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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。 相似文献
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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。 相似文献
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蒸汽压片技术对玉米营养价值及奶牛饲用效果的影响 总被引：3，自引：0，他引：3
蒸汽压片是一种整粒玉米的加工方法,先进行蒸汽处理使淀粉发生凝胶糊化,然后通过反向旋转滚筒的剪切力将玉米压成一定厚度的薄片,以增加营养成分的暴露面积。蒸汽压片技术通过破坏玉米淀粉颗粒外周的蛋白质结构,增加糊化淀粉颗粒与酶的接触面积,从而提高玉米的淀粉消化率,蛋白质及其他营养物质的消化率也有所提高。压片玉米不仅可以增加奶牛的泌乳净能,改善其生产性能,对奶牛的健康方面也起到一定的维护作用。本文主要介绍了蒸汽压片技术的机理、工艺参数、对玉米营养价值的影响及其在奶牛业上的应用,并讨论了其潜在机制。 相似文献
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Flaking corn: processing mechanics,quality standards,and impacts on energy availability and performance of feedlot cattle 总被引：9，自引：0，他引：9
Based on performance of feedlot cattle, steam flaking increases the value of corn by 18%, considerably more than is suggested by tabular values. Tabular values underestimate the energy availability of flaked corn by failing to account for digestibility of the nonstarch OM that is increased by flaking by the same magnitude (10%) as starch. Correcting for improvement in digestibility of nonstarch OM increases the NEg value of steam-flaked corn to 1.70 Mcal/kg, a value very close to values calculated from cattle performance trials. Digestibility of starch from corn grain is limited by the protein matrix that encapsulates starch granules, and by the compact nature of the starch itself. Disruption of the protein matrix (by shear forces on hot grain during flaking) is the first limiting step toward optimizing starch digestion. Five critical production factors influence the quality of steam-flaked corn: steam chest temperature, steaming time, roll corrugation, roll gap, and roll tension. For optimal shear, it is important that rolls be hot and that kernels be hot when flaked. Steam chests should be designed to allow a steaming time of at least 30 min at maximum roller mill capacity producing a flake of 0.31 kg/L (24 lb/bushel). As little as 5% moisture uptake during steaming appears adequate. The rate of flaking and distribution of kernels across the rolls also are critical. Quality standards for steam-flaked corn include measurements of flake thickness, flake density, starch solubility, and enzyme reactivity. Flake density, the most common quality standard, closely associated with starch solubility (r2 = 0.87) and enzyme reactivity (r2 = 0.79), still explains only 63% of the variability in percentage fecal starch and 52% of the variability in starch digestibility. Direct determination of fecal starch can explain 91% of the variability in starch digestion. The NEg value of corn can be predicted from fecal starch: NEg= 1.78 - 0.0184FS. Starch digestion is a Kappa Curve function of hot flake density, reaching a maximum at a flake density of approximately 0.31 kg/L. Flaking to a density of less than 0.31 kg/L, though increasing starch solubility, may reduce DMI, increase variability of weight gain among animals within a pen, and predispose cattle to acidosis and bloat without increasing starch digestion. We recommend that the steam-flaking process be optimized on the basis of fecal starch analysis. 相似文献
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R A Zinn 《Journal of animal science》1990,68(3):776-781
Four crossbred steers (395 kg) with cannulas in the rumen, proximal duodenum and distal ileum were used to evaluate effects of steaming time of corn on characteristics of digestion. The basal diet contained (DM basis) 12% forage-and 75% corn. The corn portion of the diet was provided as either dry-rolled (DR) or steam-flaked (SF), which had been exposed to steam for 34, 47 or 67 min prior to flaking to a mean density of .34 kg/liter. Longer steaming times linearly increased in vitro reactivity of corn starch to amyloglucosidase. Steaming time had a quadratic effect (P less than .05) on ruminal starch digestion. Ruminal starch digestibility of corn steamed for 47 min was 7% less than for corn steamed for 34 or 67 min. Longer steaming time linearly increased (P less than .05) flow of non-ammonia N to the small intestine with the principal increase (5.4%) between 34 and 47 min steaming time. Steaming time did not influence (P greater than .10) small intestinal or total tract digestibility of OM, starch or N. Compared with DR, SF increased (P less than .01) ruminal, small intestinal and total tract digestibility of starch 21.9, 75.1 and 9.2%, respectively. Although SF resulted in marked improvements in digestibility over DR, steaming times greater than 34 min were not beneficial. 相似文献
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Sindt JJ Drouillard JS Titgemeyer EC Montgomery SP Loe ER Depenbusch BE Walz PH 《Journal of animal science》2006,84(2):424-432
Performance and digestibility experiments were conducted to determine the influence of moisture and flake density (FD) on the feeding value of steam-flaked corn (SFC). Dietary treatments consisted of finishing diets that contained 78% (DM basis) SFC that was tempered using 0, 6, or 12% moisture and processed to either 360 (SF28) or 310 (SF24) g/L. A 3 x 2 factorial arrangement of treatments was used. In Exp. 1, 78 steers were individually fed the respective treatments for 106 d. Moisture added during tempering tended (linear; P < 0.10) to increase starch availability but linearly decreased (P < 0.01) particle size. Decreasing flake density increased (P < 0.001) starch availability and also decreased (P < 0.001) particle size. Starch availability (P < 0.001), moisture (P < 0.001), and particle size (P = 0.05) were all greater for SFC that was collected the day of processing compared with SFC that had been processed the previous day. Steers fed diets containing SF24 consumed less DM as the moisture level increased, whereas steers fed diets containing SF28 had increased DMI as moisture level increased (moisture x FD interaction; P < 0.01). Nonetheless, ADG, G:F, and most carcass characteristics did not differ among treatments. In Exp. 2, 6 multicannulated Jersey steers were used in a 6 x 6 Latin square using the same treatments as in Exp. 1. Increasing moisture intake linearly decreased (P < 0.05) starch intakes. Organic matter and N intakes followed similar trends but were not different. Decreasing FD tended to increase (P < 0.10) microbial N flow to the duodenum and increased microbial efficiency (P < 0.05). Ruminal starch digestibility was 90.5%, and total tract starch digestibility was 99.5% without adding moisture or processing beyond SF28. Moisture additions to corn before steam flaking resulted in few differences in performance or digestibility, despite increases in starch availability that occurred as moisture increased. Processing corn more extensively than SF28 may be unnecessary and cost-prohibitive. 相似文献
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Makoto Miyaji Hiroki Matsuyama Kenji Hosoda Kazuhisa Nonaka 《Animal Science Journal》2013,84(6):483-488
The objective of this study was to evaluate the effect of substituting brown rice grain for corn grain in total mixed ration (TMR) silage containing food by‐products on the milk production, whole‐tract nutrient digestibility and nitrogen balance in dairy cows. Six multiparous Holstein cows were used in a crossover design with two dietary treatments: a diet containing 30.9% steam‐flaked corn (corn TMR) or 30.9% steam‐flaked brown rice (rice TMR) with wet soybean curd residue and wet soy sauce cake. Dietary treatment did not affect the dry matter intake, milk yield and compositions in dairy cows. The dry matter and starch digestibility were higher, and the neutral detergent fiber digestibility was lower for rice TMR than for corn TMR. The urinary nitrogen (N) excretion as a proportion of the N intake was lower for rice TMR than for corn TMR with no dietary effect on N secretion in milk and fecal N excretion. These results indicated that the replacement of corn with brown rice in TMR silage relatively reduced urinary N loss without adverse effects on feed intake and milk production, when food by‐products such as soybean curd residue were included in the TMR silage as dietary crude protein sources. 相似文献
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玉米秸秆是作物残余物中最丰富的木质纤维素生物质之一,主要由纤维素、半纤维素和木质素通过氢键及其他化学键、分子键结合而成,是具有复杂聚合结构的高分子化合物,作为动物饲料的可利用率较低。蒸汽爆破即汽爆,是应用蒸汽弹射原理实现爆炸过程中对生物质预处理的技术。将蒸汽爆破技术应用于玉米秸秆处理,可高效分离纤维素,对玉米秸秆具有明显的解聚作用,有利于提高玉米秸秆的饲料化利用程度。作者介绍了蒸汽爆破工艺原理与参数,综述了蒸汽爆破处理对玉米秸秆纤维结构、化学成分和酶解产糖的影响,以及对玉米秸秆的营养成分消化率和瘤胃微生物附着的影响。已有研究表明,蒸汽爆破可使蒸汽分子渗入植物组织,经过瞬时释放将内能转化为机械能,作用于生物质组织细胞层间,达到原料分解的目的;蒸汽爆破可改变玉米秸秆的纤维结构,降低半纤维素和木质素含量,提高纤维素含量(随着蒸汽爆破的压强和维压时间的增加,半纤维素含量显著降低,而物料含水率的增加会导致纤维素含量升高);蒸汽爆破可提高玉米秸秆体外发酵酶解产糖率,随着蒸汽爆破压强和维压时间的增加,玉米秸秆体外培养酶解还原糖产量增加;蒸汽爆破可使玉米秸秆的体外发酵产气量、产气速率、干物质和酸性洗涤纤维含量显著提高,可提高反刍动物对玉米秸秆的消化利用率,充分利用玉米秸秆的纤维素,提高玉米秸秆的营养价值;蒸汽爆破通过破坏玉米秸秆的表面结构,可促进瘤胃微生物在玉米秸秆上的附着,从而促进玉米秸秆的降解。综上,蒸汽爆破技术处理玉米秸秆可提高其作为饲料的利用率。 相似文献