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以安徽省合肥市某蛋鸡养殖场有窗封闭式鸡舍为对象,对其外围护结构的冬季总热阻、夏季总热阻、总衰减度和总延迟时间等指标进行了测算,并对该鸡舍夏季和冬季舍内空气环境质量进行了测定,评价其保温隔热性能.结果表明,在安徽省合肥市及其气候相似地区,鸡舍外围护结构墙体和屋顶的冬季低限热阻分别为0.736 m2·K/W和1.226 m2·K/W,夏季低限热阻分别为0.182 m2·K/W和0.838 m2·K/W.采用24 cm厚度墙和彩钢瓦屋顶的封闭有窗式鸡舍的冬季保温性能不能达到产蛋鸡的要求,而夏季外围护结构的墙体隔热性能基本可以满足产蛋鸡的需要,屋顶结构达不到隔热要求.夏季和冬季的舍内温度分别为30.06℃和10.85℃,相对湿度超过80％,超过产蛋鸡的适合温度区间,也反映了围护结构不能满足保温隔热的需要.因此,提高外围护结构热阻和减少窗户面积有助于提高有窗封闭式鸡舍保温隔热效果. 相似文献
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三、屋顶隔热除了舍温对鸡的直接影响外,屋面隔热性能是影响蛋鸡生产的另一个重要因素。尤其是夏季,两栋舍内气温看来相近的鸡舍。屋顶隔热不良的,在强烈日晒下,内表面温度较高,将直接以较高的辐射能传给鸡体,1 相似文献
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蛋鸡产蛋的最适宜温度是13～25℃,而在北方夏季的高温季节里,鸡舍内的气温往往超过25℃,甚至可高达35℃。在高温环境下,易造成体温散发受阻、食欲减退、产蛋量下降、蛋重减轻、蛋壳变薄,重则还可导致中暑甚至死亡,因此,夏季主要应做好防暑降温工作,尤其是在开放式鸡舍里笼养的蛋鸡,因其被“困”在笼内,不能选择环境,更应注意防止高温的影响。生产实践中,应采取以下措施: (一)鸡舍建筑要合理 1.鸡舍不能太矮。顶笼距顶棚最少1.5米,尽可能座北向南,多设窗户。 2.屋顶设置隔热层,达到冬季能保温、夏季能隔热的要求,以减少鸡舍内的辐射热… 相似文献
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河北省蛋鸡舍建筑类型及配套设施调查 总被引：1，自引：1，他引：0
为了详细掌握我国北方蛋鸡生产和环境控制的现状及具体参数,本研究团队对河北省养殖密集地区的鸡舍类型及基本结构情况,蛋鸡生产配套设施基本情况进行了详细的调查,结果显示,鸡舍外围结构以花墙式为主,占72%;鸡舍屋顶结构类型以平屋顶为主,占77%;鸡舍材料以砖混结构为主,占53%。通风方式以自然通风利用率最高,清粪方式以人工清粪为主。说明样本调查区的分户散养模式下的鸡舍存在建筑及设施简陋,生物安全没有保障,不利于环境控制和疫病防治等特点。为实现蛋鸡产业升级,有必要对现有鸡舍进行改造。 相似文献
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曹云芳 《畜牧兽医科技信息》2018,(5)
半开放式蛋鸡舍具有外围护结构的保温隔热性能差,寒冷季节舍内换气困难,不能有效实施机械通风等缺陷,针对这类鸡舍的设计缺陷,本文中对鸡舍外围护结构、通风换气系统进行了有针对性的改进,进一步提高了鸡舍的保温隔热性能和不同季节鸡舍的通风换气,对改善蛋鸡饲养环境,提高蛋鸡生产性能起到了促进作用。 相似文献
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无论是建筑的合理化设计、设备的更新换代，还是环境控制和粪污处理的需要，鸡舍设备设施都需要进行现代化改造。
一传统规模化鸡舍建设的问题与改造的要求
三十年前受资金投入的制约，我国养禽业的机械使用以低成本国产化和简易节能型机械为主，这样适应当时的中国国情。采用劳动密集型的养殖方式，推动菜篮子工程的发展，满足肉蛋供应。鸡舍建筑设施简陋，砖结构为主，是开放舍或有窗舍，建筑保温隔热性能差，环境控制设备与现代养殖业的需求不配套，环境控制理念跟不上。 相似文献
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夏季高温环境对产蛋鸡造成的热应激影响极为显著。蛋鸡由于饮水量增加、采食量下降而导致产蛋率、蛋重、蛋品质下降。高温、高湿环境造成鸡舍有害气体含量过高,高温条件有利于病原微生物的孳生或存活,长期热应激引起机体免疫力下降,诱发疾病,严重影响了蛋鸡的生产效益。为了避免上述现象的发生,夏季蛋鸡饲养管理应抓好以下技术措施。一、控制饲养环境条件1.减少太阳辐射热鸡舍屋顶应加盖隔热覆盖层,高温期间可在屋顶处淋水,屋檐架设遮荫凉棚,并做好鸡舍周围环境绿化工作。2.加快鸡体散热鸡舍结构合理,鸡舍的纵轴应东西走向,并设置钟楼式气窗… 相似文献
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奶牛舍外围护结构热工性能的评价 总被引：1，自引：1，他引：0
以河南省郑州地区奶牛舍热工设计要求的冬季低限热阻、夏季低限热阻和低限总衰减度为评判依据，对河南农业大学乳牛舍外围护结构冬季总热阻、夏季总热阻、总衰减度和总延迟时间进行测算，评价了其保温隔热性能，认为在河南省及其气侯相似地区，有窗封闭式乳牛舍外围护结构的冬季保温性能足以达到奶牛的要求，而夏季的隔热性能却远远不能满足奶牛的需要.因此仅依靠改变外围护结构的隔热性能难以使防寒和防暑兼顾，应该在基本符合冬季保温要求的前提下，增加畜舍的开放程度，保证夏季有足够的自然通风面积，同时降低建筑投资，才是乳牛舍设计和建筑的正确方向 相似文献
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夏季温度较高,在集约化饲养环境下,鸡舍气温往往超过30℃,甚至高达40℃。高温对蛋鸡是一种较强的热应激源,易造成蛋鸡采食下降、产蛋减少、蛋壳变薄、蛋重减轻,严重时还会导致鸡群死亡,严重影响着养鸡生产的经济效益。要在炎热季节保持蛋鸡高产,应采取以下综合技术措施。1改善蛋鸡生产环境1.1鸡舍建筑不能太矮,尽可能坐北向南,多设窗户或通风口,屋顶设置隔热层。1.2在鸡舍四周,特别是在鸡舍南西两侧种植大叶树和藤蔓植物,鸡舍周围地面可种植草皮、蔬菜等。尽量不使地面裸露。1.3进入夏季,可在鸡舍周围搭设凉棚,鸡舍屋顶用石灰乳之类刷白,草… 相似文献
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鸡场应建在地形开阔，地势平垣．冬季背风向阳，夏季不窝风的稍有坡度（1％～3％）的地方，鸡舍的走向以座北朝南为宜．屋顶选用隔热性能好的材料（如加气混凝土、泡沫混凝土、石棉水泥隔热板、木纤维板、建筑用毛毡等材料），并将其涂成白色或浅色．也可将屋顶修建成隔热性能良好的多层屋顶。炎热地区采用上层导热性好的材料， 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