Iron Status, Erythropoiesis, Meat Colour, Health Status and Growth Performance of Veal Calves Held on and Fed Straw

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Abstract
Two experiments were designed to study the iron (Fe) status in veal calves (62 intact males) fed and held on straw. In experiment 1, two groups were fed 20 mg Fe/kg milk replacer (MR) and held unattached on rye or barley straw litter. In experiment 2, groups were fed 20 mg Fe/kg MR and held unattached on rye straw litter or on sawdust or attached on wooden slatted floors without straw litter or were fed 50 mg Fe/kg MR and held unattached on sawdust. Fe concentrations in tested straw sorts (rye, barley, wheat, triticale) were similar and ranged from 15 to 85 mg Fe/kg dry matter. Growth performance and health status were not significantly influenced by Fe intake through MR or straw. Straw intake in the group fed straw was greater (P < 0.01) at the end than at the start of the growth period, but intake of different straw sorts was similar. Calves fed 20, but not those fed 50 mg Fe/kg MR, developed marked hypoferraemia, but only moderate anaemia. Total iron binding capacity (TIBC) was significantly (P < 0.05) and transferrin (Tf) concentration was numerically higher in calves fed 20 than in those fed 50 mg Fe/kg MR on slaughter day. TIBC and Tf were positively correlated (r = 0.63). Haemin concentration and lightness of m. rectus abdominis were significantly (P < 0.01), whereas myoglobin concentration was numerically greater in calves fed 50 than in those fed 20 mg Fe/kg MR. In conclusion, haematological and blood chemical parameters and meat colour were influenced only by high Fe intake through MR, but not if calves were held on straw litter or were fed straw.