Avaliação da IATF em novilhas girolando utilizando-se diferentes protocolos com sêmen sexado

Abstract

The aim of this study was to compare the results of different protocols of Timed Artificial Insemination (TAI) using sexed semen on reproductive effciency in Girolando cattle. Sixty two heifers were used, being clinically health with a body condition between 2,5 and 3,5, divided randomly into 03 groups: control (n = 21), FSH / LH (n = 21) and eCG (n = 20). All animals received the same hormonal treatment to synchronize estrus, consisting in placing on D0 (5:00 PM) intra-vaginal device with 750 mg progesterone (P4), and 2 mg of estradiol benzoate (EB). In D8 (5:00 PM) device were removed and 2 mL of prostaglandin (0.500 mg cloprostenol) was administered. On D9 all animals received 1 mg of estradiol benzoate (EB) (5:00 PM), and were inseminated on D11 at 5:00 PM, 60 hours after device removal. On D8, heifers were randomly assigned into 3 groups. Control group without FSH / LH and eCG; Group FSH / LH - 25 IU FSH and LH administered after device removal, Group eCG - 300 IU eCG administered after device removal. Heifers were examined by ultrasonography 35 days after AI for pregnancy diagnosis and 45 days or evaluation of embryonic death. The pregnancy rate for control groups, FSH / LH and eCG were respectively 19%, 28% and 35%. Data were analyzed by chi-square, with 5% significance level. No signicant difference was seen between-groups. When it was compared control group and eCG Group in heifers that were not cycling there was a significant difference in pregnancy rate. It is concluded that in cycling animals, eCG and FSH / LH does not interfere with pregnancy rates, however in those heifers that were not cycling or had smaller than 8 mm follicles, eCG had a favorable effect thereby increasing substantially the results.