Ultrasonographic assessment of reticuloruminal motility in 45 cows.

The goal of this study was to investigate the feasibility of ultrasonographic assessment of reticuloruminal motility in 45 healthy cows. The transducers of five ultrasound machines were connected to a digital video recorder and placed simultaneously at five sites on the left side of the cows to scan the reticulorumen (reticulum; ruminal atrium; dorsal sac of the rumen; left longitudinal groove; ruminal recess, caudodorsal and caudoventral blind sacs). The video streams from all five ultrasound machines were recorded synchronously with the same time line and displayed on a single monitor. Time 0 was defined as the start of a biphasic reticular contraction. The reticulum was visualised in all cows and had 11.0 ± 2.12 biphasic contractions in 9 min. The ruminal atrium was visualised in 40 (89%) cows and had 10.7 ± 2.10 contractions in 9 min, which started at the time point 5.0 ± 0.83 sec and lasted 7.0 ± 2.14 sec. Contractions of the dorsal sac of the rumen, visible in all cows, were visualised in 29 (64%) cows. There were 9.5 ± 1.8 contractions in 9 min that started at the time point 4.0 ± 0.85 sec and lasted 8.2 ± 1.04 sec. The left longitudinal groove was seen contracting in 39 (87%) cows. There were 10.2 ± 1.98 contractions in 9 min that started at the time point 4.1 ± 1.81 sec and lasted 7.8 ± 1.19 sec. Contractions of the ventral sac of the rumen (ruminal recess) were seen in 31 (69%) cows. There were 7.5 ± 2.59 contractions in 9 min that started at the time point 14.3 ± 4.30 sec. Contractions of the caudodorsal and caudoventral blind sacs were seen in 34 (76%) cows. There were 9.0 ± 2.75 (1.0 ± 0.31) contractions/min and 9.4 ± 2.09 (1.0 ± 0.23) contractions/min of the dorsal and ventral blind sacs, and they started at the time points 6.2 ± 1.32 sec and 21.3 ± 6.20 sec, respectively. Primary contraction cycles were seen in all cows and secondary cycles in 22 (49%) cows. The former were complete in 37 (82%) cows and incomplete in 8 (18%). There were 11.0 ± 2.12 primary and 4.5 ± 2.15 secondary cycles in 9 min, and the ratio between primary and secondary cycles averaged 2.4:1. Ultrasonography is suitable for the assessment of reticuloruminal motility