共查询到19条相似文献，搜索用时 875 毫秒
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《黑龙江畜牧兽医》2016,(17)
为了进一步提高在高寒牧区柯尔克孜羊的繁殖率,试验选择180只处于非繁殖季节的空怀母羊,随机分为A组(n=60)、B组(n=60)、C组(n=60)。A组采用2次氯前列烯醇(PG)方法,B组采用孕酮阴道栓(CIDR)+孕马血清促性腺激素(PMSG)方法,C组采用CIDR+PMSG+PG方法。观察第一情期的发情情况及发情后卵巢状态,统计同期发情率、受胎率、产羔率。结果表明:C组同期发情率为85.0%高于A组(68.3%)、B组(71.7%),且差异显著(P0.05),A组、B组之间差异不显著(P0.05);C组处理后发情母羊的卵巢状态明显优于A组、B组,而且C组受胎率为88.2%高于A组(73.2%)、B组(74.4%),且差异显著(P0.05),A组、B组之间差异不显著(P0.05);A组、B组、C组产羔率分别为93.3%、96.9%、95.6%,且差异不显著(P0.05)。在高寒牧区采用CIDR+PMSG+PG方法对处于非繁殖季节的柯尔克孜羊进行处理后取得了最好的同期发情率、受胎率及产羔率。 相似文献
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采用阴道栓塞、FSH和加强饲养管理相结合的方法,对35只空怀滩母羊进行两个胎次67只次的处理.结果表明,外源激素FSH诱导滩母羊同期发情和第一情期配种妊娠率综合比较,以撤拴前12 h和撤拴同时两次肌注FSH的处理方法效果较好;繁殖季节60IU和非繁殖季节70～/80IUFSH能有效的诱导滩母羊的同期发情,并增加母羊的排卵数;采用适宜的外源激素处理基本实现滩羊一年两产并诱导一产多羔,两胎次共处理67只次,母羊年繁殖率为179.10%,年只均繁殖成活羔羊1.56只,母羊只均增加收入54.67元. 相似文献
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[目的]研究前列腺素F2α（PGF2α）、孕马血清促性腺激素（PMSG）、人绒毛膜促性腺激素（hCG）3种激素在不同处理方案下对内蒙古通辽地区乏情期母驴卵泡生长情况、排卵率、发情率、受胎率与妊娠率的影响。[方法]将50头2～6岁、体重接近、体况良好、处于乏情期的母驴随机分为A、B、C、D4组,其中D组为未使用任何激素的空白对照组。首先,采用PGF2α、PMSG进行诱导发情试验,对A、B、C3组母驴注射2mL／头PGF2α,连续处理5d,第6天对A、B组母驴分别注射PMSG 1000IU,头和500IU,头;C组不做PMSG处理。诱导发情后将A、B组再细分为A1、A2和B1、B2组,当A1、B1、C3组中母驴卵泡直径大于35mm时注射hCG（总量1500IU）进行诱导排卵;A2、B2不做hCG处理,由卵泡自然发育至排卵。对所有诱导发情后有发情表现的母驴进行自然本交。同时,在试验期间利用直肠检查和B超检查对母驴的卵巢发育进行监测。『结果]c组发情率为30％,经PGF2α处理第5天时卵巢黄体基本全部消退;A组和B组的发情率分别为93．33％和86．66％,二者差异不大,但均明显高于C组。A1、B1最终的排卵率为100％和77．78％,而A2和B2的排卵率为60．00％和50．00％。A,组受胎率和妊娠率最高,分别达到了88．89％和80．00％,其次是B,组分别为66．67％和60．00％,B2、C2组的受胎率和妊娠率都较低,D组虽然有1头母驴发情,但配种后未妊娠。[结论]单独使用PGF2α对非繁殖季节母驴诱导发情效果不明显,但其对消除母驴黄体有明显作用;PGF2α与PMSG联用对诱导乏情母驴发情效果较好。使用PGF2α与PMSG对处于乏情期的母驴诱导发情后,注射hCG对母驴卵巢上优势卵泡具有明显的促进排卵作用,能加快优势卵泡的排卵,且明显提高母驴的排卵率。该试验确定的最佳方案为：注射0．2mgPGF2α连续处理5d,第6天注射PMSG 500lU,当优势卵泡直径达35mm时注射hCG 1500lU,排卵后配种。 相似文献
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将小白鼠生殖系统影响实验筛选的3个中药方剂分别应用于10只处于间情期的健康京巴母犬。每只母犬每天经口灌服复方中草药煎剂4 mL,连用20 d,每天观察试验犬的行为变化、外观变化,在用药后的第14、18、20、25天捕杀试验犬,取其卵巢、子宫和阴道,制成切片,于光学显微镜下观察卵巢、子宫内膜和阴道等的组织学变化,中药方C应用的健康京巴母犬,在用药期间定期静脉采血,分离血清,测定E2、P4和IL-1β、IL-6的浓度变化。结果表明：中药组方C诱导犬发情时阴道黏膜增厚、充血、上皮脱落,子宫内膜和子宫腺体增生明显,卵巢出现了成熟卵泡和排卵点,E2在应用15 d达到峰值,峰值过后,E2浓度迅速下降;P4浓度在用药时及整个发情前期均很低,到17 d浓度开始持续升高;IL-1β浓度在17 d达到峰值,以后开始下降;IL-6浓度在5 d开始持续升高,到21 d排卵前后达到峰值。说明中药诱导非繁殖季节母犬发情是可行的。 相似文献
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《黑龙江畜牧兽医》2020,(16)
为了探讨复方中草药添加剂对母羊繁殖性能和血液生化指标、生殖激素含量的影响,试验将10～12月龄、体重35～40 kg的健康湖羊母羊60只随机分为3组,即对照组、试验A组、试验B组,每组20只;对照组饲喂基础日粮,试验A组、B组分别在基础日粮中每日每只添加15 g、20 g的复方中草药添加剂;预试期7 d,正试期180 d,发情后期采血检测血液生化指标和生殖激素含量,统计试验羊只的发情、受胎、产羔数及死胎数等,计算发情率、总受胎率、产羔率、羔羊初生时成活率等,测量初生羔羊的体重、体长。结果表明:与对照组比较,试验A组、B组的发情率、总受胎率和羔羊初生时成活率均有提高;试验A组、B组的血液总蛋白、球蛋白水平均极显著增加(P0.01);试验A组、B组的羔羊初生重和体长显著提高(P0.05);试验B组的血液雌二醇水平极显著高于对照组(P0.01)和试验A组(P0.05),试验A组显著高于对照组(P0.05)。说明复方中草药添加剂可改善湖羊母羊的健康状况,提高母羊发情率、总受胎率和羔羊初生时成活率,能显著促进初生羔羊生长。 相似文献
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为研究N-氨甲酰谷氨酸（NCG）对滩羊母羊在非繁殖季节诱导同期发情效果的影响,试验采用随机区组设计,选择同期经产母羊200只,分为4个试验组,每组50只,分别在母羊空怀期和妊娠期饲喂不同梯度的NCG预混料至全混合日粮（TMR）。在滩羊非繁殖季节乏情期,对空怀母羊采用PRID＋PMSG＋LRH-A3+PG诱导发情处理|对其羔羊实行早期隔栏补饲及早期断奶,羔羊组补饲营养水平及饲养管理条件一致,测定其繁殖性能指标。结果表明：试验2组第1情期受胎率（第二同期处理）、产羔率、产双羔率、断奶重和断奶成活率分别比4组（CK）提高45.83%、20.45%、210.13%、11.00%和5.83%（P ＞ 0.05）,其妊娠早期胚胎死亡率、空怀天数和产羔间距分别比4组降低33.37%、3.54 %和1.34%（P ＞ 0.05）|试验1组第1情期受胎率（第一同期处理）、羔羊初生成活率和断奶成活率分别比4组提高43.58%、5.32%和7.90%（P ＞ 0.05）,妊娠早期胚胎死亡率比4组降低65.98%（P ＞ 0.05）|试验3组羔羊初生重比4组提高4.53%（P ＞ 0.05）,妊娠早期胚胎死亡率比4组降低11.11%（P ＞ 0.05）。结果提示,在滩羊非繁殖季节乏情期,母羊添加NCG 1.027 g/d DM（空怀期）和1.195 g/d DM（妊娠期）饲粮,能提高母羊的第1情期受胎率、产羔率、产双羔率、羔羊断奶重及断奶成活率,减少妊娠早期胚胎死亡率、羔羊断奶天数、母羊空怀天数和产羔间距等繁殖力指标,可作为滩羊实现“两年三产”高频繁殖目标的优选饲粮方案。
[关键词] N-氨甲酰谷氨酸|滩羊|诱导发情|繁殖性状|两年三产 相似文献
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同期发情可使山羊发情集中,也有助于为难以进行发情鉴定母羊配种。使产羔时间集中,便于培育、饲喂和采取统一的防病措施。诱发发情可用以引起山羊非繁殖季节繁殖,以便全年供奶均衡。但母羊在炎热气候条件下受胎率及胎儿成活率下降。母山羊在非繁殖季节产羔,产奶量会降低20％。发情同期或诱导非繁殖季节繁殖的效果受季节、气候、海拔高度、饲管方式以及母羊的品种和年龄等因素的影响。没有发生过产羔障碍的母羊诱发发情效果较好。于配种前2～4周饲喂高能日粮能有效提高繁殖率。 相似文献
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在繁殖季节,通过对舍饲山羊用孕酮阴道海绵栓处理12d后注射PGF2α与FSH(T1组,76只)和肌肉注射PGF2α(T2组,34只)的方法进行同期发情处理,以自然发情山羊(C组,21只)为对照,比较这两种处理方法的同期发情效果。结果表明:T1和T2组同期发情率分别为72.37%和82.35%,T2组从取栓到开始出现发情的时间明显长于T1组,发情持续时间也长于T1组与C组;剖检T1组的11只母羊中有10只在卵巢山有经排卵形成的1～2个新生黄体(或排卵点)剖检黄体(或排卵点)率为90.91%,T2组为62.50%(58),C组为83.33%(56)。各组第1情期不返情率、受胎率和产羔率与剖检结果一致,T1组的产羔率为230%。表明孕酮阴道海绵栓法是有效的山羊同期发情方法。 相似文献
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Iida K Kobayashi N Kohno H Miyamoto A Fukui Y 《The Journal of reproduction and development》2004,50(1):63-69
The aim of the present study was to compare three methods of estrus synchronization in ewes during the non-breeding season. Forty-two ewes were randomly grouped for three treatments with different intravaginal devices for 12 days: Group A) CIDR, Group B) Self-made P sponge, Group C) MAP (medroxyprogesterone acetate) cream sponge. Furthermore, all groups were divided into two treatments with (R) or without ram presence to examine the "ram effect". Blood was collected from all treated ewes, and progesterone (P(4)), estradiol 17-beta (E(2)) and luteinizing hormone (LH) concentrations were measured by enzyme-immunoassay. All ewes showed estrus behavior between Day 0 to 3 after device removal, and the mean onset times of their estrus were 23.0, 33.0 and 21.0 h for Groups AR, BR and CR, respectively. On Day 5 as examined by laparoscopy, the ovulation rates (and number of ovulated ewes) were 1.45 (11/11), 1.25 (12/14) and 1.21 (14/14) for Groups A, B and C, respectively. In Group C, the time to LH surge was significantly (P<0.05) later (32.4 h) than those in Groups A (27.0 h) and B (25.5 h). Ram presence did not affect the number of ovulated ewes, ovulation rate or time to LH surge. The ram introduction group had significantly (P<0.05) lower E(2) concentrations during the period from 0 h to 36 h than the groups without ram presence. These results suggest that the self-made P sponge or MAP cream sponge was effective as well as CIDR, and ram introduction was not necessary, for induction of estrus and ovulation during the non-breeding season. 相似文献
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为研究中草药集中催情和孕马血清促性腺激素（PMSG）外源诱导对非繁殖季节内蒙古绒山羊产羔和血清指标的影响,选取体重相近的内蒙古绒山羊272只,分为中草药试验Ⅰ组（112只）、激素试验Ⅱ组（100只）和对照组（60只）,试验Ⅰ组饲喂中草药,每次50 g/只,发情前7 d开始饲喂,每2 d饲喂1次,共3次;试验Ⅱ组海绵栓+PMSG 250 IU/只;对照组正常饲养。在试验结束后第2天早饲前各组选择5只羊颈静脉采血,测定并分析血清中生理生化指标及生殖激素含量的变化。结果显示,试验Ⅰ组和试验Ⅱ组绒山羊的发情率、产羔率和双羔率极显著高于对照组（P<0.01）,试验Ⅱ组的产羔率和双羔率极显著高于试验Ⅰ组（P<0.01）,发情率显著高于试验Ⅰ组（P<0.05）。试验Ⅱ组绒山羊血清总蛋白（TP）、白蛋白（ALB）、尿素氮（UREA）、谷胱甘肽过氧化物酶（GSH-Px）含量显著高于试验Ⅰ组和对照组（P<0.05）,试验Ⅰ组绒山羊丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性显著高于试验Ⅱ组和对照组（P<0.05）;试验Ⅱ组血清促卵泡素（FSH）、雌二醇（E2）和促黄体素（LH）含量显著高于对照组（P<0.05）,孕酮（P4）、睾酮（T）在三组之间差异均不显著（P>0.05）,试验Ⅰ组生殖激素指标与对照组差异均不显著（P>0.05）。对激素和抗氧化酶的相关性分析显示,试验Ⅰ组绒山羊血清P4含量与GSH-Px含量呈显著负相关（P<0.05）,其相关系数为-0.594,试验Ⅱ组绒山羊血清LH含量与GSH-Px含量呈极显著正相关（P<0.01）,其相关系数为0.757。本研究结果表明,中草药和激素处理均可极显著促进内蒙古绒山羊在非繁殖季节集中发情,并提高产羔率。激素处理可提高非繁殖季节内蒙古绒山羊对蛋白质的消化利用程度和抗氧化功能,中草药处理可提高血清SOD活性;分析认为GSH-Px与P4之间存在显著颉颃作用,GSH-Px与LH之间存在极显著协同作用。 相似文献
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Hiwasa M Kohno H Togari T Okabe K Fukui Y 《The Journal of reproduction and development》2009,55(1):50-54
The present study aimed to investigate the fertility of ewes artificially inseminated with three different methods using a synthetic semen extender, AndroMed. The three methods of artificial insemination (AI) were cervical AI with fresh-diluted or frozen-diluted semen at observed estrus, and an intrauterine AI with frozen-thawed semen. A total of 80 ewes were treated with a controlled internal drug release (CIDR) containing 0.3 g progesterone per device for 12 days. In Experiment 1 (26 Suffolk ewes), superovulation was induced with 20 mg follicle-stimulating hormone and 250 IU equine chorionic gonadotropin (eCG) two days and one day before CIDR removal, respectively, during the non-breeding season. In Experiment 2 (54 Suffolk and Suffolk crossbred ewes), an intramuscular injection of 500 IU eCG was administered one day before CIDR removal to synchronize estrus and ovulation during the breeding season. In Experiment 1, fresh-diluted or frozen-thawed semen was deposited into the cervical orifice after estrus detection, and an intrauterine AI with frozen-thawed semen was performed by laparoscopy at a fixed-time basis without estrus detection. Embryos were recovered by uterine flushing 6 days after AI, and the rates of recovered, fertilized (cleaved) ova and embryos at the morula or blastocyst stage were compared among the three AI methods. In Experiment 2, the pregnancy rates after the three AI methods were compared. In Experiment 1, the rates of recovered ova were not significantly different among the three AI methods (52.5-56.7%). The rate of fertilized ova (81.0%) by laparoscopic AI with frozen-thawed semen was significantly higher compared with cervical AI of fresh-diluted (25.5%) or frozen-thawed (3.5%) semen, but the rate of embryos at the morula or blastocyst stage (17.6%) was significantly lower than that of the cervical AI with fresh-diluted semen (69.2%). The rates of ewes yielding fertilized ova were not significantly different among the three groups (44.4, 11.1 and 62.5% for cervical AI with fresh-diluted and frozen-thawed semen and intrauterine AI with frozen-thawed semen). In Experiment 2, the pregnancy rate of ewes intrauterinally inseminated with frozen-thawed semen (72.2%) was significantly higher than those of ewes inseminated cervically with fresh-diluted (5.5%) or frozen-thawed (0.0%) semen. The present results showed that acceptable fertilization and pregnancy rates could be obtained by an intrauterine AI with frozen-thawed semen using a synthetic semen extender (AndroMed), but not sufficient by the cervical AI with either fresh or frozen semen. 相似文献
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Kohno H Okamoto C Iida K Takeda T Kaneko E Kawashima C Miyamoto A Fukui Y 《The Journal of reproduction and development》2005,51(6):805-812
Two experiments were conducted to compare the effect of estrus induction by controlled internal drug release (CIDR) and intravaginal cream containing 500 mg progesterone (P cream) in ewes during the non-breeding season. In the first experiment, twenty-four ewes were randomly grouped for two treatments with the different intravaginal devices for 12 days: Group A was the CIDR group and Group B was the P cream group. Blood was collected from all treated ewes, and progesterone (P(4)), estradiol 17-beta (E(2)) and luteinizing hormone (LH) concentrations were measured by enzyme immunoassay. In the second experiment, the conception rates from natural mating, estrus-detected AI (inseminated 12 h after estrus detection), or fixed-time AI (inseminated 42 h after removal of an intravaginal device) in 127 ewes treated with CIDR or P cream were compared. In Experiment 1, the rate of estrus induction and the time of estrus onset after device removal were 91.7% and 36.3 +/- 15.7 h in Group A, and 100% and 35.0 +/- 12.6 h in Group B, respectively. There were no significant differences between the devices. The mean plasma P(4) concentration in Group B was significantly (P < 0.01) lower than Group A between day -9 and day -1 (Day 0: the day of device removal). However, no significant differences were found in the mean E(2) concentrations of the two groups after treatment. The mean time of estrus onset in ewes with an observed LH surge and the time of LH surge after treatment were 23.3 +/- 8.7 h and 30.3 +/- 5.0 h for Group A and 27.6 +/- 6.5 and 26.3 +/- 8.0 h for Group B, respectively, and there were no significant differences. However, a significant difference (P < 0.05) was found in the mean time from the time of estrus onset to LH surge between Group A (6.4 +/- 6.7 h) and Group B (-1.3 +/- 4.1 h). In Experiment 2, the conception rates for natural mating, estrus-detected AI, and fixed-time AI were 55.0, 29.4, and 25.0% for Group A and 40.7, 25.0, and 42.1% for Group B, respectively, and there were no significant differences. These results suggest that the effect of induction of estrus and ovulation and the rate of conception after treatment were comparable to CIDR even though the plasma P(4) concentration of the P cream method tended to be low during the insertion period. 相似文献
15.
目的 研究旨在通过试验观察中草药治疗奶牛子宫内膜炎疗效,以其为临床应用中草药治疗奶牛子宫内膜炎提供参考。方法 将60 头患子宫内膜炎奶牛,随机分成5 组,每组12 头,复方中草药高、中、低剂量组（分别子宫灌注150 mL/头、100 mL/头和50 mL/头）、土霉素组（子宫灌注50 mL/头）和对照组。结果 复方中草药中剂量组和高剂量组的总有效率为75.00%和83.33%,均高于土霉素组的总有效率66.67%;土霉素组在治疗结束后的平均发情天数缩短了14 d,所有复方中草药组的发情天数也缩短了11~19 d;3 个情期内土霉素组受胎率为50.00%,复方中草药组受胎率介于41.67%~66.67%之间。结论 复方中草药对奶牛子宫内膜炎的治疗效果优于土霉素,其中以高剂量组效果最佳。 相似文献
16.
The effect of gonadotropin releasing hormone (GnRH) treatment on the time of ovulation and the occurrence of follicular dominance during the non-breeding and breeding seasons (experiment 1), and on fertility after artificial insemination (AI) in the non-breeding season (experiment 2), was examined in Merino ewes. Oestrus was synchronized in 40 nulliparous ewes (experiment 1; n = 20, in the non-breeding and breeding seasons) and in 79 multiparous ewes (experiment 2) using intravaginal sponges and pregnant mare serum gonadotropin. Thirty six hours after sponge removal (SR), half the ewes were injected (i.m.) with 40 microg of synthetic GnRH and the remainder used as controls. GnRH improved the synchrony of ovulation compared with the controls in the breeding (SD = 2.8 vs 5.7 days, p = 0.04) but not the non-breeding season (SD = 3.8 vs 4.4 days, p = 0.69), with ewes ovulating from 42 to 54 h (mean 50.4 +/- 4.08 h) and 42-60 h (mean 54.4 +/- 5.47 h) after SR for GnRH and control, respectively. For both treated and control ewes, ovulation occurred earlier in the non-breeding than the breeding season (50.1 vs 54.6 h; p = 0.002). GnRH had no effect on follicular dominance, as assessed by divergence (D: the time the ovulatory follicle exceeded the average size of the other non-ovulating follicles) or on the interval from D to ovulation (IDO). However, follicular dynamics differed between seasons. The mean follicle diameter increased at a faster rate up to 36 h after SR in the non-breeding compared with the breeding season and then rapidly declined, compared with a later peak (42 h after SR) in mean follicular size during the breeding season. IDO was shorter in the non-breeding than in the breeding season (26.7 +/- 4.30 h vs 39.6 +/- 4.53 h; p = 0.05). In experiment 2, ewes (n = 38 GnRH-treated, n = 40 controls) were inseminated in the uterus by laparoscopy 42 h or 48 h after SR with frozen-thawed sperm. The fertility of ewes treated with GnRH (nine of 39, 23%) was not different to the controls (eight of 38, 21%; p = 0.01). In conclusion the application of GnRH improved synchronization of ovulation but did not improve fertility rates after AI. 相似文献
17.
Two experiments were performed to determine the endocrine and ovarian changes in medroxyprogesterone acetate (MAP)-primed ewes after ram introduction. Experiment 1 was performed during the mid-breeding season with 71 ewes primed with an intravaginal MAP sponge for 12 days. While the control (C) ewes (n = 35) were in permanent contact with rams, the ram effect (RE) ewes (n = 36) were isolated for 34 days prior to contact with rams. At sponge withdrawal, all ewes were joined with eight sexually experienced marking Corriedale rams and estrus was recorded over the next 4 days. The ovaries were observed by laparoscopy 4-6 days after estrus. Four weeks later, pregnancy was determined by transrectal ultrasonography. In eight ewes from each group, ovaries were ultrasonographically scanned; FSH, LH, and estradiol-17beta were measured every 12 hours until ovulation or 96 hours after estrus. The response to the rams was not affected by the fact that ewes had been kept or not in close contact with males before teasing. No differences were found in FSH, LH, estradiol-17beta concentrations, growth of the ovulatory follicle, onset of estrus, ovulation rate, or pregnancy rate. Experiment 2 was performed with 14 ewes during the nonbreeding season. Ewes were isolated from rams for 1 month, and received a 6-day MAP priming. Ovaries were ultrasonographically scanned every 12 hours, and FSH, LH, estradiol-17beta, and progesterone were measured. Ewes that ovulated and came into estrus had higher FSH and estradiol-17beta levels before introduction of the rams than did ewes that had a silent ovulation. The endocrine pattern of the induced follicular phase of ewes that came into estrus was more similar to a normal follicular phase, than in ewes that had a silent ovulation. The follicle that finally ovulated tended to emerge earlier and in a more synchronized fashion in those ewes that did come into estrus. All ewes that ovulated had an LH surge and reached higher maximum FSH levels than ewes that did not ovulate, none of which had an LH surge. We conclude that (a) the effect of ram introduction in cyclic ewes treated with MAP may vary depending on the time of the breeding season at which teasing is performed; (b) patterns of FSH, and estradiol-17beta concentrations, as indicators of activity of the reproductive axis, may be used to classify depth of anestrus; and (c) the endocrine pattern of the induced follicular phase, which is related to the depth of anestrus, may be reflected in the behavioral responses to MAP priming and the ram effect. 相似文献
18.
To determine whether the presence of IUDs would reduce estrous-cycle length throughout a breeding season, 51 and 58 ewes, respectively, were studied in 2 experiments. The estrous cycles of ewes with an IUD adjacent to each ovary averaged 9.6 days in length from September through November, and nearly 20 days from December through February. The same ewes showed a similar pattern in a second September-to-February breeding season. In the third breeding season, ewes with an IUD in each uterine horn were laparotomized if they had not returned to heat within 9 days after a designated estrous period. Of 54 ewes laparotomized during the course of the breeding season, corpora lutea 1) had regressed or were regressing in 49 (91%) by Day 9, and 2) had regressed in the other 5 ewes by Day 18. It is concluded that cycles longer than 9 days were usually caused by 1 or more successive ovulations without estrus, and that the increased mean cycle length for IUD-bearing ewes during the second half of the breeding season was due primarily to a greater frequency of ovulation without estrus. 相似文献
19.
Two experiments were performed to determine the endocrine and ovarian changes in medroxyprogesterone acetate (MAP)-primed ewes after ram introduction. Experiment 1 was performed during the mid-breeding season with 71 ewes primed with an intravaginal MAP sponge for 12 days. While the control (C) ewes (n = 35) were in permanent contact with rams, the ram effect (RE) ewes (n = 36) were isolated for 34 days prior to contact with rams. At sponge withdrawal, all ewes were joined with eight sexually experienced marking Corriedale rams and estrus was recorded over the next 4 days. The ovaries were observed by laparoscopy 4–6 days after estrus. Four weeks later, pregnancy was determined by transrectal ultrasonography. In eight ewes from each group, ovaries were ultrasonographically scanned; FSH, LH, and estradiol-17β were measured every 12 hours until ovulation or 96 hours after estrus. The response to the rams was not affected by the fact that ewes had been kept or not in close contact with males before teasing. No differences were found in FSH, LH, estradiol-17β concentrations, growth of the ovulatory follicle, onset of estrus, ovulation rate, or pregnancy rate. Experiment 2 was performed with 14 ewes during the nonbreeding season. Ewes were isolated from rams for 1 month, and received a 6-day MAP priming. Ovaries were ultrasonographically scanned every 12 hours, and FSH, LH, estradiol-17β, and progesterone were measured. Ewes that ovulated and came into estrus had higher FSH and estradiol-17β levels before introduction of the rams than did ewes that had a silent ovulation. The endocrine pattern of the induced follicular phase of ewes that came into estrus was more similar to a normal follicular phase, than in ewes that had a silent ovulation. The follicle that finally ovulated tended to emerge earlier and in a more synchronized fashion in those ewes that did come into estrus. All ewes that ovulated had an LH surge and reached higher maximum FSH levels than ewes that did not ovulate, none of which had an LH surge. We conclude that (a) the effect of ram introduction in cyclic ewes treated with MAP may vary depending on the time of the breeding season at which teasing is performed; (b) patterns of FSH, and estradiol-17β concentrations, as indicators of activity of the reproductive axis, may be used to classify depth of anestrus; and (c) the endocrine pattern of the induced follicular phase, which is related to the depth of anestrus, may be reflected in the behavioral responses to MAP priming and the ram effect. 相似文献