放牧与圈养育肥牛皮下脂肪组织中脂肪酸的代谢和沉积

本试验旨在评价放牧和圈养对安格斯杂交阉牛脂肪酸代谢的影响（n=24）。在试验的0d、28d、84d和140d收集瘤胃液、血清和脂肪组织样本检测。每隔14d收集牧草和日粮养分样本评定营养价值和脂肪酸组成。圈养育肥牛日粮由玉米青贮、破碎玉米、豆粕、维生素和矿物质构成。放牧阉牛的放牧顺序依次为黑小麦／一年生黑麦草、苜蓿／鸭茅和喜冷牧草／豆科牧草。圈养育肥牛日粮脂肪酸的57％是油酸，2％为亚麻酸。     

Estimating Combining Ability of 4x-2x Crosses in Cultivated Potatoes

Progenies derived from crosses between Solarium tuberosum and 2n pollen-Producing diploid hybrids, exhibit obvious hybrid vigor. The 2n pollen-producing clone can act as a bridge in crossing S. tuberosum and S. andigena with S. phureja. Populations from 4x-2x crosses show more unifomity and less segregation compared with that of 4x-4x crosses. The parent-offspring correlation for the traits, starch content and tuber number, is significant at 0.01 level. The regrssion equations are Y (mp-F1)=1.0 1.2x and Y (mp - F1) = 5.3 0.8x, respectively. The 2n pollen-producing clones play an impotant role in increasing tuber stach content. Estimates of the combining ability for the main yield components indicate that additive effect prodominatcs for such trais as plot yield, tuber weight per plant and starch content, whereas both additive and non-additive effects lay equal stress on mean tuber weight and non-additive effect is important for tuber number. In general, non-additive effect appears to be important in     

Assessment of Negative Training on the Use of Cubicle Beds by Heifers

40 in-calf heifers were observed to examine the effect of timbers placing in passage area on their use of cubicle beds. Prior to the experiment preliminary observation was taken on these 40 heifers and they were divided into two even groups (cubicle user(or control) group versus cubicle refusal (or experimental) group by whether they properly used the cubicle beds or not. The timbers were placed in passage and feeding areas for the cubicle refusal group to force the animls to lie in the cubicle beds. The results of this experiment showed that feeding behaviour was unaffected by the presence of the timbers, but lying acitvity was about 8% higher for the experimental group, which led to a mean of almost 2 hours longer lying time over 24 h. After the timbers were removed, there was a significant decline in lying by the experimental group. The diurnal pattern of lying behaviour in cubicles indicated that the major effect on lying activity exerted by the presence of the timbers was seen during midnight to 10:00 a     

美国核果类果树线虫的治理策略

美国各地核果树上发生的主要线虫有根结绒虫、剑线虫、痕线虫及轮线虫,所用控制措施包括植树前杀线剂处理、应用抗病砧木、轮作及卫生预防措施.     

乳αS1-酪蛋白基因型和日粮粗蛋白质浓度对奶山羊泌乳及N、Ca和P利用的影响

以24只产羔2周的奶山羊为试验动物进行预试验,研究乳中αS1-酪蛋白(αS1-CN)基因型(纯合基因型:A／A和F／F各12只)对产乳量和乳成分的影响。预试验结束后,试验主要研究乳中αS1-CN的基因型和日粮粗蛋白质浓度对产乳量、乳成分及N、Ca、P利用的影响。以日粮粗蛋白质浓度(分别占DM13.2％、16.8％和19.8％)和试验期(3-6周,8-11     

Close-to-nature Design and Management：Developing Effective and Harmonious Urban Forest in China

In the pastfew years, with speedilydeveloping of socialeconomy and continuously speeding up of urbanizationprogress in China, the problems of the ecologicalenvironment in urban area, such as air pollution, heat-island effect, dangers of wind and sand, and shortageof water resources, etc., have gradually been gravenessand become the focus issue concerned by citizens also.It has become the common understanding of mostcitizensthat ahealthy,secureand comfortableecologicalenvironment of human settl…     

油脂在提高公猪生产力和生育力上的潜在作用

精子及其相关精浆中所含的脂肪成分在组成和脂肪酸成分上是非常独特的。长链多不饱和脂肪酸 (即具有 2 0或 2 2个碳原子并含三个以上双键的脂肪酸 )在绝大多数主要组织所含脂肪中的含量非常有限 ,但在精子和精浆中的含量相当高 ,并具有明显的种属特异性。油脂的这种特性现在日益被认为是使受精最终成功所特别需要的。本综述根据最近一的些研究结果撰写而成 ,从精液质量和功能的一系列决定因子的角度论述了使现代种公猪精子中脂肪 /脂肪酸参数最佳化的可能性 ,可见人们对一系列参数所作的一系列重要研究 ,产生了使公猪和母猪的繁殖能力都得到提高的高度有益结果。文章还从主要的营养学特性和化学特性方面对研究结果进行了讨论 ,并与其它家畜进行了比较 ,还讨论了其对猪繁育部门可能的商业应用价值。