Micromineral concentrations (copper, cobalt, iron, molybdenum and zinc) in the liver of dairy cows from Campos Gerais Region, Paraná state, Brazil

Abstract

This study collected samples from 50 Holstein cows, most intensively bred, and from the Campos Gerais region, Paraná, with an average milk production of 30.21L/day. Samples of the liver, spleen and lymph nodes were collected to determine the levels of copper, cobalt, iron, molybdenum and zinc. Spleen and lymph nodes were subjected to histological analysis and evaluation of the degree of hemosiderosis. The average concentrations of copper (495.05ppm), molybdenum (4.19ppm), and zinc (274.49ppm) were higher than those established for the bovines. For cobalt 26% of the animals presented levels below the established level, which characterized cobalt deficiency. Only iron (299.12ppm) exhibited an adequate average level. Histopathologically hemosiderosis was observed mainly in the spleen (78%) and less frequently in the lymph nodes (20%). The observation of hemosiderin in the spleen and lymph nodes is not related to copper deficiency. Still it may be related to high levels of molybdenum, zinc, iron, or other undetermined causes.

Vitaminas e minerais na nutrição de bovinos

“…Alterações relacionadas aos macrominerais foram observadas do NRC (19) para o NRC (39) (Tabela 1). No entanto, o setor de produção de ruminantes já adotava essas alterações durante os anos que discorrem entre a atualização do NRC devido as diversas pesquisas realizadas, fazendo com que adaptações fossem realizadas conforme as novidades eram lançadas (40,41,42). Uma das grandes mudanças foi a redução da exigência de K e Na para a produção de leite, pautada na diminuição de casos de mastite reduzindo a exigência destes minerais.…”