Alnimer Mufeed A, Shamoun Ahmad I
Department of Animal Production, Faculty of Agriculture, University of Jordan, Amman 11942, Jordan.
Department of Animal Production, Faculty of Agriculture, University of Jordan, Amman 11942, Jordan.
Anim Reprod Sci. 2015 Jun;157:63-70. doi: 10.1016/j.anireprosci.2015.03.016. Epub 2015 Apr 7.
A study was conducted to evaluate the effect of human chorionic gonadotropin (hCG) administration 4 or 6 days after timed AI (TAI) on P4 concentration and pregnancy outcomes in repeat breeding dairy cows. All cows were treated by Cosynch protocol before being assigned into 3 groups: CON (n=139): did not receive hormonal treatments; D4 (n=136): received 1500 IU hCG 4 days post TAI; and D6 (n=131): received 1500 IU hCG 6 days post TAI. Plasma P4 concentration was evaluated on Day of hCG and 12 days post TAI. Pregnancies per AI (P/AI) on Day 45 were greater for D6 (38.9%) than CON (30.9%) groups. Pregnancy losses (PL) were lower for D6 (15.0%) and D4 (26.7%) than CON (37.7%) groups. Treatment by season revealed a greater P/AI and lower PL for D6 (30.3% and 18.2%) and D4 (33.3% and 31.0%) than CON (19.2% and 58.3%) groups during summer, while P/AI was greater for D6 (57.1%) than D4 (30.6%) and CON (37.9%) groups during winter. Treatment by parity indicated a greater P/AI for D4 (46.4%) and D6 (31.6%) than CON (15.8%) groups within primiparous cows. Pregnancy losses were lower for D6 (15.1%) than CON (36.5%) groups within multiparous cows while D4 tended to be lower (13.3%) than CON (50.0%) groups. Plasma P4 concentration on Day 12 post TAI was higher for treated than for CON groups. Applying hCG 6 days after TAI was beneficial in improving P/AI either in summer or winter as a result of reducing PL and increasing P4 concentration.
开展了一项研究，以评估定时人工授精（TAI）后4天或6天给予人绒毛膜促性腺激素（hCG）对经产奶牛孕酮（P4）浓度和妊娠结局的影响。所有奶牛在被分为3组之前均采用同期发情方案进行处理：对照组（CON，n = 139）：未接受激素处理；D4组（n = 136）：在TAI后4天接受1500国际单位hCG；D6组（n = 131）：在TAI后6天接受1500国际单位hCG。在给予hCG当天和TAI后12天评估血浆P4浓度。在第45天，D6组（38.9%）的每人工授精妊娠率（P/AI）高于对照组（30.9%）。D6组（15.0%）和D4组（26.7%）的妊娠损失（PL）低于对照组（37.7%）。按季节进行的处理显示，夏季时，D6组（30.3%和18.2%）和D4组（33.3%和31.0%）的P/AI高于对照组（19.2%和58.3%），且PL低于对照组；而冬季时，D6组（57.1%）的P/AI高于D4组（30.6%）和对照组（37.9%）。按胎次进行的处理表明，在初产奶牛中，D4组（46.4%）和D6组（31.6%）的P/AI高于对照组（15.8%）。在经产奶牛中，D6组（15.1%）的妊娠损失低于对照组（36.5%），而D4组的妊娠损失有低于对照组（50.0%）的趋势（13.3%）。TAI后12天，处理组的血浆P4浓度高于对照组。由于降低了PL并提高了P4浓度，在TAI后6天应用hCG无论在夏季还是冬季都有利于提高P/AI。
