蒸汽压片玉米在肉牛养殖生产中的应用研究进展

玉米是肉牛养殖生产中的重要能量饲料.经蒸汽压片处理的玉米可提高牛对玉米的消化吸收率,饲喂蒸汽压片玉米可对肉牛瘤胃发酵、生产性能、肉品质等产生积极影响.文章结合有关研究报道,简述玉米蒸汽压片技术、蒸汽压片玉米营养价值以及饲喂蒸汽压片玉米对肉牛生产性能的影响,以期为蒸汽压片玉米在肉牛养殖生产中的应用推广提供参考.     

不同泌乳期高产奶牛对蒸汽压片玉米饲喂的反应

蒸汽压片谷物（玉米或高粱）在20世纪60年代初期就开始应用于母牛或肉牛饲喂,能够明显提高饲养效率.这与蒸汽压片谷物的淀粉消化率提高有关,也与其在瘤胃发酵时丙酸比例上升和乙酸比例下降有关.但乙酸在乳脂的合成中具有重要作用,而乳脂率又在牛奶的定价中占有主导地位.蒸汽压片谷物在奶牛特别是泌乳母牛饲喂中的研究和使用,直到20世纪90年代初才开始,这是因为目前在许多国家乳蛋白质率在牛奶定价中比乳脂率占有更大的权重.     

蒸汽压片处理谷物对奶牛生产性能的影响

谷物加工主要有干碾压、蒸汽碾压和蒸汽压片处理三种方法。蒸汽压片处理是提高谷物淀粉消化率的最有效的途径。生产中采用该法处理谷物对提高奶牛生产性能有现实意义。     

谷物饲料加工新技术——蒸汽压片（之二）

国内外蒸汽压片的应用状况在欧洲和美国等畜牧业发达国家,蒸汽压片处理加工技术在奶牛、肉牛、肉羊饲养中20年前就已经广泛应用。美国有9800万头围栏育肥肉牛,100%的肉牛肥育场使用蒸汽压片处理的谷物。在奶牛饲养中近5年来使用蒸汽压片谷物的奶牛场数量也达到了60％～70%。近年来,我们相邻的韩国和日本也大量开始使用蒸汽压片谷物饲料饲喂牛羊,日本牛饲料约占整个饲料的25％,     

牛用谷物蒸汽压片及其饲养效果

蒸汽压片是美国牛用谷物普遍使用的一种加工方式。蒸汽压片能够提高谷物营养物质、尤其是淀粉的消化率,提高奶牛的泌乳性能,提高肉牛的料重比。本文介绍了蒸汽压片工艺及其对牛代谢和生产性能的影响。     

谷物饲料蒸汽压片技术及应用

蒸汽压片技术具有提高机体对谷物饲料淀粉的消化率,降低有害微生物数量,改善畜产品品质以及减少畜禽粪便排泄量等特点。此文介绍了蒸汽压片技术的原理、加工工艺及其应用。     

不同泌乳期高产奶牛对蒸汽压片玉米饲喂的反应

蒸汽压片谷物（玉米或高梁）在上世纪60年代初期就开始应用于生长母牛或肉牛，能够明显提高饲养效率。这与蒸汽压片谷物的淀粉消化率提高有关，也与其在瘤胃发酵时丙酸比例上升和乙酸比例下降有关川。但乙酸在乳脂的合成中具有重要作用，而乳脂率又在牛奶的定价中占有主导地位，所以蒸汽压片谷物在奶牛特别是泌乳母牛饲喂中的研究和使用，直到上世纪90年代初才开始，这是因为目前在许多国家乳蛋白质率在牛奶定价中比乳脂率占有更大的权重。     

蒸汽压片玉米调控瘤胃发酵与营养物质消化的研究进展

玉米作为反刍动物重要能量饲料,在饲养实践中通常需要进行一定加工处理之后进行饲喂,以提高其养分利用率.蒸汽压片技术是目前一种重要的玉米加工方式,可以显著提高玉米淀粉全消化道消化率,并在维持瘤胃微生物正常发酵方面具有重要作用.本文综述了蒸汽压片玉米调控瘤胃中营养物质消化和微生物发酵的作用功效与机理,以期为蒸汽压片玉米的进一...     

谷物蒸汽压片与养牛生产

蒸汽压片(steam-flaking)能够显著地提高谷物淀粉和其它一些成分在肠道内的消化率,改善养分在肠道内的分配和吸收,从而使奶牛的泌乳性能和肉牛的屠体品质得以改善。另外,蒸汽压片还能够增加肠道对氮的吸收,降低氮的排放量,减少对环境的污染。     

蒸汽压片玉米加工工艺及其在反刍动物生产中应用的研究进展

玉米是反刍动物养殖生产中主要的能量原料之一。反刍动物对玉米的消化率关系到饲料的利用率、生产性能及养殖的经济效益。目前,蒸汽压片工艺是玉米比较理想的加工技术,可提高玉米淀粉的消化率,改善玉米淀粉糊化度及能值,从而提高玉米的饲喂价值。蒸汽压片玉米可以调节反刍动物瘤胃发酵功能,提高生长性能,改善肉品质,进而增加养殖利润。因此,文章总结了蒸汽压片玉米加工工艺、营养价值及其对反刍动物生产性能的影响,以期为蒸汽压片玉米在反刍动物的养殖生产中的高效利用提供参考。     

蒸汽压片玉米在奶牛生产中的应用研究进展

玉米是奶牛舍饲的主要能量饲料来源之一,而蒸汽压片技术是一项目前较为成熟的日粮加工技术,主要通过机械的湿热加工方法改变原料物理形态和营养物质的化学结构,广泛应用于反刍动物日粮中。蒸汽压片处理工艺中的蒸汽压力、温度和处理时间会影响压片产品的容重和淀粉糊化度,进而影响其饲喂效果。研究发现,经蒸汽压片处理的玉米可有效提高其淀粉消化率,加快瘤胃内的发酵速度,改变瘤胃发酵模式,促进瘤胃微生物蛋白合成,有利于维持瘤胃pH及瘤胃内环境的稳定。也有研究表明,蒸汽压片玉米饲喂奶牛后,对其采食量没有明显影响,但可以提高产奶量,改善乳成分,从而提高奶牛的产奶性能。作者对蒸汽压片玉米技术及其在奶牛生产中的应用研究进展进行综述,以期为蒸汽压片玉米在中国奶牛生产中的合理使用提供参考。     

蒸汽压片玉米对奶牛生产性能和氮磷排放影响的研究

本试验旨在研究蒸汽压片玉米对泌乳早期中国荷斯坦奶牛生产性能和氮磷排放的影响.试验采用4×4重复拉丁方设计.将8头泌乳早期中国荷斯坦奶牛随机分为4组,每组2头.4种日粮处理中蒸汽压片玉米含量分别为精料的0、10%、20%和30%.试验分4期,每期28 d.结果表明:日粮中添加蒸汽压片玉米对奶牛干物质采食量无显著影响(P＞0.05),但显著提高了饲料转化率(奶料比)(P＜0.05);显著提高了奶牛产奶量,其中20%与30%组的4%标准奶产量(FCM)产量分别比对照组提高2.78和2.87 kg·d~(-1)(P＜0.01).对乳成分无显著影响(P＞0.05);乳蛋白、乳糖、乳非脂固形物含量呈增加趋势;对营养物质的表观消化率无显著影响(P＞0.05);日粮中添加蒸汽压片玉米显著降低了乳尿素氮水平(P＜0.05).试验组奶牛氮排放量分别比对照组降低了4.23%(P＞0.05)、9.37%(P＜0.05)和10.29%(P＜0.05),磷排放量分别比对照组降低了1.93%(P＞0.05)、2.59%(P＞0.05)和5.19%(P＞0.05).因此,饲喂蒸汽压片玉米能够有效提高奶牛的生产性能,降低氮磷的排放.     

Dry-rolled or steam-flaked grain-based diets and fecal shedding of Escherichia coli O157 in feedlot cattle

Hindgut is a major colonization site for Escherichia coli O157 in cattle. In this study, diets were formulated to effect changes in hindgut fermentation to test our hypothesis that changes in the hindgut ecosystem could have an impact on fecal shedding of E. coli O157. Feedlot heifers (n = 347) were prescreened for the prevalence of E. coli O157 by fecal and rectoanal mucosal swab cultures. A subset of 40 heifers identified as being positive for fecal shedding of E. coli O157 was selected, housed in individual pens, and randomly allocated to 4 dietary treatments. Treatments were arranged as a 2 x 2 factorial, with factor 1 consisting of grain type (sorghum or wheat) and factor 2 being method of grain processing (steam-flaking or dry-rolling). Four transition diets, each fed for 4 d, were used to adapt the animals to final diets that contained 93% concentrate and 7% roughage. The grain fraction consisted of dry-rolled sorghum, steam-flaked sorghum, a mixture of dry-rolled wheat and steam-flaked corn, or a mixture of steam-flaked wheat and steam-flaked corn. Wheat diets contained 52% wheat and 31% steam-flaked corn (DM basis). Fecal and rectoanal mucosal swab samples were obtained 3 times a week to isolate (enrichment, immunomagenetic separation, and plating on selective medium) and identify (sorbitol negative, indole production, and agglutination test) E. coli O157. The data were analyzed as repeated measures of binomial response (positive or negative) on each sampling day. Method of processing (dry-rolled vs. steam-flaked), sampling day, and the grain type x day interaction were significant (P < 0.05), but not the method of processing x grain type interaction. The average prevalence of E. coli O157 from d 9 was greater (P < 0.001) in cattle fed steam-flaked grains (65%) compared with those fed dry-rolled grains (30%). Average prevalence in cattle fed sorghum (51%) or wheat (43%) were similar (P > 0.10) on most sampling days. Results from this study indicate that feeding dry-rolled grains compared with steam-flaked grains reduced fecal shedding of E. coli O157. Possibly, dry-rolling allowed more substrate to reach the hindgut where it was fermented, thus making the hindgut inhospitable to the survival of E. coli O157. Dietary intervention to influence hindgut fermentation offers a simple and practical mitigation strategy to reduce the prevalence of E. coli O157 in feedlot cattle.     

饲料淀粉类酶制剂的营养机理及应用现状

饲料中的淀粉作为主要的供能物质，对动物的生长发育起着重要作用。淀粉类酶制剂的应用，提高了谷物的利用率及动物的生产效率，其研究具有重要意义。本研究综述了淀粉类酶制剂的分类及其对动物的作用，展望了淀粉酶的开发和利用前景。     

Estimating starch availability and protein degradation of steam-flaked and reconstituted sorghum grain through a gas production technique

Five steam-flaked sorghum grain (SFSG) samples with bulk densities of 476, 412, 347, 309 and 283 g/liter made by adjusting tension between mill rollers and three reconstituted sorghum grain (RSG) samples with reconstitution times of 10, 20 and 30 d and a control sample were analyzed for gas production kinetics (rumen liquor fermentation) and enzymatic glucose release (amyloglucosidase). Protein degradation was estimated from 6-h gas production and residual ammonia in the liquid. Gas production followed first-order kinetics (r2 greater than .98; P less than .01) and was used to describe rate and extent of digestion kinetics. Rate of gas production increased as processing degree increased. The magnitude of increase in gas production, however, was much less for RSG than for SFSG. Linear relationships were observed between enzymatic glucose release and the gas production rate constant k as well as gas production at 4,6 and 8 h (r2 greater than .98; P less than .01). Protein degradation decreased with processing degree of SFSG but increased with reconstitution time. A technique based on 6-h gas production and residual ammonia in the liquid is proposed to estimate both ruminal starch availability and ruminal protein degradability for processed sorghum grain.     

不同厚度蒸汽压片处理对玉米活体外瘤胃发酵的影响

试验以未处理的玉米及两种不同厚度蒸汽压片玉米(压片厚度为1.5mm,SFC 1.5;压片厚度为2.0mm,SFC 2.0)为材料,采用营养成分分析、活体外人工瘤胃产气量试验,研究不同厚度蒸汽压片处理对玉米营养成分、淀粉糊化度和活体外发酵特性的影响。结果表明,不同厚度蒸汽压片处理显著降低玉米粗蛋白质和粗脂肪含量(P0.05),显著提高了玉米的淀粉糊化度(P0.05);并且显著提高了玉米在瘤胃液内的淀粉降解率和体外产气速度(P0.05),显著降低了瘤胃液中氨态氮(NH3-N)浓度(P0.05);降低压片厚度(1.5和2.0mm),蒸汽压片玉米淀粉糊化度增加约17%(88.76%和71.60%),SFC 1.5的体外产气速度、4h干物质和淀粉产气率显著高于SFC 2.0(P0.05)。不同厚度蒸汽压片处理对玉米瘤胃48h产气量、12和24h瘤胃液pH、总挥发性脂肪酸产量及乙酸、丙酸、乙酸/丙酸、异丁酸、异戊酸、戊酸摩尔比影响均不显著(P0.05)。综上所述,不同厚度蒸汽压片处理可显著提高玉米在瘤胃内淀粉降解率和降解速度,降低瘤胃液中氨态氮浓度,而对48h产气量及其他发酵参数没有明显影响。     

Effects of planting density and processing method on laboratory characteristics of grain sorghum for ruminants

Grain sorghum grown in 38-cm (high-density) or 76-cm rows (normal-density) was steam-flaked, harvested as high-moisture grain followed by rolling and ensiling, or dry-rolled. Chemical composition, enzymatic starch availability, CP insolubility, and IVDMD in a reduced-strength buffer were evaluated. High-density planting increased (P < .10) OM and starch concentration and decreased (P < .0001) CP concentration but did not affect (P > .10) P concentration, enzymatic starch availability, or CP insolubility. High-density planting resulted in lower (P < .10) in vitro ruminal culture pH at 6, 12, and 18 h of incubation when grain sorghum was processed by steam flaking, and lower (P < .10) IVDMD at 6, 12, and 18 h of digestion when grain sorghum was processed by dry rolling. Steam flaking decreased (P < .10) CP concentration and solubility and increased (P < .10) OM concentration. High-moisture ensiling decreased (P < .10) the insolubility of CP but did not otherwise seem to alter the chemical composition of grain sorghum relative to dry rolling. Starch was more available (P < .10), and DM was digested more rapidly and extensively (P < .10) in vitro, in steam-flaked sorghum followed by high-moisture sorghum. Based on these data, it seems that planting density primarily affected chemical composition of grain sorghum, whereas processing primarily affected CP insolubility and rate and extent of starch fermentation.     

蒸汽压片玉米和颗粒玉米及其TMR日粮体外产气和发酵参数的测定

玉米是反刍家畜最重要的能量饲料,其主要成分为淀粉,含量可达64%~78%,易被消化吸收,且利用率高。特别是经过蒸汽压片处理后的玉米,能够调控淀粉在反刍家畜不同消化部位的降解率,进一步提高其营养价值。为了研究蒸汽压片玉米和颗粒玉米及其TMR日粮的营养价值,试验利用体外产气法对蒸汽压片玉米和颗粒玉米及其TMR日粮体外产气和发酵参数进行了测定。结果表明,玉米经过蒸汽压片处理后,可有效改善其在反刍家畜瘤胃内的降解率,营养价值得到了显著提高。     

Net absorption and hepatic metabolism of glucose, L-lactate, and volatile fatty acids by steers fed diets containing sorghum grain processed as dry-rolled or steam-flaked at different densities

We determined the effect of processing method (dry-rolled [DR] vs steam-flaked [SF]) and degree of processing (flake density; FD) of SF sorghum grain on splanchnic (gut and liver) metabolism of energy-yielding nutrients by growing steers. Diets contained 77% sorghum grain, either DR or SF, with SF at densities of 437, 360, or 283 g/L (SF34, SF28, or SF22). Eight multicatheterized steers (340 kg initial BW) were used in a randomized complete block design. Net output or uptake of glucose, L-lactate, VFA, and beta-hydroxybutyrate (BHBA) were measured across portal-drained viscera (PDV), liver, and splanchnic (PDV plus liver) tissues. Net absorption of glucose across PDV was negative and similar for all treatments (average of -104 g/d). Decreasing FD of SF sorghum grain linearly increased (P < or = .04) net absorption and splanchnic output of L-lactate by 20 and 130%, respectively, and hepatic synthesis (P = .06) and splanchnic output (P = .01) of glucose by 50%. Reducing FD did not alter output or uptake of acetate or n-butyrate by gut and liver tissues, but linearly decreased (P = .06) splanchnic output of BHBA by 40%. Net absorption (P = .18) and splanchnic output (P = .15) of propionate tended to be increased linearly by 50% with decreasing FD. Neither processing method (SF vs DR) nor degree of processing (varying FD) altered hepatic nutrient extraction ratios or estimated net absorption and splanchnic output of energy. Maximal contribution of propionate, L-lactate, and amino acids (alpha-amino N) to gluconeogenesis averaged 49, 11, and 20%, respectively. Feeding steers SF compared to DR diets did not alter net output or uptake of energy-yielding nutrients across splanchnic tissues, except net absorption of acetate tended to be greater (P = .13) for steers fed DR. Increasing degree of grain processing in the present study, by incrementally decreasing FD, tended to linearly increase the net absorption of glucose precursors (propionate and lactate), resulting in linear increases in synthesis and output of glucose by the liver to extrasplanchnic tissues (e.g., muscle).