Comparison of Apgar score and neonatal parameters between ET and ICSI foals

ICSI (Intracytoplasmic Sperm Injection) in the mare has been growing considerably in Brazil. This technique allows foals to be produced from mares with fertility problems, optimizes the use of rare or high-cost semen and embryos can be cryopreserved and achieve good pregnancy rates after transfer. An increasing number of ICSI foals are born each year and it is common to be asked by clients and veterinarians if these neonates have differences or altered behavior after birth compared to conventional embryo transfer (ET) foals. Therefore, the present study evaluated Apgar score and neonatal parameters in ICSI foals compared with conventional ET foals. A total of 25 Quarter Horse foals were evaluated, 11 born after conventional ET and 14 after ICSI. All parturitions were monitored and foals were evaluated. Heart and respiratory rates, muscle tone, and nasal stimulus were observed for the Apgar assessment (Knottenbelt.et.al. Equine Neonatol Med Surg 2004; 69-71) at 1 hour of life. Post-partum parameters evaluated were time to show a sucklingreflex, sit in sternal recumbency, stand and nurse. Regarding the Apgar score, there was no statistical difference (p = 0.8) comparing ET (7.64) and ICSI (7.57) foals. There was no statistical difference between groups (ET vs ICSI) for time to sit in sternal recumbency (8 vs 15.1 min, p = 0.1), show a suckling reflex (36.43 vs 34.25 min, p=0.9), stand (35.5 vs 39.92, p = 0.3) or nurse (108.88 vs 93.5 min, p = 0.4). The only detected difference was the time taken to start meconium elimination, ET foals showed an average of 122.75 compared to 61.75 min for the ICSI foals (p=0.02) but this difference has no biological significance, as values are within physiological parameters. Based on these results, foals produced by ICSI have the same neonatal parameters as conventional ET foals. Thus the same timeframes can be used to evaluate ET and ICSI neonates during the postpartum period. Acknowledgements: Fapesp 2020/10260-3 and RH Ranch (Campos dos Goytacazes – Brazil).