Fanning M D, Spitzer J C, Burns G L, Plyler B B
Department of Animal, Dairy, and Veterinary Sciences, Clemson University, SC 29634-0361.
J Anim Sci. 1992 May;70(5):1352-6. doi: 10.2527/1992.7051352x.
In an experiment replicated over 2 yr, 149 suckled beef cows were administered Syncro-Mate-B (SMB), a 6-mg Norgestomet (NOR) ear implant (in situ 9 d) in conjunction with an i.m. injection of 5 mg of estradiol valerate (EV), and either 3.0, 4.5, or 6.0 mg of NOR, 2 d after estrus. All cows were artificially inseminated at 48 h (timed insemination; TI) after implant removal (IR) and cows were reinseminated at any estrus subsequent to 24 h of TI through 30 d. Blood samples collected before treatment, every 3 d through IR, and at TI were assayed for progesterone (P4). At TI, 44, 39, and 12% of cows treated with 3.0, 4.5, or 6.0 mg of NOR, respectively, had serum concentrations of P4 greater than 1 ng/mL (3.0 and 4.5 mg vs 6.0 mg, P less than .01). Fifty-eight, 63, and 84% of cows treated with 3.0, 4.5, or 6.0 mg of NOR, respectively, exhibited a synchronized (within 5 d of IR) estrus (3.0 and 4.5 mg vs 6.0 mg, P less than .05). Pregnancy rates for the 5-d synchronized period were 38, 45, and 66% for cows treated with 3.0, 4.5, or 6.0 mg of NOR, respectively (3.0 and 4.5 mg vs 6.0 mg, P less than .05). First-service pregnancy rates were 66, 71, and 79% for cows treated with 3.0, 4.5, or 6.0 mg of NOR, respectively (P greater than .10).(ABSTRACT TRUNCATED AT 250 WORDS)
在一项持续2年的重复实验中，149头哺乳肉牛接受了Syncro-Mate-B（SMB）处理，即植入一枚含6毫克诺孕美特（NOR）的耳部埋植剂（原位放置9天），并肌肉注射5毫克戊酸雌二醇（EV），发情后2天再分别注射3.0、4.5或6.0毫克NOR。所有母牛在埋植剂取出（IR）后48小时进行人工授精（定时输精；TI），并在TI后24小时至30天内的任何发情期再次输精。在处理前、至IR期间每3天以及TI时采集血样，检测孕酮（P4）。TI时，分别用3.0、4.5或6.0毫克NOR处理的母牛中，血清P4浓度大于1纳克/毫升的比例分别为44%、39%和12%（3.0和4.5毫克组与6.0毫克组相比，P<0.01）。分别用3.0、4.5或6.0毫克NOR处理的母牛中，发情同步（在IR后5天内）的比例分别为58%、63%和84%（3.0和4.5毫克组与6.0毫克组相比，P<0.05）。在5天发情同步期内，分别用3.0、4.5或6.0毫克NOR处理的母牛的妊娠率分别为38%、45%和66%（3.0和4.5毫克组与6.0毫克组相比，P<0.05）。首次输精的妊娠率分别用3.0、4.5或6.0毫克NOR处理的母牛分别为66%、71%和79%（P>0.10）。（摘要截短至250字）
