Peripartum clinical and hemodynamic evaluation of Holstein cows under distinct obstetric conditions

Abstract

Bovine dystocias are commonly assisted through obstetric procedures. However, manual traction delivery can be a dangerous strategy for the treatment of dystocia as it may lead to maternal and fetal injuries. Use of oxytocin for uterine atonia or hypotonia to induce contractions may compromise fetal welfare due to maternal hypotension and bradycardia, because this hormone regulates renal and heart endocrine and neuroendocrine actions. The aims of this study were to compare heart rate (HR) measurement, non-invasive blood pressure (BP) and electrocardiograms records of Holstein cows during the first stage of labour, intrapartum, immediately after calving and one hour later of physiological birth and dystocia. The animals were allocated in: group EUT - eutocia (n = 10); group DYST - dystocia with obstetric assistance (n = 10); group OCT - uterine inertia treated with oxytocin (n = 10). The electrocardiograph tracing showed a normal sinus rhythm during all parturition. Tachycardia was observed in all groups, however, group OCT showed higher heart rate immediately after calving (111 ± 23 bpm) than prepartum evaluation (94 ± 11 bpm). During labor, DYST G presented significantly higher BP (Medium BP = 101 ± 24 mmHg), due to uterine and abdominal strengthened contractions. Group OCT cows didn't show significative elevation on diastolic BP during calving as occurred on EUT and DYST groups. The present results indicate superior blood pressure on manual traction delivery of bovine females, while oxytocin infusion altered transitorily hemodynamic variables with a possible bradicardiac effect and intrapartum hypotension and impose maternal circulatory adaptation during parturition.