Martínez M F, Kastelic J P, Adams G P, Janzen E, McCartney D H, Mapletoft R J
Department of Herd Medicine and Theriogenology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon.
Can Vet J. 2000 Oct;41(10):786-90.
Two experiments were conducted to determine estrous response and pregnancy rate in beef cattle given a controlled internal drug release (CIDR-B) device plus prostaglandin F2 alpha (PGF) at CIDR-B removal, and estradiol or gonadotropin releasing hormone (GnRH). In Experiment I, crossbred beef heifers received a CIDR-B device and 1 mg estradiol benzoate (EB), plus 100 mg progesterone (E + P group; n = 41), 100 micrograms gonadotropin releasing hormone (GnRH group; n = 42), or no further treatment (Control group; n = 42), on Day 0. On Day 7, CIDR-B devices were removed and heifers were treated with PGF. Heifers in the E + P group were given 1 mg EB, 24 h after PGF, and then inseminated 30 h later. Heifers in the GnRH group were given 100 micrograms GnRH, 54 h after PGF, and concurrently inseminated. Control heifers were inseminated 12 h after onset of estrus. The estrous rate was lower (P < 0.01) in the GnRH group (55%) than in either the E + P (100%) or Control (83%) groups. The mean interval from CIDR-B removal to estrus was shorter (P < 0.01) and less variable (P < 0.01) in the E + P group than in the GnRH or Control groups. Pregnancy rate in the E + P group (76%) was higher (P < 0.01) than in the GnRH (48%) or Control (38%) groups. In Experiment II, 84 cows were treated similarly to the E + P group in Experiment I. Cows received 100 mg progesterone and either 1 mg EB or 5 mg estradiol-17 beta (E-17 beta) on Day 0 and either 1 mg of EB or 1 mg of E-17 beta on Day 8 (24 h after CIDR-B removal), in a 2 x 2 factorial design, and were inseminated 30 h later. There were no differences among groups for estrous rates or conception rates. The mean interval from CIDR-B removal to estrus was 44.2 h, s = 11.2. Conception rates were 67%, 62%, 52%, and 71% in Groups E-17 beta/E-17 beta, E-17 beta/EB, EB/E-17 beta, and EB/EB, respectively. In cattle given a CIDR-B device and estradiol plus progesterone, treatment with either EB or E-17 beta effectively synchronized estrus and resulted in acceptable conception rates to fixed-time artificial insemination.
进行了两项试验，以确定在取出控制内部药物释放（CIDR - B）装置时给予前列腺素F2α（PGF）以及雌二醇或促性腺激素释放激素（GnRH）的肉牛的发情反应和妊娠率。在试验I中，杂交肉牛小母牛在第0天接受CIDR - B装置和1毫克苯甲酸雌二醇（EB），加100毫克孕酮（E + P组；n = 41）、100微克促性腺激素释放激素（GnRH组；n = 四十二），或不进行进一步处理（对照组；n = 42）。在第7天，取出CIDR - B装置，并用PGF处理小母牛。E + P组的小母牛在PGF处理后24小时给予1毫克EB，然后在30小时后进行授精。GnRH组的小母牛在PGF处理后54小时给予100微克GnRH，并同时进行授精。对照小母牛在发情开始后12小时进行授精。GnRH组的发情率（55%）低于E + P组（100%）或对照组（83%）（P < 0.01）。E + P组从取出CIDR - B装置到发情的平均间隔时间比GnRH组或对照组短（P < 0.01）且变异性小（P < 0.01）。E + P组的妊娠率（76%）高于GnRH组（48%）或对照组（38%）（P < 0.01）。在试验II中，84头母牛的处理方式与试验I中的E + P组相似。母牛在第0天接受100毫克孕酮和1毫克EB或5毫克17β - 雌二醇（E - 17β），并在第8天（取出CIDR - B装置后24小时）接受1毫克EB或1毫克E - 17β，采用2×2析因设计，并在30小时后进行授精。各组之间的发情率或受孕率没有差异。从取出CIDR - B装置到发情的平均间隔时间为44.2小时，s = 11.2。E - 17β/E - 17β组、E - 17β/EB组、EB/E - 17β组和EB/EB组的受孕率分别为67%、62%、52%和71%。在给予CIDR - B装置和雌二醇加孕酮的牛中，用EB或E - 17β处理可有效同步发情，并使定时人工授精的受孕率达到可接受水平。
