DIFFERENTIATION OF BLOOD CELLS IN ANIMALS OF PRODUCTIVE INTEREST

Blood is a connective tissue essential for the transport of oxygen and nutrients, as well as acting in the protection and regulation of the organism. In animals of productive interest, the complete blood count (CBC) is a fundamental tool for diagnosis, prognosis, and health monitoring, allowing the identification of anemias and inflammatory, infectious, and parasitic processes, often in subclinical phases. Several factors influence the hematological profile, such as age, physiological phase, species, breed, nutrition, and thermal or management stress. Iron and copper deficiencies, for example, compromise erythropoiesis, while stress alters the leukocyte series. The tissue oxygenation capacity, determined by erythrocytes and hemoglobin, directly impacts productive performance, and alterations in leukocytes reflect the energy costs of the immune response. Platelets/thrombocytes act in hemostasis, inflammation, and tissue repair. In practice, the interpretation of the leukogram assists in the differential diagnosis of infections, parasitoses, and stress, as well as in monitoring batch integrity and identifying subclinical disorders before the onset of clinical signs. Specific challenges are discussed for dairy and beef cattle, swine, and poultry, considering particularities such as iron-deficiency anemia in piglets, parasitic tristeza in cattle, swine stress syndrome, and the heterophil-to-lymphocyte ratio in poultry. It is concluded that the systematic incorporation of the complete blood count into sanitary management routines is a high-impact strategy, enabling early interventions, reducing the empirical use of medications, and improving productive efficiency, well-being, and the sustainability of farming systems.