Follicle ablation has been recognized as an efficient method of follicular wave synchronization. Treatment with recombinant bovine somatotropin (BST) has been shown to enhance follicular development in Bos taurus. This experiment assessed the effects of these treatments in Nelore (B. indicus) heifers. Eight cycling Nelore heifers were randomly assigned to 3 different treatments. On Day 2 of a synchronized cycle (Day 0 = day of ovulation), heifers assigned to Treatments 1 and 2 received 2 mL of saline, whereas heifers assigned to Treatment 3 received 320 mg of BST. On Day 5, the first-wave dominant follicle was ablated by ultrasound-guided transvaginal aspiration in heifers in Treatments 2 and 3, and all heifers received an injection of prostaglandin on Day 11. Aspiration of the dominant follicle advanced and synchronized (P < 0.05) the day of second-wave emergence (6.9 ± 0.1 vs. 8.4 ± 0.4) and the day of the pre-wave FSH peak (6.0 ± 0.0 vs. 6.9 ± 0.4), and increased FSH peak concentrations (381 ± 21 vs. 292 ± 30; pg/mL; P < 0.01). Recombinant bovine somatotropin treatment caused a two-fold increase in plasma insulin-like growth factor-I (IGF-I) concentrations (P < 0.001) and resulted in a 36% increase in the number of small follicles (<5 mm; P < 0.001) compared with saline-treated heifers. In summary, in agreement with previous reports on B. taurus, dominant follicle aspiration synchronized ovarian follicular development, and BST treatment increased peripheral concentrations of IGF-I in Nelore heifers. Recombinant bovine somatotropin also increased the number of small follicles, but this response appeared to be inferior to that reported for B. taurus.Fil: Buratini, José. University of São Paulo, São Paulo, BrazilFil: Price, C.A. University of Montreal, St. Hyacinthe, Que., CanadaFil: Visintin, J.A. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Bó, G.A. Department of Pharmacology, Institute of Biosciences, UNESP, Botucatu 18618-000 Sao Paulo, Brazil