Abstract— A study was carried out to investigate the effect of mixed Gmelina arborea and Moringa oleifera (GMMO) leaf meal inclusion and sampling periods on the haematology and serum biochemistry of Red Sokoto does fed Digiteria smutsii hay based diets. Twenty-eight (28) growing Red Sokoto does aged between 6 and 7 months with average weight of 14.71±0.09 kg were randomly assigned to four treatments balanced for weight with seven does per treatment in a completely randomized design. Experimental diets were offered at 4% of body weight. Haematological values shows that all parameters measured are significantly different. Significant (P<0.05) differences were observed cholesterol levels of the animals across the treatments. Cholesterol level was significantly higher (P<0.05) in 0% (107.90) and 10% (107.57) compared to other treatments. Effect of sampling periods on haematological parameters of growing does shows significant differences (P<0.05) in all the parameters measured except white blood cells count. There were significant differences (P<0.05) on total protein and globulin. Total protein ranged from 65.58 to 69.75 g/L at the end and middle of the experiment, respectively. It was significantly higher (P<0.05) at the mid than other periods. Values of globulin were statistically higher (P<0.05) at mid and end of the experiment than at the beginning. Values for all the parameters measured in this study were within the normal ranges for healthy goats. GMMO leaf meal inclusion and sampling periods did not have any adverse effect on blood profile of Red Sokoto does. It can be concluded that GMMO leaf meal can be included in the diets of Red Sokoto does up to 30% without detrimental effects.