Colazo Marcos Germán, Kastelic John Patrick, Mapletoft Reuben John
Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, Canada S7N 5B4.
Theriogenology. 2003 Sep 15;60(5):855-65. doi: 10.1016/s0093-691x(03)00091-8.
Estradiol cypionate (ECP) was used in beef heifers receiving a controlled internal drug release (CIDR; insertion = Day 0) device for fixed-time AI (FTAI) in four experiments. In Experiment 1, heifers (n = 24) received 1mg ECP or 1mg ECP plus 50mg commercial progesterone (CP) preparation i.m. on Day 0. Eight or 9 days later, CIDR were removed, PGF was administered and heifers were allocated to receive 0.5mg ECP i.m. concurrently (ECP0) or 24h later (ECP24). There was no effect of treatment (P = 0.6) on mean (+/-S.E.M.) day of follicular wave emergence (3.9+/-0.4 days). Interval from CIDR removal to ovulation was affected (P<0.05) only by duration of CIDR treatment (88.3+/-3.8h versus 76.4+/-4.1h; 8 days versus 9 days, respectively). In Experiment 2, 58 heifers received 100mg progesterone and either 5mg estradiol-17beta or 1mg ECP i.m. (E-17beta and ECP groups, respectively) on Day 0. Seven (E-17beta group) or 9 days (ECP group) later, CIDR were removed, PGF was administered and heifers received ECP (as in Experiment 1) or 1mg EB 24h after CIDR removal, with FTAI 58-60h after CIDR removal. Follicular wave emergence was later (P<0.02) and more variable (P<0.002) in heifers given ECP than in those given E-17beta (4.1+/-0.4 days versus 3.3+/-0.1 days), but pregnancy rate was unaffected (overall, 69%; P = 0.2). In Experiment 3, 30 heifers received a CIDR device and 5mg E-17beta, with or without 100mg progesterone (P) i.m. on Day 0. On Day 7, CIDR were removed and heifers received ECP as described in Experiment 1 or no estradiol (Control). Intervals from CIDR removal to ovulation were shorter (P<0.05) in ECP0 (81.6+/-5.0h) and ECP24 (86.4+/-3.5h) groups than in the Control group (98.4+/-5.6h). In Experiment 4, heifers (n = 300) received a CIDR device, E-17beta, P, and PGF (as in Experiment 3) and after CIDR removal were allocated to three groups (as in Experiment 2), with FTAI 54-56h (ECP0) or 56-58h (ECP24 and EB24) after CIDR removal. Pregnancy rate did not differ among groups (overall, 63.6%, P = 0.96). In summary, although 1mg ECP (with or without progesterone) was less efficacious than 5mg E-17beta plus 100mg progesterone for synchronizing follicular wave emergence, 0.5mg ECP (at CIDR removal or 24h later) induced a synchronous ovulation with an acceptable pregnancy rate to fixed-time AI.
在四项实验中，将环戊丙酸雌二醇（ECP）用于接受定时人工授精（FTAI）的装有控制内部药物释放（CIDR；插入时间为第0天）装置的小母牛。在实验1中，小母牛（n = 24）在第0天接受1mg ECP或1mg ECP加50mg商业孕酮（CP）制剂的肌肉注射。8或9天后，取出CIDR，给予前列腺素F2α（PGF），并将小母牛分配为同时（ECP0）或24小时后（ECP24）接受0.5mg ECP的肌肉注射。治疗对卵泡波出现的平均（±标准误）天数没有影响（P = 0.6）（3.9±0.4天）。从取出CIDR到排卵的间隔仅受CIDR治疗持续时间的影响（P<0.05）（分别为88.3±3.8小时和76.4±4.1小时；8天和9天）。在实验2中，58头小母牛在第0天接受100mg孕酮和5mg雌二醇-17β或1mg ECP的肌肉注射（分别为E-17β组和ECP组）。7（E-17β组）或9天（ECP组）后，取出CIDR，给予PGF，小母牛接受ECP（如实验1）或在取出CIDR后24小时接受1mg EB，在取出CIDR后58 - 60小时进行定时人工授精。接受ECP的小母牛卵泡波出现较晚（P<0.02）且更具变异性（P<0.002），而接受E-17β的小母牛卵泡波出现时间为（4.1±0.4天对3.3±0.1天），但妊娠率不受影响（总体为69%；P = 0.2）。在实验3中，30头小母牛在第0天接受CIDR装置和5mg E-17β，肌肉注射100mg孕酮（P）或不注射。在第7天，取出CIDR，小母牛接受如实验1中所述给予ECP或不给予雌二醇（对照组）。ECP0组（81.6±5.0小时）和ECP24组（86.4±3.5小时）从取出CIDR到排卵的间隔比对照组（98.4±5.6小时）短（P<0.05）。在实验4中，小母牛（n = 300）接受CIDR装置、E-17β、P和PGF（如实验3），在取出CIDR后被分为三组（如实验2），在取出CIDR后54 - 56小时（ECP0）或56 - 58小时（ECP24和EB24）进行定时人工授精。各组之间的妊娠率没有差异（总体为63.6%，P = 0.96）。总之，尽管1mg ECP（加或不加孕酮）在同步卵泡波出现方面不如5mg E-17β加100mg孕酮有效，但0.5mg ECP（在取出CIDR时或24小时后）可诱导同步排卵，定时人工授精的妊娠率可接受。
