The study investigated seasonal variation in hematological parameters of five indigenous cattle breeds Gir, Sahiwal, Tharparkar, Rathi, and Red Sindhi together with crossbred cattle under tropical climatic conditions. Red Blood Corpuscles (RBC), White Blood Corpuscles (WBC), Hemoglobin (HGB), Hematocrit (HCT), and Mean Corpuscular Volume (MCV) were evaluated across summer, rainy, and winter seasons. Breed-specific patterns indicated that Gir and Sahiwal maintained the highest RBC values in all seasons, ranging from 7.78-7.85 in summer, 9.15-9.25 in the rainy season, and 8.55-8.62 million/µL in winter. Tharparkar, Rathi, and Red Sindhi showed moderate RBC levels, while crossbred cattle consistently exhibited the lowest values (7.59, 8.95, and 8.39 million/µL). WBC counts increased from summer to winter for all breeds, with indigenous breeds ranging from 8.1-9.25 and crossbreds from 8.71-9.93 ×10³/µL. Hemoglobin values were highest in Gir (9.7-11.88 g/dL) and Sahiwal (9.6-11.80 g/dL), intermediate in Tharparkar, Rathi, and Red Sindhi, and lowest in crossbred cattle (9.46-11.65 g/dL). Hematocrit followed a similar trend, with Gir maintaining the highest HCT (35.6-39.5 percent) and crossbred cattle the lowest (33.45-37.29 percent). Indigenous cattle had MCV values between 43.6-46.1 fL, while crossbred cattle recorded substantially higher values (47.0-54.05 fL), indicating larger erythrocyte size. Overall, indigenous breeds showed superior hematological stability and greater resilience to seasonal thermal stress compared to crossbred cattle. Rainy and winter seasons provided more favourable physiological conditions, whereas summer heat load negatively influenced most hematological traits. The results reaffirm the adaptive advantage of indigenous cattle under tropical environmental conditions.
