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随着人类生活水平的不断提高,对肉蛋奶的需求量不断增加,致使畜禽生产规模愈来愈大,现代化、集约化程度愈来愈高,饲养密度及饲养量急剧增加,告禽饲养及活体加工过稃中产生的大量排泄物和废弃物,对人类、其他生物以及畜禽自身生活环境的污染总是愈来愈突出。从环境保护的角度来看畜牧生产过程,不难看出,畜牧业已变成为一个不可忽视的污染源。 相似文献
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集约化畜牧生产对环境的污染与防治对策 总被引:2,自引:0,他引:2
随着人类生活水平的不断提高,对肉蛋奶的需求量不断增加,致使畜禽生产规模愈来愈大,现代化、集约化程度愈来愈高,饲养密度及饲养量急剧增加,畜禽饲养及活体加工过程中产生的大量排泄物和废弃物,对人类、其他生物以及畜禽自身生恬环境的污染也是愈来愈突出。从环境保护的角度来看畜牧生产过程,不难看出,畜牧业已变成为一个不可忽视的污染源。可以说,1头家畜就是一个污染源。一个畜禽养殖场就是一个环境污染物生产场。 相似文献
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随着人们生活水平的提高和对肉蛋奶需求量的不断增加 ,畜禽生产规模愈来愈大 ,现代化、集约化程度亦愈来愈高。在畜禽饲养密度及饲养量急剧增加的同时 ,饲养及活体加工过程中会产生大量的排泄物和废弃物 ,其对人类及畜禽自身生活环境所造成的污染问题日益突出 ,已引起人们的普遍关注。从畜牧业生产过程看 ,一头家畜就是一个污染源 ,一个畜禽养殖场就是一个环境污染物生产场。因此 ,畜牧业生产对环境的污染已成为一个不容忽视且亟待解决的问题。1 我国畜牧业环境污染及治理现状据国家环保总局 2 0 0 0年 1 1月对全国 2 3个省(市 )、自治区规… 相似文献
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在现代畜禽养殖业中,食品安全、药残、耐药性及环境污染等问题日益受到人们蕈视,已成为国际上研究的热点和亟需解决的难题.研究开发新的安全畜禽饲养用药模式,生产绿色畜禽产品,是畜牧业可持续发展的主题.中草药具有改善畜禽机体代谢、促进牛长发育、提高机体免疫及防治疾病等多方面的作用. 相似文献
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我国的动物饲养业正以超过世界平均水平的速度发展,集约化程度愈来愈高,饲养密度和饲养量急剧增加,畜禽饲养及活体加工过程中产生的大量排泄物和废弃物,对人类、其他生物以及畜禽自身生活环境的污染愈来愈突出。畜牧业已变成继工业污染之后不可忽视的污染源。 相似文献
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环境友好型社会下如何处理畜禽粪便? 总被引:1,自引:0,他引:1
近年来,随着中国规模化养殖业的发展,养殖业给环境带来的粪便污染问题日渐严重,防治畜禽养殖业污染已成为现阶段农村环境保护的重要课题。要实现畜牧业可持续发展,建设资源节约型、环境友好型社会,必须改善生态环境,无害化处理及资源化利用畜禽粪便,保持畜牧业生产和环境保护的协调。而在发达国家,对养殖业污染的防治管理已比较成熟。本文对国内外主要国家防治畜禽粪便污染的对策加以梳理,以期为中国的畜禽粪便处理提供有益的借鉴。 相似文献
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我国的动物饲养业正以超过世界平均水平的速度发展。集约化程度愈来愈高,饲养密度和饲养量急剧增加,畜禽饲养及活体加工过程中产生的大量排泄物和废弃物,对人类、其他生物以及畜禽自身生活环境的污染愈来愈突出。畜牧业已变成继工业污染之后的一个不可忽视的污染源。 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