[Right displacement of the abomasum in cattle. 1. Pathogenesis, clinical course and prognosis].

A report is given about 462 cases (1989-1994) of abomasal displacement (RDA, n = 275) and abomasal volvulus (AV, n = 187) in cattle. The pathogenesis and the functional disturbances of abomasal hypotony, displacement, and volvulus are described. A right and dorsally displaced abomasum easily performs an additional rotation around a vertical axis. In 99% of all cases this rotation is performed to the left (counter-clockwise, seen from rear) and the duodenum twines round the abomasal fundus, where it is compressed and trapped between the abomasum and the omasum. The intestinal passage becomes obstructed. As long as the abomasal twist does not exceed 180 degrees, functional disturbances are caused mainly by a reduced abomasal outflow, resulting in dehydration and in disturbances of blood acid-base-balance (hypochloremic alcalosis). These cases have a very good prognosis (success of treatment 91.3%), when surgery is performed immediately. When the twist of the abomasum exceeds 180 degrees (abomasal volvulus), the twine gets more contracted, strangulating the abomasal nerves and blood vessels. Serious cases like this (n = 136) were treated successfully in 64.7%. When the abomasal volvulus is complicated by an omasal (RDAO, n = 31) or an omasal and reticular involvement (RDAOR, n = 20) the success of therapy decreases to about 40%.