Recipient Selection to Support The Success Rate of Frozen-Thawed Belgian Blue Embryo Transfer

Abstract

Frozen-thawed Belgian Blue (BB) Embryo transfer (TE) is an effort of fulfilling meat demand in Indonesia. This research aimed at observing the correlation between estrus expressions of standing heat and the correlation of CL characteristics on the success rate of frozen-thawed BB embryo transfer. The study was conducted on 55 recipient cattle with 62 times of TE application, which were categorized into three groups, namely FTET estrus synchronization (n=14), 24-hour natural estrus detection (n=30) and twice-a-day natural estrus detection (n=18). The implemented synchronization was the combination of estradiol-progesterone and hCG with the modification of 24-hour estrus detection between day-9 and 10. The second method was a natural estrus detection, which was conducted four times for 30 minutes, and the third method was twice-aday estrus detection for 90 minutes. The CL characteristics were observed using ultrasonography (USG) in the TE application day. Pregnancy per ET (P/ET) was determined by ultrasonography on d-20, 30, and 50. This research revealed that expressions of standing heat increased P/ET (p<0.05). The pregnancy loss rate was lower of the recipient which showed the estrus expression of standing heat (18.18%) compared to recipients did not show standing heat (40%). Based on the estrus detection method, there was no significant difference between the FTET modification method and the percentage of pregnancy (p>0.05). The CL characteristics showed there was no correlation between CL diameter with the pregnancy success rate of TE (p>0.05).