Abstract
Ferritin, iron and total iron-binding capacity (TIBC) of the serum from young steers were estimated during a prolonged period of caloric undernutrition and a subsequent recovering period. Holstein young steers of 3 months of age (n=8) received 42% ration for 5 months and 136% ration for 4 months on the basis of TDN for 0.7 kg daily weight gain. The control animals (n=8) received 100% ration for 9months. The prolonged caloric restriction caused a mild normocytic and normochromic anemia without a decrease in total serum protein nor albumin. The anemia thus induced was eliminated during the recovering period. TIBC decreased gradually with the progress of the malnutritional period and was improved quickly by the increase in rations. A decrease in serum iron concentration was observed only at the end of the undernutritional period. Serum ferritin started to rise shortly after the beginning of the undernutritional condition with the highest level at the end of that period, and returned to the control level in 3 months of the recovering period. The magnitude of changes in serum ferritin was exceedingly larger than that in TIBC. Serum ferritin seems to be a sensitive indicator for the malnutritional status of steers.
