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我国南方地区夏季热应激严重,给奶牛养殖带来严重影响,做好防暑降温,优化设计饲料配方,选择抗热应激的新型饲料添加剂,可以有效缓解热应激,提高奶牛养殖效益。1科学调制饲料热应激可明显降低奶牛的采食量,影响产奶量。提高干物质采食量,是夏季饲养管理工作的重点。根据调查,一些规模化奶牛场尚未饲喂TMR全混合日粮;饲喂全混合日粮,可以提高干物质采食量,缓解和防治瘤胃酸中毒。适当增加TMR含水 相似文献
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刘懿 《畜牧兽医科技信息》2013,(6)
夏季天气炎热、气温高,湿度较低,有时气温可达35℃以上.由于奶牛的汗腺不发达,对高温炎热的耐受性很差,所以易产生应激反应.奶牛表现采食量减少,产奶量下降,安静发情,发情紊乱,发病率增高,如果不认真对待,有可能会造成很大的经济损失.
1 加强奶牛饲料的营养
进入夏季后,气温逐渐升高,天气闷热,奶牛受热应激的影响,采食量明显减少,产奶量也随之下降.有些饲养户为追求产奶量,盲目加大精补料的饲喂量,这样易导致奶牛急慢性瘤胃酸中毒.奶牛拒绝采食精补料,只采食少量的青贮或干草,产奶量大幅度下降,造成经济损失.因此进入暑期后应调整日粮的组合,以玉米青贮为主,泌乳牛必须喂干草,每头每天至少饲喂3kg,优质苜蓿最好.采食量的减少,同样出现能量供应的负平衡,这是导致产奶量下降的重要因素之一.所以在奶牛日粮中添加1％～2％的脂肪酸钙可减少或减轻因热应激所带来的后果. 相似文献
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本试验用过瘤胃豆粕替代新产料中17%的豆粕,以探讨过瘤胃豆粕对高产泌乳牛的干物质采食量、产奶量以及乳成分的影响。根据胎次、泌乳天数和产奶量一致的原则随机选择对照组(n=42)和试验组(n=39)牛群,每5d记录一次各组牛干物质采食量和产奶量,试验前后及每个月测定一次乳脂率和乳蛋白率。结果表明,试验组和对照组在整个试验期内干物质平均采食量分别为23.10kg/d和22.34kg/d。不同试验天数试验组的产奶量均高于对照组,但是差异不显著(P>0.05),平均产奶量分别为42.78kg/d和41.63kg/d,比对照组高出1.15kg/d。对试验前后奶牛乳成分进行分析发现,饲喂过瘤胃豆粕对奶牛乳成分没有显著影响(P>0.05)。 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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《中国草食动物科学》2016,(5)
为测试全混合日粮饲喂方式对奶山羊产奶量、奶品质等方面的影响,以关中奶山羊为试验对象,进行两组不同饲喂方式对比试验。结果表明:饲喂全混合日粮的试验组平均产奶量较传统方式饲喂的对照组高9.46%(P0.01),乳脂率提高0.12个百分点(P0.05)。利用全混合日粮方式饲喂奶山羊,可以显著提高奶山羊产奶量和乳脂率,同时对提高奶山羊采食量、降低饲料浪费也具有明显作用。 相似文献
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泌乳期间的低采食量会导致母猪体储备的过度损失而显著降低体重和背膘储备 ,延长断奶到重新交配的时间 ,降低妊娠率和产仔数 ,缩短母猪的使用年限。母猪泌乳期间的饲喂水平也会影响仔猪的生产性能 ,母猪泌乳期间饲料消耗同产奶量直接相关 ,采食量增加 ,产奶量也会有较大提高 ,产奶量的高低会影响哺乳仔猪的生长速度。提高母猪泌乳期饲料采食量的方法之一是确保母猪妊娠期间不要过度饲喂。母猪泌乳期的饲料采食量和妊娠期的饲料采食量呈负相关 ,妊娠期的饲料采食量增加 ,泌乳期的饲料采食量则下降。因此 ,妊娠期的饲料采食量应减少 ,否则妊娠… 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