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《畜牧兽医科技信息》2015,(7)
<正>能量负平衡是指物质摄入减少但是奶牛的需求仍在增加,这也是围产期奶牛的能量代谢特点。围产期是奶牛生产全过程中至关重要的组成部分,也是奶牛能量代谢障碍性疾病高发的时期,了解围产期奶牛能量负平衡的现象特征是进行疾病防治的基础。本文对围产期奶牛出现能量负平衡的原因进行了深入的分析,旨在为解决围产期奶牛能量负平衡问题与疾病预防提供新思路。1围产期奶牛能量负平衡的产生原因能量负平衡多高发时期是奶牛日产奶量达到30kg前的 相似文献
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《畜牧与饲料科学》2015,(Z1)
为了解黑龙江省某集约化牛场奶牛产后能量负平衡与乏情的发生状况,该试验选取产后14~21 d奶牛100头,检测其能量平衡相关指标BHBA、NEFA、GLU,根据其结果将奶牛分为能量正平衡组和能量负平衡组。跟踪奶牛至产后60~90 d,并通过B超和直肠检查确定奶牛是否发情,同时明确乏情奶牛卵巢状态,确定乏情类型,对各组奶牛数量及各项临床指标进行记录统计。结果显示:能量负平衡与正平衡奶牛所占比例分别为49%和51%。去除患病牛后的73头奶牛跟踪到产后60~90 d乏情与发情在负平衡组所占比例分别为94.4%和5.6%,在正平衡所占比例为62.2%和37.8%。负平衡组乏情奶牛中卵巢静止所占比例最高,达61.8%。该牛场奶牛产后能量负平衡和乏情现象较普遍,已成为影响该牛场奶牛健康和繁殖性能的严重问题。卵巢静止在能量负平衡所致的乏情牛中所占比例最大,因此,能量负平衡是引发奶牛卵巢静止的重要致病因素。 相似文献
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能量是高产奶牛发挥泌乳潜力的重要因素,满足奶牛的能量需要,是提高产奶量,改善奶牛繁殖性能和健康状况的重要措施。在泌乳初期奶牛饲养中,由于能量负平衡的存在,满足这一阶段奶牛能量的需求成为奶牛生产的重点。介绍了泌乳初期奶牛产生能量负平衡的原因和危害,影响这一时期奶牛能量需求的因素,阐明了改变饲养方法,添加脂肪及酵母培养物等解决方法。 相似文献
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奶牛产后疾病高发是导致奶牛淘汰率增加的最主要因素,造成奶牛产后疾病高发的因素很多,其中围产期奶牛体质下降是主要原因。而围产期奶牛体质下降主要归结为能量负平衡。通过对能量负平衡的发生机理,以及奶牛能量负平衡与产后疾病高发的相关性进行分析,为早期预防奶牛疾病,保障奶牛健康提供相关指导。 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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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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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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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
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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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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