Context Climatic changes considerably affect feed availability; consequently, animals face undernutrition.Aims This study aimed to evaluate the productive, reproductive and metabolic responses of Barbarine ewe lambs to feed restriction under hot conditions (30-50 degrees C).Methods Forty-eight 6-month-old ewe-lambs (BW 24.4 kg) were assigned to high (H; 500 g straw, 600 g concentrate) or low (L; 400 g straw, 200 g concentrate) feeding groups for 120 days where the temperature exceeded 40 degrees C (restriction phase). During refeeding (50 days, T <= 30 degrees C), both groups received 500 g of straw and 600 g of concentrate (H). During this phase, both groups were renamed based on their previous nutritional status: HH (previously high-fed animals) and LH (previously low-fed animals). BW, body condition score, rectal temperature, respiratory rate and heart rate were measured, and blood samples were collected every 2 weeks. At the end of this phase, rams were introduced to ewe ambs to assess their reproductive aptitudes.Key results During feed restriction, under heat stress, H ewe lambs gained 5.1 kg, whereas the L group maintained a constant weight without health issues (P = 0.0001). During refeeding, the LH group's BW increased by 6%, but remained lower than that of HH with no compensatory growth. During restriction, under hot conditions, the respiratory rate and heart rate were higher in H than L (P < 0.05), whereas the rectal temperature remained stable (P > 0.05). During refeeding, no significant changes were observed in all physiological parameters. Compared with H, glucose and urea decreased for the L group, and creatinine increased, whereas the rest of the metabolites remained constant in both groups. In terms of reproduction, only 50% and 25% of ewe lambs showed estrus behavior for HH and LH, respectively. Consequently, only 33 (HH) and 12% (LH) of total ewes lambed.Conclusion Feed restriction combined with heat stress significantly impairs growth and may affect the long-term reproductive performance of Barbarine ewe lambs. Monitoring their progress should provide important information on the adaptive capacities of this breed to different environmental challenges.Implications Insights into adaptative responses help develop sustainable feeding and management strategies to enhance the resilience of Barbarine ewe lambs to environmental challenges while maintaining productivity in arid and semi-arid regions.