Abdominal Fat Necrosis: Introduction
(Lipomatosis) |  |
| Hard masses of necrotic fat are relatively common in the peritoneal cavity of adult cattle, especially the Channel Island breeds. The disease has also been seen in some species of deer maintained on pastures consisting primarily of tall fescue. The masses are commonly mistaken for a developing fetus because they feel like “floating corks” similar to cotyledons; they may result in episodes of intestinal obstruction characterized by moderate abdominal pain and the passage of small
amounts of feces. The lipomatous masses are located in the small omentum, large omentum, and mesentery in cattle and more diffusely in sheep and goats. The composition of the fatty deposits is identical to that of fat of normal cows, and there is no suggestion that the disease is neoplastic. |
| Fat necrosis may also be seen in cattle ≥2 yr old after prolonged grazing of tall fescue infected with
Acremonium
coenophialum
(see also
fescue poisoning, ). The condition is seen throughout the USA where tall fescue is used as the primary pasture plant. Over 90% of such pastures are infected. Hard masses of necrotic fat form in the omentum, mesentery, and perirenal fat and may cause clinical disease when they compress the intestine, obstruct the birth canal, or compress ureters. Rectal examination is useful in diagnosis and in determining prevalence in a herd. Removal
of cattle from endophyte-infected pastures or dilution of intake by supplying legume or other grass pasture promotes slow reduction in the size of masses. In affected deer herds, 90% of the females may be involved. Clinical signs include anorexia, depression, and uremia associated with large masses of necrotic abdominal fat constricting the ureters, causing hydroureter and hydronephrosis. |
| A second form, less well defined, appears to be related to pancreatic problems. Although not associated with a clinical syndrome, the lesions (discrete or confluent masses of necrotic adipose tissue) may be found throughout the abdomen and are not a rare finding at necropsy. |
| A third form, a focal necrosis of abdominal and retroperitoneal fat, is seen most often in sheep but also in pigs, horses, and other species. |
