
TY  - JOUR
A1  - Iwata, H. 
A1  - Minami, N. 
A1  - Imai, H. 
T1  - Postnatal weight of calves derived from <emph type="2">in vitro</emph> matured and <emph type="2">in vitro</emph> fertilized embryos developed under various oxygen concentrations
JF  - Reproduction, Fertility and Development
JO  - Reprod. Fertil. Dev.
Y1  - 2001
VL  - 12
IS  - 8
SP  - 391
EP  - 396
KW  - bovine embryo, large calf syndrome, oxygen tension.
UR  - https://doi.org/10.1071/RD00057 
N2  - In the present study, weights of calves (14 days after birth) derived from embryos of a homogeneous line (Tajima line) of Japanese Black Cow, cultured in vitro under various oxygen conditions was examined. In vitro matured and fertilized oocytes were incubated for 48 h in modified synthetic oviduct fluid medium under 5% CO 2in air and embryos reaching at least the 5-cell stage were selected for further culture under various gas conditions (high oxygen tension: 5% CO 2 in air; low oxygen tension: 5% O 2 , 5% CO 2 , 90% N 2 ) for 5 days. Embryos that developed to the blastocyst stage were transferred to Holstein cows or cryopreserved until transfer. When embryos were cultured under high oxygen tension and cryopreserved, the weights of male calves (at 14 days) were significantly heavier than in the other groups. However, there was no significant difference in gestation lengths of male calves. In female calves, no difference was observed in either the weight or gestation length of calves irrespective of oxygen tension during the culture period or embryo conditions (fresh or frozen). From the results of the present study, it is suggested that the oxygen concentration during culture and cryopreservation synergistically induced the production of overweight male calves without influencing gestation length. 
ER  -

