A two-month trial was conducted to investigate the effects of pelleting rations with 70:30, 65:35, and 60:40 concentrate to high-quality roughage (alfalfa hay) ratios on hematological and biochemical parameters of ostriches. A total of 18 seven-month-old male ostrich chicks, initially weighing an average of 60-70 kg, were distributed into three different outdoor paddocks at a stocking density of six birds per paddock. In the morning, blood collection was made from the wing vein after about 12 h of fasting. All rations resulted in no significant change in hematological parameters. However, with increasing alfalfa inclusion rate, the heterophil/lymphocyte ratio tended to be lower (P = 0.089); whereas the values of hemoglobin, packed cell volume (PCV), and mean corpuscular hemoglobin (MCH) tended to be higher (P values 0.069, 0.072 and 0.094, respectively). In terms of plasma biochemical parameters, increasing the ratio of concentrate to alfalfa hay in ostrich diets resulted in significant (P < 0.05) depression in the values of glucose (up to 20.2 %), total cholesterol (up to 19.2 %), creatine kinase (up to 27.9 %), and aspartate aminotransferase (up to 29.9 %). Additionally, the 65:35 or 60:40 rations caused a decrease in low-density lipoprotein cholesterol level (27.9 and 42 %, respectively; P = 0.008) compared to the 70:40 ration. Without exception, no rations affected the values of leukocyte subsets, total protein, albumin, globulin, uric acid, alanine aminotransferase, gamma glutamyl transferase, triglycerides, high-density lipoprotein cholesterol, and very low density lipoprotein. Based on our results, the concentrate to alfalfa ratio of 60:40 could be suggested as optimum ratio for good health conditions of juvenile ostriches
