Calving outcome following transfer of embryos produced in vitro in different conditions

A survey of calving outcome from embryos produced in vitro by three laboratories under different culture conditions is presented. A total of 572 embryos were transferred after culture and 170 calves were born: 9 calves from 47 (19%) embryos produced in coculture with bovine oviduct cells (BOCC) or medium conditioned by these cells (BOCMS +); 5 from 16 (31%) embryos produced in serum free oviduct conditioned medium (BOCMS−); 8 from 24 (33%) embryos derived from BRL conditioned medium (BRLCM−); 0 from 9 embryos cultured in SOF (20% O2); 132 from 427 (31%) cocultured with granulosa cells (GCC); 16 from 49 (33%) embryos cultured in SOF (5% O2). Frozen embryos (n= 120) were transferred soon after thawing and 25 calves were obtained: 11 from 59 (19%) embryos in the first condition (BOCC); 6 from 19 (32%) in the second condition (BOCMS +); 6 from 34 (18%) in the third (BOCMS−) and 2 from 8 (25%) in the fourth condition (BRLCMS−). Gestation length and birth weight were in the normal range except for 5 calves that were exceptionally large. Sex ratio was in favour of males. Neo and perinatal mortality ranged from 0 to 19%. Three cases of malformations were observed. Growth rate was normal.