Sonographic investigation of reticular contractions in healthy sheep, cows and goats and in cows with traumatic reticulo-peritonitis.

The objective of the study was (a) to compare sonographically the sequence of reticular contractions between grass and roughage eaters (cows, sheep) and intermediate feeders (goats) and (b) to check whether sonography may be useful for the investigation of cattle with a history of traumatic reticulo-peritonitis (TRP). All animals were investigated from the left ventral Regio parachondriaca with a 2.5 MHz sector scanner. Reticular contractions were recorded on video and evaluated later on. Duration of the contractions was found to be surprisingly uniform between individuals of the investigated species. However, in cattle and sheep the reticular floor moves over longer distances during both contractions in cranio-dorsal direction compared to goats, i.e. the velocity with which the reticulum contracts was markedly higher in sheep (5.3 +/- 1.4 cm* s-1) and cows (4.4 +/- 2.0) than in goats (2.1 +/- 0.9). Thus, in sheep and cattle feed particles are transported with a higher force in caudo-dorsal direction resulting in a longer retention time of particles in the reticulorumen than in goats. Sonographic investigation of eight cows with clinical symptoms of acute TRP indicated that sonography is a valuable method for the diagnosis of TRP. Implications of sonographic signs for the clinical course in such patients are discussed.