内蒙古天然草地退化成因的多因素灰色关联分析

选取内蒙古草地典型草原、草甸草原及农牧交错带典型区,通过对区域内影响草地退化的社会、经济和环境等因素进行定性分析,应用灰色系统理论的关联分析方法,以草地退化面积为参考数列,以牧草生长季积温、降水变率和年大风日数等气候因子,草地超载比例、人工种草与围栏草场面积、年割草量、畜棚与畜圈面积和牧民人均收入等人类活动因子作为比较数列,对草地退化进行了多因素关联分析。研究结果客观、定量地揭示了草地退化与各因素间的相互关系,认为草地生态系统的退化受损是气候变化和人类活动共同胁迫的结果,人类对草地的管理方式对草地生态系统具有巨大影响,人类可以通过多种管理措施来减轻牲畜对草场的压力,积极解决人与资源的平衡。     

Effect of presence of rumen protozoa on degradation of cell wall constituents in gastrointestinal tract of cattle

The cell wall constituents of feces from three faunated and three defaunated (without ruminal ciliate protozoa) cattle fed on a Sudangrass hay and concentrate mixture (8:5) were analyzed. There was little difference in digestibility of dry matter between the faunated and defaunated cattle. Analysis of the fecal sugar residues revealed that the digestibilities of arabinose and galactose, derived from pectic and hemicellulosic substances located within the compound middle lamella, were higher in the defaunated cattle than the faunated cattle (P < 0.05), whereas the digestibilities of glucose and xylose, derived mainly from cellulose and xylan, were unchanged by the removal of protozoa. The digestibility of lignin was not different between the faunated and defaunated cattle, but those of mannose and p‐coumaric acid were lower in the defaunated than in the faunated animals (P < 0.05). The ratio of primary cell wall to secondary cell wall in fecal plant materials was lower for the defaunated than for the faunated cattle. The results in this study suggested that the defaunation enhanced the microbial degradation of the thin cell walls, but depressed the degradation of developed cell walls.     

菜籽饼中硫葡萄糖甙的去除方法

硫葡萄糖甙(GS)是菜籽饼中主要的抗营养因子。本文对硫葡萄糖甙的性质及其降解产物的毒害作用和菜籽饼的脱毒方法进行综述。     

论草地退化

在总结草地退化概念的基础上,从草地退化的成因,退化的表现形式和学科角度3个方面剖析了草地退化的内涵;将草地退化过程概括为量变阶段,量变与质变交互阶段和质变阶段3个时期,并阐述了每一退化过程的主要特征;以新疆为例,提出治理退化草地应首先对草地退化阶段进行科学诊断,以生态置换工程为依托,从落实转变思想观念、整合资源等方面从根本上遏止退化源,进而从补偿制度、农牧区畜牧业联营政策及人口政策等方面进行调控,从而推进退化草地治理的进程,达到草地资源的可持续发展。     

Contribution of a straw bedding to digestible nutrient intake of pigs fed diets based on either native or pregelatinized potato starch

In a 2 × 2 factorial arrangement, 16 groups of 12 pigs were assigned to one of two housing systems (straw bedding, S vs. Barren, B) and to one of two starch types (native, N vs. pregelatinized potato starch, P, each included at 35%) to study effects on apparent faecal digestible nutrient intakes. Intake of straw from bedding material was estimated, using several markers, and results are discussed. Straw intake of the S-pigs was estimated between 143 and 234 g DM/d for P-pigs and between 96 and 156 g DM/d for N-pigs, depending on the method used. Nutrient digestibility was reduced in N-pigs when compared with P-pigs. Intake of digestible dry matter, energy, starch and ADF was increased in S-pigs, but the intake of digestible protein was reduced. Despite greatly reduced nutrient digestibility in S-pigs, additional digestible nutrient intake due to housing on a straw bedding can be considerable.     

Effects of different types of dietary non-digestible carbohydrates on the physico-chemical properties and microbiota of proximal colon digesta of growing pigs

The effect of different types of fibre on the intestinal digesta and microbial diversity was evaluated in growing pigs. The animals were fed during forty-two days with one of four experimental diets including a control group, a diet enriched with resistant starch type I, by coarse ground corn, and other two diets containing sugar beet pulp (8%) and wheat bran (10%) (as sources of soluble and insoluble non-starch polysaccharides respectively). Body weight (BW) and average daily feed intake (ADFI) were assessed at day 7, 21 and 42. Luminal samples of digesta from proximal colon were collected to analyse water retention capacity (WRC), concentration of short-chain fatty acids (SCFA) and the microbial diversity. Overall, animals fed with higher amounts of non-digestible carbohydrates had lower ADFI and BW. Sugar beet pulp provoked an increase of WRC, a higher concentration of SCFA, and a more stable microbial diversity throughout the experimental period. On the other hand, animals fed with wheat bran presented a lower bacterial diversity.     

奶牛常用饲料干物质和淀粉瘤胃降解规律的研究

以3头安装有永久性瘤胃瘘管的泌乳前期荷斯坦奶牛为试验动物，在精粗比为55：45的日粮条件下，采用Insacco法测定了奶牛常用饲料瘤胃内干物质和淀粉的降解规律。试验结果表明。不同饲料干物质和淀粉的降解率不同。能量饲料中，麸皮干物质和淀粉的瘤胃降解率高于玉米：蛋白质饲料中，干物质和淀粉的降解率由高到低顺序依次是豆粕〉胡麻饼〉棉粕：常用粗料中，玉米青贮干物质和淀粉的降解率均高于青干草。     

高寒地区小黑麦在断奶初期奶公犊瘤胃内动态降解的研究

选用3头3月龄左右装有瘤胃瘘管的荷斯坦奶公犊,按3×3完全拉丁方试验设计,喂给3种日粮,日粮组成按精粗比分别表示为:Ⅰ组70∶30、Ⅱ组60∶40、Ⅲ组50∶50,研究不同日粮组成下高寒地区小黑麦的DM、CP以及NDF在断奶初期奶公犊瘤胃内动态降解。试验结果表明:精粗比为60∶40日粮时,其CP的消失率和降解参数明显低于精粗比为70∶30和50∶50的日粮,差异显著(P<0.05);其DM和NDF的消失率和降解参数明显高于精粗比为70∶30和50∶50的日粮,差异显著(P<0.05)。     

新疆艾比湖绿洲土地退化遥感动态监测

层次分析法是一种将决策者对复杂系统的决策思维过程模型化、数量化的过程.采用层次分析法,对影响和指示土地退化的生物量、归一化植被指数、土壤水分指数和土壤盐碱化4个影响因子进行分析.通过计算每个影响因子的权重,基于ASTER,SPOT,TM,MODIS产品以及野外调查数据等多源数据,对新疆艾比湖地区2000年8月至2004年8月的土地退化状况进行了评价,并且分析了层次分析法应用于土地退化研究的适用性及其优缺点.研究表明:艾比湖地区耕地退化现象普遍,占耕地总面积的55.78%,分布广,程度重.     

青海省同德县草地现状及畜牧业可持续发展策略

在调查同德县草地退化现状的基础上,综合分析了同德县草地退化的原因,指出了同德县畜牧业可持续发展的策略。同德县的草地退化是自然因素和人为因素共同综合作用的结果。人类活动和气候变化是导致同德县草地退化、区域生态环境恶化的两大因素,鼠虫害对它们产生的影响起了促进作用。只有合理利用和保护天然草地,综合治理退化草地,优化畜牧业产业结构,使草地生态系统步入良性循环,才能使同德县的草地畜牧业协调发展。