GROWTH-INDUCED HEMODYNAMIC-CHANGES IN HEALTHY FRIESIAN CALVES

This study investigated the pattern of growth-induced haemodynamic cha nges in normal calves during their first year of life. The central ven ous pressure (CVP), the right ventricular pressure (RVP), the pulmonar y arterial pressure (PAP), the pulmonary capillary wedge pressure (PW) , the systemic arterial pressure (SAP) and the cardiac output (CO) wer e measured in 41 healthy Friesian calves. The heart rate (HR), the str oke volume (SV), the cardiac and stroke indices (CI and SI, respective ly), the pulmonary and systemic vascular resistance (PVR and SVR, resp ectively), the right ventricular and left ventricular work (RVW and LV W, respectively) and their corresponding indices (PVRI, SVRI, RVWI and LVWI, respectively) were also measured or calculated. The cardiac out put, SV, SAP, PVRI, SVRI, Rvw and LVW increased significantly while th e HR, CI, PVR, SVR, RVWI and LVWI decreased significantly with somatic growth. The right-sided vascular pressures did not change significant ly. 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 in duce a reduced cardiac pumping reserve in young calves. In consequence , a therapeutic inotropic intervention may have little potential benef it at this age.