Growth-induced haemodynamic changes in healthy Friesian calves

This study investigated the pattern of growth-induced haemodynamic changes in normal calves during their first year of life. The central venous pressure (CVP), the right ventricular pressure (RVP), the pulmonary arterial pressure (PAP), the pulmonary capillary wedge pressure (PW), the systemic arterial pressure (SAP) and the cardiac output (CO) were measured in 41 healthy Friesian calves. The heart rate (HR), the stroke volume (SV), the cardiac and stroke indices (CI and SI, respectively), the pulmonary and systemic vascular resistance (PVR and SVR, respectively), the right ventricular and left ventricular work (RVW and LVW, respectively) and their corresponding indices (PVRI, SVRI, RVWI and LVWI, respectively) were also measured or calculated. The cardiac output, SV, SAP, PVRI, SVRI, RVW and LVW increased significantly while the HR, CI, PVR, SVR, RVWI and LVWI decreased significantly with somatic growth. The right-sided vascular pressures did not change significantly. The significant increase in systemic arterial pressure may be due to the simultaneous increase in CO. The high CI observed in the first few weeks of life was attributed to a high metabolic rate and might induce a reduced cardiac pumping reserve in young calves. In consequence, a therapeutic inotropic intervention may have little potential benefit at this age.