Dynamics of Moraxella bovis infection and humoral immune response to bovine herpes virus type 1 during a natural outbreak of infectious bovine keratoconjunctivitis in beef calves

Infectious bovine keratoconjunctivitis (IBK) is an acute disease caused by Moraxella bovis (Mb). Several factors may predispose animals to an IBK outbreak; one commonly observed is infection with bovine herpes virus type 1 (BHV-1). The aim of this study was to investigate the dynamics of BHV-1 virus infection and its relation with clinical cases of IBK in weaned calves from a beef herd with a high prevalence of lesions caused by Mb. Sampling was carried out in six stages and included conjunctival swabs for isolating Mb as well as blood samples for identifying antibodies specific for BHV-1. A score for IBK lesions after observing each eye was determined. The findings of this study showed a high prevalence of BHV-1 virus infection (100% of animals were infected at the end of the trial); 67% of animals were culture-positive for Mb, but low rates of clinical IBK (19% of calves affected) were detected at the end of the trial. These results suggest that infection with BHV-1 did not predispose these animals to IBK, and that Mb infection produced clinical and subclinical disease in the absence of BHV-1 co-infection.     

5个日本枇杷品种植物学性状调查及果实品质比较

以大五星枇杷为对照,调查了引种四川的5个日本枇杷品种的植物学性状,测定果实维生素C、总酸、总糖及可溶性固形物等含量。结果表明,引进品种里见和有间综合性状表现最好,除可食率低于大五星外,单株产量与大五星无显著差异,单果重、维生素C、可溶性固形物含量等都高于大五星,适合在四川地区种植。     

安格斯牛与西藏犏牛杂交生产肉牛试验初报

[目的]犏牛可以生活在海拔2 800~4 200 m,对高寒缺氧的生态环境具有很强的适应能力,是“世界屋脊”的著名牛种,为了提高西藏犏牛资源的综合利用,其后代变废为宝。[方法]在试验区选择200头经产母犏牛通过引进安格斯牛的细管冻精,依靠人工授精技术,应用种间三元杂交技术生产优质商品肉牛试验,测定初生、3月龄的体重、体尺指标,观察高寒气候的适应性。[结果]结果显示:参配母犏牛200头,实配160头,其中104头母犏牛怀孕受胎,98头顺利产犊。实配率80%,人工授精受胎率65%,成活率94.23%。犏牛平均妊娠期(266.81±11.93) d。安格斯与西藏犏牛杂交后代的出生体尺、体重与传统杂交犊牛(多勒)相比,平均体重增加8.95 kg,提高73.23;体高、体斜长、胸围、管围平均分别比传统杂交犊牛(多勒)增加7.491 cm,1.394 cm,8.998 cm,0.063 cm,提高了13.94%,2.56%,15.70%,0.068%。安格斯与西藏犏牛杂交后代的3月龄与传统杂交犊牛(多勒)相比,平均体重增加43.3 kg,提高168.89;体高、体斜长、胸围、管围平均分别比传统杂交犊牛(多勒)增加15.67 cm,16.95 cm,26.31 cm,1.64 cm,提高23.27%,24.76%,34.31%,15.83%。[结论]弥补了犏牛传统杂交后代普遍存在的体躯发育差、生长发育慢等缺陷,且很好地适应西藏高寒生态环境和管理条件,杂种优势十分明显,因此安格斯牛可作为高原环境下繁殖犏牛生产肉牛的理想父本品种使用,并拥有开发高端产品的巨大潜力。     

草业是青海经济开发与生态环境治理的基础

分析了青海经济开发与生态环境失调产生的问题及生态环境失调的主要原因，指出在经济发展中忽视生态环境治理和在生态环境治理上实行重林轻草违背自然规律的失误，草业是青海经济开发与生态环境治理的基础。     

Studies on the Intracellular Ca2+ Concentration of Frozen–Thawed Dog Spermatozoa: Influence of Equex from Different Sources, Two Thawing Diluents and Post-thaw Incubation in Capacitating Conditions

The addition of 0.5% (v/v) of Equex STM Paste (Nova Chemical Sales, Scituate Inc., MA, USA), whose active ingredient is sodium dodecyl sulphate (SDS), to a Tris–egg yolk extender was demonstrated to improve the longevity of frozen–thawed dog spermatozoa during in vitro incubation at 38°C. The aim of the first experiment was to compare the effects of two SDS‐containing compounds, Equex STM Paste and Equex Pasta (Minitüb, Tiefenbach, Germany), when added to a Tris–egg yolk based extender, on the post‐thaw longevity of dog spermatozoa, as well as on the intracellular Ca²⁺ concentration of spermatozoa, during post‐thaw incubation at 38°C. The post‐thaw sperm survival and longevity, as well as the quality of the sperm movement, were significantly better when using Equex STM Paste. Such prolonged sperm longevity, however, was associated to a higher intracellular Ca²⁺ concentration in a large subpopulation of the live spermatozoa. A second experiment was aimed to evaluate the effects of sperm dilution immediately post‐thaw with a Tris buffer containing glucose or fructose. The two Tris buffers were no different for any of the sperm parameters studied. The aim of a third experiment was to evaluate the sperm longevity, motility patterns and intracellular Ca²⁺ concentration of cryopreserved dog spermatozoa during post‐thaw incubation in capacitating conditions [canine capacitating medium (CCM) with or without 5 μg/ml of heparin]. Heparin had no significant effects on any of the sperm parameters evaluated. During the first 8 h of incubation, the majority of the live spermatozoa had a high intracellular Ca²⁺ content. However, after 8–10 h of incubation, it had significantly declined. The highest proportion of fast motile sperm, and the highest curvilinear velocity, average path velocity and amplitude of lateral head displacement for the total motile sperm were observed during the 2–4‐h incubation period. It was concluded that: (a) the addition of 0.5% (v/v) of Equex STM Paste to a Tris–egg yolk based extender significantly improved the post‐thaw longevity of dog spermatozoa, but the same concentration of Equex Pasta had no significant beneficial effects; (b) sperm dilution after thawing with a Tris buffer containing glucose or fructose made no difference in post‐thaw sperm longevity; (c) the addition of 5 μg/ml of heparin to CCM had no significant capacitating effects on frozen–thawed dog spermatozoa.     

简述青稞秸秆加工利用技术的应用

为积极探索构建粮饲兼顾、农牧结合、循环发展的新型草牧业结构和模式,在青海半农半牧地区推广青稞秸秆利用,减少秸秆浪费和营养流失,切实提高青稞秸秆价值,促进农牧民稳步持续增收,掌握青稞秸秆加工利用技术意义重大。     

MACRO- AND MICROMORPHOMETRIC INVESTIGATION ON SOIL-DEXTRAN INTERACTIONS

The effect of three microbial dextrans of defined molecular weight, on shrinkage and porosity inside clods has been studied on two Italian clay soils, a Fluvisol and a Vertisol. Shrinkage was determined on dried soil samples using an electro-optical apparatus. The same apparatus was also used to measure porosity and pore size distribution inside the clods. For this purpose large thin sections were prepared from cracked soil samples after shrinkage measurements. Dextrans influenced shrinkage and the size distribution of clods and cracks in the two soils. The major effect was found in the Fluvisol where the arrangement of cracks was changed visibly. The dextrans caused a marked increase in total porosity in the Fluvisol but had only a small effect in the Vertisol. In both soils the pore size distribution was changed resulting in a greater number of larger pores in the dextran treated samples.     

分子遗传技术在家畜遗传评定中的应用

基于表型信息和谱系信息估计基因加性效应值的种畜遗传评定方法在家畜遗传改良中发挥了很大作用,但因其无法真正了解控制经济性状的遗传本质,影响了家畜遗传改良的进一步进展。分子标记辅助选择可在一定程度上提高种畜遗传评定准确性,但在目前不能精确定位QTL或基因时,其效率受到很大影响。提高种畜遗传评定准确性的最有效途径应是直接利用控制经济性状的基因,后基因组时代的功能基因组研究的快速发展为实现这一目标提供了契机。同时,多个家畜品种基因组测序完成和大量SNP多态性的发现,使得利用覆盖全基因组多态性标记信息的基因组选择方法为家畜遗传评定开拓了又一条途径。     

青海互助土族民间利用野生植物调查

采用民族植物学和人类学的研究方法,对青海互助土族民间利用野生植物进行了调查.结果表明,与当地土族直接相关的野生植物包括32种,经常食用的有12种.     

黄河上游高寒地区建植人工草地引种试验

对8种多年生禾本科牧草品种在黄河上游高寒草地进行人工草地引种试验.结果表明:当年均出苗且生长良好,但种子不能成熟,只能达到拔节期;第2年越冬率达90%以上,无芒雀麦Bromus inermis,垂穗披碱草Elymus mutans,多叶老芒麦E.exceisns,老芒麦E.sibiricus青干草产量均达3 000 kg/hm2以上,冷地早熟禾Poa crymphila,草地早熟禾P.pratensis青干草产量在1 500 kg/hm2左右;种子成熟好的有冷地早熟禾、多叶老芒麦、老芒麦、垂穗披碱草,说明供试的8种多年生禾本科牧草品种在青海省黄河上游海拔3 400 m左右的地区推广种植,效果良好.