不同覆盖方式对旱地玉米田土壤环境及玉米产量的影响

分析普通地膜覆盖、小麦秸秆覆盖及露地栽培3种不同处理对旱地玉米田土壤环 境、玉米产量构成因素的影响,结果表明:覆盖栽培能改善土壤环境,降低土壤容重,提高土壤 水分利用率,调节土温、湿度,协调水热资源利用的同步性;秸秆覆盖能增加土壤养分含量,特 别是速效钾含量;在玉米生长后期,提高叶面积指数,延长叶片功能,提高玉米的光合能力从而 防止玉米早衰,增加穗重,提高玉米产量。     

牛得喜对奶牛生产性能的影响

实验研究了奶牛日粮中添加牛得喜(SCCNCMl077)对奶牛生产性能的的影响。实验选用了50头奶牛,根据产奶量、泌乳天数和胎次相近的原则分为试验组和对照组。试验结果表明,试验组平均产奶量比对照组提高了1.52kg,差异显著(P<0.05),而试验组乳脂率、乳蛋白率分别下降了0.09%、0.07%,但均差异不显著(P>0.05)。     

羊、鸡抗鼠脂肪细胞膜抗血清对大鼠体脂与生长性能的影响

应用提取的鼠脂肪细胞膜分别免疫羊和鸡 ,所产生的抗血清用于 Wistar大鼠被动免疫。实验 1: 组腹腔注射羊正常血清 , 组腹腔注射羊抗鼠脂肪细胞膜抗血清 ,剂量均为 1m L /只 ,连续注射 4 d。结果表明 ,羊抗鼠脂肪细胞膜抗血清免疫促进了大鼠体增重 ,降低了体脂沉积 ,与对照组相比 ,7周末体重增加 6 .35 % (P<0 .0 5 ) ,饲料摄入增加6 .85 % (P<0 .0 1) ,料重比 (F/G)提高 4 5 .0 0 % (P<0 .0 5 ) ;肾周、附睾、网膜脂肪垫重量分别降低 2 3.92 % (P<0 .0 5 )、34.4 5 % (P<0 .0 5 )、0 .98% ,脂肪总量降低 2 0 .92 %。实验 2 :1组腹腔注射鸡正常血清 ,2组腹腔注射鸡抗鼠脂肪细胞膜抗血清 ,剂量均为 1m L/只 ,连续注射 4 d。结果表明 ,鸡抗鼠脂肪细胞膜抗血清免疫对大鼠的生长发育产生了不利影响 ,7周末 ,免疫大鼠平均体重较对照组减少 4 0 g(P<0 .0 5 ) ,饲料摄入显著降低 (P<0 .0 1) ;对体脂的沉积和血液中 TG和 FFA的影响没有规律 ,且无统计学意义     

饲喂柠条对肉兔生产性能及胴体性状影响的研究

选用45～48日龄平均体重1050g的伊普吕(父系)幼兔64只,分成4组,进行柠条饲喂肉兔试验.对照组饲粮中谷草比例为33.4%,试验Ⅰ、Ⅱ、Ⅲ组分别用10%、20%和33.4%柠条替代等比例谷草.48天试验结果为:对照组、试验Ⅰ、Ⅱ、Ⅲ组日均采食量、日增重、料肉比分别为89.84g、92.95g、90.77g、79.95g,22.60g、23.30g、19.24g、17.90g,3.98:1、3.99:1、4.72:1、4.47:1.试验Ⅰ、Ⅱ组与对照组日采食量、日增重、料肉比差异不显著(P＞0.05);屠宰试验结果为:试验Ⅰ、Ⅱ与对照组在胴体重、屠宰率、净肉率、肉骨比、心脏、肺脏、肝脏、肾脏等指标方面无显著差异(P＞0.05);而试验Ⅲ组日采食量、日增重均显著较对照组差(P＜0.05).试验结果表明:生长肉兔饲粮中添加10%～20%柠条粉是可行的,且饲粮成本较低.     

黑毛和牛在内蒙古呼和浩特地区的繁育

黑毛和牛肉质在日本肉牛中占绝对优势，是世界闻名的独特肉牛品种。通过胚移在内蒙古呼和浩特繁育，表现良好，生长发育指标已达到日本国内品种标准。同黑白花奶牛杂交，其杂种经育肥，32月龄体重达624．8kg，屠宰率为56．3％，净肉率为49．9％；高档肉占净肉的11．6％，优质肉占净肉的22．7％，大理石花纹等级为1、2等级牛占76％。肉的品质均高于我国地方良种。     

几种绿色饲料添加剂在肉鸡生产上的应用效果

选1日龄AA肉鸡390只,分成13组,分别添加不同种类和不同种类组合的绿色饲料添加剂。试验结果表明,益生素能显著(p<0.05)提高肉鸡的生产性能,改善肉品质。     

酵母铬与L-肉碱对蛋鸡生产性能及脂质代谢的影响

选用21周龄海兰褐壳蛋鸡288只,随机分为9组,每组32只,采用3×3(铬×L-肉碱)2因子3水平有重复交叉试验设计,预试2周后,在玉米-豆粕型日粮的基础上添加不同水平的酵母铬(以铬计:0、400、600μg/kg)与L-肉碱(0、50、100mg/kg),以饲喂基础日粮组为对照组,用以研究二者对蛋鸡生产性能及脂质代谢的影响,并初步探讨二者的互作效应,试验期7周。结果表明:600μg/kg铬或100mg/kgL-肉碱对脂质代谢多数指标效果显著(P<0.05或0.01);二者同时添加对蛋黄胆固醇、肝脏甘油三酯及腹脂率等均产生显著互作效应(P=0.0003～0.0500),且400μg/kg铬和100mg/kgL-肉碱混合添加对降低蛋黄胆固醇比其它各组均表现出优势,400μg/kg铬和50mg/kgL-肉碱混合添加对降低腹脂率比其它各组均表现出优势。铬或(与)L-肉碱在降低蛋鸡肝脂、腹脂及蛋黄胆固醇的同时并未影响蛋鸡的生产性能。     

Effect of recent cropping history and herbicide use on the degradation rates of isoproturon in soils

Five soil samples were taken from each of five fields with different crop management histories. Three of the fields were in an arable rotation, the fourth field was temporary grassland, and the final field was under permanent grass. Of the three arable fields, two had been cropped with winter wheat in three of the preceding 6 years, and the third had last been cropped with winter wheat once only, 6 years previously. With one exception, the winter wheat had been sprayed with the herbicide isoproturon. The rate of isoproturon degradation in laboratory incubations was strongly related to the previous management practices. In the five soils from the field that had been treated most regularly with isoproturon in recent years, <2.5% of the initial dose remained after 14 days, indicating considerable enhancement of degradation. In the soils from the field with two applications of the herbicide in the past 6 years, residues after 27 days varied from 5% to 37% of the amount applied. In soils from the other three sites, residue levels were less variable, and were inversely related to microbial biomass. In studies with selected soils from the field that had received three applications of isoproturon in the previous 6 years, kinetics of degradation were not first‐order but were indicative of microbial adaptation, and the average time to 50% loss of the herbicide (DT₅₀) was 7.5 days. In selected soils from the field that had received just one application of isoproturon, degradation followed first‐order kinetics, indicative of cometabolism. Pre‐incubation of isoproturon in soil from the five fields led to significant enhancement of degradation only in the samples from the two fields that had a recent history of isoproturon application.     

江河源区披碱草和星星草混播草地土壤物理性状对牦牛放牧强度的响应

在江河源区披碱草Elymus natans 星星草Puccinellia tenuflora混播人工草地上研究了牦牛放牧强度对土壤物理性状的影响,2年的试验结果表明:随着放牧强度的增加,不同土壤层含水量均呈降低趋势,土壤容重、土壤坚实度呈增大趋势.相关分析表明, 放牧强度与不同土壤层含水量呈极显著的负相关(P＜0.01), 与土壤容重和坚实度呈极显著的正相关(P＜0.01),而且土壤容重和坚实度均具有累积效应.     

洞庭湖湿地虉草替代大白菜对肉兔生产性能的影响

试验采用48只青年期(40～45日龄、体重约800 g)发育良好、健康无病的新西兰肉兔,随机分为4组:1组饲喂基础日粮,2～4组分别用占日粮5%,15%和25%的虉草Phalaris arundinacea代替日粮中等量的大白菜,试验期35 d.试验结果表明:各组间兔的日增重、屠宰率、料肉比等指标差异均不显著(P＞0.05),可见虉草代替大白菜不影响兔的生长,以15%的替代量的3组增重效果最佳,经济效益最好.