贺兰山野生有蹄类动物的经济价值及种群动态变化

记述了贺兰山的4种野生有蹄类动物——马麝、马鹿、岩羊、鹅喉羚的经济价值及目前的种群动态变化,对贺兰山野生有蹄类动物的种群致危原因进行了分析,并据此提出了相应的保护管理建议。     

Studies on Thysanura. III. Some Factors Affecting the Distribution of South African Thysanura

To evaluate the impact of climatic change on rodent sahelian communities, we analysed the contents of over 2500 barn owl (Tyto alba) pellets collected along the Senegal river between 1989 and 2003, and from the Ferlo sahelian area in 2003. These results are compared with data from the 1970s and 1980s in the same zones. Rodents were the most common prey (over 90%). Gerbillinae were most common in dry areas (84 to 96%) whereas in wetlands and rice fields murines were most common (77 to 88%). Nowadays, the genus Gerbillus constitutes the main prey in dry areas (77% to 88%). The genus Taterillus, which was the most abundant rodent in the Ferlo in the 1970s, now represents only 7% of rodents. Gerbils were not present in Senegal before the 1980s: G. tarabuli and G. henleyi were trapped for the first time in 1989 at the northern border of Senegal, and G. nigeriae 10 years later at the same place. The latter is now present a hundred kilometres southwards and as abundant in owl pellets as the two other gerbils.     

影响猪肌肉品质因素的初步研究

通过对华中农业大学种猪场的抗应激品系的猪采用不同屠宰方法，对抗应激品系的猪和应激敏感的猪采用相同的屠宰方法和测定时间，其结果之间差异极显著，表明影响猪肌肉品质的因素既有内因因素，又有外因因素。对抗应激猪和应激猪采用不同时间连续测定，结果应激狸的不同时间测定值差异不显著，抗应激猪的不同时间测定值差异较大，说明时间对抗应激猪的肉质有一定的影响，因此必须选择正确的评定方法才能有效地区别优质肉与劣质肉。研     

影响特种野猪繁殖率的因素及对策

特种野猪肉因其肉质鲜美,瘦肉率高而受到广大消费者的好评,然而在特种野猪生产的过程中,其低繁殖率一直是一个困扰着广大科研工作者与养殖户的大问题,并且在一定程度上制约了特种野猪规模化的生产。本文主要从影响特种野猪繁殖率的因素以及提高特种野猪繁殖率策略两大方面进行综述。     

基于地理探测器模型的川西北家畜空间分布差异影响因素分析

川西北放牧家畜分布具有空间尺度分异的特征,以乡镇为单位的基础数据,在研究自然和人为因素对家畜空间分布的影响方面,有助于得出更细致、更客观的结果,将为川西北地区畜群结构的优化提供科学依据.试验以气象、地形、植被类型、植被覆盖度、土地利用类型、人口、出栏管理等方面的数据为基础,利用GIS空间分析和地理探测器模型相结合的方法...     

Epidemiological factors that influence time-to-treatment of trypanosomosis in Orma Boran cattle raised at Galana Ranch, Kenya

Four thousand nine hundred and seventy-one trypanosomosis-surveillance records from an open population of Orma Boran cattle raised under natural trypanosomosis challenge in Galana Ranch, Kenya between the years 1990 and 2000 were analysed. The objective of the analysis was to identify epidemiological factors that influenced time-to-treatment of trypanosomosis cases. Under the surveillance programme, blood was being examined fortnightly for trypanosomosis using buffy coat technique. Infected animals were treated when their packed cell volumes (PCV) fell to 25% or lower. The number of days between the first diagnosis and treatment of trypanosomosis cases was obtained from the difference between diagnosis and treatment dates. Days-to-treatment clustered around the screening periods; therefore, time-to-treatment was represented by a series of time points 0-8 at 14-day intervals. Factors postulated to affect the outcome (time-to-treatment) were age of an animal at time of diagnosis, sex, number of trypanosome infections, trypanosome species and season of the year. Five animal generations were generated from birth dates and treated as nuisance parameters. Conditional logistic regression and Cox proportional hazards models were fitted to the data, the former to analyse factors that influenced treatment after time 0 (outcome dichotomised as time 0 or >0) and the latter to analyse factors that influenced time-to-treatment for cases that were treated after time 0, excluding all cases treated on time 0. The majority of the cases (89.5%) were treated on the same day of diagnosis. Trypanosome infections were more likely to be treated after time 0 in dry than in wet season. Similarly, the rate of treatment was lower in the dry than the wet season. An increase in number of previous trypanosome infections reduced the odds of an animal being treated after time 0. Animals that had been exposed to many infections before had higher rates of treatment than those that had minimal experiences. We offer possible reasons for these observations and conclude that selection of animals for breeding purposes in programmes geared towards improving trypanotolerance should take into consideration the environmental factors that affect classification of an animal as being resistant or susceptible.     

影响牧草植物量形成的因素

牧草植物量的形成受许多因素的影响,其中以降水和温度最为显著。在高寒地区,牧草植物量受气温影响最大;而在干旱地区,降水的作用最为突出,气温则次要。除此之外,它还受土壤、放牧强度、刈割、施肥、焚烧等的影响。就这些因素作一简要的介绍,为今后有关植物量的研究提供了一个比较系统的认识和依据,对指导牧草生产具有重要的意义。     

影响酸奶粘度的主要因素分析

本文选择了干物质含量、稳定剂、菌种、温度、搅拌强度5个主要影响发酵酸奶（搅拌型）粘度的指标,进行了正交实验,结果表明,储藏温度是影响酸奶粘度的首要因素,干物质、稳定剂、搅拌强度对粘度也有影响,菌种虽对粘度影响不大,但影响酸奶的风味。通过本试验筛选出最佳的指标参数,从而得到更好的酸奶品质。     

奶牛体外受精效果几种影响因素的研究

文章研究了卵巢的保存温度、保存时间、不同的培养液成分、培养方法等对奶牛体外受精后的卵裂率、囊胚发育率的影响.结果表明①采集的卵巢在37℃保存2h时,卵巢卵母细胞体外受精后的卵裂率(71.3%)和囊胚率(31.4%),与25℃保存组的卵裂率(75%)和囊胚率(30.7%)相比,差异不显著(P＞0.05);但与40℃保存组(55%和15%)和4℃保存组(47.8%和12%)有显著差异(P＜0.05);当卵巢保存6h时,25℃保存组的卵裂率(70.2%)和囊胚率(29.2%)均显著高于37℃保存组(50.9%和13%)(P＜0.05);与40℃保存组(30%和7%)和4℃组(30.1%和8.2%)差异极显著(P＜0.01);但与保存2 h组差异不显著.在25℃温度下,屠宰牛卵巢保存时间达到8h时,卵母细胞的卵裂率和囊胚率显著下降,分别为55%和14%.②作为早期胚胎的培养液,CRlaa的效果好于TCM-199.③50μl微滴组的卵裂率(71%)与微滴100μl组(75%)和500μl组(72%)无显著差异(P＞0.05),但囊胚率(15.8%)显著低于100μl组(32%)(P＜0.05);大体积培养组(2 ml)的卵裂率和囊胚率(55%和14.8%)显著低于100μl组和500μl组(P＜0.05).     

苜蓿体细胞胚发生的影响因素

在组织培养过程中诱导苜蓿体细胞胚发生的关键因素有两个：一是植物材料，包括基因型和外植体类型；二是培养基成分。研究结果认为：紫花苜蓿体细胞胚发生能力较强，无菌苗子叶和下胚轴是发生率较高的外植体；2．0mg／L的2,4-D补加适宜浓度的NAA、KT和BA等激素是相对平衡的激素组合，也是必需的。添加一些有机物有利于提高体细胞胚发生率。     

影响家禽就巢发生的因素及其研究进展

本文对影响家禽就巢的内分泌、遗传和环境因素及其研究进展进行了阐述,分析了目前就巢性研究中存在的问题,并提出就巢性研究的策略和思路。     

影响猪皮肤颜色的因素

良好肤色与毛况的猪是养殖户追求的目标。肤色与毛况较好的猪往往能卖到较好的价钱。同时,健康的肤色也是猪只健康的标志。除了遗传、品种等因素外,猪的肤色与毛况还与营养和环境因素有较大关系。     

几种野生动物疫病的诊断报告

野生动物疫病是一个重要的自然疫源 ,是贮存病原的基因库 ,人间、兽间及人兽间流行的许多疫病与野生动物的疫病有着密切的关系 ,因此调查及研究野生动物的疫病是一项极其重要的工作 ,这对于有效防制人、畜 (禽 )传染病的发生 ,保护野生动物有着重大意义。近期我们收检有关部门送检的野生动物病料 ,作了病原学实验室检验 ,现作如下报告 :1　大天鹅结核杆菌病1999年 5月 2 4日 ,我省某公园动物园引入大天鹅发病 ,表现为渐进性消瘦 ,精神萎糜 ,羽毛无光泽而松乱 ,食欲不振 ,其中 1只大天鹅拉稀便 ,呈灰白色 ,随病程发展 ,相继出现死亡现象 ,据…     

影响蚕茧价格变动的因素分析

蚕茧是丝绸工业的原料 ,蚕茧收购价格的高低不仅影响蚕农的收入和生产积极性 ,而且影响丝绸工业的经济效益 ,关系到蚕丝业的可持续稳定发展。本文就蚕茧价格政策、蚕茧的供求关系、养蚕成本、蚕茧与粮棉比价及通货膨胀等因素与蚕茧价格变动的关系进行了理论与实证分析     

浅谈影响牛冻精受胎率的因素

文章从冻精质量和剂型、冻改技术水平、母畜三方面阐述了影响牛冻精改良受胎率的主要因素,旨在为牛冻精改良提高生产效率提供技术指导。     

桑叶茶品质的影响因素

桑叶茶的品质与桑叶所含的功能成分以及加工工艺密切相关。通过选择桑树品种、改善桑树生长条件、加强桑园管理、选择适宜的采收时间、采收适宜的叶位、优化加工工艺等措施,可以提高桑叶茶的品质。低温、避光保存与科学泡茶,可以充分发挥桑叶茶的保健功效。     

新型桑树专用肥田间效果试验初报

本文就新型桑树专用化肥与普通桑树专用化肥、普通化肥进行了田间效果对比试验，结果表明，前者的增产效果明显优于后两者。     

影响草地早熟禾成坪质量的几个因素

我国对于草坪学的研究起步较晚,但随着社会发展和人民生活水平的提高,草坪建植已经成为衡量生态环境的重要指标之一,草坪学已成为一种引人注目的新兴研究领域.草地早熟禾作为目前世界上应用最广泛的冷季型草坪草之一,其成坪质量越来越受到人们的重视.现针对影响草地早熟禾成坪质量的几个因素进行简要分析.     

影响设施大棚蚕茧质量因素的调查

蚕茧作为茧丝绸工业的主要原材料,蚕茧质量好坏直接影响蚕茧资源利用、产品档次和经济效益.淳安县作为我国国内重要优质原料茧生产基地,也是设施大棚养蚕推广面积规模最大县之一,虽然淳安县能大量生产5A级生丝的原料茧,但是生产能缫制精品6A级生丝的原料茧却很少.为提升蚕茧质量,摸清原因,2019年,我们对设施大棚养蚕所生产的蚕茧进行质量、缫丝成绩试验、测试和对比分析,结果表明:设施大棚内养蚕要比普通蚕室内养蚕结茧率低3.15％、死笼率高3.57％;设施大棚内生产出的蚕茧比普通蚕室内生产出的蚕茧上车茧率低0.77％、茧丝长短25.6 m、解舒率低1.23％、茧丝纤度低0.03 dtex、出丝率低0.45％、洁净低0.19分,差异显著.因此,做好设施大棚内养蚕期间和蔟中管理过程中对温湿度的调节和通风换气,可有利于提高设施大棚蚕茧质量和茧丝品质提升.