Clinical and pathological study of an outbreak of obstructive urolithiasis in feedlot cattle in southern Brazil
Alexandre Paulino LorettiI,*; Luciana Oliveira de OliveiraII; Cláudio Estêvão Farias CruzI; David DriemeierI
IDepartamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9090, Cx. Postal 15094, Porto Alegre, RS 91540-000, Brasil
IIHospital de Clínicas Veterinárias (HCV), UFRGS, Porto Alegre, RS, Brasil
The epidemiology, clinical picture and pathology of an outbreak of urolithiasis in cattle in southern Brazil are described. The disease occurred in August 1999 in a feedlot beef cattle herd. Five out of 1,100 castrated steers were affected. Clinical signs included colic and ventral abdominal distension. White, sand-grain-like mineral deposits precipitated on the preputial hairs. Affected cattle died spontaneously 24-48 hrs after the onset of the clinical signs. Only one animal recovered after perineal urethrostomy. Necropsy findings included calculi blocking the urethral lumen of the distal portion of the penile sigmoid flexure, urinary bladder rupture with leakage of urine into the abdominal cavity and secondary fibrinous peritonitis. Daily water intake was low since water sources were scarce and not readily available. The animals were fed rations high in grains and received limited amounts of roughage. Biochemical analysis revealed that the calculi were composed of ammonium phosphate. A calcium-phosphorus imbalance (0.4:0.6) was detected in the feedlot ration. For the outbreak, it is suggested that contributing factors to urolith formation include insufficient fiber ingestion, low water intake and high dietary levels of phosphorus. No additional cases were observed in that feedlot after preventive measures were established. Similar dietary mismanagement in fattening steers has been associated with obstructive urolithiasis in feedlot beef cattle in other countries.
Index terms: Obstructive urolithiasis, uroperitoneum, cattle, feedlot, ammonium phosphate, southern Brazil.
Pesq. Vet. Bras. vol.23 no.2 Rio de Janeiro April/June 2003. Open Access Article.