Lesions in broiler chickens following experimental intoxication with cobalt.

Dietary levels of 0, 125, 250, and 500 mg of cobalt per kg of feed were given to 1-day-old broiler chicks for 14 days. All levels of cobalt reduced feed intake, body weight gain, and gain: feed ratio and caused a dose-dependent increase in mortality. Chickens fed 250 and 500 mg cobalt/kg feed developed pancreatic fibrosis, multifocal hepatic necrosis, and lesions in skeletal and cardiac muscle and smooth muscle of the duodenum. The results demonstrate that excessive dietary cobalt has serious adverse effects on the health and performance of broiler chickens.