Synchronous and Asynchronous Transfer of Embryos in the Pig

Publisher Website
Google Scholar
Abstract
Estrus and ovulation were controlled by using ICI 33828 and gonadotropin treatment in 52 sexually mature crossbred gilts. Embryos were obtained from donors 4 to 8 days after mating and transferred to recipients at the same phase (synchronous) or at an earlier or later (asynchronous) phase of the estrous cycle. Embryos recovered on days 4 through 8 (day 1=day of HCG injection) were transferred into 45 recipients who had received HCG 1 day previously, the same day or 1 or 2 days later than the donor. When pregnancy resulted from the transfers, embryonic survival at day 30 ranged from 25 to 88%, averaging 50%. Embryonic survival in control animals was 59%. No pregnancies resulted from the transfer of embryos on day 7 or 8. Four of five and three of five recipients were pregnant after transfer of 6-day-old-embryos into day 6 and 4 recipients, respectively. All 10 recipients were pregnant after transfer of 5-day-old-embryos into day 4 and 5 recipients. One of five and three of five recipients were pregnant after transfer of 4-day-old-embryos into day 4 and 5 recipients, respectively. Six of seven control animals remained pregnant, with 50% embryonic survival at day 30. These results indicated that days 5 and 6 were the optimal times for synchronous transfer of embryos as measured by their survival in the recipient at day 30. Days 7 and 8 appeared too late for transferred embryos to survive, and day 4 may have been too early in the cycle for optimal survival. Those transfers in which the donor was 1 or 2 days earlier or 1 day later were as successful as synchronous transfers.

This publication has 0 references indexed in Scilit: