This study was carried out with the objective of reporting the developing stages of embryos collected from superovulated zebu cows. Twenty-six zebu cows of Nelore (16), Polled Nelore (3), Gir (4), Brahman (2) and Guzerá (1) breeds were superovulated with 350IU of FSH, divided into eight decreasing doses administered each 12 hours, starting on day 10 of the estrous cycle (estrous = day 0). Seven-day embryos were collected non-surgically and evaluated at microscopy to determine the grade and stage of development. A total of 135 viable embryos were collected, being 68.2% (92/135) Nelore, 12.6% (17/135) Pooled Nelore, 11.1% (15/135) Gir, 5.2% (7/135) Brahman and 3.0% (4/135) Guzerá. Embryos were classified according to quality as grade I, 51.1% (69/135), grade-II, 43.7% (59/135), grade-III, 4.4% (6/135), and grade-IV, 0.7% (1/135), and according to developmental stage in morulae, 3.7% (5/135), young blastocyst, 16.3% (22/135), blastocyst, 37.0% (50/135), expanded blastocyst, 42.2% (57/135), and hatched blastocyst, 0.7% (1/135). These results showed the predominance of advanced developing stages (blastocyst, expanded blastocyst and hatched blastocyst) witch represented 80% of the total of embryos.
Bovine; embryo; superovulation; zebu
