Banca de QUALIFICAÇÃO: PAULO CASTELO BRANCO DE GOUVEIA FILHO

Biotechnologies applied to cattle and buffaloes

Buffalo. Nellore. Embryo. eCG. Follicles. Oocytes competence.

Buffalos originate from Asia having been taken to Europe, Oceania and America. In Brazil, the herd was originally brought from Italy in February 1895, they came from Rome acquired by the farmer Vicente Chermont de Miranda from the Italian prince Rospigliosi Camilo and landed at the Dunas farm on Ilha do Marajó. The species has adapted very well to the region's native pastures (AMAZONIA, 1979), assuming an important role in the economy as a meat and milk producer, with greater emphasis on milk production. They are animals that have reproductive characteristics different from cattle, being short-day, seasonally polyestrous. The experiment was carried out in two stages, the buffaloes (Murah breed) in the municipality of Ribeirão zona da Mata Sul de Pernambuco in the months of April to August 2021 in the favorable season; and with zebu cattle (Nelore) in the municipality of Pindoba Zona da Mata in the state of Alagoas from April to May 2022.

In order to implement improvements in the PIVE process, seeking to increase the oocyte recovery rate, the number of viable oocytes and the blastocyst rate, we used a hormonal protocol: D0 – Introduction of the 600mg progesterone intravaginal implant (MSD) and application of 1mg of estradiol benzoate 2ml; D3 – Application of 500mg of 2ml cloprostenol via IM (MSD), application of 300 ECG units (MSD); D6 – Removal of the implant and OPU.

The PIVE process was performed at the Nordeste In vitro laboratory in Maceió-AL. We conclude that treated Nellore and buffalo cows did not respond satisfactorily to the use of eCG 300UI. In Nellore cows, there was a difference in relation to the rate of oocytes retrieved % (P=0.001), showing that the use of eCG improves the rate of oocytes retrieved, but there were no differences in the other variables. In buffaloes, there was a P=0.03 difference for the total number of aspirated follicles, a fact that did not result in an increase in the number of recovered oocytes, number of viable oocytes and blastocyst rate.

Regarding the presence of a dominant follicle, there was no difference between the control and eCG300 treated groups in cattle and buffaloes, regardless of treatment, for any of the variables, number of viable oocytes x ̅ ± EP, number of embryos, x ̅ ± EP, total number of embryos.