Die Bodenkultur - Journal for Land Management, Food and Environment
W. Knaus, W. Zollitsch, F. Lettner, G. Schlerka and R. Pangerl:
Effects of Iron Supplementation on the Performance, Blood Hemoglobin, Iron Concentration and Carcass Color of Veal Calves
The effects on the performance, blood hemoglobin, iron concentration and carcass color of an extra 25ppm of iron(II)fumarat added to a commercial milk replacer, given until the 38th day of the trial, were studied during a fattening period of 79 days on two groups of 24 calves. Two weeks, four weeks and 41 days after the withdrawal of the supplemental iron 14, 18 and 16 calves were slaughtered, respectively. The dietary regimen had a significantly positive impact on the fattening performance only within the time when the milk replacer was supplemented with extra iron. The feed efficiency was also clearly improved. The effects of the supplementation on the progression of the iron concentration and blood hemoglobin values were reflected in the visual assessment of the carcass color of the surface muscles.
Because of the results obtained in the first experiment, a second feeding trial was conducted with 48 calves which were divided into two groups. The commercial milk replacer fed to the experimental group was supplemented with 25 ppm of iron(II)-fumarat. After six weeks the experimental group was split into two subgroups (2a and 2 b) with 12 animals each, where as only the milk replacer for group 2a was supplemented with 15 ppm of iron(II)-fumarat. During that time (29 days), the milk replacer used was a 50 /50 % mixture of a commercial product and a milk replacer containing 53,7 % whey powder, 14,5 % soy protein and 4,5 % potato protein as protein sources. Contrary to the results of the first experiment, no significant differences in average daily gain were found between the two groups during the first fattening period (36 days). Supplemental iron had a positive influence on the feed conversion within the first 6 weeks. A significantly higher average daily growth performance was only observed in group 2a, which was fed supplemental iron until the end of the experiment. The apparent digestibility of iron was also markedly higher in group 2a.
In contrast to the findings made in experiment one, no change in the blood hemoglobin and iron concentration was observed. Supplementing iron during the whole fattening period did not negatively affect the veal color.
It is concluded that an extra iron supplementation to the commercial milk replacers can improve the fattening performance without necessarily having a detrimental impact on the color of veal, although it must be noted that the meat color depends on the amount of iron supplemented and on the length of time it is administered.
Key words: Iron, Performance, Hemoglobin, Veal, Color.