Four experiments were conducted to evaluate the influence of eight shrub leaves on digestion, nitrogen retention and ruminal digestion characteristics by sheep. In general, in all experiments, only few variations in nutrient intake, nutrient digestion coefficients and N retention were observed between sheep fed diets containing M. sativa hay and sheep fed diets with different levels of shrubs. The same responses were detected in sheep rumen fermentation parameters and data for digestibility values: a, b and c values and effective degradability of dry matter, crude protein and neutral detergent fiber of individual forages. Even though, all shrub species contained high levels of crude protein, it seemed that plant secondary compounds in browse species affected their nutritional quality, reducing the nutrition of sheep fed diets with different levels of browse plants. However, native shrubs growing in semiarid regions of northeastern Mexico may have potential as an economical supplementary feed for sheep fed diets based on roughages of low nutritional quality.