Effects of High Dietary Iron as Ferrous Carbonate on Performance of Young Dairy Calves

Abstract Eighty female Holstein calves were used to examine the effects of high amounts of added dietary Fe as ferrous carbonate on performance of young dairy animals. Experimental starters containing either 0, 500, 1000, 2000, or 4000ppm supplemental Fe as ferrous carbonate were fed for 8 wk beginning at 1 wk of age. The control starter contained 170ppm Fe, all of which came from the major feed ingredients. The calves were fed limited amounts of whole milk for the first 5wk. Weight gains and feed consumption were not consistently reduced at the higher amounts of supplemental Fe, but the lowest average values were at 2000ppm added Fe. However, during wk 7 and 8, when no milk was fed, calves fed 2000 or 4000ppm had reduced feed intakes and weight gains. Feed efficiency and health of the calves were not affected by supplemental Fe. The results of this study indicate that the performance of calves was not affected appreciably by 4000ppm supplemental Fe as ferrous carbonate from a pure lenses of siderite ore. This is a higher tolerance than shown previously for ferrous sulfate Fe.