Ferritin in blood serum of dairy cows

Concentration of ferritin in blood serum of dairy cows was measured by a two-site immunoradiometric assay to assess changes in the iron nutritional status during gestation, parturition, and lactation. Although anemia did not occur in pregnancy of dairy cows, there were slight decreases of red cell counts, hemoglobin, and hematocrit in the early stage of lactation. Ferritin concentration remained relatively constant in late gestation (35 ng/ml), but deviations were considerable. Ferritin rose gradually from 3 days prepartum with a sharp elevation after parturition. At 1 to 2 wk postpartum, it had increased to about twice amounts in late gestation. During the subsequent 8 wk postpartum, it fell gradually and thereafter maintained almost unchanged (40 ng/ml). Both iron in blood serum and total iron-binding capacity declined from 2 wk prepartum to the end of gestation but showed a rise beginning about 2 wk after parturition. Because changes in iron-related proteins just before and after delivery may be results of inflammatory reactions accompanying delivery, ferritin concentration is not a good index for diagnosis of iron deficiency in lactating cows just after parturition.