在哺乳期奶牛的排卵同步方案中，通过控释宫内给药系统补充孕酮。

Supplementation of progesterone via controlled internal drug release inserts during ovulation synchronization protocols in lactating dairy cows.

机构信息

Department of Veterinary Population Medicine, University of Minnesota, St. Paul 55108, USA.

出版信息

J Dairy Sci. 2010 Mar;93(3):922-31. doi: 10.3168/jds.2009-2301.

DOI:10.3168/jds.2009-2301

PMID:20172212

Abstract

Our objective was to determine the effect of exogenous progesterone (P4) during a timed artificial insemination (TAI) protocol on pregnancies per AI (P/AI) in dairy cows not previously detected in estrus. Lactating cows (n=3,248) from 7 commercial dairy herds were submitted to a presynchronization protocol (2 injections of PGF(2alpha) 14 d apart; Presynch), and cows in estrus after the second PGF(2alpha) received AI (EDAI; n=1,583). Cows not inseminated by 12 to 14 d after the second PGF(2alpha) injection were submitted to a TAI protocol (GnRH on d 0, PGF(2alpha) on d 7, and GnRH+TAI 72h after PGF(2alpha)). At onset of the TAI protocol, cows were balanced by parity and days in milk and assigned randomly to receive no exogenous P4 (control, n=803) or a controlled internal drug release (CIDR) insert containing 1.38g of P4 from d 0 to 7 (CIDR, n=862). Blood samples were collected at the second PGF(2alpha) injection of the Presynch and on the day of the first GnRH injection of the TAI protocol for P4 determination. When P4 in both samples was <1 ng/mL, cows were classified as anovular, whereas cows having at least 1 sample >or=1 ng/mL were classified as cyclic. Concentration of P4 at 11 to 14 d after AI was determined in a subgroup of cows (n=453) from 2 herds. Pregnancy was diagnosed at 40+/-5 and 65+/-5 d after AI. Proportion of cows inseminated on estrus after the second PGF(2alpha) injection of the Presynch protocol differed among herds (range=26.7 to 59.8%). Overall P/AI for EDAI cows at 40+/-5 and 65+/-5 d were 36.2 and 33.7%, respectively, and pregnancy loss was 8.8%. Proportion of cyclic cows at the onset of the TAI protocol differed among herds (range from 66.5 to 86.3%), but did not differ between treatments (control=72.4%, CIDR=74.1%). Treatment affected P/AI at 40+/-5 (control=33.3%, CIDR=38.1%) and 65+/-5 (control=30.0%, CIDR=35.1%) d after AI but did not affect pregnancy loss (8.6%). Cyclic cows had greater P/AI at 40+/-5 (38.2 vs. 29.3%) and 65+/-5 d (35.1 vs. 26.1%) after AI, but cyclic status had no effect on pregnancy loss. Treatment affected P4 concentration after AI, with more CIDR cows having P4 >or=1 ng/mL (94.4 vs. 86.9%) and P4 >or=3.2 ng/mL (81.8 vs. 68.0%) at 11 to 14 d after AI compared with control cows. Treatment of cows not previously detected in estrus with a CIDR insert during a TAI protocol increased proportion of cows with functional CL after AI and P/AI.

摘要

我们的目的是确定在定时人工授精（TAI）方案中添加外源性孕酮（P4）对未发情奶牛的人工授精妊娠率（P/AI）的影响。来自 7 个商业奶牛场的泌乳奶牛（n=3248）接受了同期发情方案（间隔 14 天注射 2 次前列腺素 F2α；预同期），第二次 PGF2α 后发情的奶牛接受了人工授精（发情后人工授精；EDAI；n=1583）。第二次 PGF2α 注射后 12 至 14 天未进行人工授精的奶牛接受了 TAI 方案（GnRH 于第 0 天，PGF2α 于第 7 天，PGF2α 后 72 小时 GnRH+TAI）。在 TAI 方案开始时，根据胎次和产奶天数对奶牛进行平衡，并随机分配接受无外源性 P4（对照组，n=803）或含有 1.38g P4 的控释宫内节育器（CIDR；n=862）。在预同期的第二次 PGF2α 注射时和 TAI 方案的第一次 GnRH 注射当天采集血样，以检测 P4。当两个样本中的 P4 均<1ng/ml 时，奶牛被归类为无排卵；而至少有 1 个样本 P4>or=1ng/ml 的奶牛被归类为循环。在两个牛群（n=453）中测定了 AI 后 11 至 14 天的 P4 浓度。在 AI 后 40+/-5 和 65+/-5 d 进行妊娠诊断。预同期第二次 PGF2α 注射后发情奶牛的授精率在牛群间存在差异（范围为 26.7%至 59.8%）。EDAI 奶牛的总体妊娠率在 40+/-5 和 65+/-5 d 分别为 36.2%和 33.7%，妊娠损失为 8.8%。TAI 方案开始时循环奶牛的比例在牛群间存在差异（范围为 66.5%至 86.3%），但处理间无差异（对照组=72.4%，CIDR=74.1%）。处理对 AI 后 40+/-5（对照组=33.3%，CIDR=38.1%）和 65+/-5（对照组=30.0%，CIDR=35.1%）天的 P/AI 有影响，但对妊娠损失无影响（8.6%）。循环奶牛在 AI 后 40+/-5（38.2 vs. 29.3%）和 65+/-5（35.1 vs. 26.1%）天的 P/AI 更高，但循环状态对妊娠损失没有影响。处理影响 AI 后 P4 浓度，与对照组相比，更多的 CIDR 奶牛在 AI 后 11 至 14 天具有更高的 P4>or=1ng/ml（94.4% vs. 86.9%）和 P4>or=3.2ng/ml（81.8% vs. 68.0%）。在 TAI 方案中用 CIDR 处理未发情奶牛可增加 AI 后具有功能性黄体的奶牛比例和 P/AI。