共查询到20条相似文献，搜索用时 78 毫秒
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粗饲料质量已经成为制约我国奶牛养殖业快速发展的重要因素。本文分别从青贮收割时期，加工长度，霉菌污染和瘤胃微生物活性等方面，分析了影响粗饲料消化率的几个主要原因。研究发现，要提高粗饲料的消化率，一方面要提供给奶牛质量好，加工完全，无霉菌污染的粗料；另一方面要注意增强瘤胃微生物的活性，微生物活性将直接决定粗饲料的利用效率. 相似文献
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瘤胃素在反刍动物生产中的应用 总被引：5，自引：2，他引：3
瘤胃素又称莫能霉素或莫能菌素（monensin），是由链霉菌（Streptomycescinnamonesis）产生的一种聚醚类抗生素。瘤胃素能够调节瘤胃微生物区系，减少革兰氏阳性菌（Russell等，１９８８）和原虫（易建民等，１９９８）数量，抑制乳酸产生菌、氨产生菌和产气菌活性，提高乳酸利用菌活性（Dennis等，１９８１；Callaway等，１９９６；王中华等，１９９９）。饲料中添加瘤胃素可提高饲料转化率和养分吸收率。１９４５年美国正式将瘤胃素列为肉牛饲料添加剂，现已广泛用于肉牛生产中。瘤胃素在奶牛上的研究起步比较晚，试验表明，瘤胃素可提… 相似文献
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莫能霉素在反刍动物中的应用 总被引：6，自引：1，他引：5
莫能霉素是一种聚醚类抗生素，学名为莫能霉素钠(monensin sondium)，在饲料应用时又称为瘤胃素，是离子载体中最具代表性的一种。它在以下几方面对反当动物起作用：①抑制瘤胃革兰氏阳性菌的生长；⑧增加瘤胃丙酸产量和比例；⑨减少甲烷产生；④抑制乳酸的产生，提高瘤胃pH；⑥降低饲料蛋白在瘤胃的降解；⑧减少氨的产生，增加血中葡萄糖的含量。莫能霉素已在国外肉牛业和禽业中广泛应用，也作为治疗性药物用于防治奶牛酮病，是一种很有发展前景的饲料添加剂。 相似文献
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浅谈影响瘤胃纤维降解的主要因素及其调控技术 总被引：2，自引：0，他引：2
提高反刍动物瘤胃的纤维降解率是增加粗饲料利用的有效途径。本文综合分析了国内外相关研究后认为；针对影响瘤胃纤维降解的主要因素，瘤胃调控手段可从瘤胃环境的物理、营养、瘤胃徽生物系统等方面进行。 相似文献
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实验以瘤胃内分别灌注３０、６０、１００ｍｌ乳酸，模拟绵羊过食谷物时瘤胃内乳酸增高的状况；以瘤胃平滑肌电为指标对瘤胃运动进行监测，研究了病理量的乳酸对绵羊瘤胃的毒性作用及其机理。结果表明：小剂量的乳酸主要通过神经反性地抑制瘤胃的收缩频率和收缩强度；大剂量的乳酸除通过神经作用外，还可直接抑制瘤胃的兴奋性和收缩传导速度；严重乳酸中毒时，通过兴奋神经很难恢复瘤胃运动。 相似文献
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稀土对阿尔巴斯白绒山羊瘤胃发酵,消化代谢及其生产性能的影响 总被引：5，自引：0，他引：5
实验１用４只安装永久性瘤胃漏管的阿尔巴斯白绒山羊（母），进行瘤胃消化代谢试验；实验２用６只成年母绒山羊进行消化代谢试验；试验３选用同品种成年妊娠母羊进行放牧补饲实验。实验１得出，稀土的使用可促进瘤胃内ＮＨ３－Ｎ的利用；细菌数比对照组提高３５．６７％；丙酸产量提高２８．６３％。实验２得出，稀土可提高绒山羊日粮ＤＭ、ＯＭ、ＧＥ及ＡＤＦ消化率，分别为１１．５８％、１２．２７％、１６．６９％和２６．２９％；每日氮存留率比对照组提高１８０．１％。实验３得出，稀土组产绒量比对照组提高８．９０％。 相似文献
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间接法评定绵羊瘤胃丙酸产生、吸收和流通规律研究 总被引：3，自引：1，他引：2
利用非同位素标记丙酸的启动－连续灌注的方法，采用非标记酸灌注条件下计算丙酸基本产生量的原理，研究了绵羊瘤胃碳水化合物产生丙酸的基本速率和通过灌注提高丙酸产生速率后，丙酸在瘤胃的消失率，离开瘤胃的流通速率；丙酸在瓣胃和真胃及小肠的吸收及其它有关液相指标的影响。研究表明：当试验绵羊饲喂粗精比为54：46的日粮并满足维持饲养水平时，测得的丙酸基本产生速率为22．4mmol/h，瘤胃丙酸库容量为51.94mmol,仅占丙酸日产量的9．6％，还确定了瘤胃灌注丙酸后获得稳态的条件是：瘤胃液相pH的变异系数CV＜0．5％，丙酸浓度的变异系数＜6％，标记物Co浓度的变异系数＜5％；丙酸在瘤胃的吸收速率与其在瘤胃的产生速率成正比（P＜0．01），当丙酸的产生速率从37．14提高至145.07mmol/h时，瘤胃吸收的丙酸占丙酸产生量的2／3以上，而随液体离开瘤胃的丙酸不足丙酸产生量的1／3。进一步的研究证实，离开瘤胃的丙酸在瓣胃和真胃有96％以上被吸收，有3％－4％进入十二指肠；同时还获得了一系列通过瘤胃丙酸产生速率（PROD丙酸，mmol/h）预测其它液相特性指标的关系方程。 相似文献
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脲酶抑制剂可抑制反刍动物瘤胃微生物脲酶活性,调节瘤胃微生物代谢,降低瘤胃内氨的释放速度,提高微生物蛋白质合成量和粗纤维消化率等,从而起到提高奶山羊产乳量,增强奶羊体质, 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