Cobalt deficiency in cattle and its impact on production

Abstract

ABSTRACT: Two outbreaks of cobalt deficiency in beef cattle were diagnosed in Midwestern Brazil. We discuss the clinical, epidemiological, pathological features, therapeutic measures, and impact aspects of the production system associated with these outbreaks occurring outbreaks in two farms of extensive cattle raising-system in the state of Mato Grosso do Sul. Seven affected cattle were euthanized and necropsied. Tissues for histopathology and microelements dosage were secured. At Farm A, 3100 cattle of all ages got sick, and 396 died; at Farm B, 148 were affected, and 110 died. In both farms, cattle were fed the same mineral supplement. The main clinical signs were weight loss and weakness, even though a good supply of forage was available in the paddocks. Many cattle stop grazing and chew at tree barks, wood chips from fence posts, and bones. In addition to the deaths, there was a compromised growth, and the reproductive rates fell sharply. The necropsied cattle were thin, with rough hair coat and pale mucous membranes. The liver was diffusely orange and showed a lobular pattern. The bone marrow was gelatinous and diffusely yellow. Histological changes included hemosiderosis in the liver and spleen, hepatocellular vacuolar degeneration, and myeloid and erythroid hypoplasia of the bone marrow. In the white matter of four cattle’s brains, the myelin sheath was markedly distended (spongy degeneration). Proliferative parasitic abomasitis was observed in three cattle. The presumptive diagnosis was based on the association of the clinical picture, the necropsy findings, and the ruling out of other possible causes. The diagnosis was confirmed by the favorable response to treatment with cobalt and vitamin B12 orally and by mineral supplementation.