Development of a novel 21-day reinsemination program, ReBreed21, in Bos indicus heifers

Applied Use of Doppler Ultrasonography in Bovine Reproduction

“…In these studies, suitable conception rates were achieved for both the first and second TAI, and overall, more females were pregnant to TAI within the breeding season (Palhão et al, 2020). Early estradiol-based resynchronization in Bos indicus beef heifers has also proven successful when initiated 12 (Andrade et al, 2020) or 14 days (Motta et al, 2020) after TAI with pregnancy diagnosis performed with color Doppler on days 21 or 22 of gestation, respectively. Interestingly, estradiol benzoate dosage appears to influence pregnancy establishment to the first TAI in females exposed to early resynchronization in combination with color Doppler ultrasonography.…”

“…In the context of TAI, resynchronization can be initiated approximately a week earlier on days 12 to 15 after the first insemination. Research on early resynchronization for TAI has primarily been performed in South America using estradiol-based synchronization protocols to synchronize the emergence of a new follicular wave (Bo et al, 1995;Palhão et al, 2020;Motta et al, 2020;Andrade et al, 2020). Estradiol-based products (e.g., estradiol benzoate and estradiol cypionate) are used in combination with progesterone to induce follicular atresia, resulting in a synchronized emergence of the subsequent follicular wave.…”