Romano Juan E, Alkar Abdalhamid, Amstalden Marcel
Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4475, USA.
Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4475, USA.
Theriogenology. 2017 Apr 1;92:45-50. doi: 10.1016/j.theriogenology.2016.12.019. Epub 2016 Dec 31.
The objectives of these two experiments were to determine the day of onset of luteolysis after exogenous PGF-2α administration during the estrous cycle and the fertility of this synchronized estrus in goats. In the first experiment, during the breeding season, 48 Nubian does were estrous synchronized, using intravaginal sponges impregnated with a progestin, and estrus was detected by vasectomized bucks. The does were divided at random into three groups of 16 does each to be treated at days 2, 3, and 4 of the estrous cycle (estrus = day 0). Then, at each day of injection, the does were again randomly divided to receive a single dose of natural prostaglandin F-2α im (PGF-2α; 5 mg/doe; treatment [TRE] group) or sterile saline solution (control [CON] group; 1 mL/doe). Finally, the following groups were originated: TRE-2, CON-2, TRE-3, CON-3, TRE-4, and CON-4. The overall estrus response after treatment with PGF-2α (TRE group, 70.8%) was higher than saline (CON group, 12.5%, P ≤ 0.001). Estrus response for TRE-2, CON-2, TRE-3, CON-3, TRE-4, and CON-4 was 25% (2 of 8), 12.5% (1 of 8), 87.5% (7 of 8), 12.5% (1 of 8), 100% (8 of 8), and 0% (0 of 8) for the same groups, respectively. Estrus response was different between day 2 and days 3 and 4 (P ≤ 0.04) and not between day 3 and day 4 (P ≥ 0.05). In the second experiment, 15 multiparous Boer does were estrous synchronized with control internal drug release (CIDR, 300 mg progesterone = P) and PGF-2 and randomly divided to receive one single dose of PGF-2α im at days 2, 3 or 4, after synchronized estrus (n = 5 at each day). The does were detected twice a day for estrus, and blood was collected daily for P determination for 11 days after the synchronized estrus. Each doe in estrus was bred by hand mating to a proven male. All the does with a functional corpus/corpora luteum/lutea (CL; ≥1.0 ng/mL of P) responded to PGF-2α with a drop in P levels that either lasted only 24 h for the does that did not show estrus (0.27 ± 0.10 ng/mL; n = 4) or persisted longer in all the does that showed estrus (0.22 ± 0.18 ng/mL; n = 10; P = 0.47). Estrus response for days 2, 3, and 4 was 20% (1 of 5), 80% (4 of 5), and 100% (5 of 5), respectively (P = 0.05). The conception rate was 100%, 100%, and 80% for the same days of administration, respectively (P = 0.64). It was concluded that luteolytic action of PGF-2α begins at day 3 of the estrous cycle by inducing an ovulatory and fertile estrus in goats.
这两项实验的目的是确定发情周期中外源性前列腺素F-2α给药后黄体溶解开始的日期，以及这种同步发情对山羊繁殖力的影响。在第一个实验中，在繁殖季节，使用浸有孕激素的阴道海绵对48只努比亚母羊进行发情同步处理，并用输精管结扎的公羊检测发情情况。母羊被随机分为三组，每组16只，在发情周期的第2、3和4天（发情日=第0天）进行处理。然后，在每次注射当天，母羊再次被随机分为两组，分别接受一次肌肉注射天然前列腺素F-2α（PGF-2α；5mg/只；处理[TRE]组）或无菌生理盐水（对照[CON]组；1mL/只）。最后，形成了以下几组：TRE-2、CON-2、TRE-3、CON-3、TRE-4和CON-4。用PGF-2α处理后的总体发情反应（TRE组，7）高于生理盐水处理组（CON组，12.5%，P≤0.001）。TRE-2、CON-2、TRE-3、CON-3、TRE-4和CON-4组的发情反应分别为25%（8只中的2只）、12.5%（8只中的1只）、87.5%（8只中的7只）、12.5%（8只中的1只）、100%（8只中的8只）和0%（8只中的0只）。第2天与第3天和第4天的发情反应不同（P≤0.04），第3天和第4天之间无差异（P≥0.05）。在第二个实验中，15只经产波尔山羊母羊采用对照型缓释内植剂（CIDR，含300mg孕酮=P）和PGF-2进行发情同步处理，并在发情同步后第2、3或4天随机分为三组，每组5只，分别接受一次肌肉注射PGF-2α。每天对母羊进行两次发情检测，并在发情同步后11天每天采集血液测定孕酮水平。每只发情的母羊通过人工授精与一只经证实的公羊交配。所有具有功能性黄体（CL；孕酮≥1.0ng/mL）的母羊对PGF-2α的反应是孕酮水平下降，未发情的母羊（0.27±0.10ng/mL；n=4）孕酮水平下降仅持续24小时，而所有发情的母羊（0.22±0.18ng/mL；n=10；P=0.47）孕酮水平下降持续时间更长。第2、3和4天的发情反应分别为20%（5只中的1只）、80%（5只中的4只）和100%（5只中的5只）（P=0.05）。相同给药日的受孕率分别为100%、100%和80%（P=0.64）。得出的结论是，PGF-2α的黄体溶解作用在发情周期的第3天开始，可诱导山羊排卵并形成可受孕的发情。
