Characterisation of testicular perfusion dynamics using digital pulse wave Doppler ultrasonography in indigenous cattle reared under coastal tropical climate

Testicular blood flow and haemodynamics play a critical role in maintaining spermatogenesis and thermoregulation in bulls. The assessment of the testicular blood flow provides detailed insights into the reproductive function in male animals. This study aimed to characterise the testicular perfusion pattern using pulse wave Doppler ultrasonography in the Shweta Kapila breed of indigenous cattle reared in their native habitat on the Indian west coast. Healthy Shweta Kapila bulls (n = 8) maintained under semi-intensive systems were examined. A digital Pulse Wave Doppler ultrasound system equipped with a linear array probe was used to assess peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) along the spermatic cord part of the testicular artery (sTA), marginal region (mTA), and intra-testicular branches (iTA) of the testicular artery. Mean PSV ranged from 4.93 cm/s to 12.32 cm/s, EDV ranged from 3.63 cm/s to 5.14 cm/s, RI ranged from 0.23 to 0.58 and PI ranged from 0.68 to 1.05 across different arterial segments. Significantly higher mean PSV values (P < 0.05) were recorded in the proximal sTA compared to distal arterial segments. RI demonstrated low within-bull variability and repeatability suggesting its potential as a reliable indicator of testicular perfusion. The stable and low intra-testicular RI values also suggest enhanced vascular adaptation and thermoregulatory efficiency. These findings establish the first baseline reference values for testicular perfusion and haemodynamics in native Shweta Kapila cattle. Pulse wave Doppler ultrasonography provides a reliable, non-invasive and real-time tool for evaluating vascular function and reproductive soundness in indigenous cattle reared under coastal tropical climate.