Cactus is currently being used as a livestock feed across arid regions of the world due to its availability and nutritive value. However, limited knowledge exists on the effects of some cactus species on ruminant metabolism. In this context, this study was conducted to evaluate the effects of increasing levels [25, 50, and 75% on dry matter (DM) basis] of crushed red cactus [Opuntia stricta (Haw.) Haw.] on hay-based diets for goats. Response variables included intake, nutrient digestibility, performance, intestinal morphology, and gastrointestinal organs of goats. Fifteen young bucks (non-castrated male goats), averaging 11.7±0.9 kg body weight (BW) at the beginning of the study, were used. The trial lasted 75 days and the goats were fed individually. Feed was offered twice a day, at 09h00 and 16h00. Water was offered ad libitum throughout the experimental period. Voluntary water intake decreased with increasing quantities of red cactus. The digestibility of DM, organic matter (OM), and crude protein (CP) presented greater values with 50 and 75% DM of red cactus compared with 25%. Significant differences (P=0.0021) were observed for daily BW gain with the greatest value (46 g/day) recorded in goats fed with 50% DM red cactus, whereas the lowest value (14 g/day) was recorded in goats fed with 25% DM red cactus. Red cactus intake decreased the length and width of duodenum villi. It is concluded that the inclusion of red cactus in goat diet up to 50% DM promotes an efficient nutrient utilization and animal performance, without causing digestive disturbances and adverse effects on the intestinal mucosa.