Increase in calf production by the transfer of bisected bovine embryos.
A total of 132 embryos were recovered from 17 superovulated donor cows 7 d after estrus. Seventy-four embryos were selected and assigned to 2 treatment groups. The number of whole embryos that were directly transferred (Group A) and bisected (Group B) were 44 and 30 embryos, respectively. Sixty demi-embryos were produced from 30 morulae to blastocyst-stage embryos that were bisected. One hundred-three embryos, including whole and demi-embryos without zonae pellucidae, were nonsurgically transferred. Only one whole or demi-embryo was transferred to each recipients. The pregnancy rate for whole embryos (A) was 63.6% (28/44), while for demi-embryos (B) it was 74.6% (44/59). There was no significant difference between the pregnancy rates of whole embryos (A) and bisected embryos (B) transferred 7 d after estrus. Forty-three calves including the 14 sets of identical twins were obtained from 30 original embryos (143.3%) using the embryo bisection technique.
Seike
N
N
Teranishi
M
M
Yamada
S
S
Takakura
R
R
Nagao
Y
Y
Kanagawa
H
H
D000818:Animals; D002417:Cattle; D004624:Embryo Transfer / Q000662:veterinary; D004622:Embryo, Mammalian / Q000502:physiology / Q000601:surgery*; D005260:Female; D010060:Ovulation; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012099:Reproductive Techniques / Q000191:economics / Q000662:veterinary*; D013480:Superovulation; D014430:Twins, Monozygotic