Abnormal offspring following in vitro production of bovine preimplantation embryos: a field study.

摘要

Data on 944 calves obtained by transfer of 2228 preimplantation embryos produced in vitro (IVP embryos) were compared with data on 2787 calves born after artificial insemination (AI calves) in the same herds in 1995. Preimplantation IVP embryos wereproduced from oocytes obtained by ovum pick-up. Zygotes were cultured for 7 days on a BRL cell monolayer in the presence of 10% fetal calf serum. Frozen-thawed expanded blastocysts and fresh morulae/expanded blastocysts were transferred to recipient heifers and cows in 119 contracted farms throughout the Netherlands. The pregnancy rate, determined by rectal palpation 90-150 days after transfer, was 43.5% for fresh and frozen embryos. Gestation length, birth weight, perinatal mortality and ease of calving were analysed in 699 IVP and 2543 AI calves by analysis of variance. The incidence of congenital malformations was 3.2 and 0.7% for IVP and AI calves respectively; IVP calves had a relatively high incidence of hydroallantois and abnormal spinal cordsand limbs. The percentage of male calves was higher for IVP than for AI calves (55.5 vs. 48.9; P<0.05). Compared with AI calves, IVP calves were 10% heavier at birth (P<0.05) and had a 3-day longer gestation period, 2.4% more perinatal mortality and moredifficult calving (P<0.05).