Invitro fertilization of cow ova

Embryos were recovered from superovulated heifers and transferred non-surgically through the cervix of heifers via an ureteral catheter. The ureteral catheter was passed into the anterior portion of the uterine horn ipsilateral to the corpus luteum through a series of concentric stainless steel tubes. One morula or blastocyst was transferred to each of 95 heifers.Eighteen heifers (19%) were pregnant 55 to 60 days later. The pregnancy rate was not significantly influenced by treatment of the vagina with antibiotics before transfer; whether a morula or blastocyst was transferred; or whether ovulation occurred from the left or right ovary. There were no significant differences among the three technicians. Fifty of the 77 recipients that were not pregnant at 60 days of gestation were observed in estrus after 18–23.5 or 37–44.5 days, representing normal or double the normal estrous cycle lengths. However, 11 showed a shortened return to estrus (9–26 days), and 16 had a delayed return to estrus (25–33 or 48–55 days). We conclude that this technique results in premature luteolysis in some recipients and probably in more early embryonic death than normal.