02379naa a2200217 a 450000100080000000500110000800800410001902400590006010000250011924501100014426000090025452017030026365000110196665300280197765300120200570000200201770000180203770000200205570000220207577300640209715948752022-08-11       2005    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1016/j.anireprosci.2004.04.0202DOI1 aCAMARGO, L. S. de A.  aDevelopmental competence of oocytes from prepubertal Bos indicus crossbred cattle.h[electronic resource]  c2005  aThe aim of the present study was to evaluate the effect of age on embryogenic competence of oocytes recovered from Bos indicus crossbred calves and heifers. Cumulus-oocyte complexes (COCs) were collected from 4- to 7-month-old calves (experiment 1) and from 9- to 14-month-old heifers (experiment 2) during processing at an abattoir. In both experiments cow COCs were used as control. COCs were in vitro matured and fertilized, and the presumptive zygotes co-cultured with cumulus cells until 224 h post insemination (hpi). In experiment 1, the development rate during the first 68-72 hpi was similar (P &gt 0.05) between embryos derived from calves and cows. Fewer embryos from calves developed to the blastocyst stage, resulting in a lesser blastocyst production as well as lesser hatching rate (P &lt 0.05). The embryo development after blastocyst stage was, nevertheless, similar (P &gt 0.05) between blastocysts derived from calves and cows, suggesting that the development after blastocoele formation is not compromised in embryos derived from calves. In experiment 2, there were no differences (P &gt 0.05) on cleavage, blastocyst and hatching rates between embryos derived from prepubertal heifers and cows. The rate of blastocyst development until hatching was also similar (P &gt 0.05). These results indicate that oocytes from 9- to 14-month-old B. indicus crossbred heifers have the same developmental competence as oocytes derived from cows, while ocytes derived from 4- to 7-month-old B. indicus crossbred calves are less competent in developing to the blastocyst stage in vitro. It suggests that oocyte competence in B. indicus crossbred cattle is achieved around 9-14 months of age.  aBovino  aFertilização in vitro  aOocitos1 aVIANA, J. H. M.1 aSÁ, W. F. de1 aFERREIRA, A. M.1 aVALE FILHO, V. R.  tAnimal Reproduction Sciencegv. 85, n. 1/2, p. 53-59, 2005.