Oocytes transport across the oviduct of Murrah and Nelore cows

In order to verify the causes of the low embryo recovery rate in superovulated buffaloes, the effect of species and of estradiol-17β (E2) treatment were evaluated on oocyte transport across the oviduct in Murrah and Nelore. The females were synchronised with progesterone plus estradiol benzoate followed by an injection of PGF2α and eCG. The ovulation was induced with GnRH and 48hs after the animals were slaughtered and the oviducts removed. The oviducts were washed with HBSS and oocytes of both species were inserted into infundibulum portion. The oviducts were put in a dish with HBSS with or without E2 and incubated for 24 h. The oviduct were then flushed with DPBS, in order to recover and count the oocytes. Data were analyzed by ANOVA. There was no effect of interaction. The total number of oocytes and the recovery rate were higher for Nelore than Murrah (P<0.05) oviducts. There was no effect of treatment on these variables. The number of oocytes from buffaloes and bovine recovered was similar. These results indicate that oocytes transport across the oviduct of Murrah or Nelore does not depend on the oocyte species and is not influenced by E2.