Abstract
Blood pressure is generally recognized as the fourth vital sign, alongside body temperature, heart rate, and respiratory rate. This study aimed to establish such a reference interval in healthy neonatal calves. Sixty-four healthy Holstein calves, aged 2-18 days were included. Blood pressure and heart rate were measured using an easy-to- operate, non-invasive, mobile oscillometric device that does not require special equipment. Measurements were taken from the right and left forelimbs (arteria radialis) and the tail (arteria coccygea medialis) to determine reference intervals. Additionally, a single blood sample was collected from the jugular vein following blood pressure measurement. Hematological analyses were performed and compared with serum amyloid A concentrations determined by ELISA to verify the clinically healthy status of the calves. Furthermore, N-terminal pro B-type natriuretic peptide, and cardiac troponin I levels were measured by ELISA for neonatal cardiac risk assessment. Systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP) values from both forelimbs were statistically significantly higher than those from the tail (P<0.001). The reference intervals (90% confidence) were as follows: left forelimb – SBP: 123–207 mmHg, DBP: 66–158 mmHg, MAP: 77–176 mmHg; right forelimb – SBP: 116–188 mmHg, DBP: 59–146 mmHg, MAP: 78–172 mmHg; tail – SBP: 89–174 mmHg, DBP: 40–126 mmHg, MAP: 57–133 mmHg. This study defined reference intervals for oscillometric blood pressure in healthy calves using a mobile non-invasive monitor. The tail is recommended as the ideal site for routine measurements due to its consistency and clinical practicality.