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寒冷季节的被毛损失是导致产蛋鸡实际采集量高出经典采集量预测值的主要原因。在较高环境温度下,被毛损失有利于生产性能的发挥,而在适温区下限以下时,则显著提高维持需要,降低饲料转化率。被毛状况受遗传,年龄,饲养方式等许多因素的影响。被毛覆盖状况的评分方法很多,作者认为目前比较合理的是躯体被毛覆盖重量指数法,即IBPW计分法,现有的评分法末充分考虑鸡体不同部位的不同散热效率和气候适应的影响,有必要将被毛附 相似文献
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《青海畜牧兽医杂志》2019,(6)
放牧家畜采食量是家畜生产力的主要限制因子,同时也是决定放牧季节内的最适饲养管理标准。然而,近年来对放牧家畜采食量的研究主要集中于测定方法和放牧强度对家畜采食量的影响,没有系统的研究影响放牧家畜采食量的因素。本文通过分析不同放牧方式、不同放牧季节、不同放牧家畜和不同放牧草地状况对放牧家畜采食量的影响,以及不同放牧管理对家畜采食量的影响。从而为放牧家畜的科学管理和放牧草地的合理利用提供参考依据,同时提出了放牧家畜采食量研究今后需要进一步解决的问题。 相似文献
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《动物营养学报》2020,(7)
采食是动物-植物相互作用的重要途径,是维持生态系统物质和能量循环的主要过程。动物的生产水平和草地的可持续性取决于动物的采食量,明确放牧家畜采食量是草地管理的关键之一。目前,直接观测法、指示剂法、粪氮指数法和近红外光谱法等现有技术被广泛运用到采食量的测定中。直接观测法利用较低成本对采食量进行计算,但主观性较强;食道瘘管法能够把握采食量却忽略了动物福利;近红外光谱法和饱和链烷烃法在测定采食量的同时能够认识家畜的择食特征。为此,本文对现有常规测定方法进行综述,分析影响测定放牧家畜采食量的主要因素,并提出放牧行为与无人机技术相结合等新思路,为今后草原精准化管理提供技术支撑。 相似文献
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作都研究了年龄对海猪色力克斯兔皮板成熟和救皮品质的影响。兔只分6月龄、7月龄和8月龄三个阶段取皮,日采食量限制在自由采食量的75%。从活体动物上测定的性状有:被行长度和密度、色泽和枪毛品质。 相似文献
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正奶牛应激损失最大的是产奶量的损失。研究表明,在采食量降低幅度相似的条件下,因为限制采食导致的产奶量降低只占热应激下采食量下降导致的产奶量下降幅度的35%~50%,而其他是由代谢变化引起的,也表明产奶量的下降不但与采食量的降低有关,而且更重要的是其他生理、代谢方面的变化。奶牛热应激采食量降低导致的能量负平衡也与泌乳早期的能量负平衡不同,并不会导致生长激素(ST)和游离脂肪酸水平 相似文献
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放牧家畜采食量是评价草地生态系统转化效率和动物生产力的主要参数,受草地植被生长情况、环境条件、放牧方式、家畜生理特征及其瘤胃内环境等因素影响。放牧家畜采食量的准确测定一直以来都是食性研究的难点和热点问题,关系到动物营养状态的评估、补饲策略的制定以及食性理论的探索。传统采食量估测方法大多基于观察法或放牧前后牧草生物量差值法,这些方法对动物的干扰较小,但是受技术本身和适用范围的限制,如未能估测单个动物的采食量,很难适用于大范围的采食量估测。链烷烃技术和近红外技术的出现为准确测定采食量提供了前所未有的机遇,不仅能克服传统测定方法的缺点,还在准确率、适用范围(圈养动物和放牧动物)等方面优势较为明显,但由于粪便回收率和数据库完整性等因素的影响,目前应用于生物多样性较高草地的放牧动物采食量估测尚有难度。在简要总结不同方法的原理和影响因素基础上,综述了差值法、内标法、链烷烃法和近红外法在放牧家畜采食量测定方面取得的最新进展及存在的问题,并建议多种方法结合可以准确测定放牧家畜采食量,以期为制定合理的草地生态系统管理策略和实现草地可持续生态服务功能提供新思路和启发。 相似文献
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<正>1呼吸系统疾病的危害在肉鸡养殖过程中,过了育雏期很多鸡就会出现呼吸道的症状,一般表现为咳嗽、甩鼻或者呼噜,并且因为呼吸道的发生,而继发气囊炎、堵气管、肺坏死、栓塞等现象,给养殖业造成极其惨重的损失。2临床表现鸡群的采食量在刚发病时不增加或略微下降,而发病鸡支气管堵塞后,采食量均有不同程度的下降,严重的采食量下降过半。鸡群精神粪便基本正常,但也存在个别鸡羽毛逆毛,呆立,排黄白粪现象。 相似文献
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采食量是保证动物生产性能充分发挥的关键因素。也是提高生产效率的重要前提。生产实践中,动物采食量的重要性与作用常被过低估计,不同养殖场猪采食量的变异至少达到25%。这将不可避免地对猪的生长和养殖场的效益产生巨大影响。猪的采食量低下问题突出地表现在哺乳母猪、小猪和仔猪上,本文现就仔猪的采食量话题作一阐述。[第一段] 相似文献
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Beran GW 《Preventive veterinary medicine》2008,86(3-4):198-207
When early people made their appearance, zoonotic infectious diseases were already waiting, but epidemic diseases did not appear in human history until people began to live in large numbers under conditions of close contact, mainly during the last 10,000 years. Disease has decimated urban populations, conquered armies, and disrupted society. The focus here is on (1) the plague of Athens and the Black Death; (2) smallpox, influenza, and rabies; (3) avian influenza prion diseases, and foot & mouth disease; and (4) emerging and re-emerging diseases. All have veterinary public health associations. In Athens, Greece, in 430 BC, when the Spartans ravaged the countryside, hordes crowded into Athens so that orderly movements, space in which to live, and adequate supplies of food became impossible. Crowding of any population fosters disease transmission; chaos and disorder enhance it all the more. Out of northern Egypt came a terrible plague from across the Mediterranean Sea. The identity of the plague of Athens remains unsure, but the well-considered conclusion is Rift Valley Fever, a mosquito borne, viral zoonosis. The Black Death, also called the Plague, raged in Asia for centuries. In 1347, the Black Death was brought by a ship out of Asia to Sicily. The scenes of devastation were repeated throughout Europe, with 90% or more of the people dying in city after city. Influenza, too, has been a cause of periodic human epidemics, but the great pandemic of influenza occurred in the last months of World War I. In the years of highest occurrence, more than half the world's population became clinically infected. If veterinary public health had been born earlier, it could have led to elucidating the epidemiology of influenza and the plagues of Athens, Europe, and Asia. In turn, smallpox had also caused continual tragedy. In 1796, Edward Jenner began to harvest pustules of cowpox from children or infected cows and inject them into susceptible children. In 1980, the World Health Organization declared that smallpox had been eliminated from the world. Rabies, though, still strikes terror. A number of animal diseases, broadly termed emerging and re-emerging diseases, need surveillance because they have the potential to impact human health. From late in 2003 to 2007, the highly pathogenic H5N1 influenza virus in poultry infected at least 121 people and caused 62 deaths in four countries. The prion diseases, too, all have very high numbers in concentrated contacts. To control these diseases, veterinary public health is essential, with diagnosis, epidemiological surveillance, clinical manifestations, and prevention as primary measures. 相似文献
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在动物的异常行为中以刻板行为最为常见,而咽气癖又是马最常见的口部刻板行为之一。作者就咽气癖在生理方面和心智方面对马体产生的影响、行为基础、诱因的研究进展及常见的防治措施进行综述。 相似文献
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Dekker A Dercksen D Snoep J van Wuyjckhuise L 《Tijdschrift voor diergeneeskunde》2007,132(18):695-701
On 26th of july 2007 a new case of bluetongue was notified in the Netherlands and on 2nd of august 2007 foot-and-mouth disease was diagnosed in Surrey, England, which raised the threat of having both infections simultaniously in one area. Bluetongue and foot-and-mouth disease have a different pathogenesis, but symptoms may resemble each other at a later stage of infection. The pathogenesis and possible clinical symptoms of both infections are discussed and illustrated with pictures. 相似文献
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在归纳总结RFLP和PCR-RFLP标记技术的原理、优缺点的基础上,系统论述了其在牦牛遗传育种研究中的应用现状,并提出了个人的建议和看法。 相似文献
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近几年,世界饲用添加剂市场增长较快,预计今后将进一步增长,据世界粮农组织(FAO)首领会议的倡议,到2015年,将使世界营养不良的人口削减一半,其间,肉制品将会以每年2%的速度增长,特别是加快猪肉和禽肉增长。这将促进世界添加剂,尤其是蛋氨酸和赖氨酸需求量的增加。 相似文献