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在种鹅蛋的孵化后期需要将鹅蛋放在摊床上出雏。在过去的生产中,鹅蛋在２５日龄就从孵化机转入摊床上孵化,采用的办法是用毯铺床,上面盖上３～４层毯及一床棉被,简称自温孵化,但是其孵化效果不很理想。为了提高鹅蛋孵化率,我场改用电热毯孵化,在２８日龄将鹅胚蛋从... 相似文献
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在种蛋优良、孵化条件掌握得当时,鸡蛋的孵化期为2l天,鸭蛋28天,鹅蛋32天。怎样用好电孵化机,提高孵化率呢?现简述如下: 1 孵化温度 是所有孵化条件中对孵化率和健雏率起决定性作用的因素。孵化的用温制度为2种:一是变温孵化,适用于整台孵化机上满相同胚胎种蛋的情况;二是恒温孵化,适用于在一台孵化机中分批上蛋,并采 相似文献
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(一)何谓摊床孵化 摊床孵化法是依靠胚蛋本身的代谢热而进行自温孵化的一种孵化方法,一般是使用孵化机,孵化到第2次照蛋以后即可进行摊床孵化,而原有的孵机(箱)又可入孵新蛋. 相似文献
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1 夏季孵化环境通风量的把握
观察孵化机恒温时间来调节孵化机通风量。当恒温时间过长时,说明机内胚胎代谢热过剩,机温接近或超过了设定温度,因而不再需要加热器工作。若孵化机没有设立降温系统,胚胎发育又处于中后期,就可能会导致“自温”超温。 相似文献
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孵化率的高低标志着一个鸡场孵化工作的好坏、ＳＰＦ鸡场也不例外。首先在种卵的选择上就有一定的要求，最好选种鸡产蛋率高时所产的蛋。此外在取蛋前先应补给公鸡和母鸡一定的维生素和矿物质、种蛋最好选３日之内．至多７日内．放置温度在１４℃左右、湿度在６０％～７０％。种蛋从外面转到孵化室前应进行熏蒸消毒。用甲醛及高锰酸钾熏蒸２０ｍｉｎ，每立方米容积用甲醛４０ｍｌ。高锰酸钾２０ｇ。入蛋以后应注意孵化机内温度、湿度、换气、翻卵的调整。１适宜温度及其调节入卵后前１８ｄ孵化机温度以３７．８－３８℃为宜。第１８ｄ以后可… 相似文献
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一正确校正孵化机温、湿度孵化机的温度、湿度是孵化过程中两大重要参数。孵化机操作人员掌握好孵化过程中温度、湿度是操作人员必备的技能。要控制好孵化过程中的温、湿度,首先要正确校正好孵化机内温度与湿度,使孵化机内温度计和湿度计的读数与测量显示的温度、湿度一致。1校 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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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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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
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 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