Chromium: a final adjustment in cattle diets

Chromium can be found in feed, and if not, it must be supplemented. Within forages, the legume family is the one with the highest concentration (0.2 to 4 ppm DM) followed by grasses (0.1 to 0.35 ppm). While cereals contain much lower concentrations (0.01 to 0.55 ppm), amongst which corn is especially deficient (0.02 ppm-DM) (Lashkari et al. , 2018).

Chromium is only bioavailable to animals in the form of trivalent chromium (Cr+3), where it is associated with organic material. When this element enters the body as hexavalent chromium (Cr +6) it is not absorbed and can be useful as an inert indicator of dry matter consumption (Kim et al. , 2005).

Cr is transported in the blood bound to transferrin and then taken by insulin-sensitive tissues, a hormone responsible for stimulating its uptake. When insulin binds to surface receptors on cells, Cr is taken up by a protein called chromodulin, which in turn stabilizes the hormone-receptor complex and facilitates its action by activating tyrosine kinase.

The moment insulin stops acting, Cr-bound chromodulin is released from the cell (Vincent, 2000). Endogenous Cr is eliminated especially in urine, while smaller amounts are eliminated through feces and milk (Bowen et al., 2009).

Chromium requirements