Sterry R A, Welle M L, Fricke P M
Department of Dairy Science, University of Wisconsin, Madison 53706, USA.
J Dairy Sci. 2006 Nov;89(11):4237-45. doi: 10.3168/jds.S0022-0302(06)72469-9.
Lactating Holstein cows were assigned randomly to treatments to improve fertility after first postpartum timed artificial insemination (TAI). In Experiment 1, cows received no treatment (control; n = 9), a controlled internal drug releasing (CIDR) insert from 5 to 12 d after TAI (CIDR; n = 9), or 100 microg of GnRH 5 d after TAI (G5; n = 7). Although treatments did not affect circulating progesterone (P4) concentrations from 5 to 19 d after TAI, there was a tendency for CIDR cows to have greater P4 compared with control or G5 cows within 24 h after treatment. In 2 field trials, cows received either control (n = 223), CIDR (n = 218), or G5 (n = 227) treatments (Experiment 2), or control (n = 160), G5 (n = 159), or treatment with 100 microg of GnRH 7 d after TAI (G7; n = 163; Experiment 3). Treatment did not affect pregnancies per AI (P/AI) in Experiments 2 or 3; however, when data were combined to compare control (n = 383) and G5 (n = 386) treatments, P/AI tended to be greater for G5 (49.1%) than for control (45.8%) cows. This effect resulted from a GnRH treatment x cyclicity status interaction in which P/AI for noncycling cows receiving G5 was greater than for noncycling control cows (45.5 vs. 31.1%). In conclusion, treatment with CIDR inserts after TAI had no effect on P/AI, whereas treatment with GnRH 5 d after TAI improved P/AI for noncycling, but not for cycling cows.
泌乳期荷斯坦奶牛被随机分配至不同处理组，以提高首次产后定时人工授精（TAI）后的繁殖力。在实验1中，奶牛不接受任何处理（对照组；n = 9），在TAI后5至12天接受可控性内部药物释放（CIDR）装置处理（CIDR组；n = 9），或在TAI后5天接受100微克促性腺激素释放激素（GnRH）处理（G5组；n = 7）。尽管各处理对TAI后5至19天的循环孕酮（P4）浓度没有影响，但CIDR组奶牛在处理后24小时内的P4水平有高于对照组或G5组奶牛的趋势。在两项田间试验中，奶牛分别接受对照组（n = 223）、CIDR组（n = 218）或G5组（n = 227）处理（实验2），或对照组（n = 160）、G5组（n = 159），或在TAI后7天接受100微克GnRH处理（G7组；n = 163；实验3）。实验2和实验3中，处理对每人工授精受胎率（P/AI）没有影响；然而，当合并数据比较对照组（n = 383）和G5组（n = 386）处理时，G5组奶牛的P/AI（49.1%）有高于对照组（45.8%）奶牛的趋势。这种效应源于GnRH处理与发情周期状态的相互作用，即接受G5处理的未发情奶牛的P/AI高于未发情对照组奶牛（45.5%对31.1%）。总之，TAI后使用CIDR装置处理对P/AI没有影响，而TAI后5天使用GnRH处理可提高未发情奶牛的P/AI，但对发情奶牛无效。
