The aim of this study was to evaluate the ability to induce sexual activity in nulliparous Droper ewes during the anestrus season throughout the male effect in northern Mexico (26° N). Dorper rams (n = 8; 83 ± 3.6 kg BW) and 55 nulliparous anovulatory ewes (42 ± 2.36 kg BW) were used. Before to be in contact with males, ewes received 60 mg i.m. of progesterone to avoid short cycles and expect ovulation once estrus activity occurred, then ewes were divided in 4 homogeneous groups in terms of BW and BCS. Prior exposure to females, males were randomly divided in 4 experimental groups and treated during 30-d with: Glutamate (GG, n = 14 ewes; 2 males treated with 7 mg kg⁻¹ BW of Glutamate, i.m.), Testosterone (TG, n = 14 ewes; 2 males treated with 25 mg i.m. of testosterone), Glutamate + Testosterone (GTG, n = 14 ewes; 2 males received 7 mg kg⁻¹ BW of L-Glutamate and 25 mg of testosterone) and Control (CONT, n = 13; 2 males received 0.5 mL of saline). Since the first day of contact with males, estrus response and interval to estrus onset (h) were registered. Thereafter, embryo implantation rate was determined on d-45 from male exposure throughout transrectal ultrasound scanning. Data regarding the onset of estrus were analyzed using t-test, while the estrus response and implantation rate considered X² (SYSTAT 12.0). Ewes exposed to rams treated with glutamate or glutamate + testosterone showed the best reproductive outcomes (P < 0.5), depicting, in average, the shortest interval to estrus (37.7 h) while the largest implantation (100%) and estrous response (100%) rates. Therefore, glutamate administration in rams emerges as an interesting option to improve the male effect. Nonetheless, it is futher required to elucidate the role played by testosterone in the GTG group, because ewes exposed to rams treated with testosterone alone (TG group) had the lowest reproductive outcomes.