Pulsed wave-doppler ultrasonographic evaluation of the mammary blood flow in the ewe

The authors investigated mammary blood flow by means of a pulsed wave-Doppler ultrasonographic technique in ewes during different production phases. Three groups (Ga, Gb, and Gc, five animals in each) of Comisana sheep were used in the experiment. Ga sheep were milked twice a day by means of a milking machine; Gb sheep nursed their lambs, and group Gc was made up of dry sheep. Recordings of systolic and diastolic pressure of the left and right lateral mammary veins (SSLMV and DSLMV) and arteries (SSLMA and DSLMA) were carried out by means of a Pulse Doppler system. Recordings for Ga were taken before and after milking in the morning and in the afternoon. In Gb and Gc sheep, recordings were taken only in the morning and in the afternoon. Statistical analysis was carried out of the mean values of the recordings taken as mentioned above and the Student's t-test for paired data was used. A statistically significant difference was found in Ga recordings carried out before and after morning (0.05 < P < 0.001) and afternoon (0.05 < P < 0.01) milking. Ga morning mean flow speeds were between 7.00 ± 1.87 and 12.20 ± 2.28 cm/sec for SSLMV; 19.70 ± 3.51 and 32.40 ± 4.77 cm/sec for SSLMA; 2.40 ± 0.55 and 5.60 ± 0.55 cm/sec for SDLMV, and 4.00 ± 1.00 and 8.20 ± 3.83 cm/sec for SDLMA. Ga afternoon mean flow speeds were between 8.80 ± 1.30 and 12.60 ± 2.30 cm/sec for SSLMV; 20.20 ± 2.86 and 29.20 ± 5.76 cm/sec for SSLMA; 2.40 ± 0.55 and 6.40 ± 2.30 cm/sec for SDLMV, and 3.20 ± 0.84 and 7.00 ± 2.83 cm/sec for SDLMA. No significant differences were found between morning and afternoon recordings in Gb and Gc sheep or between systolic and diastolic speeds of right and left mammary veins and arteries in the 3 groups. Our results showed that mechanical milking may influence the vascular mammary flow. It may lower the intramammary pressure, increase blood flow and activate mammary metabolism. Furthermore ultrasonographic techniques could be useful for functional assessment of mammary gland activity.