Normal bovine RBC:

Bovine erythrocytes are similar in size to horse erythrocytes and lack central pallor. A small degree of anisocytosis can be seen in smears from healthy cattle. Cattle rarely display rouleaux formation in heatlh or disease. The approximate erythrocyte lifespan is 160 days. Polychromatophils are not usually observed in blood smears from healthy non-anemic cattle, although they do release reticulocytes in response to an anemia (their capacity for regeneration is not as marked as the dog). Note that marked poikilocytosis (variation in red cell shape), thrombocytosis (often > 1 million cells/uL) and microcytosis are features of healthy calf blood. Calves do remain microcytic for up to 1 year of age, which is attributed to a physiologic iron deficiency.