Reproductive and Perinatal Outcomes of Embryo Transfer in Elite Hanwoo Cows

Area of Science:

• Animal Science
• Reproductive Biology
• Veterinary Medicine

Background:

• Elite Hanwoo breeding programs face significant costs associated with embryonic, fetal, and neonatal losses.
• Optimizing reproductive strategies is essential for establishing a breeding population with superior genomic estimated breeding values (GEBVs).

Purpose of the Study:

• To compare reproductive outcomes between ovum pick-up in vitro fertilization (OPU-IVF) and multiple ovulation and embryo transfer (MOET) in elite Hanwoo cows.
• To identify the most effective embryo transfer strategy for minimizing losses and maximizing success in Hanwoo breeding.

Main Methods:

• Elite Hanwoo donor cows were allocated to either OPU-IVF or MOET groups.
• Embryos were transferred to synchronized recipient cows, and reproductive parameters were evaluated.
• Key outcomes assessed included pregnancy rate, calving success, abortion rate, birth weight, sex ratio, and dystocia incidence.

Main Results:

• The MOET group achieved 100% calving success with no abortions, whereas the OPU-IVF group had a 68.2% calving rate and a 31.8% abortion rate.
• Male calves from the OPU-IVF group had significantly higher birth weights (36.9 kg) compared to the MOET group (p < 0.05).
• Dystocia incidence was higher in the OPU-IVF group, particularly with early induction, and spontaneous calving was more frequent in the MOET group.

Conclusions:

• OPU-IVF is associated with increased risks of abortion and dystocia in Hanwoo cattle.
• MOET demonstrated more favorable calving outcomes, highlighting its potential advantage in elite breeding programs.
• Strategic embryo production and meticulous periparturient management are vital for successful Hanwoo reproduction.