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在饲料生产过程中 ,常需对谷物饲料及其他饲料原料进行粉碎加工 ,主要目的是增加饲料在胃肠道中与消化液接触的表面积 ,使饲料更容易被消化。但是 ,如果饲料粒度过细则会产生相反作用 ,主要表现在两个方面 :一是由于饲料加工机械磨损加快 ,使生产成本提高 ;二是容易引起猪的胃病 ,影响生产性能。因此 ,合理地选择饲料的粉碎粒度 ,使之既经济又有利于家畜的健康。美国堪萨斯州的专家研究了不同饲料粉碎粒度对母猪生产性能的影响。试验选用了玉米—豆饼型日粮 ,玉米的粉碎粒度分别为 12 0 0、90 0、6 0 0、4 0 0 μm4个规格。试验时把 10 0头… 相似文献
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加工工艺对饲料营养价值与畜禽生产性能的影响 总被引:5,自引:1,他引:5
1 饲料粉碎粒度与均匀度11 粉碎粒度 Cabrera等(1994)报道,玉米粉碎粒度对蛋鸡生产性能无影响,将高粱粉碎粒度从1000μm减至400μm时,产蛋率、蛋重及饲料转化率均有所提高;减少玉米、高粱的粉碎粒度不能改善4~14日龄与7~28日龄肉仔鸡的生产性能。Healy等(1994)报道,对于玉米、硬胚乳高粱与软胚乳高粱,使7日龄肉仔鸡0~7d增重达最高与饲料转化率达最佳的粒径分别为700、500与300μm;Healy等(1994)认为,如果对高粱进行合理加工,其对肉仔鸡的营养价值与玉米相似。堪萨斯州立大学人员发现,将饲料粒度从1000μm降到50… 相似文献
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Keith C.Behnke Robert Goodband Joe D.Hancock 《饲料与养殖》2006,(2):18-20
谷物是多数家畜日粮的主要能量来源。谷物生产者不仅要关注谷物成分,而且还应关心如何加工谷物使其养分能被家畜充分利用。饲料费用占畜产品生产总成本的65%-75%,因此提高原料利用率对控制生产成本具有重大影响。差不多所有饲料原料都要进行某种方式的饲料粉碎(原文:particle size reduction,直译即降低粒度-译注)。粉碎可以加大谷物的表面积,从而可与消化酶系和化学物更好地发生反应,并使饲料处理、搅拌混合及进一步加工更加容易进行。不过,精细粉碎会增加饲料加工的能量费用,还可能导致家畜消化道溃疡、饲料结拱和粉尘问题。因此,精细粉碎所增加的费用必须由提高饲料转化率抵销,才有所值。 相似文献
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通常来说,在猪或家禽的生产中,饲料占总生产成本的65%~75%。因此提高饲料的利用率将对生产成本有极大影响。几乎所有的饲料原料都要受到某种形式的微粒尺寸来加工。粒度减小增加了表面积,促进了饲粮与消化酶的消化作用,对搬运和混合也提供了方便。但细粉碎会增加饲料的加工成本,还可能导致结拱现象和粉尘污染,以及引发猪胃溃疡和角质化等一系列问题。因此,细粉碎增加的成本应由饲料转化率的提高来补偿。现在关于猪饲料的最佳粒度的测量基础是以微米测量的微粒几何平均直径和几何平均标准差来评定的。这些测定结果能为优化猪生… 相似文献
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《河南畜牧兽医(综合版)》2000,(7)
K.J.Wondra等人选用哺乳猪(二产)38头 ,饲喂以豆粕和玉米为主组成的饲料 ,饲料中玉米粉碎粒度(大小)分为1200、900、600和400μm四种规格 ,研究玉米粒度对营养素代谢的影响。试验结果表明 ,玉米粉碎粒度对体重和背脂肪厚度均没有明显的影响。但是 ,玉米400μm粒度与1200μm粒度相比 ,前者的干物质(DM)和氮(N)的表观消化率比后者分别提高7 %和10 % ,粪中DM和氮的排泄量分别减少35%和45 % ,还有 ,前者提高了饲料可消化能(DE)和代谢能(ME)量 ,即玉米粒度为400μm时 ,ME… 相似文献
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饲料原料的粉碎是饲料加工中非常重要的一个环节,通过粉碎可增大单位质量原料颗粒的总表面积,增加饲料养分在动物消化液中的溶解度,提高动物的消化率;而且,粉碎原料粒度的大小对后续工序(如制粒等)的难易程度和成品质量都有着非常重要的影响;另外,粉碎粒度的大小直接影响着生产成本,在生产粉状配合 相似文献
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1饲料粉碎粒度控制
粉碎粒度的大小直接影响动物的消化吸收和饲料后续加工工序及产品质量。控制好物料的粉碎粒度是饲料生产的关键环节。合适的粉碎粒度对饲料营养价值和其他品质的贡献主要表现在增加动物肠道消化酶或微生物作用的机会,提高饲料的消化利用率, 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