怎样提高奶牛人工授精的受胎率

<正>一、提高种公牛精液的品质我们在奶牛配种实践中发现,活力强的精子在体外保存时间较长、运行速度较快,在母牛生殖道内的存活时间也显著延长,能促进受精、提高受胎率;而衰弱的精子在母牛生殖道内存活时间短或受精后胚胎发育不正常导致死亡,从而影响受胎率。精液品质除受遗传因素影响外,还与种公牛的饲养水平有关。因此,要重视种公牛配种准备期的饲养,日粮营养要合理搭配,尤其要注意蛋白质饲料和必需氨基酸的供给,这是提高精液品     

STR基因座在奶牛个体识别中的应用

通过分析2份冷冻精液样本和4头可疑种公牛血样的BM1862、BM2113、BM720和TGLA122 STR基因座遗传多样性,旨在判断该2份冷冻精液的种公牛来源,为建立奶牛个识别方法奠定基础。结果表明,应用STR基因座对个体进行识别,鉴别能力达0.9999。说明四个STR基因座可以用于冻精质量监测或奶牛个体识别和亲子鉴定。     

STR基因座进行奶牛个体识别的应用

通过分析2份冷冻精液样本和4头可疑种公牛血样的BM1862、BM2113、BM720和TGLA122 STR基因座遗传多样性，旨在判断该2份冷冻精液的种公牛来源，为建立奶牛个识别方法奠定基础。结果表明，应用STR基因座对个体进行识别，鉴别能力达0.9999。说明四个STR基因座可以用于冻精质量监测或奶牛个体识别和亲子鉴定。     

绵羊人工授精技术

<正>绵羊人工授精在当前仍然是较先进的繁殖技术之一,在绵羊的杂交改良、新品种育成等方面都发挥着重要作用。绵羊人工授精不仅可以提高优秀种公羊的利用率、加速品种改良步伐和育种工作进程,还能有效地防止疾病的传播。正确掌握发情鉴定、精液采集、精液处理、精液输入四步骤,是绵羊人工授精成功的关键。一、羊人工授精站的建设1.应选在母羊相对集中,有试情场地的非疫区建设羊人工授精站。中心站最好建在养羊大户、牧场或家庭     

奶牛性控冻精人工授精效果的研究

为研究奶牛性控冻精人工授精效果并合理制定人工授精方案,采用流式细胞仪制备性控冻精,对3 947头健康荷斯坦牛进行人工授精。结果表明:①性控冻精和常规冻精的受胎率、产犊率差异不显著(P0.05),但性控冻精的雌犊率和繁殖率分别达到92.01%和50.03%,对照组仅为51.13%和34.97%,差异极显著(P0.01)。②青年牛的情期受胎率达到55.25%,极显著高于经产牛(P0.01);青年牛的产犊率达到98.31%,显著高于经产牛(P0.05);青年牛的繁殖率为51.84%,经产牛为42.12%,存在极显著差异(P0.01)。③采用第1次人工授精后10~11 h重复授精1次,每次1支性控冻精的授精方案,其情期受胎率为55.17%,繁殖率达到55.81%,同其他方案相比,差异极显著(P0.01)。应用性控冻精进行人工授精可以显著提高母牛的繁殖效率。     

黄牛冷配改良技术的应用

七十六团现存栏牛11520头，其中能繁殖母牛5040头。占总数的43．8％。自2003年起，七十六团加大了对黄牛品种的改良工作，采取“以黄牛冷配改良、牛胚胎移植为主，良种公牛自交为辅”的技术方针，积檄培训冷配技术人员，调动牧工积极参加黄牛冷配改良。2003-2004年完成牛冷配I641头，总受胎率为87％．2个情期的受胎率保持在56％-57％。在2年时间内，七十六团黄牛冷配改良，取得较好的成绩。     

肉牛人工授精中输精时间的把握

提高肉牛人工授精受胎率的关键是把握母牛的最佳输精时间,做到这一点需要掌握母牛的发情与排卵规律,生产中可从以下几个方面入手: 1．根据外部表现确定输精时间。发情盛期过后,母牛神态由不安转为安静,发情表现即将结束,不接受公牛爬跨,外阴部肿胀开始消退。若在4小时内输精,受胎率较高。     

性别对秦川牛肉品质的影响

性别是影响生长发育和肉品品质的一个重要的因素。本研究选取发育正常、健康无病、年龄在3岁左右的秦川牛公牛3头、母牛3头、阉牛3头共9头牛进行屠宰试验,并在同一部位（背最长肌处）进行取样测定水分、粗灰分、粗脂肪、粗蛋白、肉色、蒸煮损失、失水率、嫩度和系水力9项指标。结果如下：秦川牛的性别对背最长肌处的水分,粗灰分和肉色的影响不显著（p﹥0.05）,而其余指标在不同性别之间则有显著或极显著的差异(P<0.05或P<0.01) 。其中母牛嫩度（2.15N）优于阉牛(3.41N),公牛最差(4.47N);母牛蒸煮损失（29.5％）大于公牛（28.08％）,阉牛最低（26.13％）;阉牛系水力大于母牛,公牛最差,失水率结果与之相反;公牛粗蛋白含量（25.86％）高于阉牛（23.02％）,母牛最低（21.90％）;粗脂肪含量结果与之相反。综合几个指标可以得出：秦川牛阉牛肉质优于母牛,公牛最差。     

肉羊人工授精技术要点

人工授精可以提高优秀种公羊的利用率,节约饲养大量种公羊的费用,并可防止疾病传播。肉羊养殖过程中采用人工授精技术要把握好试情、器械准备与消毒、采精、精液品质检查、精液处理等主要技术环节。一、试情母羊发情症状不明显,发情持续     

家蚕交配囊精液的活化与人工授精

采用姬姆萨染色及显微镜下直接观察家蚕交配囊中精液,并用交配囊精液进行人工授精,研究发现：交配20~30min雌蛾交配囊中精液与雄蛾储精囊中精液一样,精液未被活化,含有大量有核精子束。用不同浓度的胰蛋白酶处理精液后在显微镜下观察与人工授精的结果显示,0.2μg/ml的胰蛋白酶处理精液受精卵得率最高。用胰蛋白酶、血纤维蛋白溶酶、胃蛋白酶及琥珀酸钠处理精液,仅胰蛋白酶能够在很好的溶解有核精子束的同时提高无核精子的运动性,也只有胰蛋白酶处理的精液人工授精能够得到受精卵。研究还发现经2倍稀释的精液人工授精效果最佳。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.