Abstract: | Seventy-five necropsy reports of cattle diagnosed as abomasal impaction by the Pathology Department of the Western College of Veterinary Medicine were reviewed. Twenty percent of all affected animals had lesions of traumatic reticuloperitonitis and 60% were believed to be primarily dietary in origin resulting from the ingestion of too much fibre. The remaining 20% did not fit into either category. Abomasal tears, ulcers, and necrosis of the walls of the rumen, omasum, or abomasum were recorded in almost half of the cases. Pyloric stenosis was not encountered. The disease occurred mostly in winter in association with straw feed. Sixty percent of impacted beef cattle suffered from the dietary form, but the majority of dairy cattle, which would have been fed better diets, had the traumatic form which may have been precipitated by dry fibrous feeds. There was no indication of a higher incidence in heavily pregnant animals. Thirty-five of the animals necropsied had been presented alive, and the clinical features of the two main types of abomasal impaction were examined. Cattle with impactions associated with traumatic reticuloperitonitis were sick for a longer period than those animals with dietary related impactions, were single incident cases, and had a statistically significant rise in serum protein. |