冷冻精液输精深度和时间对蒙古羊受胎率的影响

[目的] 研究冷冻精液输精深度和时间对蒙古羊受胎率的影响。[方法] 选取体况健康、繁殖机能正常的蒙古羊母羊作为试验动物,采用孕酮海绵栓对受体母羊进行同期发情处理。应用常规人工输精法（n=135）、过子宫颈输精法[过子宫颈第一皱褶（1~2 cm）输精（n=120）,过子宫颈第二到第三皱褶（3~4 cm）输精（n=120）]、腹腔镜辅助子宫内输精法（n=128）对发情后的母羊进行冷冻精液人工授精。接受常规人工输精法和过子宫颈输精法处理的受体母羊在发情后约14 h和22 h各输精1次,接受腹腔镜辅助子宫内输精法处理的受体母羊在发情后30~36 h输精1次。输精后40 d用B超仪检测母羊妊娠情况,计算并比较接受不同输精方法处理母羊的受胎率。[结果] 腹腔镜辅助子宫内输精法的受体母羊受胎率平均值最高,为60.2%;其次为过子宫颈第二到第三皱褶（3~4 cm）输精,受胎率平均值为58.3%;过子宫颈第一皱褶（1~2 cm）输精和常规输精法的受体母羊受胎率平均值分别为37.5%和36.3%。统计学分析表明,腹腔镜辅助子宫内输精法和过子宫颈第二到第三皱褶（3~4 cm）输精的受体母羊受胎率平均值显著（P<0.05）高于常规输精法和过子宫颈第一皱褶（1~2 cm）输精。[结论] 蒙古羊母羊发情后30~36 h采用腹腔镜辅助子宫内输精法完全穿刺子宫颈输精1次,可获得比常规输精法更高的受胎率;采用过子宫颈输精法在母羊发情后约14 h和22 h各输精1次,当授精深度接近4 cm时可达到与腹腔镜辅助子宫内输精法接近的受胎率。     

腹腔镜输精对绵羊超数排卵受精率的影响

用促卵泡素和CIDR诱导发情超排228只母羊,将正常发情的供体母羊随机分成3组进行输精。其结果显示:①供体羊发情后全部采用人工授精,其受精率显著低于(P<0.05)采用内窥镜输精方法;腹腔镜和人工授精方法结合使用,虽然有受精率提高的趋势,但差异不显著(P>0.05)。②诱导发情的母羊应该在撤栓后36h进行子宫内输精,但考虑到撤栓后发情时间,多在母羊发情开始后12～18h输精,其受精效果好。③输入有效精子数为20×106以上时的输精效果好。     

连续重复超数排卵、冲胚对引进品种肉羊快速扩繁的效果研究

[目的] 评价引进品种肉羊的连续重复超数排卵（超排）、冲胚、胚胎移植等繁育技术集成模式的应用效果。[方法] 于2016—2018年,对选取的1 575只澳洲白（n=230）、白头杜泊（n=228）、黑头杜泊（n=541）、白头萨福克（n=200）、黑头萨福克（n=376）5个品种母羊,进行间隔30 d以上的连续同期发情（孕酮海绵栓）与超排（330~450 IU FSH+200~300 IU PMSG+0.1 mg PG）处理;经过腹腔内窥镜输精后进行子宫角冲胚,回收胚胎后计数并评估质量,挑取部分胚胎进行移植;对比分析品种、季节、重复超排次数等对胚胎生产指标的影响。[结果] 共获得18 496枚胚胎,有14 971枚可用胚;胚胎移植后的受胎率为69.8%,产羔率为93.2%;只均总胚数和只均可用胚数2项指标显示,胚胎生产特性以白头萨福克、黑头萨福克、黑头杜泊较好,澳洲白次之,白头杜泊最差;不同品种母羊连续重复超排冲胚后回收的只均总胚数和只均可用胚数持续增长,直到第4或第5次;澳洲白的超排冲胚效果在春季较好,而其他品种在冬季较好。[结论] 连续重复超数排卵、冲胚技术对于扩繁引进肉羊品种群体是可行的,应根据不同品种及其表现出的季节特性科学、适时应用。     

利用腹腔内窥镜方法比较不同输精时间对羊体内胚胎生产效率的影响

为提高供体绵羊胚胎生产效率,实验选取99只供体母羊,用FSH+CIDR法诱导发情超排。将正常发情的供体母羊随机分成两组进行输精,分别在超排撤栓后的第48 h和54 h利用腹腔内窥镜法输精。其中48 h输精组供体母羊51只,54 h输精组供体母羊48只。其结果显示:撤栓后54 h输精胚胎回收率极显著高于48 h输精组(P0.01);54 h输精组供体卵母细胞受精率(97.27%)极显著高于48 h输精组(87.02%)(P0.01);54 h组供体平均可用胚数显著高于48 h组(P0.05);撤栓后54 h利用腹腔内窥镜输精组可用胚比率(89.70%)显著高于48 h组(80.53%)(P0.05);移植后受体妊娠率,54 h组(70.44%)极显著高于48 h组(56.92%)。本研究结果显示,利用本实验超排方案,供体撤栓后54 h利用内窥镜一次定时输精相对于48 h输精显著提高了供体胚胎生产效率,对羊体内胚胎生产提供理论和技术支持。     

不同同期发情及定时输精技术对新疆细毛羊受胎率的影响

新疆细毛羊为季节性发情动物,大多数细毛羊每年产1胎,多为1胎单羔。因此,受胎率是决定养羊经济效益的关键因素之一。定时输精技术可以有效地提高母畜的利用率和受胎率,已成为养羊生产中的一项重要技术。为了提高绵羊的繁殖效率,本试验采取3种不同方法分别对青年母羊进行同期发情处理,比较研究了发情后不同定时输精技术及输精时间对受胎率的影响。结果表明,3种同期发情的处理方法均取得了较高的同期发情率,其中CIDR栓+PGF2α方法的同期发情效果较好;青年母羊最佳定时输精技术是腹腔镜输精技术;最佳输精时间为发情后的48 h。     

杜蒙杂交母羊的繁殖规律研究

旨在研究杜蒙杂交母羊的繁殖规律。对内蒙古自治区乌兰察布市四子王旗范围内养殖的杜蒙杂交母羊（n=668）的首次发情时间、妊娠期、产羔率、产双羔率等指标数据进行整理;采用公羊试情方法,观察并记录杜蒙杂交母羊（n=302）的发情周期和发情持续时间。对上述指标数据进行分析,探究该地区杜蒙杂交母羊的繁殖规律。结果表明：杜蒙杂交母羊平均首次发情时间为8.5月龄（最早7.0月龄、最晚10.7月龄）,平均发情周期为16.0 d（最短13.5 d、最长18.5 d）,平均发情持续时间为24.0 h（最短20.0 h、最长27.5 h）,平均妊娠期为146.0 d（最短143.0 d、最长149.0 d）,产羔率为119.7%,产双羔率为19.7%。研究结果为掌握杜蒙杂交母羊自然发情规律,以及准确把握最佳配种时间提供了依据。     

人绒毛膜促性腺激素对母驴促排卵效果的研究

[目的]研究人绒毛膜促性腺激素（human chorionic gonadotropin,hCG）对母驴卵泡发育、排卵率、受胎率以及血清生殖激素水平的影响。[方法]选择优势卵泡直径在30~35 mm以及大于35 mm的母驴各30头,不同优势卵泡直径的母驴群体分别设置1个500 IU/头hCG处理组（n=10）、1个1 000 IU/头hCG处理组（n=10）、1个不接受hCG处理的对照组（n=10）。采用肌肉注射方法对各组母驴进行hCG处理。每隔24 h进行1次B超检查,观察各组母驴卵泡发育情况,测量卵泡直径;记录各组发生排卵的母驴数量,计算排卵率。对各组母驴进行人工输精,输精后第18天进行孕检,记录各组受胎母驴头数,计算各组受胎率。于hCG处理后0、24、48、72 h分别测定各组母驴血清中雌二醇（estradiol,E₂）和孕酮（progesterone,PROG）水平。[结果]2个群体母驴的卵泡直径随hCG注射剂量的增加而增大;优势卵泡直径大于35 mm的母驴群体中,肌肉注射hCG的2个组在处理后24 h内均出现排卵,而对照组母驴没有排卵;优势卵泡直径不同的2个母驴群体,在hCG处理48 h后排卵母驴数和排卵率与对照组相比均有所提高,其中,hCG处理后72 h,优势卵泡直径大于35 mm的母驴群体中,1 000 IU/头 hCG处理组的排卵率达到100%。2个母驴群体中,接受hCG处理的母驴,受胎率均高于对照,并且随hCG剂量的增加,受胎率有所提高;优势卵泡直径大于35 mm的母驴群体中,1 000 IU/头 hCG处理组的受胎率达到50%。2个母驴群体中,1 000 IU/头处理组在hCG处理后24 h的血清E₂浓度均较0 h时有较大幅度的提升,在0~72 h内血清PROG浓度的总体提升幅度较大。[结论]hCG处理可提高母驴的排卵率、受胎率以及血清中E₂和PROG水平,1 000 IU/头剂量的效果更好。     

腹腔镜输精与传统输精方式对湖羊受胎率的影响

选择冀北地区规模化养殖场达到体成熟的青年母羊,通过阴道埋植孕酮栓并结合注射外源性激素(PMSG)进行同期发情处理,分别采用腹腔镜输精、子宫颈输精以及本交方式对同期发情后150、124、146只母羊进行配种,以探究腹腔镜输精与传统输精方式对同期发情母羊受胎率的影响。结果：采用腹腔镜输精和子宫颈输精的母羊受胎率分别为92%和88%,二者差异不显著(P>0.05),但均极显著高于本交方式母羊的受胎率66%(P<0.01)。试验表明,腹腔镜输精方式可以提高母羊情期受胎率,便于规模化羊场组织生产。     

高原型藏羊非繁殖季节同期发情效果研究

为探讨高原型藏羊非繁殖季节同期发情效果,本试验在母羊阴道放置CIDR,第14 d撤栓后,对肌注PMSG 300IU/只的羊分三组,采用腹腔镜子宫角输精技术,分别在48～56 h冻精、60～68 h冻精,60～68 h鲜精配种,跟踪统计母羊情期受胎数、受胎母羊产羔数和羔羊成活数。结果表明:48～56 h用冻精授配,情期受胎率比60～68 h高38.09个百分点(P0.01),撤栓60～68 h用鲜精比同时间段冻精授配,情期受胎率高9.86个百分点(P0.05)。冻精腹腔镜子宫角输精,68 h内总受胎率和羔羊成活率分别达到71.43%和100.00%。冻精授配受胎率低是长期困扰该技术推广的瓶颈,本试验应用内窥镜子宫角冻精授配取得了好的授配效果,在此基础上,辅试情、复配,可在藏羊商品肉羊生产中推广应用。     

肉羊腹腔镜冷冻精液输精对受胎率的影响

为了克服子宫颈输精的不足,提高母羊繁殖率,本试验借助腹腔镜技术,采用腹壁穿刺的方法,通过专用输精枪将肉羊细管冷冻精液输入母羊的子宫角内。试验结果表明,母羊同期发情后48~52 h输精,4个试验羊场受胎率分别为73.6%、71.9%、68.5%、32.7%,说明多胎羊受胎率高于单胎羊,年龄与胎次相仿母羊群受胎率高于胎次不清母羊群。在同等饲养条件下自然发情(试情)与同期发情,母羊受胎率分别为61.3%和60.9%,二者受胎率没有差异。     

Influence of body weight and number of inseminations on fertility of progestogen-treated ewe lambs raised in controlled environments

The influence of body weight at breeding on reproductive response to one and two artificial inseminations (AI) of fresh extended semen was assessed in 195 crossbred ewe lambs selected for early breeding and compared with 159 adult ewes, all housed indoors in a controlled environment. In six trials, ewe lambs and adult ewes in progestogen-induced estrus were inseminated 55 to 57 h after sponge removal. One-half of the lambs and one-fourth of the adults received a second insemination at 60 h. Resultant reproductive performance of both groups indicated no advantage in a double insemination. Overall fertility, litter size and fecundity after one and two inseminations were 33%, 1.7 and .6 for ewe lambs and 68%, 2.4 and 1.6 for adult ewes, respectively. Embryonic mortality after the first 2 wk of pregnancy was estimated at 24% for ewe lambs and 9% for adults. The influence of body weight was analyzed by grouping the ewe lambs according to body weight at breeding. The lambs in group 1 weighed 30 to 35 kg; group 2, 36 to 40 kg; group 3, 41 to 45 kg and group 4, 46 to 50 kg. The proportion of ewes lambing in groups 1, 2, 3 and 4 was 16, 34, 39 and 48%, respectively. Corresponding litter sizes were 1.4, 1.6, 1.8 and 2.0. Fecundity increased (P less than 01) from .2 in group 1 to 1.0 in group 4. The results indicate that even when ewe lambs are bred by AI (eliminating a ram behavioral problem), sheep with heavier body weights produce more lambs per ewe bred.     

Influence of PMSG and time of artificial insemination on fertility of progestogen-treated sheep in confinement

The need for pregnant mates' serum gonadotropin (PMSG) in breeding confined sheep by artificial insemination (AI) at progestogen-synchronized estrus was assessed in 152 adult crossbred ewes brought into season by a controlled light regimen. One-half of the ewes received 500 IU PMSG after intravaginal progestogen treatment; all ewes were inseminated either 54, 57 or 60 h after sponge removal or at 54 and again at 60 h. Based on progesterone determinations 18 d after AI, conception rates with single insemination 54, 57, or 60 h and double insemination at 54 and 60 h were 76, 72, 47 and 72%, respectively, among ewes receiving PMSG, compared to 17, 22, 47 and 43%, respectively, among ewes not give PMSG (P less than .01) Lambing rates were higher (P less than .01) with PMSG (67, 67, 37 and 61%) than without PMSG (11, 11, 26 and 33%). While there was only a small increase (.06 less than P less than .05) in litter size with PMSG, fecundity decreased (P less than .01) from 1.4 to .3 when PMSG was not used. These data indicate that, even with controlled lighting to induce estrous activity, additional stimulation of ovulation by PMSG at progestogen-synchronized estrus is necessary for normal fertility when confined sheep are bred by AI.     

Conception rates in early postpartum ewes bred naturally or by intrauterine insemination

Ewes were treated with a medroxyprogesterone acetate (MAP) sponge for 8 d followed, at sponge removal, with 500 IU pregnant mare serum gonadotropin (PMSG) at d 30, 40 or 50 (d 0 = lambing) to induce estrus. Dry and lactating ewes were divided into equal numbers at each postpartum day and bred at estrus. Conception rates and number of accessory sperm were determined by flushing the oviducts 3 d after mating and examining the recovered ova. There was no effect (P greater than .05) of lactational status on conception rates. Conception rates increased (P less than .05) from d 30 (10%) to d 40 (45%) and from d 40 to d 50 (80%). There were fewer (P less than .05) ova with accessory sperm (5/26) in d-30 ewes compared with d-40 (10/27) or d-50 (12/24) ewes. In Exp. 2, ewes were assigned to two groups after receiving PMSG on d 30: 1) mated naturally or 2) inseminated during laparotomy near the uterotubal junction (UTJ). Dry and lactating ewes were divided evenly within each of the two treatments. Oviducts were flushed and ova were examined for cleavage. The conception rate was 60% in ewes that were inseminated in the UTJ vs 10% in ewes mated to rams (P less than .05). Lactational status had no effect on results. In conclusion, conception rates in postpartum ewes treated with MAP sponge and PMSG increased from postpartum d 30 to d 50 with natural breeding, and d-30 conception rates were increased over natural mating by insemination into the uterine horn near the UTJ.     

夏河县种羊场牦牛人工授精探讨

[目的]为综合利用牦牛资源,提高牦牛生产性能。[方法]2020年夏河县种羊场通过自然发情和同期发情方式对955头牦牛采用娟珊牛冻精进行人工授精。[结果]受胎470头,成活179头,受胎率为49.2%,繁殖成活率为38.1%。     

Effect of megestrol acetate and progesterone on oestrous and fertility in cyclic Malpura and Chokla ewes

In Rajasthan, India megastrol acetate and progesterone were administered to ewes (25 Chokla, 25 Malpura, aged between 3 and 4) in November 1968. Each ewe received 50 mg of either megastrol acetate or progesterone. Administration was intravaginal or intramuscular. During treatment only 3 ewes (2 megastrol acetate-injected and 1 progesterone-injected ewes) came into heat; thus, the progestogens exerted an inhibiting effect. 76% and 88% of the megastrol acetate and progesterone ewes, respectively, exhibited heat within 96 hours of therapy's end. Breed showed no significant effect on occurrence of estrus after therapy. Release of estrus within 96 hours occurred in 91.3% and 74.0% of intravaginally and intramuscularly treated ewes, respectively. 17 (41.5%) of the 41 ewes inseminated at their synchronized estrus lambed as a result of breeding in that first cycle. Thus, questions arise as to efficiency of ovulation, fertilization, nidation, and lambing in the case of synchronized estrus by use of different progestogens. 75% of ewes showing typical fern pattern at insemination lambed. An antiseptic vaginal douche applied after withdrawal of the sponge used in iv administration might be responsible for increased posttreatment fertility in this group.     

Fertility after artificial insemination using a soybean-based semen extender in sheep

The present study aimed to compare the fertility of ewes intrauterinally inseminated with frozen-thawed semen using a soybean-based semen extender (AndroMed) with those of ewes intrauterinally inseminated with frozen-thawed semen using a Tris-based extender containing either egg yolk or BSA. Suffolk ewes (n=104) were treated with an intravaginal sponge containing 40 mg fluoroprogesterone acetate (FGA) for 12 days and an intramuscular injection of 500 IU equine chorionic gonadotropin to induce estrus and ovulation during the non-breeding season (July, 2007). Intrauterine insemination was carried out 40-46 h after removal of the FGA sponge (n=90), regardless of the incidence of estrus. The pregnancy rates were not significantly different among the semen extenders containing egg yolk (64.5%) or BSA (58.6%) and AndroMed extender (56.7%). The lambing rates (64.5, 55.2 and 56.7% for the semen extenders containing egg yolk, BSA and AndroMed, respectively) and prolificacy (1.59 to 1.75) were also not significantly different. The present results indicate that an egg yolk-containing semen extender can be replaced with the non-animal derived extender AndroMed, which could be used for intrauterine insemination using frozen-thawed ram semen without reducing fertility.