Ferrokinetic studies in normal and iron deficiency anemic calves.

Ferrokinetic studies were performed on control calves and on calves with experimentally induced iron deficiency anemia, all 15 weeks old. The plasma iron clearance half time was about 4 times shorter in the experimental than in the control group. The low plasma iron concentration in the anemic calves was partially compensated by a more rapid plasma iron disappearance. Therefore the difference in the plasma iron turnover rate was reduced. The mean value of plasma iron daily renewal rate was about 3 times higher in the experimental than in the control group. The maximum uptake of injected Fe into blood cells was reached 14 to 16 days after injection. The uptake of Fe was about 10% higher in the control than in the experimental group. Using the values from the ferrokinetic study, the iron need for calves could be estimated. The requirement of iron to maintain a normal and constant Hb in a calf weighing 100 kg at a growth rate of 1 kg/daily was estimated as being 17.5 mg/day. Based on information in the literature and assuming a retention of dietary Fe of 25%, the total daily iron need for such a calf gaining 1 kg/day would be 160–180 mg.