COMPLETE BLOOD COUNT, BONE MARROW AND RELATED INDICES IN CALVES: REFERENCE VALUES

The evaluation of bone marrow aspirates can give valuable information about the hemopoietic system and reference ranges are important in order to characterize any hematological abnormalities. The cytological examination of peripheral blood and bone marrow smear at the same time provide information on blood cell distribution, morphology and maturation. A clinical study was performed in order to assess health status and possible parasitological infections in a group of 10 female calves (9 Holstein and 1 cross Holstein"Belgian Blue), aged 7–12 months, owned by University of Pisa. Collection of bone marrow from calves aged over 12 months was unsuccessful with standard bone marrow needles. From the bone marrow collected from ribs, smears were prepared and evaluated for quality, cell distribution and the presence of megakaryocytes. Moreover, 300-cell differential counts (total 900 cells) were done by three different experienced operators with good agreement. Reference values for complete blood counts, bone marrow differential counts (myeloid and erythroid cell lines) and related indices were calculated based on 2.5 and 97.5% percentiles. Six different indices (M/E: Myeloid/Erythroid ratio, EMI: Erythroid Maturation Index, I/Me: Erythropoiesis Index, MMI: Myeloid Maturation Index, I/Mg: Granulopoiesis Index, I/M: Myelopoiesis Index) not reported previously in the literature, with the exception of the M/E, were determined.Collection of bone marrow from the rib in calves under 12 months provides quite easy access to hemopoietic system. Calculated reference ranges can provide the basis for interpretation of any hematological disorder and useful information about the health status of the animal. Ve