USO DE LH COMO INDUTOR DE OVULA O EM PROTOCOLO DE IATF PARA NOVILHAS NELORE

The aim of this present work was to evaluate, the use of LH (luteinizing hormone) in the FTAI protocol, as inducer of ovulation and the follicular diameter influence in the moment of AI over the pregnancy rate of Nelore heifers. For that, 118 heifers of Nelore breed were utilized, they aged 20 to 28 months and their medium weight was 362 Kg and the corporal score was 3.0 (1-5). First of all, the animals with unknown state of estrous cycle were randomically divided in two groups: G-C (control, n=58) and G-LH (n=60). In the D0 in the morning, each animal received a vaginal implant of progestogen and 2 mg of IM BE. In both groups, the implants were removed in the D9, concomitant with the application of de prostaglandin F2α (PGF2α – 112.5 g) and 10 mg of FSHp. Only G-LH animals received 0.5 mg de BE. In the morning of D10, the animals of GLH received 1.0 mg de BE. In the morning of D11, only the G-LH animals received 3.125 mg of LH and in the afternoon of the same Day, both groups were inseminated at fixed time. There were no differences (p>0.05) between the pregnancy rate of G-C and G-LH, they were respectively 38% and 43%, despite of a 5% increase in pregnancy rate in group G-LH. There was effect (P<0.05) of follicular diameter in the pregnance.