Comparison of blood profiles between housed and grazing Korean indigenous cattle (Hanwoo)

The objective of this study was to compare the hematology profiles of Korean indigenous cattle (Hanwoo) raised in a barn (housed) or on pasture (grazing). Our findings showed significant differences in the red blood cell (RBC) profiles of these 2 groups. When compared to cattle raised in a barn, a significant decrease in hematocrit (P = 0.000), hemoglobin (P = 0.000), and red blood cells (RBCs) (P = 0.000) and a significant increase in mean cell volume (P = 0.015) and reticulocytes (P = 0.000) were observed in grazing cattle, which indicate regenerative anemia. Furthermore, indirect bilirubin was significantly higher in grazing cattle, which indicates intravascular hemolysis and neutropenia (P = 0.000), and monocytosis (P = 0.000) was also identified. To the best of our knowledge, this is the first study that demonstrates changes in reticulocyte count and indirect bilirubin levels secondary to regenerative intravascular hemolysis in grazing cattle.