补充青贮玉米对复合稻草块体外发酵特性的影响

应用体外发酵产气技术,研究了青贮玉米以不同比例(0%～100%)替代复合稻草块中稻草对其体外发酵特性的影响。结果表明:随着青贮玉米比例的升高,复合稻草块的24h产气量、产气速度常数、有机物消化率、代谢能呈逐渐上升的趋势(P<0.05)。替代比例低于40%时24h产气量组合效应不显著(P>0.05),替代比例高于40%后出现逐渐增大的正组合效应,当替代比例为50%时,正组合效应值(9.68)显著增加(P<0.05),以后变动幅度不大。综上可见,用青贮玉米替代复合稻草块中40%以上的稻草较为适宜,当替代比例为50%时,就可获得较好的消化率。     

A free-choice intake of mineral blocks in beef cows during the grazing season and in winter

A herd of 25 beef cows were offered four types of mineral blocks (A, B, C, D) with a different Ca to P ratio (A 0.6:1, B 0.8:1, C 2:1 and D 3.6:1). The Mg content was identical in all blocks whereas the Na content was equal in B, C and D, while the Na content in A block was double. The mineral block intake was monitored for 1 year, which was broken down to the grazing period (Pa) and the winter period (Wi). The intake of pasture grass and winter forage was assessed and the feed chemical composition was analysed; based on the obtained values, a macroelement balance (for Ca, P, Mg, Na and K) was calculated.The results showed the forage diet met requirements for all the observed macroelements (except in Na). The macroelement intake from forage was considerably higher than from mineral blocks. There were significant seasonal (Pa versus Wi) differences in B and C blocks intake. The consumption of D block was relatively invariable all year round; block A was refused in both seasons though it contained the highest amount of highly deficient Na.It can be concluded that mineral content in forage meets beef cattle requirements for Ca, Mg and K, P content is just satisfactory, and Na content is insufficient. It appears that cows control, to some extent, the Ca to P ratio in their diet by choosing the appropriate type of mineral block. However, the preference or refusal of some types of mineral blocks regardless of the season suggests the influence of other factors affecting mineral block intake which were not the subject of our observation.     

履带式收割机全田块路径跟踪算法设计与试验

针对中小型传统收割机无人化作业需求，该研究设计了一套后装式全田块自动驾驶系统。以沃得锐龙单边制动转向型履带式收割机为平台，搭建手自兼容自动驾驶系统，并进行系统特性辨识试验，明确其测控性能限制。针对测控性能限制设计一种PD-Fuzzy-BangBang组合路径跟踪算法，并进行样机集成与试验。水泥地面直线行驶试验表明，组合算法相较单一PD算法的上线距离缩短57.3%，稳态标准差缩小81.3%。全田块模拟试验证明，组合算法在理想条件下的路径跟踪最大偏差为6.00 cm，标准差为2.42 cm，样机具备全田块自动驾驶功能。实际水田收割作业试验证明，样机在车速0.7 m/s条件下，上线过程的路径跟踪最大偏差为12.00 cm，标准差为 6.18 cm，全田块不漏割，割幅利用率大于80%，满足田间作业需求。     

刨切单板贴面实木地板工艺探讨

针对山毛榉实木地板生产中因表面材质缺陷导致地板优等品率及出材率低的问题，采用山毛榉刨切单板对山毛榉实木地板进行贴面，并对改善实木地板表面质量的工艺技术进行了探讨。     

混交造林模式与用苗量计算

混交图式是造林学中的一个基本概念,生产中经常要用到它。它虽然有看图易懂的特点,但存在着三个缺陷:(1)画图难度较大,增加了造林作业设计工作量;(2)在造林类型表中无法表示,因此需要附加图式;(3)用苗量难以计算。为了克服混交图式上述缺陷,我们探讨试用混交造林模式表达混交图式。混交造林模式虽然克服了混交图式的缺陷,但不能代替造林典型设计图,尤其在某些特殊立地条件下,如在流动风沙地的不同类型沙丘上造林,农田防护林的营造和庭园绿化     

Where does it hurt? Problems with interpretation of regional and intra‐synovial diagnostic analgesia

Detailed clinical evaluation and diagnostic analgesia are crucial for accurate lameness diagnosis. This review discusses the ways in which local analgesic techniques can cause confusion and highlights how important it is to recognise that the majority of methods are less specific than was formerly thought. Interpretation of responses must be done together with the results of clinical examination and careful assessment of diagnostic images. With the knowledge of false negative and false positive results of local analgesic techniques and the recognition that there may be more than one focus of pain contributing to lameness, it is still possible to reach accurate diagnoses, provided that a logical, thoughtful approach is utilised.     

A型口蹄疫病毒VP1蛋白间接ELISA检测方法的建立

以原核表达经纯化复性制备的A型口蹄疫病毒(FMDV)VP1蛋白代替传统病毒抗原包被,建立快速、安全、有效的A型FMDV抗体ELISA检测方法。对前期制备的A型VP1蛋白进行Western-Blot检测,结果表明,VP1蛋白能够特异性识别A型FMDV阳性牛血清,可作为检测抗原建立检测A型FMDV抗体的方法。以最佳质量浓度1mg/L VP1蛋白为检测抗原,方阵滴定法确定最佳检测血清稀释度为1∶50[V(血清)∶V(封闭液)],最佳的酶标二抗稀释度为1∶2 000[V(酶标二抗)∶V(封闭液)],建立A型FMDV抗体ELISA检测方法。该方法的敏感性为94.32%,特异性为99.09%,批内与批间重复试验变异系数均小于8%。采用该方法检测201份临床血清,与液相阻断ELISA试剂盒的符合率达92.54%。研制的VP1-ELISA试剂盒特异、敏感、稳定、操作简便,可用来监控A型口蹄疫抗体水平。     

高产奶牛血清镁含量分析

为调查南宁地区某奶牛场奶牛血清镁含量及其是否与该场奶牛蹄病有关,选取40头健康奶牛和46头蹄病奶牛,采用原子吸收分光光度法分析每头牛血清镁含量,结果表明全部被检牛血清镁平均含量为22.72±3.11mg/L;健康组与蹄病组奶牛血清镁含量分别为23.02±3.19mg/L和22.45±3.09mg/L,两组间差异不显著(P＞0.05).     

云南省水稻细菌性基腐病病原的初步鉴定

 2000年从云南省楚雄市采到水稻细菌性基腐病标本,经病害症状观察,细菌分离培养,革兰氏染色,鞭毛染色,致病性测定及致死温度测定的结果,基本上与前人^［1］报道的相符,其病原菌初步鉴定为菊欧氏杆菌（Erwinia chrysanthemi)。