高温季节如何预防奶牛中暑

1预防牛舍温度过高 奶牛最适宜的温度为8—20℃，夏季舍温常常高于30℃，所以牛舍要注意空气流通，把牛舍门窗打开，有条件的可安装吊扇，以利通风和散热，也可在奶牛舍粪沟或牛床上方设喷头或钻孔水管，酌情定时或不定时给奶牛淋浴，或用晒过的水给奶牛洗澡，这都有利于牛体的散热和降低舍内温度，防止中暑及其他热应激疾病的发生。     

高温期蛋鸡的饲养管理

蛋鸡的生理特点是代谢率高,体内产热量多．因鸡体缺乏开腺,其散热途径主要依靠辐射、对流和蒸发（呼吸蒸发）,随环境温度的升高,辐射和对流散热所占的比例逐渐降低,而呼吸散热逐渐成为鸡体散热的主要途径,当环境温度升高至35℃时,呼吸散热可占散热总量的90％．当环境超过一定限度时就会导致蛋鸡生理状态的改变和生产性能的降低,因而,高温期蛋鸡饲养的关键是减轻持续性热应激对鸡的不良影响．1效应激对蛋鸡生理状态的影响蛋鸡生产的最佳环境温度为21-26℃．环境温度达26－32℃时,表现热喘息,生产性能下降10％－20％．温度达32－35…     

浅析如何减轻奶牛夏季热应激

近年来，奶牛饲养业在全国各地城郊农村得到迅速发展，正在成为广大农民增收的新的经济增长点。但时至夏日，热应激严重影响了奶牛的产奶量，特别是一些高产奶牛，对其生产和健康带来了巨大的负面效应。奶牛适宜的环境温度为０℃～２０℃，高产奶牛为８℃～１６℃，最适泌乳温度１２℃～１５℃，气温超过２３℃时，奶牛就会出现热应激，使正常的生理机能受到影响。而夏季牛舍的平均气温可达到２８．１℃，使得奶牛体温升高，呼吸加快，产生严重的热应激。一、奶牛热应激反应的原因奶牛体型大，而单位体重的散热面积小，被毛和体组织的保温性…     

猪、鸡喂点煤灰效果好

夏季已到,气温增高,给奶牛生产带来不利影响。那么如何减少热应激给奶牛生产带来危害呢?这里给广大奶牛养殖场户一个提示:调整奶牛日粮能有效减少奶牛热应激。目前,我国的奶牛大多是荷斯坦牛。荷斯坦牛原产于夏季凉爽的荷兰,在那里即使是最热的7月,平均气温也只有17℃。奶牛适宜温度一般在5～20℃,当环境温度低于适宜温度时,每降低1℃,奶牛会增加维持能量需要1.2%,而环境温度高于适宜温度时对奶牛影响更大,气温每升高1℃,会增加3%的维持能量需要。随气温升高,奶牛体温上升,脉搏、呼吸加快,电解质损失增加。气温35℃时,维持需要比31℃时可增…     

奶牛热应激的危害及预防

夏季热应激对泌乳奶牛造成的危害极大，发生热应激时，奶牛为了减少体热会减少采食量。据测定，气温在22～25℃时，采食量开始下降；超过30℃，采食量下降10％以上；40℃以上时采食量下降50％以上，个别奶牛将停止采食。采食量的下降造成奶牛营养不良。研究表明，在21℃以上时，气温升高会引起体温上升，体温每升高0．6℃，采食量下降1．4kg，产奶量下降1．8kg，     

中草药防治夏季奶牛热应激研究进展

奶牛是一种耐寒怕热的动物，对体温调节能力有限。在诸多应激因素中。高温环境对奶牛的应激影响尤为突出。饲养实践证明，普通奶牛产乳的适宜温度为10-15℃C，黑白花奶牛产乳的最适温度为0-20℃。此时产热和散热维持动态平衡，奶牛产乳量高，饲料利用经济。超过适宜温度范围，奶牛产热大于散热，体温开始升高，容易引起热应激反应。近年来随着规模化、     

夏季提高奶牛受胎率的措施

奶牛耐寒怕热，对热应激敏感。夏季气温高，奶牛散热困难。导致子宫血流量减少、生殖道温度升高、血中孕酮水平增高、雌二醇水平下降，不利于受精卵发育和附植，进而使胚胎早期死亡率大大提高。夏季如何保持奶牛较高的受胎率?成为每一位奶牛饲养者关心的问题。结合生产经验，现介绍以下措施，供参考。     

盛夏减轻奶牛热应激危害的几项措施

1热应激的症状,奶牛的理想温度范围为4℃～18℃。温度一旦超过27℃,奶牛的采食量就会下降,开始对奶牛生产不利影响。当温度达到或超过32℃时,其产奶量往往会明显下降,减产3％～20％：湿度也是热应激的一个重要因素。当温度为38℃,湿度为20％时,应当认真采取措施以减轻奶牛所受的环境压力。此时应采取一些散热措施。当温度达38℃,湿度为50％时,奶牛就会发生危险。而38℃的温度和80％的湿度对奶牛是致命的。由于奶牛的排汗速度仅为人的10％,因此,较容易产生热应激。这就需要用人工方法帮助奶牛进行散热,如给牛体喷水,通过水分蒸发来帮助散热;利用有效的通风系统来散热。在空气污浊且不流通的地方,奶牛在短时间内就可能发生危险,甚至毙命。因此必须保证牛舍的快速通风。处在热应激下,奶牛的采食量会下降8％-12％或更多。采食量的下降导致了瘤胃中挥发性脂肪酸产量的减少．从而降低了产奶量。     

高温天气奶牛的饲养管理

夏季炎热多雨 ,气温过高 ,造成奶牛热应激现象极为普遍 ,严重影响奶牛生产性能的正常发挥和养殖效益的提高 ,为防止高温天气对奶牛生产性能的影响可采取如下措施。1　降低高温对奶牛环境温度影响早晚要及时打开门、窗、防风帘 ,保持牛舍通风干燥。牛舍内安装排风扇和高压喷雾降温装置 ,加大蒸汽散热及对流散热 ,以降低牛舍内温度。在不影响通风的情况下 ,运动场周围可种植阔叶树木遮阴。屋顶铺上青草或干草减弱其吸热能力 ,避免阳光照射下舍内温度快速升高。奶牛运动场要搭建凉棚 ,防止阳光直射。2　改进管理措施 ,降低高温对牛体影响经常清…     

夏季奶牛的饲养管理技术

奶牛耐寒不耐热,最适宜的环境温度为10～20℃。奶牛在2～24℃温度范围内生活比较适宜。当夏季来临时,气温高于24℃,有些地区最高气温甚至高达35～40℃时,就会给奶牛带来极大的危害。因此,如何搞好夏季奶牛的饲养管理,减少夏季热应激,已成为广大奶牛饲养者普遍关注的问题。1饲料的调整夏季高温的应激使奶牛的采食量减少。据测定,奶牛在22～25℃时采食量就开始下降,高于30℃下降幅度达40%以上。因此,增强奶牛食欲是夏季饲养的重要措施。此举一可提高日粮的营养浓度。在配合饲料中增加豆饼、鱼粉的含量,使日粮蛋白质含量提高4%左右,过瘤胃蛋白…     

细菌发酵大豆异黄酮甙元的工艺及高效液相色谱检测

大豆异黄酮是一类存在于大豆中能对人体发挥有益作用的非营养物质。β-葡萄糖苷酶是一种能将大豆中的异黄酮由结合型糖苷向具有生理活性的游离型苷元转化的活性酶[1]。据报道,发酵大豆制品中游离型糖苷的含量远高于未发酵的大豆[2],这说明在大豆加工发酵过程中某些微生物所产β-葡萄糖苷酶使糖苷向甙元进行了转化。本文用本课题组筛选的产β-葡萄糖苷酶的菌种,对大豆黄素(大豆异黄酮甙元的一种)发酵条件进行优化,并通过HPLC(高效液相色谱)进行检测。1材料与方法1.1材料大豆(购于武汉市中百仓储超市)、细菌B.SP-4(本课题组筛选)。1.2主要…     

Superoxide production by stimulated equine polymorphonuclear leukocytes-inhibition by anti-inflammatory drugs

Polymorphonuclear leukocytes (PMNLs) were isolated from an inflammatory exudate induced in the intercarpal joints of horses by an administration of carrageenin. Their superoxide production at rest and following stimulation with either serum-treated zymosan (STZ) or phorbol myristate acetate (PMA) was measured by cytochrome-c reduction. Stimulation of the cells increased the cytochrome-c reduction 10-15 times that of resting cells. The maxima were 20 nmol of reduced cytochrome-c per 10(6) cells per ml at 120 min (STZ) and 35 nmol of reduced cytochrome-c per 10(6) cells per ml at 60 min (PMA). The maximum inhibition of the cytochrome-c reduction by superoxide dismutase (Palosein) was 83.6% (STZ stimulation) and 72.1% (PMA stimulation). The non-steroidal anti-inflammatory drugs, phenylbutazone, salicylic acid, aspirin, sodium salicylate in addition to D-penicillamine and dimethylsulfoxide caused dose-dependent inhibition of the cytochrome-c reduction when the cells were stimulated by PMA. The maximum inhibitions were 64% and 36% for aspirin (10(-2) M), 32% and 17% for phenylbutazone (10(-3) M), 15% and 31% for dimethylsulfoxide (6.4 x 10(-1) M), 32% and 19% for salicylic acid (10(-2) M), 0% and 17% for sodium salicylate (10(-2) M) and 2.2% and 2.5% for D-penicillamine (10(-4) M) when the cells were stimulated by STZ and PMA, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Proteolytic cleavage of immunoglobulin by enzymes released by Fasciola hepatica

Immature Fasciola hepatica release a papain or cathepsin B-like proteolytic enzyme which cleaves immunoglobulins (Ig) of mouse, rat, rabbit and sheep in vitro. Mouse IgG and IgM molecules are both susceptible to cleavage as is hemoglobin. Whether single or multiple proteases are responsible for Ig cleavage is unknown. The proteolytic activity of secreted enzyme(s) is optimal at pH 3.5-4.5, but activity is also present at pH 7. Proteolysis is enhanced in the presence of 5 mM dithiothreitol or 100 mM cysteine. Based on studies with protease inhibitors, the F. hepatica enzyme activity has been identified as a thiol protease. It is destroyed by heating at 56 degrees C for 1 h, but retains activity after storage at -20 degrees C for 7 days. Whether inhibition of the proteolytic activity increases the susceptibility of F. hepatica immature worm to any extant immune effector mechanisms in hosts remains to be determined.     

Colostrum production by ewes and the amounts ingested by lambs

Studies involving 49 ewes which were well nourished during the last eight weeks of pregnancy indicated that ewe weight loss during pregnancy and lamb birth weights followed the recognised pattern and were within acceptable "normal" limits. Colostrum production ranged from 1238 to 4593 g per ewe during the 48 h following the first suckling and there was evidence that production levels were related to demand by the lambs. Colostrum consumption by individual lambs was related to litter size. The smaller the litter size the greater was the amount ingested during the first 48 h of life. No clear relationship was established between the amount of colostrum consumed and the level of immunoglobulin in a lamb's circulation. Possible reasons for this are discussed.     

奶牛过瘤胃氨基酸的补加

最近的研究表明，补加氨基酸可减少奶牛日粮中过瘤胃蛋白质（ＵＤＰ）的供应量，同时提高总产奶量和乳蛋白含量。 在泌乳前期，奶牛的干物质采食量较低，而泌乳量较高。这就需要在日粮中有足够的可利用能量和蛋白质。现在瘤胃保护脂肪或过瘤胃脂肪被用来补充以谷类为基础的传统精料，为高产奶牛提供了可通过瘤胃的足够能量。相类似地提供足够的瘤胃微生物蛋白质，以便提供足够的氨基酸，从而使高产奶牛获得最大产奶量和乳蛋白。２０世纪９０年代早期，人们就发现蛋氨酸和赖氨酸是合成奶蛋白的限制性氨基酸，在此基础上奶牛营养学家借助计算…     

Death by cyathostominosis

In autumn 2002 and 2003, the Animal Health Service received several young horses for post mortem investigation that had died or had been euthanised. It was found that severe cyathostominosis was the cause of death. The aetiology, pathology and diagnosis of this infection is discussed. Advice is given for preventative measures and usage of anthelmintics.