Abstract
Iron deficiency can cause anemia in calves and is therefore of economic importance for the cattle industry. Low iron levels are commonly caused by feeding whole milk without the addition of dietary supplements, leading to the most frequent cause of anemia in calves. Other reasons for the development of anemia include congenital iron deficiency, malnutrition, bleeding ulcers or bloodsucking parasites. In this study, blood samples from 40 calves were analyzed for different hematologic parameters as well as the content of copper, glutathione peroxidase, serum iron and serum ferritin. Eight calves showed decreased hemoglobin and hematocrit values and a significantly lower number of erythrocytes compared with non-anemic calves. Interestingly, 19 of 40 calves had a low serum iron. Considering their serum ferritin levels, only fourteen calves, including six calves with both low iron and low ferritin levels, were classified as iron deficient. Our data indicate that the determination of hemoglobin and serum iron is of only limited suitability for the diagnosis of iron deficiency in calves and that the determination of serum ferritin is the better option. In addition, no direct correlation between serum ferritin and serum iron was detected. Comparing milk diets, more calves fed milk replacer showed reduced levels of ferritin compared with calves fed whole milk. We suggest that the determination of serum ferritin should be the preferred parameter for the diagnosis of anemia, since serum iron levels are subject to physiological fluctuation and a deficiency can be caused by inflammation or neoplastic diseases.

Key words: anemia, calves, ferritin, iron deficiency, serum iron.