The Apgar Score in Foals: Association with Clinical, Behavioral and Reproductive Parameters

The Apgar score is commonly used to assess neonatal vitality in foals, although its clinical relevance remains unclear. This retrospective study evaluated 144 foals investigating associations between a four-parameter Apgar score assessed within 5 min of birth as well as selected neonatal and maternal variables. Inclusion criteria required availability of Apgar scores and body temperature measurements. Maternal, reproductive, and peripartum determinants were evaluated using ordinal logistic regression. Spearman's rank correlation, Kruskal-Wallis analysis, and Fisher's exact test were applied as appropriate according to type and distribution. Multiple comparisons were controlled using the Benjamini-Hochberg false-discovery-rate procedure. Most foals showed good neonatal vitality (median Apgar score 8/8, IQR 7-8; 91.7% had scores ≥ 7/8). Higher Apgar scores were associated with higher heart rate, respiratory rate, and shorter time to sternal recumbency, therefore supporting the score's internal consistency. No associations were found with neonatal behavioral milestones, blood glucose, IgG concentrations, or maternal and reproductive variables. Umbilical abnormalities were not associated with low Apgar score after multiple-comparisons correction. However, few foals scored ≤ 6/8, which limited the evaluation of clinically compromised neonates. Overall, the Apgar score appears to be a practical tool for evaluating immediate neonatal vitality in foals. However, the associations with subsequent neonatal and maternal variables were limited.