Observations on circulatory adjustment in newborn reindeer and elk

Haemodynamics of two reindeer (18 h and 4 days old) and one elk (1 week old) calves were studied by catheterization and angiography. Early closure of foetal shunts, high cardiac output and large ejection fractions were observed in all three animals. Pulmonary arterial blood pressure decreased to the full-grown level during the first days of life in the reindeer. Electrocardiography showed cranial-orientated QRS vector in both species. The cardiovascular system of the Cervidae is well developed at birth and adapts rapidly during the neonatal period.