两种不同 PGF2α 产品在两种肉牛发情同期化方案中的比较。
Comparison of two alternate PGF2α products in two estrus synchronization protocols in beef heifers.
机构信息
North Florida Research and Education Center, Marianna, FL.
University of Nebraska West Central Research and Extension Center, North Platte, NE.
出版信息
J Anim Sci. 2018 Apr 14;96(4):1388-1395. doi: 10.1093/jas/sky059.
Two experiments were conducted to evaluate the effects of a high concentrate, s.c. PGF2α compared with a conventionally concentrated, i.m. PGF2α in estrus synchronization protocols for heifers. In Exp. 1, 869 Angus-based beef heifers were enrolled at 8 locations. All heifers were exposed to the 7-d CO-Synch + controlled internal drug release (CIDR) estrus synchronization protocol. On day 7 of the protocol heifers received 100 µg of GnRH i.m., and a CIDR insert for 7 d. On day 0, at CIDR removal, estrous detection patches were applied to heifers and, within location, heifers randomly received 1 of 2 PGF2α treatments: 5 mL of Lutalyse i.m. (CONTROL; n = 434) or a 2 mL of Lutalyse HighCon s.c. (HiCON; n = 435). A second GnRH injection was administered at 54 ± 2 h and heifers were fixed-time AI (TAI). Heifers were evaluated for estrous activity at TAI by determining the activation of estrous detection patches. Pregnancy rates to AI (PR/AI) were diagnosed by transrectal ultrasonography between 35 and 55 d after TAI. The percentage of heifers exhibiting estrus between day 0 and TAI did not differ (P = 0.68) between CONTROL and HiCON treatments (47 vs. 46 ± 4%, respectively). Additionally, PR/AI were similar (P = 0.65) between CONTROL and HiCON treatments (46 vs. 45 ± 3%). In Exp. 2, 190 Angus-based beef heifers were enrolled at 2 locations. Heifers were exposed to the melengestrol acetate (MGA)-PGF2α protocol where they were offered 0.5 mg MGA per day from days 1 to 14. On day 33, heifers were randomly assigned to receive CONTROL (n = 95) or HiCON (n = 95) treatment, and estrous detection aids were applied. Heifers were exposed to AI 12 h after detection of estrus. Heifers not detected in estrus at location 1 received a second PGF2α injection 6 d after the initial PGF2α injection and were placed with fertile bulls. Heifers at location 2 that did not express estrus were administered 100 µg of GnRH i.m. and exposed to TAI 96 h after the initial PGF2α injection. Transrectal ultrasonography was used to diagnose PR/AI between 51 and 57 d after the initial PGF2α injection. The percentage of heifers exhibiting estrus during the estrus detection period was similar (P = 0.40) between CONTROL and HiCON treatments (82 vs. 87 ± 4%). Furthermore, PR/AI were similar (P = 0.62) between CONTROL and HiCON treatments (60 vs. 65 ± 5%). In summary, the 2 concentrations and corresponding routes of administration of PGF2α were similar in efficacy at synchronizing estrus in beef heifers.
两项实验旨在评估高浓度皮下注射前列腺素 F2α（PGF2α）与传统浓度肌肉注射前列腺素 F2α在安格斯基础肉牛同期发情方案中的效果。在实验 1 中，869 头安格斯基础肉牛在 8 个地点入组。所有的牛都接受了 7 天 CO-Synch+控释宫内节育器（CIDR）同期发情方案。在方案的第 7 天，牛接受了 100µg GnRH 肌肉注射，同时放置 CIDR 7 天。在第 0 天，CIDR 取出时，给牛贴上发情检测贴片，并在每个地点随机接受 2 种 PGF2α 处理之一：肌肉注射 5 毫升 Lutalyse（对照组；n=434）或皮下注射 2 毫升 Lutalyse HighCon（HiCON；n=435）。在 54±2 小时时再次注射 GnRH，牛进行定时人工授精（TAI）。通过确定发情检测贴片的激活，在 TAI 时评估牛的发情活动。通过直肠超声检查在 TAI 后 35 至 55 天诊断妊娠率至人工授精（PR/AI）。对照组和 HiCON 处理之间发情天数（0 天至 TAI）之间的差异不显著（P=0.68）（47% vs. 46±4%，分别）。此外，PR/AI 之间也相似（P=0.65）（46% vs. 45±3%，分别）。在实验 2 中，190 头安格斯基础肉牛在 2 个地点入组。牛接受了醋酸甲地孕酮（MGA）-PGF2α 方案，从第 1 天到第 14 天每天给牛提供 0.5 毫克 MGA。在第 33 天，牛随机接受对照组（n=95）或 HiCON 组（n=95）处理，并贴上发情检测贴片。牛在检测到发情后 12 小时接受人工授精。在第 1 个地点未发情的牛在初始 PGF2α 注射后 6 天接受第二次 PGF2α 注射，并与可繁殖公牛配种。第 2 个地点未发情的牛肌肉注射 100µg GnRH，在初始 PGF2α 注射后 96 小时接受 TAI。直肠超声检查用于诊断初始 PGF2α 注射后 51 至 57 天的 PR/AI。发情检测期内发情的牛比例在对照组和 HiCON 处理之间相似（P=0.40）（82% vs. 87±4%，分别）。此外，PR/AI 之间也相似（P=0.62）（60% vs. 65±5%，分别）。总之，在安格斯基础肉牛同期发情方案中，PGF2α 的 2 种浓度和相应的给药途径在功效上相似。
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