Blood cell count and morphology, and vitamin B12 concentration in pre- and post-weaned calves

Haematological indicators may resent physiological variation by age. Vitamin B12 promotes haematopoiesis. The aims of this study were: 1) to compare the values of the haematological variables and the concentration of vitamin B12 in pre- or post-weaned veal calves and 2) to identify the possible association between the values of the haematological variables and the concentration of B12 in the blood of veal calves. Blood was collected on the same day from 31 pre-weaned and 31 weaned calves of the Limousine breed from the same farm. The complete blood count, including the blood cell morphology evaluation, was performed and the serum B12, total protein and albumin concentrations were determined. The serum concentration of vitamin B12, the haematocrit (HCT), the haemoglobin concentration (HGB), the platelet count and the lymphocyte count were significantly higher in the weaned calves. A very strong positive correlation was found between the concentration of the vitamin B12 and HCT and HGB before weaning, while these correlations were moderately positive following weaning and in the total population tested as well. The observed variation in the blood cell count and morphology, such as poikilocytosis and the presence of macrocytes and hypersegmented neutrophils, along with the age of the animal seem to be related to the vitamin B12 concentration.