基质和沙土不同配比对蒙古莸容器苗生长的影响

蒙古莸为马鞭草科莸属的一种旱生灌木,具有药用、观赏、提取芳香油等较高的经济价值,抗性强,可用于水土保持和园林绿化。容器育苗作为当前广泛应用的苗木生产技术,采用容器育苗对于加快蒙古莸繁育应用具有重要意义,本试验利用基质和沙土作为原料,研究基质和沙土不同配比对蒙古莸容器苗生长的影响,以期筛选出较为经济、适用的基质配比。结果表明,基质和沙土不同的配比对蒙古莸的苗高度、地径和生物量的生长产生一定的影响。随着沙土比例的增加,蒙古莸高度、地径和生物量随之降低。但处理1、处理2、处理3间的高度与生物量生长间不存在显著差异,处理1与处理3间地径间有显著地差异,由此可知处理2和处理3为较理想的沙土与基质配比比例。     

饲料粒径对不同规格彭泽鲫幼鱼生长性能的影响

为研究饲料粒径对彭泽鲫幼鱼生长性能的影响及不同规格彭泽鲫幼鱼混养与单养的生长差异,共进行3个生长对比试验:同粒径饲料投喂不同规格彭泽鲫幼鱼生长试验;不同粒径饲料投喂大规格彭泽鲫幼鱼生长试验;不同规格彭泽鲫幼鱼混养与同规格幼鱼单养生长对比试验。各生长试验均为2个处理组,每组3个重复,饲料粒径分别为2.00和3.00 mm,试验幼鱼的平均初始体质量分别为1.32和13.42 g,试验期为30 d。结果显示:试验一中,不同规格彭泽鲫幼鱼摄食2.00 mm粒径的饲料均能获得生长效果,大规格幼鱼组的增重率(WG)和特定生长率(SGR)显著高于小规格幼鱼组(P0.05),饲料系数(FCR)和摄食率显著低于小规格幼鱼组(P0.05);试验二中,2.00 mm粒径饲料组增重率和特定生长率显著高于3.00 mm粒径饲料组(P0.05),饲料系数显著低于3.00 mm粒径饲料组(P0.05),不同粒径的饲料对彭泽鲫幼鱼的摄食率无显著影响(P0.05);试验三中,大规格彭泽鲫幼鱼单养组增重率和特定生长率显著高于大规格和小规格幼鱼混养组(P0.05)。研究表明,不适宜的饲料粒径对彭泽鲫幼鱼的生长造成显著的负面影响。     

小肽、牛至油及其相互作用对生长肥育猪抗病效果的影响

为研究小肽、牛至油及其相互作用对生长育肥猪生产性能的影响,探索其作为抗生素替代品促进肥育猪生长使用的可行性,试验在基础日粮中分别添加抗生素、小肽、牛至油和小肽+牛至油饲喂生长肥育猪,进行20~≤40 kg、40~≤60 kg、60~≤90 kg这3个体重阶段的比较,测定分析生长肥育猪生产性能、发病情况、血液生化指标等。结果表明:1)在20~≤40 kg小猪阶段以添加小肽+牛至油组效果最优;2)在40~≤60 kg中猪阶段以添加小肽效果最优;3)在60~≤90 kg大猪阶段以添加牛至油效果最优。     

坪床基质对兰引Ⅲ号结缕草根系生长及分布的影响

坪床结构对草坪草根系和草坪使用质量的影响很大。为探讨5种坪床基质对兰引Ⅲ号结缕草（Zoysia japonica ‘LanyinNo. III’）根系生长的影响,试验设计5种坪床基质：100% 纯砂（A）,砂：泥炭（85%：15%）（B）,砂：土（85%：15%）（C）,砂：土：泥炭（85%：7.5%：7.5%）（D）,100% 纯土（E）。结果表明：根长密度、根表面积密度随坪床深度的加深而减小,纯土坪床的上述根系指标显著小于砂基坪床;一级根在0～5 cm的根层中分布最多l而二级根在5～10 cm根层分布最多;3种砂质混合基质中,砂+泥炭混合基质好于砂+土和砂+土+泥炭2种混合基质。在土壤各层深度中,砂基坪床的根平均直径显著大于纯土坪床。纯砂坪床的地下生物量最大,而纯土坪床0～5 cm根层内根系生物量所占比例最大。综合分析认为,砂基坪床适合做运动场草坪,其中以砂与泥炭混合基质最好,纯土坪床则排水不良,不适宜做运动场草坪。     

不同覆盖基质对天麻产量的影响

天麻人工栽培环境直接影响其产量与品质。用田间试验的方法研究了不同覆盖基质对天麻产量的影响,结果显示,与其它两种处理相比,处理3即白杨木棒+杂木棒,细沙∶土(2∶1)基质覆盖栽培,能显著提高天麻一级和四级产品规格以及试验小区的产量,建议在生产中推广应用。     

饲粮样品粉碎粒度对ADF和NDF尼龙滤袋法测定值的影响

为探讨样品粉碎粒度对饲粮NDF和ADF测定值的影响,将肉羊全混合饲粮碾磨过2mm筛而1mm筛上物分别为80％（1组）、40％（2组）,过1mm筛而0．5mm筛上物分别为80％（3组）、40％（4组）、0％（5组）,共5种粒度,用自制200目和400目尼龙滤袋测定ADF和NDF的含量。结果表明：用200目尼龙滤袋测定的ADF的含量,1组显著高于3、4、5组,2、3组显著高于4、5组（P〈0．05）;而用400目尼龙滤袋测定的结果,1、2、3组显著高于5组,2组显著高于4组（P〈0．05）;用两种尼龙滤袋测定的ADF值,随饲粮样品粉碎粒径的变小而降低。用200尼龙滤袋测定的NDF含量,l组显著高于2、3、4、5组,2组显著低于3、4、5组（P〈0．05）;用400目尼龙滤袋测定的结果中,1、3、4组显著高于2、5组;用两种尼龙滤袋测定的NDF值,除了2组外,有随饲粮样品粉碎粒径的变小而降低的趋势。饲粮样品的粉碎粒度对用尼龙滤袋法测定的ADF和NDF的结果存在明显影响,样品粒径越小,ADF和NDF的测定值就越低。     

兰州市屋顶绿化地被植物种植基质的筛选

为了筛选出适宜兰州市屋顶绿化地被植物种植基质配比的类型,以小花草玉梅(Anemone rivularis)和金娃娃萱草(Hemerocallis fulva ‘Golden Doll’)为供试材料,以田园土、泥炭、蛭石和椰糠为基质原材料,选用L_9(3~4)正交表进行试验,并以田园土为对照,对4种基质原材料10种不同配比基质中小花草玉梅和金娃娃萱草的成活率、越夏率、越冬率、120 d植株的株高、冠幅以及生长速率等指标进行测定与分析。结果表明:Ⅱ号、Ⅲ号和Ⅵ号基质的持水性较长,Ⅲ号、Ⅳ号、Ⅴ号、Ⅵ号基质中的小花草玉梅和金娃娃萱草成活率均为100%;Ⅴ号和Ⅵ号基质中小花草玉梅和金娃娃萱草的越夏率和越冬率均为100%;Ⅲ号和Ⅵ号基质中小花草玉梅和金娃娃萱草的株高和冠幅均较其他基质高,生长势也较好。4个因素对小花草玉梅生长速率影响的主次顺序依次为泥炭、椰糠、田园土和蛭石,对金娃娃萱草影响的主次顺序依次为泥炭、田园土、椰糠和蛭石。小花草玉梅和金娃娃萱草生长表现最好的基质为Ⅵ号基质,即田园土∶泥炭∶蛭石∶椰糠=3∶6∶1∶2,建议在兰州市屋顶绿化地被植物种植中使用Ⅵ号基质配比方案。     

金华猪不同类型肥育性能的对比研究

<正> 金华猪是我国地方优良猪种之一,具有皮薄骨细,早熟易肥,肉质鲜美,繁殖力高,遗传性稳定等优良特性。长期以来由于产区饲养条件和群众对猪种的选择要求不同,形成了大、中、小3个类型。为了进一步了解不同类型与生产性能的关系,为育种     

不同基质对红颊草莓生长发育及果实品质的影响

本研究以红颊草莓为试验材料,在温室立体阶梯式高架栽培模式下,通过对比国外专用基质和国内基质对“红颊”草莓的生长和果实品质的影响,从而筛选出适合“红颊”草莓的基质。结果表明上层国外专用基质红颊草莓在营养生长阶段比国内基质上层生长健壮;中层和下层国外专用基质和自己配制基质处理对草莓营养生长发育没有显著性差异;果实品质方面无论是上层、中层或下层,国外专用基质和国内基质处理也没有显著性差异。同一基质上、中、下三层之间果实品质也没有差异。综合这两种基质对草莓植株生长和果实品质等指标的影响,两种基质对草莓的生长发育差异不显著,国内基质完全可以代替国外专用基质使用。     

不同氮肥和基质类型对匍匐翦股颖草坪质量的影响

为了更好地了解不同氮肥和基质类型对高尔夫果岭草坪质量的影响,在温室里模拟果岭用PVC管建造4种基质类型的匍匐翦股颖Agrostis stolonifera cv.Prenncross草坪,出苗后施用Hoagland和Arnon营养液培育至成坪,成坪后选用速效氮尿素和控释肥丁异叉双缩脲进行氮肥类型处理。试验结果表明,基质类型对匍匐翦股颖的生长和坪用质量有着显著影响并表现出阶段性差异。4种基质类型的草坪成坪速度快慢顺序为：土壤基质>改良沙基质>半改良沙基质>纯沙基质,这也是表层有机质累积量的大小顺序;外观质量高低为：改良沙基质>半改良沙基质>纯沙基质>土壤基质;在播种建坪的初期施用速效氮肥有助于匍匐翦股颖的生长和快速成坪;缓释氮肥释放速率慢,更符合草坪成熟后对氮的需求规律。缓释氮肥起效慢,应在草坪逐渐成熟时与速效氮肥搭配施用。     

前后期饲粮不同粉碎粒度组合对肉鸡生长性能的影响

本试验旨在研究不同粉碎粒度对饲料加工质量的影响以及肉鸡不同粉碎粒度饲粮对不同生长阶段肉鸡生长性能的影响。选用864只1日龄白羽爱拔益加(AA)肉鸡,随机分为6组,每组8个重复,每个重复18只鸡,进行为期42 d的饲养试验,分为前期(1~21日龄)和后期(22~42日龄)2个阶段。前、后期饲粮分别采用1.5、2.0和2.5 mm筛片孔径进行粉碎,每个筛片孔径设4个重复。前期设3个组,1.5 mm组设24个重复,2.0 mm组设16个重复,2.5 mm组设8个重复;后期设6个组,将前期1.5 mm组平均分为3个组,2.0 mm组平均分为2个组,2.5 mm组不变,每组8个重复。结果表明:1)饲料的几何平均粒径随着筛片孔径的增加而增加,其中2.5 mm组的几何平均粒径显著大于1.5和2.0 mm组(P0.05);颗粒耐久性指数(PDI)、颗粒硬度和淀粉糊化度随着筛片孔径的增加而降低,其中1.5 mm组的PDI和颗粒硬度显著大于2.0和2.5 mm组(P0.05);随着筛片孔径的增加,各组饲料的粗蛋白质体外消化率无显著差异(P0.05)。2)1~21日龄时,2.0 mm组的21日龄平均体重、平均日采食量和平均日增重均为最高。22~42日龄时,前期2.0 mm、后期2.5 mm组的42日龄平均体重和平均日增重最高,料重比最低;前期1.5 mm、后期2.5 mm组的平均日采食量最高。综合以上结果,前期2.0 mm、后期2.5 mm组的生长性能最好。所以,肉鸡前期饲粮采用筛片孔径为2.0 mm、后期饲粮采用筛片孔径为2.5 mm进行粉碎,生长性能最佳。     

盐酸金霉素超微粉制备及其在鸭体内的药代动力学研究

[目的] 研究盐酸金霉素超微粉在鸭体内的药代动力学特征。[方法] 采用气流粉碎技术将盐酸金霉素普通原粉制备成800目超微粉,再添加适宜辅料制成含量为20%的盐酸金霉素可溶性粉,通过影响因素试验和加速试验对制备的盐酸金霉素超微粉进行稳定性评价;将30只90日龄绍兴麻鸭随机分为A、B、C 3个试验组,每组10只,分别经口单剂量灌服60目普通原粉制备的盐酸金霉素可溶性粉、800目超微粉制备的盐酸金霉素可溶性粉、80目普通原粉制备的盐酸金霉素可溶性粉,剂量均为15 mg/（kg·BW）（以金霉素计）,比较不同粒径原料制备的盐酸金霉素可溶性粉在鸭体内的药物代谢过程。[结果] 利用800目超微粉制备的盐酸金霉素可溶性粉处方、工艺稳定可行,通过稳定性试验考查,质量可靠;不同粒径原料制备的盐酸金霉素可溶性粉主要药代动力学特征如下：试验B组达峰时间（T_max）显著（P<0.05）快于A组和C组;试验B组药时曲线下面积（AUC_0-t）、达峰浓度（C_max）均显著（P<0.05）大于A组和C组;试验B组消除半衰期时间（t_1/2）显著（P<0.05）长于A组和C组,A组和C组之间无统计学差异（P>0.05）;试验B组体内存留时间（MRT）显著（P<0.05）长于A组和C组。[结论] 鸭灌服相同剂量的金霉素[15 mg/（kg·BW）],相较于普通原粉制备的盐酸金霉素可溶性粉,盐酸金霉素超微粉在体内1.5 h即达到血药峰浓度,吸收迅速且有效血药浓度维持时间长。研究获得的药动学数据可为盐酸金霉素用于动物临床治疗提供参考。     

瘦肉型种公猪生长曲线分析

随着瘦肉型猪饲养量的不断增加,对瘦肉型猪生长发育规律的研究成为养猪业研究的重要方面之一。本研究采用Logistic方程与非线性混合效应模型方法,分析瘦肉型种公猪30￣100kg生长情况,结果表明:采用Logistic方程、非线性混合效应模型均能很好地拟合杜洛克、长白与大白种公猪的生长曲线,但非线性混合效应模型的拟合效果要优于Logistic方程,Logistic方程拟合低估了猪只的生长潜能。采用非线性混合效应模型拟合的结果还表明,瘦肉型长白种公猪的成熟体重要高于杜洛克、大白种公猪,表明目前长白种公猪选育更趋向于个体大型化,而大白种公猪趋向于个体小型化。     

Equine Demineralized Bone Matrix: Relationship Between Particle Size and Osteoinduction

The osteoinductive capability of four particle sizes of equine demineralized bone matrix (DBM) was evaluated. Matrix particles were implanted in brachiocephalicus muscle pouches in six horses and were harvested 8 weeks later. Matrix particle sizes of 2.0 mm³ to 4.0 mm³ and 5.0 mm³ to 10.0 mm³ were associated with osteoinductive activity and minimal signs of local inflammation. The two smaller particle sizes (0.425 mm³ to 0.850 mm³ and 0.850 mm³ to 2.0 mm³) were minimally osteoinductive and were associated with a greater local inflammatory response. Microscopic events associated with new bone production in the two largest particle sizes included the presence of new osteoprogenitor cells in matrix vascular spaces, multinucleated osteoclast-like giant cells, and the formation of cartilage, osteoid, and new mineralized bone. The two smaller particle sizes were associated with increased fibrous tissue ingrowth and the presence of increased numbers of inflammatory cells. The temporal events of osteoinduction in response to heterotopic implantation of allogeneic DBM were delayed in horses when compared with other species. Although the demineralization technique used was effective in previous investigations on other species, incomplete demineralization occurred in the two smaller particle sizes that was not detected until after DBM implant harvest. The demineralization process may need to be altered for equine bone and precise monitoring for complete demineralization before implantation is required. Equine DBM is osteoinductive in muscle pouch sites in horses but matrix particle size does affect osteoinductive capability.     

Effects of soybean meal particle size on growth performance of nursery pigs

We used 360 nursery pigs (35 +/- 3 d of age) in two 21-d growth assays to determine the effects of soybean meal particle size on growth performance. In both trials, there were six pigs per pen and 10 pens per treatment. Pigs were weaned on d 21 and fed the same phase I diet for 7 d after weaning, followed by a phase II diet from d 7 to 14. On d 14, all pigs were weighed and randomly allotted to one of three dietary treatments. Experimental diets contained 61.9% corn, 34.4% soybean meal, and 3.7% vitamins and minerals. In Exp. 1, 90 barrows and 90 gilts (9.2 +/- 2.3 kg BW) were fed diets containing extruded-expelled soybean meal ground to 965, 742, or 639 microm, which resulted in whole-diet particle sizes of 728, 719, and 697 microm, respectively. Reducing extruded-expelled soybean meal particle size from 965 or 742 to 639 microm in the diet did not affect (P > 0.10) ADG (541, 538, and 542 g/d), ADFI (886, 875, and 855 g/d; as-fed basis), or gain:feed ratio (0.61, 0.61, 0.64), respectively. In Exp. 2, 90 barrows and 90 gilts (9.9 +/- 2.6 kg BW) were fed diets containing solvent-extracted soybean meal ground to 1,226, 797, or 444 microm, which resulted in whole-diet particle sizes of 732, 681, and 629 microns, respectively. Like Exp. 1, reducing particle size of solvent-extracted soybean meal did not affect (P > 0.10) ADG (482, 487, and 484 g/d), ADFI (738, 742, and 736 g/d; as-fed), or gain:feed (0.65, 0.65, and 0.65). Reducing particle size of extruded-expelled soybean meal or solvent-extracted soybean meal increased the angle of repose (maximum degree at which a pile of material retains its slope), indicating that as particle size decreased, flowability characteristics decreased. However, the angle of repose of the complete diets was greater than that for the soybean meals, which indicates that decreasing the particle size of soybean meal had minimal effects on flow characteristics of the complete diet. Previous research has shown that decreasing grain particle size improves digestibility and feed efficiency, and decreased soybean meal particle size has resulted in improved amino acid digestibility. However, the results of our experiments suggest decreasing particle size of either extruded-expelled soybean meal or solvent-extracted soybean meal does not affect nursery pig growth performance.     

仿生消化系统测定玉米和大豆粕酶水解物能值影响因素的研究

本试验旨在通过探讨饲料样品的粉碎粒度、未水解残渣的清洗次数和透析袋处理后的存放时间对仿生消化法中玉米、大豆粕干物质消化率和酶水解物能值的影响,为确立基于仿生消化系统（ＳＤＳ １）测定饲料酶水解物能值的操作规程提供参考。试验采用单因素完全随机设计,共设１１个处理,每个处理５个重复,每个重复１根消化管。其中处理１～３、４～７、８～１１分别考察饲料样品的粉碎粒度、未消化残渣的清洗次数、透析袋处理后的存放时间对玉米和大豆粕干物质消化率及酶水解物能值的影响。结果表明：１）粉碎粒度对玉米、大豆粕的干物质消化率和酶水解物能值都有显著性影响（Ｐ＜０．０５）。当玉米的粉碎粒度从 ４０目减少到 １００目时,其干物质消化率和酶水解物能值依次增加,而且变化幅度较大的粒度范围出现在 ４０～６０目。而大豆粕的粉碎粒度从４０目减少到１００目时,尽管６０目样品的干物质消化率与酶水解物能值最高,但与其他 ２个粉碎粒度样品的干物质消化率相差在 ０．７０％以内。２）未消化残渣的清洗次数对玉米、大豆粕的干物质消化率与酶水解物能值均有显著性影响（Ｐ＜０．０５）。随着清洗次数的增加,玉米、大豆粕的干物质消化率和酶水解物能值逐步趋于稳定。在清洗 ６次后,玉米、大豆粕的干物质消化率与酶水解物能值的变异已趋于 ＳＤＳ １的测定误差的允许范围之内。３）透析袋处理后的存放时间对玉米、大豆粕的干物质消化率和酶水解物能值也有显著性影响（Ｐ＜０．０５）,但在 ４个存放时间的处理水平内,玉米、大豆粕的干物质消化率、酶水解物能值的变化都在０．９４％和 ０．３７ＭＪ／ｋｇ以内,处于 ＳＤＳ １测定误差的允许范围内。综合上述结果,ＳＤＳ １测定饲料酶水解物能值时,样品的粉碎粒度应为 ６０目、未消化残渣的清洗次数为 ６次。透析袋前处理后 ４℃下存放 ９０ｄ内均可用于对玉米、大豆粕干物质消化率和酶水解物能值的测定。     

Effects of Corn and Soybean Meal Particle Size on Phosphorus Use in Turkey Poults

Two 28-d experiments were conducted to evaluate the effect of grinding corn or soybean meal (SBM) to various particle sizes on P utilization in turkey poults. Dietary Ca was formulated to be 1.20% in the corn-SBM-based diets of both studies and nonphytate P (NPP) was calculated to be 0.40% in experiment 1 and 0.48% in experiment 2. In experiment 1, corn that had been processed through a roller mill was used or was ground through 3 different screen sizes in a hammer mill to yield 4 corn particle sizes ranging from about 600 to 1,100 μm. Initial (7 d) growth was reduced when the coarsest corn was fed due to lower feed intake. Phosphorus utilization was improved the first 2 wk as corn particle size increased as measured by incidence of rickets, tibia ash, and total P retention. Gizzard weight and phytate P retention were increased at 28 d as corn particle size increased. In experiment 2, corn was ground to approximately 850 μm and commercial SBM (856 μm) was used or ground to 2 finer particle sizes in a hammer mill. Gizzard weight and phytate P retention were increased at 28 d as SBM particle size increased. Other parameters were not affected at least partially due to the higher dietary NPP level fed to prevent severe rickets observed in the first trial. These studies show that young poults can utilize P better from coarser corn and soybean meal, especially when dietary P is low.     

玉米粉碎粒度对育肥猪颗粒饲料加工质量及猪生长性能的影响

本试验旨在研究同一配方下,玉米不同粉碎粒度对颗粒饲料加工质量和育肥猪生长性能的影响。选用1.5/2.0、2.0/2.0、2.0/2.5、2.5/2.5、2.5/3.0和3.0/3.0 mm孔径的筛片对玉米进行粉碎,分别得到几何平均粒径为303.91、346.08、356.81、358.51、373.29和387.70μm的玉米原料,采用同一配方和相同的加工参数(其他原料粉碎筛片孔径2.0 mm,制粒调质温度80℃、模孔直径3.0 mm、长径比9∶1)加工成含不同粉碎粒度玉米的饲粮。选取108头平均体重为(62.68±5.59)kg的"杜×长×大"杂交猪,随机置于6个组(每个组3个重复,每个重复6头猪,公母各占1/2),分别饲喂含不同粉碎粒度玉米的饲粮,试验周期为8周。结果表明:随着筛片孔径的增大,粉碎能耗从9.02 k W·h/t降低到6.86 k W·h/t,制粒能耗从19.06 k W·h/t升高到22.30 k W·h/t;粗蛋白质体外消化率随玉米粉碎粒度的增加呈现上升的趋势,其中2.5/2.5 mm组最高,且显著高于1.5/2.0 mm组(P0.05);颗粒硬度2.5/3.0、3.0/3.0 mm组显著高于其他组(P0.05);随粉碎粒度的增加饲粮干物质表观消化率降低,其中1.5/2.0和3.0/3.0 mm组分别为84.43%和80.62%,后者比前者降低了4.5%,且差异显著(P0.05);随玉米粉碎粒度的增加饲粮粗蛋白质表观消化率整体呈现下降的趋势,且1.5/2.0 mm组粗蛋白质表观消化率为86.14%,与其他各组差异显著(P0.05);各组平均日增重和料重比均无显著性差异(P0.05),2.5/2.5 mm组平均日采食量最高,但与各组间无显著性差异(P0.05)。根据本试验结果,建议育肥猪饲粮玉米粉碎粒度采用2.5/2.5 mm筛片孔径。     

Risk factors for local spread of foot-and-mouth disease, 2010 epidemic in Japan

To provide a basis for effective foot-and-mouth disease (FMD) prevention measures, factors associated with local spread were investigated in this study using data of the 2010 FMD epidemic in Japan. Thirty-eight local clusters within a 500-m radius from source farms were selected. In the clusters with pig source farms, more neighboring farms were infected in a short time compared with the clusters with cattle source farms. The influence of distance and wind upon local spread did not show a significant difference between infected and noninfected neighboring farms. Large-size pig farms posed a greater risk of inducing local spread; the odds ratio with reference to small-size cattle farms was 16.73. Middle-size and large-size cattle farms had a greater risk of infection; odds ratios with reference to small-size cattle farms were 15.65 and 25.52, respectively. The present results are useful for understanding features of local spread and prioritizing farms for control measures.     

TMR制作粒度对肉牛增重与瘤胃微生物发酵的影响

为研究不同粒度全混合日粮(TMR)对肉牛增重和瘤胃发酵的影响,试验选取新疆褐牛(♂)与哈萨克牛(♀)杂交一代、体重为(305.6±5.6)kg的公牛70头,随机分为2组,预试期14 d,正试期44 d。日粮为不同搅拌时间的TMR,使用宾州筛进行粒度分布测定。对照组TMR搅拌时间为30 min,平均粒度为7.1 mm;试验组TMR搅拌时间为40 min,平均粒度为6.1 mm。结果表明:与对照组相比,试验组第1层(>19 mm)比例下降了6.3个百分点,第2层(>8 mm)和底层(≤1.18 mm)比例下降了3个百分点(P<0.01);结合剩料粒度分析结果研究发现,虽然延长搅拌时间后没有提高TMR总采食量,但提高了肉牛对TMR中粒度大于8 mm长纤维饲料的进食量,并提高了肉牛育肥全期平均日增重(P<0.05),饲料转化效率提高了12.7%(P=0.01);对TMR及宾州筛各层样品采用体外瘤胃发酵测试结果表明,延长TMR搅拌时间对体外干物质消化率、发酵产气量与产气速率、氨氮和挥发性脂肪酸(VFA)生成量无影响;但随着筛分粒度的下降,总VFA生成量升高(P=0.02),其中乙酸比例下降而丁酸比例升高(P<0.05)。综上所述,通过延长搅拌时间降低TMR粒度虽未能提高采食量,但可促进肉牛生长继而显著提高饲料转化效率,并有利于维持瘤胃微生物的正常发酵功能。