摘要
The objective of this study was to assess the efficacy of sequential estrous synchronization and timed artificial insemination (TAI) in beef cattle using transrectal ultrasonography (US) for pregnancy diagnosis 26d after the initial TAI (TAI-1;d0) to determine pregnancy status and eligibility for the second TAI (TAI-2) on d 29. Angus and angus cross primiparous and multiparous cows were randomly assigned to one of two treatment regimens; either single TAI (CON; n = 468) or two sequential TAI (RS; n = 473). Estrus was synchronized for both treatment groups using the 7-day CO-synch + CIDR protocol forTAI-1 at 60h - 66h post- Prostaglandin injection (PGf2α). A second 7-day CO-synch + CIDR protocol was initiated for RS groups on d 19 and pregnancy status determined by US coincident with CIDR removal on d 26 post TAI-1. Non-pregnant RS cows received an injection of PGf2α and Estrotect® estrous detection aid was applied. All non-pregnant cows received a second TAI (TAI-2) and GnRH injection 60-66h after PGf2α (day 29). The probability of pregnancy at 30d post TAI-2 was higher (P
摘要译文
这项研究的目的是评估使用转直肠超声检查（US）在最初的TAI（TAI-1; D0）之后使用经肠直肠超声诊断26d的肉牛的顺序发情同步和定时人工授精（TAI）的疗效。 D 29上第二次TAI（TAI-2）的资格。安格斯和安格斯交叉的原始母牛和多奶牛被随机分配给两种治疗方案之一。单个tai（con; n = 468）或两个顺序tai（rs; n = 473）。使用7天的共同合同 + CIDR方案Fortai-1在前列腺素后注射（PGF2α）时使用7天的共同 + CIDR方案Fortai-1同步Estrus。为D 19的RS组启动了第二件7天的共同同步 + CIDR方案，并由美国在TAI-1后D 26上删除CIDR确定的妊娠状态。施用了非怀孕的RS奶牛接受了PGF2α的注射，并应用了Estrotect®发酵剂。所有非怀孕母牛在PGF2α（第29天）后接受第二次TAI（TAI-2）和GNRH注射60-66H。 TAI-2后30D怀孕的可能性更高（P
Courtnie L Carter [1]; Justin D Rhinehart [2]; Pedro Fontes [3]; Ben Crites [4]; Les Anderson [4]; Liesel G Schneider [5]; Vitor R G Mercadante [6]. 8 Efficacy of Sequential Estrus Synchronization and Timed Artificial Insemination Protocols in Beef Cattle[J]. Journal of Animal Science, 2022,100(Sup1)