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蚕种催青是蚕桑生产过程中的一个重要技术环节,催青质量与蚕种一日孵化率和蚁体强健度密切相关,并直接影响到广大蚕农饲养期间的管理操作。为了稳定提高蚕种一日孵化率,近年来我们通过蚕种催青管理软件和高压喷雾加湿系统的应用、按时发种的调控、运种工具的改进、适用补催青技术的全面推广。使全年各期催青蚕种的一日孵化率保持在较高水平．为方便蚕农饲养管理打下了良好的基础。 相似文献
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普通蚕蚕种一日孵化率的高低受蚕种制造、浸酸(浴种)、冷藏、催青及蚕农补催青等诸多技术环节的影响,其中蚕种催青技术的好坏,起到至关重要的作用.随着小蚕一日二回育等省力化养蚕新技术的推广、普及,蚕农对蚕种孵化率的要求更高,一日孵化率要求达到95%以上,这对蚕种催青工作提出了更高的要求. 相似文献
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孵化率是检验蚕种催青好坏的重要指标。尤其是在大面积推广小蚕一日二回育技术后 ,蚕农对孵化率的要求更高 ,希望发种不带苗蚁 ,隔日收蚁一日孵化率要求达９５ %以上 ,远远高于全国和省定的实用孵化率标准。而蚕种孵化率的高低牵涉到制种、冷藏、浸酸、催青、补催青等诸环节 ,催青则是最后环节。近几年来 ,我市经过不断摸索、总结 ,规范操作 ,催青质量稳定 ,收蚁孵化率基本达到了蚕农的要求。据１９９９～２００１年９５４批１５２４７０３张蚕种跟踪调查 ,农村收蚁一日孵化率达９６．９２ %以上 ,催青室留样蚕种收蚁一日孵化率达９８．６８… 相似文献
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蚕种的一日孵化率关系着蚕农的经济效益,提高蚕种的一日孵化率有着较为重要的实践意义。文章依据具体的工作经验,从蚕种的催青环境、相关的催青技术参数以及蚕种的补催青等方面探讨提高蚕种一日孵化率的具体措施。 相似文献
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影响丰县农村蚕种一日孵化率的因素有蚕种冷藏、催青、补催青等环节,丰县农村实行丝茧育省力化养蚕后,催青工作成了重中之重的步骤。根据笔者十多年的催青实际情况,认为加强催青技术、重视补催青管理两个方面,是提高丰县农村丝茧育蚕种一日孵化率的主要途径。 相似文献
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<正> 蚕种催青是养蚕的基础,催青质量的好坏直接影响孵化率的高低和蚁体健康程度。影响蚕种一日孵化率的因素很多,与原蚕饲养、制种、蚕种保护、冷藏、浸酸、催青、蚕种领运、补催青等方面的技术处理都相关。但作为技术推广部门,要提高蚕种的一日孵化率,主要是采用先进的催青设备,抓好蚕种的催青管理工作,根据我局近年来的实践,针对不同的季别、蚕品种、批次、性状和蚕卵胚子发 相似文献
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蚕种催青是养蚕生产过程中的一个首要环节 ,催青质量的好坏直接影响到蚕种一日孵化率的高低。近年来 ,随着农村经济改革的不断深入 ,广大蚕农的质量意识也普遍提高 ,蚕农对蚕种质量的要求也更高 ,对蚕种既要头数足、蚁体强 ,又要一日孵化率高。笔者根据几年来的催青实践 ,认为加强催青技术管理 ,是提高蚕种一日孵化率的关键。1 掌握好三期重点胚子 ,促使胚子发育齐一1 1 调节好起点胚子丙2 胚子是抵抗低温的临界胚子 ,是催青中决定外温的起点胚子。起点胚子的齐否 ,关系到整个催青阶段胚子发育的整齐度及温湿度等有关技术措施的调节。在实… 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