Maternal, fetal and neonatal heart rate evaluation and its variability in the Paint Horse breed

ABSTRACT:

The aim of this study were to describe the heart rate (HR) and indexes of maternal and fetal heart rate variability (HRV) in final period of pregnancy, as well as to describe the evolution of the development of autonomic nervous system during fetal and neonatal period. There were 20 animals in each category, whose maternal and fetal electrocardiographic examinations were performed at 15 and 7 days antepartum. Neonatal ECG it was evaluated at birth until the first 48 hours of life, and then once a week up to 35 days. There were significant differences in fetal heart rate (FHR) during this period, but the fetal HRV indexes have not changed. There were no significant differences in the rates of maternal HRV. The mean of fetal HR decreased significantly from 15 to seven antepartum days (95.6±11.4 bpm; 83.1±12.6, respectively), though the fetal HRV indexes have not decreased. The results of fetal and neonatal HRV in the present study, when compared to maternal indicate the parasympathetic dominance during fetal and neonatal sympathetic phase during to the third and/or fourth weeks of age, at which point begins the modulation of the two systems.

INDEX TERMS:
Heart rate; horses; Paint Horse; electrocardiogram; neonatal hypoxia; foals; autonomic nervous system; physiology