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超数排卵的目的是通过对母畜进行外源激素处理,最大程度地获得可利用胚胎,进而在移植后获得较高的妊娠率。但是大量的商业化胚胎移植结果显示,不同母畜之间的超排反应、胚胎生产数量和质量有较大的变异性。超排反应这种变异性是限制胚胎移植计划在小反刍动物上应用的主要因素。没有反应的供体(排卵数少于5枚)(绵羊占20%,山羊占10%)对胚胎回收是没有价值的。通过对不同品种肉用绵羊超数排卵效果的分析,研究不同品种绵羊之间的超排反应、胚胎生产数量和质量的变异性,以便了解在绵羊胚胎移植商业化运作中各品种的超排反应特点,合理预测其成本和… 相似文献
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胚胎移植技术(Embryo Transfer)已进入商业化阶段,超数排卵(Multiple Ovulation)是胚胎移植的—个关键技术环节。利用外源激素对母畜进行超排,可增加排卵数,获得较多的胚胎。可大大提高优良母畜的繁殖效率。虽然超排技术已得到广泛应用,但不同的奶牛品种、不同的药物、不同的季节、不同的处理方案、不同的营养和饲养管理、不同的个体都是影响超排效果的因素。试验在河南科迪集团生物工程股份有限公司进行,分析影响超数排卵效果的主要因素,以求得较好的处理方案。现报道如下。 相似文献
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由于胚胎移植技术难度大、受胎率低、移植成本高,因此,在国内的产业化进程相对缓慢。我们对不同产地的FSH、不同年龄的奶牛进行了超排和移植效果的对比试验,以求获得最低成本、最佳效果的胚胎移植成果。 相似文献
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超排是极为复杂的过程,从发现超排几十年来,人们对超排方法的选用还没有十分把握,效果不够稳定,特别是个体之间差异很大。通常在超排情况下,由于人为提供的外源激素的参与,生殖内分泌轴(下丘脑-垂体-性腺轴)的活动,特别是卵巢本身经历着异常的刺激都对超排效果产生极大的影响。所以不同品种,特别是不同个体反应的差异较大,效果不够稳定,迄今为止,超排程序的改进仍是胚胎移植中亟待解决的问题。归纳起来影响超数排卵效果的主要因素主要有家畜个体情况、超排处理方式、环境条件等。 相似文献
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影响绵、山羊超排效果的主要因素 总被引:1,自引:0,他引:1
绵、山羊的胚胎移植技术目前在部分养羊省区的养羊生产中得到广泛应用,对于加快良种繁殖、育种进展、提高优良种羊利用率等方面取得了较好的效果,超数排卵是胚胎移植生产中的重要一环,超排效果的好坏直接关系到胚胎移植生产的成败。一般认为,激素处理后,反应较差的个体,即排卵数小于5,对于超排是没有意义的,在绵羊中约占10%~20%,山羊占10%左右,这似乎与季节、遗传、营养及个体间反应差异有关(Brebion et al,1989)。除此之外超排效果还受品种、年龄、超排季节、饲养管理、激素的种类、剂量、效价、生产公司及生产批次、处理方案、操作人员及… 相似文献
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使用促性腺激素对牛进行超数排卵处理时产生的不同效果,是超数排卵(简称超排)反应出现个体差异性的主要原因之一。文章就牛胚胎移植研究和生产应用中使用不同的促性腺激素及其使用方法的研究进行综述,以提供简化有效的使用激素超排的方法,为牛的超排和胚胎移植提供有价值的参考。 相似文献
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影响萨福克羊超排效果的因素较多,主要包括供体、激素及其它一些影响供体生理状态的因素。本试验以萨福克羊为研究对象、超排方法的选择,卵巢处于不同生理状态时期的超排、促排激素、超排季节、供体年龄、重复超排、饲养管理等因素对供体超排效果的影响情况进行了研究,结果表明:通过同一季节利用不同方案对萨福克羊的超数排卵处理发现,以国产FSH6~7mg和加拿大FSH250mg进行4d递减处理的排卵数和可用胚率最高,是超数排卵处理的最佳方案。由于进口激素价格高,故推荐使用国产FSH6~7mg进行4d递减处理方案进行萨福克羊超数排卵。在供体发情周期第10~14天中任何一天开始超排都能取得较好的超排效果,可用胚胎平均数为7.1(6.1~8.2)。供体发情配种时用LH/HCG促排激素比LHRH-A3更能使更多的卵泡排卵,但末受精的数量也相应增加,综合考虑,萨福克羊发情配种时用LHRH-A3促排激素的效果最佳。超排季节对供体超排效果没有显著影响(P>0.05)。供体羊的年龄对超数排卵效果没有显著的影响,对性成熟不久的供体羊初次诱导排卵时适当降低FSH剂量,可取得与成年经产母羊一样的较好的超排效果。供体羊重复超排处理时,平均排卵率无显著差异(P>0.05),但采集可用胚胎数量有显著差异(P<0.01)。补饲养条件下的绵羊供体羊平均采集可用胚胎数量显著高于不补饲供体羊可用胚胎数量(P<0.01)。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献