A total number of 27 mature Ossimi ewes divided into three groups (9 ewes/each). The 1^st group, which served as control (C), was treated with distilled water (10 mL/kg B.W. /day), the 2^nd group treated with selenium nanoparticles (SeNPs 1 mg/kg B.W. /day), and the 3^rd group treated with L-Carnitine (L-Car 350 mg/Kg/day). Data revealed that the hematological parameters hematocrit (HCt) had significant differences (at 90 days of pregnancy, P = 0.0299) and mean cell volume (MCV) showed significant differences (at days 45 and 90, P = 0.0014 and P = 0.0580, respectively). Triglyceride (TG) levels changed significantly at 45, 90, and 150 days of pregnancy; total cholesterol levels changed significantly at 150 days; low-density lipoprotein (LDL) levels changed at 45 and 90 days of pregnancy; and high-density lipoprotein (HDL) levels changed at 45 and 90 days of pregnancy. AST and ALT decreased due to the treatment with SeNPs and L-Carnitine (L-Car) during 45, 90, and 150 days of pregnancy, while ALT decreased during 90 and 150 days of pregnancy due to the treatment with SeNPs and L-Car compared with the control group. The urea concentration showed a significant decrease due to the treatments during 90, and 150 days of pregnancy, and the creatinine concentration significantly decreased at 90 days of pregnancy. Furthermore, data showed significant decreases in oxidized glutathione (at days 90 and 150, P = 0.0001) and nitric oxide (at days 45 and 150) due to the treatment with SeNPs and L-Car. It was found that there was a significant improvement in blood serum ATP and an increase in reduced glutathione and superoxide dismutase due to LC and SeNPs treatment during different pregnancy periods. Hence, SeNPs and L-Car administration improved different biochemical and hematological parameters and serum antioxidant activities for Ossimi ewes during different periods of pregnancy.