Effect of breed, intake, and carcass composition on the status of several macro and trace minerals of adult beef cattle

The objective was to determine the association between breed, intake, and carcass compo- sition and the status of liver Cu, Zn, and Fe, and serum Cu, Zn, Ca, and Mg of 118 mature cows representing nine breeds of cattle. Breeds used were Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Red Poll, Pinzgauer, and Simmental. The cows were fed one of four levels of DMI: 58, 76, 93, and 111 g of DMI-w~-.~~.~-~. A ground alfalfa, corn, and corn silage diet was fed for up to 5 yr. There was no relationship between liver and serum concentrations of Cu, a negative correlation (P < .05) existed between liver and serum concentrations of Zn and a positive correlation ( P.O 1) existed between liver concentra- tions of Cu and Zn. Concentrations of serum Ca were positively correlated (Cu and Zn, P < .01; Mg, P < .05) with serum concentrations of Cu, Zn, and Mg, but negatively correlated ( P < .O 1) with liver Fe. Liver Cu was higher ( P < .05) for the Limousin breed than all others, except Angus. Liver Zn concentrations were higher ( P < .05) for Limousin than for Pinzgauer, but no other breed differences were observed. Liver Cu concentration was not affected by daily intake, but liver Zn concentration increased ( P < .05) with increased daily intake. Liver Fe decreased ( P < .01) in a curvilinear manner with increased daily intake. No breed differences in serum concentrations of Cu or Zn were observed. Serum Ca concentrations were higher (P < .05) for Angus, Red Poll, and Limousin than for Simmental, and Red Poll had higher ( P < .05 j concentrations of serum Ca than for Braunvieh. Serum Mg concentrations ( P < .05) were higher for Angus than for Hereford. Serum Zn and Ca were not affected by daily intake, and serum Cu was a quadratic function of intake ( P < .05). There was a stronger association of carcass lipid (percen- tage) with liver and serum Cu concentrations (P < .01) than existed between carcass protein (percen- tage) and liver and serum Cu concentrations (P < .05). These results indicate that breed differences may exist in Cu metabolism. Liver Cu and serum Cu concentrations were not related, carcass composition was associated with Cu concentrations in both liver and serum, liver Cu and Zn were positively correlated, increased intake was associated with increased liver Zn, decreased liver Fe, and no change in liver Cu.