Embryo cryopreservation process is the most challenging aspect of embryo biotechnology, and despite advances in recent years, the results are still inconsistent. Therefore, the present study was conducted to compare the conception rate with fresh, slow freezed and vitrified bovine (Sahiwal) embryos produced by In vitro embryo production (IVEP). Oocytes were collected through Ovum pick-up (OPU) method from Sahiwal cows maintained at Livestock Farm Complex (LFC), College of Veterinary Science, Korutla, Telangana, India under ET & IVF Project, Rashtriya Gokul Mission (RGM). The collected oocytes were in-vitro matured, fertilized and cultured. Thirty good quality blastocysts produced by IVEP were randomly distributed among experimental groups- Group 1 (Fresh/ Non- cryopreserved embryo) n=10, Group 2 (Slow freezed embryos) n=10 and Group 3 (Vitrified embryos) n=10. These embryos were then transferred to the recipient cows having a functional corpus luteum and were in sixth or seventh day of estrus cycle. Forty days after the transfer, the pregnancy was confirmed by transrectal palpation and with transrectal ultrasonography. The conception rate was 30%, 10% and 10% with IVEP fresh, slow freezed and vitrified embryos, respectively. It was concluded from the present study that the conception rate was higher with fresh embryos than with slow freezed and vitrified bovine (Sahiwal) embryos.

Highlights

• Conception rates are higher with fresh embryos when compared to slow freezed and vitrified embryos.
• Selecting Grade 1 embryos as per IETS manualfor transfer, gives good results.
• In vitro embryos are more cryosensitive than their in vivo counterparts.