also noting potential usefulness in identifying other high-risk neonatal conditions, including prematurity and sepsis. (pubmed.ncbi.nlm.nih.gov)

North Carolina State’s earlier description of the work offers some additional context on how the team is thinking about clinical use. In a research forum Q&A, Javier Perez Quesada said the group compared blood biomarkers in foals with neonatal maladjustment syndrome, foals sick from other illnesses, and healthy foals, and found that glial fibrillary acidic protein was reduced in sick foals and foals with neonatal maladjustment syndrome compared with healthy foals. He also underscored a common challenge in equine neonatology research: unlike human neonatology, veterinary studies often have far smaller case numbers, which makes validation especially important before biomarkers can be adopted broadly. (cvm.ncsu.edu)

No broad industry reaction was readily available, but the findings fit with a longer-running shift in equine neonatology toward more objective markers of disease severity and mechanism. Reference materials from Merck Veterinary Manual, IVIS, and UC Davis all describe neonatal maladjustment syndrome as a multifactorial condition tied to perinatal hypoxia, abnormal transition to extrauterine life, and persistent neuroinhibitory steroids. In that context, a biomarker panel that reflects both neurologic injury and endocrine transition would be a logical extension of current thinking, though that’s still an inference rather than a proven clinical pathway. (ivis.org)

Why it matters: For veterinary professionals, the practical value here is less about replacing clinical judgment and more about sharpening it. Equine neonatal patients often present with overlapping syndromes, and the stakes are high because treatment decisions, referral timing, prognosis, and cost discussions can all move quickly. If validated, blood biomarkers could help clinicians distinguish primary neurologic maladjustment from systemic illness sooner, interpret ambiguous cases more confidently, and potentially follow response to treatment over the first 48 hours. They may also support more consistent case definitions in research, which could improve future trials in foal critical care. (pubmed.ncbi.nlm.nih.gov)

There are still important caveats. The current study supports association, not a ready-to-use diagnostic cutoff for field practice, and neonatal foals are biologically dynamic patients whose laboratory values can shift rapidly after birth. Earlier work has emphasized that age-specific reference data are limited in foals, which is one reason interpretation can be difficult even for standard clinical pathology. Any eventual biomarker test will likely need robust reference intervals, timing guidance, and external validation across breeds, hospitals, and case mixes before it changes routine workflows. (pubmed.ncbi.nlm.nih.gov)

What to watch: Watch for follow-up studies that define diagnostic thresholds, test performance against sepsis and prematurity, and whether these markers can be adapted into a faster clinical assay that fits equine hospital workflows. (pubmed.ncbi.nlm.nih.gov)