[Investigations of anemia of male rearing calves. 4. Relations between weight at birth, duration of keeping and increase of the ive weight in the period of the calves being fed on colostrum as well as the count erythrocytes in the weaning period of the calves].

With 195 male rearing calves which received concentrates ad libitum beside fluid feed with milk from their 5th day of life onward, investigations were made if and how far the characteristics of the development of the calves while they are fed on colostrum (body weight at birth, live weight increase and duration of keeping or stalling age) correlate with the hemoglobin content (Hb), the hematocrit (Hc) and the average corpuscular hemoglobin concentration (MCHC) of the animals on the 3rd, 28th resp. 56th day of keeping in the weaning period. There was a significant simple dependence particularly between body weight at birth, live weight increase and stalling age on the one hand and the hematologic values on the 3rd day of keeping in the weaning period on the other. A partial correlation analysis showed that the live weight increase while the calves were fed on colostrum was the main variable for all three hematologic parameters at the beginning of the weaning period of the calves. With increasing live weight, Hb, Hc and MCHC were diminished. This analysis was supplemented by the results of a cross--section investigation of the development of the milk and concentrate consumption and the Fe-intake of the calves fed on colostrum. The calculation of the Fe-balance showed that the mere ad libitum supply with feed supplements rich in Fe cannot prevent Fe-deficiency. Anaemia developing in the first month of the calves' lives is not a physiologic one but essentially caused by Fe-deficiency.