Apgar Score, Clinical, Hemato-Biochemical, and Venous Blood Gas Parameters in a Cohort of Newborn Mule Foals: Preliminary Data.
Authors: Bindi Francesca, Vernaccini Matilde, Bonelli Francesca, Nocera Irene, Fanelli Diana, Sgorbini Micaela
Journal: Journal of equine veterinary science
Summary
# Newborn Mule Foals: Early Vitality and Metabolic Adaptation in the First 48 Hours Understanding the normal physiological transition from intrauterine to independent life in hybrid equines requires species-specific reference data, which has largely been absent for mules. Researchers collected Apgar scores, clinical observations, and blood parameters (haematochemistry and venous blood gas analysis) from seven newborn mules at five timepoints across the first 48 hours, with six foals completing the full assessment protocol. Most mules demonstrated robust early vitality with Apgar scores of 7–8/8, rapid achievement of sternally recumbent posture (within 2 minutes in six foals), and prompt standing (38.7 ± 13.4 minutes) and nursing initiation (72.3 ± 30.5 minutes); however, meconium passage was notably delayed at 416.3 ± 401.8 minutes compared to equine norms. Metabolically, mules displayed intermediate characteristics between their equine and asinine parents—specifically shorter times to functional independence than horses but lower respiratory rates, and lower body temperature than donkeys—whilst serum creatinine and lactate declined progressively over 48 hours and glucose concentrations increased from 12 hours onwards. These findings underscore the biological distinctiveness of mules as a hybrid species and highlight the clinical risk of misinterpreting their vital signs and laboratory values using equine or donkey reference ranges; establishing mule-specific normal parameters is essential for veterinarians managing neonatal mule emergencies and assessing viability in this increasingly common production animal.
Read the full abstract on PubMed
Practical Takeaways
- •Newborn mules have intermediate physiological characteristics between horses and donkeys; practitioners should not apply equine or donkey reference values directly to mules without caution
- •Establish mule-specific baseline values for hemato-biochemical parameters and vital signs to properly assess neonatal health and identify pathology in this population
- •Monitor meconium passage timing in newborn mules as they may take longer (>6 hours) than horses, and delayed passage may warrant intervention based on mule-specific thresholds rather than equine standards
Key Findings
- •Newborn mules had Apgar scores of 7-8/8 (6/7 foals after exclusion), with all showing suckling reflex within 20 minutes and head raising within 1 minute
- •Mean time to stand was 38.7±13.4 minutes and to nurse 72.3±30.5 minutes, shorter than horses but comparable to donkeys
- •Creatinine and lactate decreased from birth to 48 hours; blood glucose increased from 12 hours; mules showed intermediate body weight and heart rate but lower respiratory rate compared to horses
- •Mules displayed longer time to pass meconium (416.3±401.8 minutes) and lower body temperature compared to donkeys, indicating distinct physiological parameters requiring species-specific reference ranges