[The reference values of the hemoglobin content, the hematocrit and the mean concentration of corpuscular hemoglobin of calves reared without iron substitution. 1. Dependence on the rearing period].

A total of 1.088 blood samples (1 to 6 per animal) were taken from 491 rearing calves in the colostral period, the milk feeding period and the weaning period (at the age of 4, 22, 51, 79, 105, 122 and 145 days); the hemoglobin content (Hb), the hematocrit (Hc) resp. the mean corpuscular hemoglobin concentration (MCHC) were determined resp. calculated. Hb, Hc and MCHC were drawn in diagrams in dependence on the rearing period as arithmetic means with standard deviations, as quartiles and as frequency distributions on an interval scale. During the rearing periods with milk feeding the anaemic frequency was considerable. Anaemia resp. hypochromia frequency had an inverse relation to the developing increase of concentrated feed and roughage consumption and thus makes it probable that the cause of anaemia is the intake and/or absorption of iron insufficient for the weight gain performance achieved. The consumption of solid feed by the hematologically examined calves developed more quickly than in other GDR rearing farms due to the early ad libitum supply with this feed component and the composition of fluid feed with milk. Reference is made that the frequency of hypoferric anaemia can also be considerable during the milk feeding period in the intensive rearing of lambs and kids if an effective iron intervention is not made.