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奶牛热应激及其防治对策 总被引：10，自引：0，他引：10
热应激给奶牛业造成很大的经济损失，为能有效地解决奶牛热应激问题，笔者综述了奶牛的热应激发病表现、发病机理及对奶牛生产性能、繁殖性能和免疫功能的影响的研究进展。旨在为开发热应激剂、诊断和防治奶牛热应激提供理论依据。 相似文献
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热应激是奶牛养殖业中一直存在的一个巨大的挑战,它对奶牛的生产性能、繁殖性能、免疫功能和瘤胃的健康均有着不良影响,从而给整个奶牛养殖业造成较大的经济损失。本文主要总结了热应激对奶牛的影响以及过瘤胃产品对热应激的调控机理,旨在为缓解奶牛热应激营养调控方面提供有效合理的对策。 相似文献
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热应激对泌乳奶牛各生产阶段均有不利影响,尤以高产奶牛为甚。热应激导致奶牛产奶量大幅下降,乳脂、乳蛋白含量降低,同时导致机体免疫力、繁殖性能下降,给牛场造成严重经济损失。本文探讨了南方某牛场采用喷淋+机械通风方式缓解了奶牛热应激,给牛场带来了可喜的利润,供业界同仁参考。 相似文献
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人们一般以为高温高湿造成奶牛热应激只是南方才有的问题．事实上在北方每年的七、八月份期间，热应激对奶牛的生产性能影响也很大。在干热和湿热的气候条件下．热应激降低奶牛的生产性能和采食量．影响奶牛健康及行为活动。本文主要讨论有关热应激的产生和它给奶牛业在产奶量和繁殖性能上带来的问题：同时提供一些能够帮助减轻热应激的方法。 相似文献
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热应激与牛血液成分的变化 总被引：20，自引：1，他引：19
本文在应激概念的基础上，阐明了热应激对牛血清成分的变化有显著的影响。并且从牛血清中血糖、血红蛋白、T3、T4、皮质醇、生殖激素、维生素、酶等方面的变化分析了牛热应激作用的机理。 相似文献
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为探讨热应激对科尔沁牛和科尔沁肉牛抗氧化功能的影响,选择体况相近、身体健康的母牛各20头,分别在热应激（夏季）和非应激（春季）对其进行了抗氧化指标比较。结果表明,在热应激状态下,科尔沁肉牛血清中的SOD、GSH含量差异显著高于科尔沁牛（P＜0.05）,T-AOC含量有比科尔沁牛有升高趋势,但差异不显著（P＞0.05）,MDA含量极显著低于科尔沁牛（P＜0.01）;在非应激期间科尔沁肉牛和科尔沁牛差异不显著（P＞0.05）;热应激下科尔沁牛和科尔沁肉牛血清中的SOD、GSH、T-AOC含量较非应激状态极显著降低（P＜0.01）,科尔沁牛的MDA含量较非应激状态极显著升高（P＜0.01）,科尔沁肉牛的MDA含量较非应激状态显著升高（P＜0.05）。生理指标中热应激期间科尔沁牛的直肠温度显著高于科尔沁肉牛（P＜0.05）,而呼吸频率无显著差异（P＞0.05）。综上表明,在热应激状态下科尔沁肉牛比科尔沁牛的抗氧化能力更强,耐热应激能力强于科尔沁牛,更能较好地适应高热环境。 相似文献
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Heat stress in cattle results in millions of dollars in lost revenue each year due to production losses, and in extreme cases, death. Death losses are more likely to result from animals vulnerable to heat stress. A study was conducted to determine risk factors for heat stress in feedlot heifers. Over two consecutive summers, a total of 256 feedlot heifers (32/ breed/ year) of four breeds were observed. As a measure of stress, respiration rates and panting scores were taken twice daily (morning and afternoon) on a random sample of 10 heifers/ breed. Weights, condition scores, and temperament scores were taken on 28-day intervals during the experiment. Health history from birth to slaughter was available for every animal used in this study. It was found that at temperatures above 25 °C, dark-hided animals were 25% more stressed than light-colored; a history of respiratory pneumonia increased stress level by 10.5%; each level of fatness increased stress level by approximately 10%; and excitable animals had a 3.2% higher stress level than calm animals. Not only did the stress level increase with these risk factors, but average daily gain was reduced. The Charolais cattle gained significantly more than all other breeds of cattle tested. Calm cattle gained 5% more than excitable cattle. Finally, cattle treated for pneumonia gained approximately 8% slower than non-treated cattle. The results of this study have not only revealed heat stress risk factors of breed (color), condition score (fatness), temperament, and health history (treated or not treated for pneumonia), but have also shown the effectiveness of using respiration rate as an indicator of heat stress. 相似文献
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奶牛热应激遗传机制研究知识图谱分析 总被引：1，自引：1，他引：0
本文基于关键词共现分析和文献共引分析等计量学方法,分析了1990—2020年科学引文索引数据库所收录的奶牛热应激遗传机制领域共1 026条科技文献,统计了这些文献的作者、发文机构和年度发文量等,绘制了该领域共被引文献与关键词的共现网络图谱。重点通过高被引文献和高频关键词,透视了国际上该领域整体研究状况和研究热点,解读了该领域的发展脉络和趋势。此外,本文还通过中国知网数据库检索了国内在相关领域进行的研究,共检索到52篇文献,对国内在热应激遗传机制领域进行的研究进行了总结。通过国内外文献的关键词和文献共被引分析发现,热休克蛋白、单核苷酸多态性、氧化应激和繁殖性能一直是该领域的研究热点。随着研究的不断深入,热应激遗传机制研究从对热应激相关基因表达量的关注逐渐深入到对耐热多态的挖掘和对热应激相关基因表达调控的研究。在热应激基因表达过程中,表观修饰和miRNA是目前研究最广泛的两种调控方式。在奶牛热应激遗传机制研究领域,本文有助于我国研究人员宏观地了解本领域的研究现状及知识结构,快速定位首要关注点和重点文献。 相似文献
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Parameters for the determination and evaluation of heat stress in dairy cattle in South Africa 总被引：2，自引：0，他引：2
Du Preez JH 《The Onderstepoort journal of veterinary research》2000,67(4):263-271
Not all parameters are trustworthy and practical to use as parameters to determine heat stress in dairy cattle. The temperature-humidity index (THI) is still the best, simplest and most practical index (parameter) for measurement of environmental warmth which cause heat stress in dairy cattle. It is practical, easy to determine and relatively trustworthy to use body temperature and respiratory rate as parameters to determine heat stress in dairy cattle. These physiological parameters must always be used together with THI values to determine and evaluate heat stress in dairy cattle. For practical purposes, plasma cortisol concentration and milk composition cannot be used as parameters to determine heat stress in dairy cattle although good indications of acute or chronic heat stress can be obtained. Vanillic acid is a break-down product of adrenalin found in milk, but before its concentration in milk can be used as an indicator/parameter of heat stress in dairy cows, more about the pharmacodynamics of adrenaline in the milk has to be known. Selection and breeding of dairy cows on the basis of their adaptibility to heat stress using the most practical heat stress parameters will ensure that their offspring will have superior performance in the prevailing environmental conditions. 相似文献
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浅谈热应激对奶牛的影响及调控措施 总被引：1，自引：0，他引：1
在炎热的夏季,热应激会导致奶牛生理机能发生紊乱,采食量下降,生产性能降低,甚至导致奶牛发病,严重者造成死亡。预防夏季奶牛热应激的发生,为奶牛创造适宜的、良好的饲养环境,可使奶牛安全、顺利地度过炎热的夏季,防止热应激造成不必要的损失。笔者等从奶牛热应激发生的原因与生理机制入手,综合论述热应激对奶牛的危害和预防热应激的调控措施。 相似文献
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Hosam J Al-Tamimi George E Rottinghaus Donald E Spiers Jim Spain Darryl Chatman Peggy A Eichen Thomas L Carson 《Journal of veterinary diagnostic investigation》2003,15(4):355-360
Claviceps purpurea infects the seed heads of cereal grains and grasses and produces ergopeptine alkaloids that cause hyperthermia and agalactia in cattle during periods of heat stress. A field experiment was undertaken to examine the effects of ergopeptine alkaloids found in barley on thermal status of dairy cattle during periods of heat stress. Production end points were also measured to identify the effect of the change in thermal status. Contaminated barley screenings containing known levels of ergopeptine alkaloids were fed to lactating Holstein cattle (10 microg total ergopeptine alkaloids/kg BW/day) for 10 days during summer heat stress. Air temperature increased 14.4 C during the first 8 days of treatment and then declined the same during the last 2 days. Extreme daily values for rectal temperature and respiration rate, using averages of all animals, showed maximum increases of 2.3 C and 56.8 breaths/minute, respectively, during this period. Group afternoon milk production decreased 2 kg/day during the heat stress period, with no measurable change in feed intake. A greater level of hyperthermia occurred in cattle consuming the diet with ergopeptine alkaloids, with only marginal symptoms of ergot toxicosis reflected in feed intake and milk production. Therefore, the ergopeptine alkaloid dose used in this study represents a level for minimal induction of the ergot toxicity response. 相似文献