The goal of the present study was to examine the musculophrenic vein of 29 healthy Swiss Braunvieh cows using colour-Doppler sonography to determine vessel morphology and diameter, and blood flow velocity. The hair over the reticular region was clipped, and the left musculophrenic vein was examined before and 10min after sedation using 0.03mg/kg xylazine. The musculophrenic vein appeared as a vessel with a diameter of 0.5-1.1cm located in the diaphragmatic musculature. The spectral display was a broad band structure with a wave-like shape. The Doppler measurement point was 1.5-2.7cm from the body surface. The diameter of the vein and the blood flow velocity did not differ significantly before and after sedation. Before sedation, the mean diameter (+/-SD) of the musculophrenic vein was 0.7 (0.2) cm, the maximum blood flow velocity 90.2 (38.6) cm/s, the mean blood flow velocity 60.4 (22.3) cm/s and the minimum blood flow velocity 41.4 (24.2) cm/s. There were significant correlations (r=0.45-0.90) between blood flow velocity before and after sedation and between minimum, maximum and mean blood flow velocities.

The morphology and diameter of the milk vein of 29 healthy Swiss braunvieh cows and the velocity of blood flow through it was measured by colour Doppler ultrasonography before and 10 minutes after they had been sedated with 0·03 mg/kg xylazine. The milk vein was situated immediately under the skin. It had a diameter of 0·8 to 1·6 cm and valves were visible in the milk vein of 12 of the cows. The spectral display appeared as a broad band structure with a wave‐like course. The Doppler measurement point was 0·4 to 0·8 cm from the body surface. The diameter of the vein and the blood flow velocity did not differ significantly before and after the cows were sedated. The mean (sd) diameter of the milk vein before they were sedated was 1·3 (0·3) cm. The mean maximum blood flow velocity before they were sedated was 45·4 (12·5) cm/second, the mean velocity was 33·5 (9·5) cm/second, and the mean minimum was 25·8 (11·6) cm/second. There were significant correlations between the blood flow velocities before and after the cows were sedated and between individual cow's blood flow velocities, with correlation coefficients ranging from 0·69 to 0·94.