This study evaluated partially mixed ration (PMR) silages based on banana leaves alone (BL-PMR) or combined with tomato agro-industrial residue (BLTR-PMR) in diets of lambs managed under semi-arid conditions. Twenty-seven female lambs were assigned to three treatments during a 52-day trial (12 days adaptation; 40 days data collection): control (concentrate), BL-PMR, or BLTR-PMR. Animals grazed deferred pasture from 09:00 to 15:00 h and received supplements daily at 15:00 h in individual pens. Both silage-based diets reduced drinking water intake compared with the control (- 28.8% in BL-PMR and - 41.8% in BLTR-PMR; P < 0.001), corresponding to approximately 670 mL/head/day saved in BLTR-PMR and a 40% reduction in drinking water use per kg of weight gain. The BLTR-PMR diet reduced voluntary concentrate intake by 19.1% relative to the control (P < 0.001), without affecting average daily gain (P >= 0.545), feed efficiency (P >= 0.515), and final body weight (P >= 0.275). Silage characterization revealed elevated butyric (20.22 and 36.55 g/kg DM for BL-PMR and BLTR-PMR, respectively) and acetic acid concentrations, consistent with clostridial-type fermentation. Despite this fermentation profile, productive performance, carcass weights, and meat quality traits were maintained, indicating no detectable impairment under the present conditions. Under the conditions of this study, the results suggest that PMR silages based on banana leaves, with or without tomato residue, can reduce drinking water demand under deferred-pasture management in semi-arid systems, while the inclusion of tomato residue may further decrease reliance on concentrate supplementation without compromising growth performance.