Characteristics of meconium impaction/retention in newborn foals: From 2006 to 2024

Background: Meconium impaction/retention is a significant cause of colic in foals. Historically, limitations of both medical and surgical treatment are noted. Outcomes of meconium impaction/retention have not recently been reported. Objective: To describe case characteristics and outcomes in foals with meconium impaction/retention. Study design: Retrospective, single referral hospital. Methods: Medical records from 2006 to 2024 were searched for foals ≤3 days old with a history of straining to defecate, abdominal distention, colic, weakness and/or tail flagging. Signalment, presenting complaint, treatment, outcome and comorbidities were summarised and compared between groups based on sex and survival. Associations between comorbidities and survival were evaluated by zero-inflated Poisson regression. Results: Forty-three foals met the inclusion criteria. Male foals dominated (30/43; 70%). All foals were managed with enemas; phosphate (11/43; 30%), water with soap/lube (25/43; 58%), not specified 9/43 (21%), multiple types (8; 19%), acetylcysteine retention (1; 2%). Forty foals (93%) survived to discharge, and three (7%) were humanely euthanised. Of surviving foals, 37/40 (93%) responded fully to medical treatment. Surgical treatment was required in 4 foals (9%); 3/4 (75%) survived. Comorbidities were common including sepsis (10/43; 23%), pneumonia (10/43; 23%), failure of passive transfer (6/43; 14%) and hypoxic-ischaemic encephalopathy (5/43; 12%). Non-survivors (3/43; 7%) were euthanised due to sepsis, limb malformation and pneumonia. Main limitations: Small sample size and low number of non-survivors prevented meaningful statistical analysis. Conclusion: Medical management of meconium impaction/retention is successful in the great majority of cases. Prognosis depends on the comorbidities present.