人工灌丛草场土壤理化性状的变化

１调查地区自然条件及土壤理化性状调查地区为乌盟南部（俗称前山地区）的清水河、和林、凉城３县;以及北部（俗称后山地区）的武川、化德２县。共５县。前山地区气候温和,年均气温５～７℃,年均降水量３５０－４５０ｍｍ,无霜期１１０～１３０天,≥１０℃的积温为２...     

中国农户规模生猪成本要素分析

本文通过历年来我国农户规模养猪成本资料,分析农户规模生猪成本对产出和产值的影响,得出了在规模生猪发展过程中,中等规模(100～1000头)生猪养殖可能是最经济的结论。     

Dairy sheep production research at the University of Wisconsin-Madison,USA-a review

Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased milk production to supplements high in energy and/or     

瘤胃乙酸、丙酸比例对绵羊体内氧化代谢和血浆胰岛素水平动态变化的影响

本研究以全胃营养灌注绵羊为试验动物 ,用物质代谢区室分析方法和同位素示踪技术研究了瘤胃乙酸、丙酸比例对体内氧化代谢和血浆胰岛素水平动态变化的影响。不同试验处理间营养灌注液能量、蛋白质水平相同 ,而瘤胃灌注混合挥发性脂肪酸的乙酸、丙酸比例不同。三种混合挥发性脂肪酸的乙酸、丙酸比例分别为75 :15(VFA1)、65 :25(VFA2)、45 :45(VFA3)。由测定引入 14C -乙酸后血液二氧化碳放射比强度—时间曲线上升段斜率(k值)反映体内氧化代谢强度。试验结果为 ,瘤胃灌注VFA1 时的k值显著高于灌注VFA2 和VFA3 时的k值(P<0.05) ,而VFA2 和VFA3 两处理间的差异不显著(P>0.05) ,说明瘤胃灌注VFA1 时绵羊体内氧化代谢强度增加。向停止灌注24小时的绵羊瘤胃内灌注VFA1,血浆胰岛素水平在恢复灌注后缓慢上升。将瘤胃灌注混合挥发性脂肪酸由VFA1 换为VFA2 后 ,血浆胰岛素水平迅速上升 ,之后迅速下降 ,而由VFA2 换为VFA3 后未出现血浆胰岛素水平的明显变化 ,说明血浆胰岛素水平的变化与体内糖代谢调节状态有关 ,而瘤胃灌注VFA1 时的体内糖代谢调节状态与灌注VFA2 和VFA3 时明显不同。     

菊苣种子产量构成因子与产量的关联性分析

采用正交施肥试验设计与大样本取样,于2007年对菊苣(Cichorium intybus L.)种子产量及其构成因子进行研究,并通过相关分析、通径分析及回归分析,明确影响种子产量的主要因子和提高种子产量的主要因子,以期了解并掌握相应的关键技术。结果表明:菊苣的花序数、生殖枝数和种子产量主要受水肥条件控制;每株生殖枝数、每株花序数和千粒重是影响菊苣种子产量的主要因素,其回归模型为Y=-13.8887+1.73862X_{2+0.00241X3+21.7579X6;提高每株生殖枝数和每株花序数是菊苣种子高产的关键技术措施。}     

兔场布局技巧

<正>1养兔区是兔场的核心,应安置在兔场的上风向。基础种兔(核心群)要放在僻静和环境最佳的位置,其次是繁殖群、育成群和幼兔舍。考虑出售的方便,幼兔舍在兔场的一侧入口处。2管理区通常     

春季产蛋鸡饲料的调整

春季,母鸡进入产蛋高峰期后要取得较好的饲养效益,必须调整好饲料中的营养成分比例。实验表明春季产蛋鸡的饲料调整必须做到“四个变化”。其具体的是:1.能量需求的变化。产蛋鸡在冬季气温较低的情况下,代谢能含量一般为每千克2800大卡,春季气温转暖后,能量饲料多会使鸡体重增加,非但不能促进鸡产蛋,反而降低鸡的产蛋率。这时,如果把鸡饲料中的代谢能含量降低到2700大卡,则可显著提高鸡的产蛋率。其减少鸡饲料代谢能含量的方法主要是减少玉米等谷物在鸡饲料中的含量比例。2.蛋白质需要的变化。母鸡产蛋期需要较多的蛋白质。所以,母鸡产蛋期…     

影响胚胎移植犊牛成活率因素的调查

在2007年8月-2008年4月期间对云南某牛场的1231头犊牛出生成活率及健康状况进行调查。调查结果表明：不同月份、母牛怀双胎的比例、犊牛出生体重、受体母牛的体况等对犊牛的成活率都有影响。1月份产犊高峰期,犊牛双胎率最高达到55．7％,10月份犊牛的死胎率最高达到25％,犊牛的健康比例最高为67．85％,健康比例最小为32．39％。并根据此提出了提高犊牛成活率的营养、环境卫生、饲养管理、疾病防疫等相关措施。     

不同小黑麦品种的种子产量及产量构成因素比较

以32份小黑麦品种为试验材料,研究了各品种的产量构成因素（穗长、小穗数,穗粒数、穗粒质量）以及他们之间的相关性。结果表明,小黑麦品种OH2276株高最高,为136．77cm,但其种子产量低;安新麦83—25的综合性状最优,穗粒数最多,为J09。19;北联4号,89D-8和DH796综合性状也较好,具有良好的应用前景;HB200上的综合性状最差,HB200下和OB74的综合性状较差。