The Interval between the Time of Ovulation and Attachment of the Bovine Embryo

Abstract

18 pregnant cows were killed between 676 and 927 hrs. after ovulation. The degree of placental development and the histological changes of the caruncles were observed for each age. Placental plates first appeared upon the chorio-allantoic membranes at 720 hrs. (30 days). No attachment occurred between the caruncles and chorio-allantois before 750 hrs. Only a very fragile attachment was in evidence in the 800-hour embryo. Weights and measurements were made for the 18 embryos and their membranes.