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1纯繁体系纯种繁育为在本种群范围内,通过选种选配、品系繁育、改良培育条件等措施,提高种群性能的育种方式。我国在新疆建立了中国美利奴羊(军垦型)繁育体系。中国美利奴羊于1986年育成,繁育体系有27个农牧场参加,有40万只细毛羊,设中心育种场1 相似文献
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中国美利奴羊育种目标中性状边际效益的计算方法 总被引：7，自引：0，他引：7
借助差额法推导出一系列细毛羊育种目标中性状边际效益的计算公式。并根据调查与研究，给出中国美利奴羊（新疆军垦型）计算边际效益的有关生物学、育种学和经济学参数，计算出各育种目标性状的边际效益。根据新疆军垦型羊群３个品系的不同特点，分别考虑它们的目标性状以及各性状的选择重要性。经统计分析得知，Ｂ品系的毛用、肉用和繁殖性状的相对选择重要性之比为３∶１∶１，Ｃ品系近似于５∶２∶３，而Ａ品系的相对选择重要性则 相似文献
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在中国美利奴羊的一个品种内,以４个不同品系,采用双杂交的方法获取高产个体,利用高产个体培育新的品系,来推动品种性能的提高。１方法取体大的Ａ品系、毛质好的Ｂ品系各１只公羊作为父本,为了保证品系的纯度,２只公羊都是系祖的亲缘体,近交系数为０．３７。同时取... 相似文献
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文章对高山美利奴羊的培育技术路线进行简要介绍,并对高山美利奴羊个体育种目标、高山美利奴羊超细品系、无角品系个体育种目标、群体数量、育种方法、个体生产性能测定、等级鉴定、个体遗传评定、选种选配方案等进行阐述,以供参考。 相似文献
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南非肉用美利奴羊起源于闻名的德国肉用美利奴羊,1932年南非农业部为了育种项目引入了10只德肉美母羊和1只公羊,通过从毛质与形态上的选育,在1971年确认育成了独特的非洲品系,这一品种命名为南非肉用美利奴羊(SA Motton Merino).南非肉用美利奴羊是肉毛兼用型品种(综合育种指数加权系数,产肉∶产毛=60∶40),对南非养殖环境具有高度适应力.这一品种被发展成为生产兼有高质细毛的早期育肥羔羊专用品种.作为一个适应力较强的优良毛肉兼用型品种,它在我国的引入及应用将对我国肉羊产业的发展起到重要作用. 相似文献
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中国无角美利奴羊血红蛋白多态性研究 总被引：1，自引：0，他引：1
测定分析３４只中国无角美利奴育成公羊的血红蛋白多态性和生产性能结果表明：中国无角美利奴育成公羊血红蛋白基因型分为ＨｂＡ、ＨｂＢ、ＨｂＡＢ三型,受基因ＨｂＡ、ＨｂＢ控制;血红蛋白基因型为ＨｂＡＢ的羊剪毛后体重显著高于基因型为ＨｂＡ的羊,而与基因型为ＨｂＢ的羊差异不显著。 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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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
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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