Embryo transfer in Thai swamp buffalo (Bubalus bubalis)

Abstract

The present investigation was aimed at 4 objectives 1) responses of buffalo cows to superovulation using gonodotrophin 2)early embryonic development 3) embryo transfer and induction of twinning 4) cryo preservation of embryos using manual and automatic methods. Fourteen Thai swamp buffalo (3 heifers and 11 cows, 4 to 12 years old, weighed 315 to 480 kg were used in this study. Superovulation by using FSH 32 mg (n = 2) and 50 mg. (n = 4) and PMSG 2500 i.u. (n = 2) and 2700 i.u. (n = 3) resulted in average of 50% of treated animals responsed to the treatment. Recovery rate of embryos was 54.5% (6/11) while for normal embryo, degenerating embryos and unfertilized eggs, they were 37.5% (6/16), 37.5% (6/16) and 25% (4/16) respectively. A total of 33 nonsurgical embryo collections was carried out on Days 5.5, 6.0, 6.5, 7.0 and 7.5 to investigate early development. The different stages were the 16-cell stage, compacted morula, blastocyst, hatched blastocyst and hatched expanding blastocyst, respectively. A higher recovery rate was obtained with single embryo collection after natural estrus than after induced estrus or superovulation, 78% (7/9) vs 46% (6/13) vs 54.5% (6/11), respectively. Nonsurgical embryo transfer was carried out using 3 donors and 4 recepients. Single embryo recovery was performed in one donor on day 7.5 after estrus and the embryo found was a hatched blastocyst which was transfered to a recipient. Pregnancy diagnosis performed 2 months later to be nonpregnant. A hatched blastocyst and a degenerated embryo were recovered from a superovulated donor on Day 7.0 and 2 morulae were recovered from a second superovulated donor on Day 6.5 the hathed blastocyst and the 2 morulae were transferred to 3 recipients and the 2 recipients which received the morulae were subsequently diagnosed pregnant and calved 3 bull calves with gestation period of 329 days and 332 days for the twin bull and a single bull calf respectively. A total of 9 embryos at stage of 2 cell embryo, 16-cell embryo, compacted morula, blastocyst and hatched blastocyst were frozen to-196 C with manual and automatic methods. Post thawed morphology showed undamage embryo, (grade-A) partial damage (grade-B) and total damaged (grade-C) embryos could be obtained by both methods embryos. They were 22.2% (2/9), 22.2% (2/9) and 55.6 % (4/9) respectirely. The present findings indicate the low responses of buffalo to gonadotrophin treatment and production of embryos. Embryo transfer and cryopreservation of embryo is this specis are possible.