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氨气是一种刺激性很强的气体,能强烈地刺激鸡呼吸道黏膜和眼角膜。它主要来源于鸡排泄的粪便及鸡舍地面上潮湿垫料之中,当鸡粪在舍内长时间不清理,垫料严重潮湿,长时问不开窗通风换气,无排风设施等均可造成舍内氨气蓄积,使氨气浓度增大。氨气危害常发生在寒冷季节,尤其是育雏阶段,养鸡户往往偏重于对育雏舍的温度、湿度的要求,而忽视舍内有害气体含量对雏鸡的危害,特别是舍内温度达不到要求标准。 相似文献
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鸡舍内氨气的控制措施 总被引:2,自引:0,他引:2
氨气是一种刺激性很强的气体,能强烈地刺激鸡呼吸道粘膜和眼角膜。它主要来源于鸡排泄的粪便及鸡舍地面上潮湿垫料之中,当鸡粪在舍内长时间不清理,垫料严重潮湿,长时间不开窗通风换气,无排风设施等均可造成舍内氨气蓄积,使氨气浓度增大。氨气危害常发生在寒冷季节,尤其是育雏阶段,养鸡户往往偏重于对育雏舍的温度、湿度的要求,而忽视舍内有害气体含量对雏鸡的危害, 相似文献
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氨气是一种刺激性很强的气体,能强烈地刺激鸡呼吸道黏膜和眼角膜.它主要来源于鸡排泄的粪便及鸡舍地面上潮湿垫料之中,当鸡粪在舍内长时间不清理,垫料严重潮湿,长时间不开窗通风换气,无排风设施等均可造成舍内氨气蓄积,使氨气浓度增大. 相似文献
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鸡舍垫料的选择,不仅需要考虑垫料的吸水性,以保持鸡舍地面干燥,同时还要考虑垫料的来源和成本。一般来说,冬天鸡舍内垫料的湿度应在40%左右,夏天垫料湿度应在20%左右。如果湿度太大,则鸡羽毛不洁,胸部出现水泡,雏鸡易得球虫和各种传染病,舍内氨气升高,给生产带来困难。一般地,北方常用刨花,锯末作育雏垫料,南 相似文献
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鸡舍内经常有硫化氢、氨气、一氧化碳等有害气体存在,特别是氨气对鸡的生长发育危害最大,引起使鸡生长缓慢、鸡群发育不良、产蛋率下降等综合症。因此必须控制有害气体的发生。消毒并控制鸡舍的湿度:采取通风、铺撒生石灰、吸收鸡舍内的水分等方法,保持舍内干躁。配比合理日粮:日粮中添加木炭渣,或添加2%~5%沸石粉,提高饲料利用率和产蛋率。定时清粪和垫料:每天清粪1次防止球虫病的发生。控制有害气体:在垫料中混入硫磺每10平方米混入2.5千克硫磺),减少氨的产生。每周用硫酸亚铁7份、干煤灰3份混匀,按鸡群重量10%撒入鸡舍,清除氨气和硫化氢… 相似文献
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在寒冷季节 ,必须为鸡群保证适宜的最小通风量 ,提供高质量的空气 ,并从鸡舍内排除过量的氨气、二氧化碳和湿气。尽管温度和通风这对矛盾在冬季显得更加突出 ,但应该明确的是 ,保证最小通风量是解决这对矛盾的前提。无论舍内环境温度有多低 ,湿度有多大 ,都必须保证鸡舍最小的通风量。最小通风量的大小决定于以下因素 :鸡群只数和体重、鸡舍湿度、舍内氨气含量、粉尘。尽量减少通风量无疑可以减少舍内热量的损失 ,由此减少燃料消耗而降低饲养成本。但减少通风量必须以减少舍内氨气含量和舍内湿度为前提 (由于冬季舍内湿度较大 ,粉尘不是主要… 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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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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Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献