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试验旨在研究日粮阴阳离子平衡对不同泌乳期热应激奶牛生产性能的影响,选取64头试验奶牛分为8组,每组8头牛,日粮阴阳离子平衡(DCAB)分别为泌乳前期:A1组(DCAB为185 mEq/kg干物质(DM))、B1组(DCAB为243 mEq/kgDM)、C1组(DCAB为317 mEq/kgDM)和D1组(DCAB为442 mEq/kgDM);泌乳中后期:A2组(DCAB为83 mEq/kgDM)、B2组(DCAB为172 mEq/kgDM)、C2组(DCAB为217 mEq/kgDM)和D2组(DCAB为357 mEq/kgDM)。研究结果表明:在一定范围内增加日粮DCAB,能提高泌乳前期奶牛的产奶量,各组间差异不显著,B1组奶牛产奶量较高,乳蛋白和乳密度显著高于其他组;日粮高DCAB水平能显著增加泌乳中后期热应激奶牛的产奶量,乳蛋白含量随DCAB增加呈二次变化,差异显著,乳脂肪随DCAB的增加而增加,D2组显著高于其他试验组,差异显著,综合产奶量和乳成分分析,泌乳前期日粮DCAB为243 mEq/kgDM,泌乳中后期调节日粮DCAB为217 mEq/kgDM时能提高奶牛的产奶性能,利于奶牛机体健康和生产高质量牛奶。 相似文献
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为研究日粮阴阳离子平衡(DCAB)对泌乳期热应激奶牛生产性能的影响,选取试验奶牛64头,分为8组,每组8头,日粮DCAB分别为泌乳前期:A1组(DCAB为185 mEq/kgDM)、B1组(DCAB为243mEq/kgDM)、C1组(DCAB为317mEq/kgDM)、D1组(DCAB为442mEq/kgDM);泌乳中后期:A2组(DCAB为83mEq/kgDM)、B2组(DCAB为172mEq/kgDM)、C2组(DCAB为217 mEq/kgDM)、D2组(DCAB为357 mEq/kgDM)。结果表明:在一定范围内增加日粮DCAB,能提高泌乳前期奶牛的产奶量,各组间差异不显著(P>0.05),B1组奶牛产奶量较高,乳蛋白、乳密度显著高于其他组(P<0.05);日粮高DCAB水平能显著增加泌乳中后期热应激奶牛的产奶量(P<0.05),乳蛋白含量随DCAB增加呈二次变化,差异显著(P<0.05),乳脂肪随DCAB的增加而增加,D2组显著高于其他试验组(P<0.05)。综合产奶量和乳成分分析,泌乳前期日粮DCAB为243 mEq/kgDM、泌乳中后期日粮DCAB为217 mEq/kgDM时能提高奶牛的产奶性能,利于奶牛机体健康和生产高质量牛奶。 相似文献
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日粮阴阳离子对泌乳前期热应激奶牛生产性能的影响 总被引：16，自引：1，他引：15
试验选择泌乳前期奶牛15头,随机分成3组,每组5头,采用3×3重复拉丁方设计,分别饲喂3种不同DCAB水平的日粮。其中对照组A(基础日粮,DCAB为83meq/kgDM),B组(DCAB为275meq/kgDM),C组(DCAB为425meq/kgDM)。结果表明,DCAB对热应激奶牛的生产性能具有显著影响,其中B组和C组的产奶量及4%标准乳产量分别比对照组提高10%(P<0.05)和10.1%(P<0.05),3.9%(P>0.05)和3%(P>0.05),但DCAB对奶牛的乳脂率和乳蛋白率无显著影响。说明在泌乳前期当DCAB为275meq/kgDM,饲喂效果最佳。 相似文献
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试验旨在研究日粮阴阳离子平衡对泌乳中后期热应激奶牛血液生化指标的影响,选取试验奶牛32头分为4组,每组8头,日粮DCAB分别为对照组83 mEq/kgDM、试验Ⅰ组172 mEq/kgDM、试验Ⅱ组217 mEq/kgDM、试验Ⅲ组357 mEq/kgDM.研究结果表明:DCAB增加可在一定程度上提高奶牛血液的缓冲能力,缓解奶牛热应激,随DCAB增加,血液的pH值及HCO3-浓度升高,CO2分压下降,差异均不显著(P>0.05);高的DCAB能增加血液Na+、K+浓度,K+显著增加,Cl-显著下降(P<0.05);高水平的DCAB日粮,能使泌乳中后期血液ALP含量增加, CK、ALT含量减少,差异不显著(P>0.05).综合DCAB对血液缓冲能力、血液生化指标等方面考虑,在泌乳中后期DCAB为217 mEq/kgDM时饲喂效果较好. 相似文献
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热应激条件下日粮阴阳离子平衡对奶牛生产性能的影响 总被引：3，自引：2，他引：1
本试验在北京安定棚沨奶牛养殖场选取75头健康的泌乳中期（104.8±12 DIM）中国荷斯坦奶牛,根据胎次（2.0±0.2）、产奶量（26.52±0.33 kg）、体重相近的原则随机分为5组,分别以添加不同水平的阴阳离子平衡盐来调整日粮DCAB值,试验共设5个处理,分别为试验Ⅰ、Ⅱ、Ⅲ、Ⅳ组和对照组,分别饲喂DCAB值为195.76、186.68、177.77、166.94、239.12 m Eq/kg DM的日粮。试验期为67 d,其中预试期7 d,正式试验期60 d。试验通过改变日粮DCAB值来研究在热应激条件下,不同DCAB值对奶牛生产性能的影响。试验结果表明,在热应激条件下,饲喂不同DCAB日粮对奶牛生产性能及乳品质产生了一定的影响,与对照组相比,试验Ⅰ、Ⅱ组产奶量分别提高了1.6%和0.8%,然而试验Ⅲ、Ⅳ组的产奶量分别下降了2.2%和1.7%,但各试验组之间差异不显著（P>0.05）;通过改变日粮DCAB值对乳脂率、乳蛋白率、乳糖、总固形物及体细胞无显著影响。对牛奶中硝酸盐和亚硝酸盐浓度的影响差异不显著(P>0.05)。 相似文献
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DCAB对荷斯坦奶牛泌乳性能、血液酸碱平衡及血清矿物质含量的影响 总被引：8，自引：0，他引：8
试验选用荷斯坦泌乳早期奶牛15头,采用3X3复拉丁方试验设计,研究日粮DCAB水平分别为+367、+514、+663mmol/kgDM对奶牛生产性能、血液酸碱平衡和血清矿物质含量的影响。试验结果,不同DCAB水平日粮对奶牛奶产量差异不显著(P>0.05),高DCAB水平日粮可增加奶牛血液标准HCO-3含量(P<0.05),不同DCAB水平对奶牛各种血清常量矿物质含量没有影响(P>0.05)。试验表明,日粮DCAB水平超过+514mmol/kgDM可对奶牛奶产量产生不利影响。 相似文献
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日粮阴阳离子平衡(Dietary Cation Anion Balance,DCAB)已成为奶牛营养学研究的一个新方向,它直接影响到奶牛业的生产和经济效益。文中综述了热应激奶牛生产性能、繁殖性能和免疫机能等方面的变化以及DCAB对热应激奶牛的生产性能、机体酸碱平衡和奶牛健康的影响。 相似文献
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日粮阴阳离子平衡（DCAB）已成为奶牛营养学研究的一个新方向，它直接影响到奶牛业生产和经济效益。本文介绍了DCAB的概念和计算方法；DCAB对奶牛干物质采食量、饲料利用率、产奶性能、热应激及奶牛健康的影响；DCAB在奶牛日粮配合中的应用。 相似文献
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日粮阴阳离子平衡对高温环境中奶牛生产性能和血液指标的影响 总被引：9，自引：0，他引：9
选择泌乳前期奶牛15头,随机分成3组,每组5头,采用3×3重复拉丁方设计,分别饲喂3种不同日粮阴阳离子平衡(DCAB)的日粮,其中对照组A(DCAB为83meq/kgDM),B组(DCAB为275meq/kgDM),C组(DCAB为425meq/kgDM),研究DCAB对高温环境中奶牛生产性能和血清生化特性的影响。结果表明:(1)DCAB显著影响泌乳奶牛的血气指标,与对照组相比B组和C组血清的pH值显著增加(P<0.05)。血液中的HCO3-浓度和CO2总量)随着DCAB的增加而显著降低(P<0.05)。血液中的)随着DCAB的增加而显著增加。血液中的CO2分压(PCO2(TCO2)随着DCAB的增加而增加(P<0.05)。(2)血清中雌激素(E2)的浓度随着DCAB的)和O2饱和度(SATO2O2分压(PO2增加而显著增加。血清中的肌酸磷酸激酶(CK)随着DCAB的增加而降低,与对照组相比B组和C组奶牛血清中的CK分别降低了29.1%(P<0.01)和25.2%(P<0.01)。血清中的碱性磷酸酶(ALP)和谷丙转氨酶(GTP)受DCAB影响不显著。(3)DCAB对热应激奶牛的生产性能具有显著影响。275meq/kgDM组的产奶量及4%标准乳产量分别比对照组提高10%(P<0.05)和10.1%(P<0.05)。DCAB对奶牛的乳脂率和乳蛋白率无显著影响。从对血液缓冲能力、激素和酶水平及生产性能等方面考虑,在泌乳前期当DCAB为275meq/kgDM时饲喂效果最佳。 相似文献
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日粮阴阳离子平衡对泌乳中后期奶牛生产性能的影响 总被引：2，自引：1，他引：2
试验选择泌乳中后期奶牛15头,随机分成3组,每组5头,采用3×3重复拉丁方设计,分别饲喂3种不同阴阳离子平衡水平的日粮。其中对照组A(DCAB为DM 77 m eq/kg),B组(DCAB为DM 175 m eq/kg),C组(DCAB为DM 325 m eq/kg)。结果表明,DCAB对热应激奶牛的生产性能具有显著影响,其中B组和C组的产奶量分别比对照组提高6.6%(P>0.05)和0.1%(P>0.05);而4%标准乳产量则分别提高8.3%(P<0.05)和0。DCAB对奶牛的乳脂率和乳蛋白率无显著影响。说明在泌乳中后期当DCAB为175 m eq/kgDM,饲喂效果最佳。 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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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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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