Hepatic lipidosis in feedlot cattle: report of two outbreaks.

Two outbreaks of hepatic lipidosis were diagnosed in beef cattle under feedlot conditions in the province of Buenos Aires, Argentina. Although this metabolic disease is common in high-producing dairy cows, its occurrence in feedlot cattle is unusual and probably underreported. Outbreak 1 affecting steers, over a 20-day period, was associated with a nutritional imbalance characterized by a deficient ration in physically effective fiber leading to chronic ruminal acidosis and secondary ketogenesis. Outbreak 2 affected finishing steers in association with a prolonged reduction in feed intake, linked to inconsistent manual feeding practices, leading to hepatic lipidosis. In both outbreaks, affected animals showed isolation from the herd, anorexia, weakness, muscular tremors and spontaneous falls. Steatosis and excessive production of ketone bodies were evidenced and confirmed by biochemical and histopathological studies. These cases highlight the importance of nutritional and metabolic monitoring in intensive fattening systems, as well as the need to prevent periods of stress or hyporexia that may trigger energy imbalances and associated hepatic dysfunction.