Type 5 abomasal ulcer associated with omental bursitis in dairy cattle: A retrospective clinicopathological study of 14 cases.

This study aimed to characterize the epidemiological, clinical, and pathological findings in cattle with type 5 abomasal ulcers associated with omental bursitis. A retrospective hospital-based study was conducted with 14 dairy cattle, 11 females (79%) and three males (21%), with a mean age of 41.8 ± 22.2 months. Among the females, 72% (8/11) were in late gestation or within 60 days postpartum. The most frequent clinical findings were anorexia/hyporexia (100%; 13/13), ruminal hypomotility/atony (92%; 12/13), apathy (85%; 11/13), and tachycardia (77%; 10/13). Increased abdominal wall tension was observed in 54% (7/13) of cases and fluid was detected on right flank ballottement in 77% (10/13), often associated with subtympanic to tympanic resonance on percussion (54%; 7/13); melena occurred in 15% of cases (2/13). All animals presented concurrent clinical conditions. Hematological abnormalities included leukocytosis (60%; 6/10) and hyperfibrinogenemia (60%; 6/10), hypoproteinemia (86%; 6/7), and hypoalbuminemia (100%; 7/7). Ultrasonography identified peritonitis in 60% (6/10) of cases and suggested type 5 abomasal ulcer and omental bursitis in one animal (17%; 1/6). Abdominocentesis (50%; 7/14) revealed inflammatory abdominal alterations in all evaluated animals, and laparotomy confirmed omental bursitis in one case (25%; 1/4). All animals died or were euthanized, with diagnosis confirmed by necropsy in all cases (100%/14/14). Peritonitis was observed in 93% (13/14) of animals; the omental bursa was distended with brownish fluid containing feed material and exudate, and a perforated abomasal ulcer was identified. Histologically, marked fibrinonecrotic abomasitis was observed in all animals. A type 5 abomasal ulcer associated with omental bursitis is a severe condition in dairy cattle, characterized by nonspecific clinical and laboratory findings. Diagnosis may be supported by ultrasonography and abdominocentesis, although a definitive diagnosis remains challenging and frequently requires post-mortem confirmation.