共查询到20条相似文献，搜索用时 62 毫秒
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《中国畜牧兽医文摘》2016,(4)
我国蛋种鸡本交笼养模式经历了近30年的曲折发展,在当今畜牧业福利化和机械化的大趋势下得到了新的活力。本文从设备、工艺以及经济效益等方面分析了本交笼养相对于一般蛋种鸡笼养的优势,为蛋种鸡养殖户提供了借鉴;同时分析了本交笼养模式中限制生产效率和福利水平的因素,为公母小群混养的蛋种鸡笼养模式的支撑技术指出了研究方向,如鸡笼外形尺寸的优化、笼养蛋种鸡行为学研究、公母种鸡配置、特殊的配套设备等。 相似文献
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关注欧盟蛋鸡福利计划 总被引：1，自引：0，他引：1
蛋鸡饲养环境一直是动物福利所关心的一个重大问题.目前蛋鸡的饲养方式是动物生产最集中的形式之一.而公众的广泛争论也催生了能给动物提供更舒适环境的饲养体系以取代传统的笼养方式.欧盟关于禁止蛋鸡笼养的1999/74/EC号指令促进了当前笼养系统的技术革新,不但改良了传统的鸡笼,而且还发展了笼养的替代方式.对饲养在这些新的笼养系统中蛋鸡尤其是商业化生产的鸡场,很有必要就其实际福利状况进行评估.…… 相似文献
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1选用标准的鸡笼 肉种鸡的体型、体重均大于蛋用型种鸡，它对笼具的要求条件也较高一些。有的场家使用蛋鸡笼饲养肉种鸡或由于肉种鸡笼的造价较高，为节约成本而使鸡笼的规格达不到标准，这将限制肉种鸡遗传潜力的发挥，进而影响它的健康和生产性能。 相似文献
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<正>1选用标准的鸡笼肉种鸡的体型、体重均大于蛋用型种鸡,它对笼具的要求条件也较高一些。有的禽场使用蛋鸡笼饲养肉种鸡,有的为节约成本而使用规格达不到标准的鸡笼,这将限制肉种鸡遗传潜力的发挥,进而影响其健康和生产性能。 相似文献
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肉种鸡的体型、体重均大与蛋用型种鸡，它对笼具的要求条件也较高一些。有的场家使用蛋鸡笼饲养肉种鸡或由于肉种鸡笼的造价较高，为节约成本而使鸡笼的规格达不到标准，这将限制肉种鸡遗传潜力的发挥，进而影响它的健康和生产性能。 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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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