Non-invasive measurement of blood pressure and its possible use in future in-depth studies on farrowing-related complications

BACKGROUND: Farrowing is the most critical phase in a sow's production cycle and has major implications for both animal welfare and productivity. Early identification of sows at risk of farrowing-related disorders is therefore essential. In human obstetrics, blood-pressure measurement is a key tool for detecting individuals at increased risk of pregnancy-related complications, and both hypertension and excessive increase in blood pressure have been associated with adverse outcomes. Previous work has suggested that low systolic blood pressure may be linked to prolonged farrowing, a condition known to increase stillbirth rates and neonatal mortality. Invasive arterial catheterisation remains the reference method for blood-pressure assessment but is impractical for routine or repeated use in pregnant sows, whereas non-invasive oscillometric tail-cuff techniques have shown potential feasibility. The aim of this study was to evaluate a non-invasive method for blood-pressure monitoring in sows and to describe preliminary gestational blood-pressure patterns that may inform future work on identifying individuals at risk of farrowing-related complications. RESULTS: Measurements could be performed as planned during all stages of gestation and lactation. The non-invasive tail-cuff method functioned well both when the sows were confined in feeding stalls and when they were moving freely in the farrowing pens. Non-invasive blood-pressure measurements revealed a progressive pattern of decline in systolic, diastolic and mean blood pressures throughout the sows' gestation. CONCLUSION: Non-invasive blood-pressure measurement in sows under commercial production conditions proved feasible, and the measurements obtained in this study demonstrated a significant decline in blood pressure during late gestation. These findings highlight the need for further research to establish reliable reference intervals and to determine thresholds for critically low blood pressure in relation to farrowing.