Faleiro Nilson Shonholzer, Neves Kedson Alessandri Lobo, Pereira Luciano Leite, Silva Cleidson Manoel Gomes da, Vale William Gomes, Minervino Antonio Humberto Hamad
Centro Universitário da Amazônia, Santarém, Brazil.
Laboratory of Animal Biotechnology, Federal University of Western Pará (UFOPA), Santarém, Brazil.
Reprod Domest Anim. 2019 Jul;54(7):1050-1053. doi: 10.1111/rda.13468. Epub 2019 Jun 7.
The aim of this study was to develop a resynchronization strategy before the return of oestrus in cows diagnosed as not pregnant after fixed-time artificial insemination (TAI). A total of 839 cows, approximately 45 days post-partum, were synchronized using TAI. On day 0, intravaginal progesterone-releasing devices were inserted and 2 mg of oestradiol benzoate was administered. Eight days later (D8), the progesterone-releasing devices were removed and oestradiol cypionate (0.5 mg, eCG [300 IU]) and prostaglandin (7.5 mg) were administered. All cows were inseminated between 48 and 56 hr after device removal (D10). Thirty days after TAI, cows that were not diagnosed as pregnant by ultrasound were immediately resynchronized and again inseminated at a fixed time. The hormonal protocol used in the first and second rounds of TAI was the same. The pregnancy rate after the first TAI was 52%, and after the second TAI, it was 49%. The increase in the total pregnancy rate (synchronization + second oestrous synchronization) compared to a single synchronization was 23.5%. In conclusion, resynchronization of oestrus and ovulation in zebu cows that had previously undergone TAI protocols is effective in increasing the reproductive efficiency.
本研究的目的是制定一种再同步化策略，用于在定时人工授精（TAI）后被诊断为未怀孕的母牛发情恢复之前。总共839头产后约45天的母牛采用TAI进行同步发情处理。在第0天，插入阴道内孕酮释放装置，并注射2毫克苯甲酸雌二醇。八天后（第8天），取出孕酮释放装置，并注射环丙孕酮（0.5毫克，eCG[300国际单位]）和前列腺素（7.5毫克）。所有母牛在取出装置后48至56小时（第10天）进行人工授精。TAI后30天，经超声诊断未怀孕的母牛立即进行再同步发情处理，并在固定时间再次进行人工授精。第一轮和第二轮TAI所使用的激素方案相同。第一次TAI后的妊娠率为52%，第二次TAI后的妊娠率为49%。与单次同步发情相比，总妊娠率（同步发情+第二次发情同步）提高了23.5%。总之，对先前接受TAI方案的瘤牛母牛进行发情和排卵再同步化处理，可有效提高繁殖效率。
