This study aims to evaluate the effect of treating groundnut vines with different levels of calcium oxide on rumen and blood measurements, nutrient digestibility and productive performance of growing saidi lambs. The nutritional treatments were divided into four treatments: the first diet: the control diet: a basic groundnut vines diet without calcium oxide (CaO); The second diet consists of the control diet +1.5% CaO; The third diet consists of the control diet + 3% CaO and the fourth diet consists of the control diet + 4.5% CaO; Twenty-eight lambs from Upper Egypt were used for the four experimental groups (each group of 7 lambs) in a completely randomized design for 180 days. The average initial body weight was 21.75 kg, ±1.52%. The percentage of crude protein in all experimental rations was 13.21%. The results showed that the dry matter intake was increased numerically with increasing in the percentage of calcium oxide, as the fourth group (4.5% CaO) recorded: the highest value for the dry matter intake (1224 g/day) and the lowest value was recorded in the control group (1208 g/day). The best digestion coefficients of all nutrients were showed for the fourth group.  while the control group (0%CaO) had the lowest digestive values ​​for all nutrients. The fourth group (4.5%CaO) achieved the highest significant values ​​for both rumen ammonia-nitrogen and volatile fatty acids (32.68 mg/dL and 8.33 meq/dL, respectively) while the lowest values ​​were found for the control group (26.13 mg/dL and 6.33 meq/dL, respectively). All blood parameters were significantly superior for the fourth group, to the control group (p<0.05) unless albumin and globulin were non-significant differences between the experimental groups. The fourth group recorded the highest total weight (31.38 kg) and average daily gain (174.33 g/d) while the lowest total weight and average daily gain was recorded for the control group (26.48 kg and 147.11 g/d respectively).