奶牛常用饲料瘤胃干物质和淀粉降解规律的研究

以3头安装有永久性瘤胃瘘管的泌乳前期荷斯坦奶牛为试验动物,在精粗比为55∶45的日粮条件下,采用In sacco法测定了奶牛常用饲料瘤胃内干物质和淀粉的降解规律。试验结果表明,不同饲料的干物质和淀粉在奶牛瘤胃中的降解率不同。能量饲料中,麸皮的干物质和淀粉的瘤胃降解率均高于玉米;蛋白质饲料中,干物质和淀粉的降解率顺序是豆粕>胡麻饼>棉粕;常用粗料中,玉米青贮的干物质和淀粉的降解率均高于青干草。     

玉米不同处理方式对泌乳奶牛瘤胃降解规律的影响

为了研究不同加工处理方法对玉米在奶牛瘤胃内降解率的影响,本试验选用5头荷斯坦泌乳牛利用尼龙袋法测定玉米渣、膨化玉米、玉米片和蒸汽压片玉米的干物质和淀粉在泌乳奶牛瘤胃中的降解率．．结果表明,48h的瘤胃降解率规律为：玉米片〉膨化玉米〉蒸汽压片玉米〉玉米渣。瘤胃内可降解干物质为：膨化玉米和玉米片〉蒸汽压片玉米和玉米渣;而可降解淀粉则为：膨化玉米〉玉米片〉蒸汽压片玉米〉玉米渣,以上结果表明,加工过程中温度湿度和压力的作用下,玉米籽实的结构发生变化,改变了瘤胃微生物接触淀粉的机会,从而影响玉米在瘤胃内的降解率。     

玉米的不同温度和时间烘烤加工处理对泌乳奶牛瘤胃干物质和淀粉降解规律的研究

以3头安装永久性瘤胃瘘管的泌乳前期荷斯坦奶牛为试验动物，在精粗比为55：45的日粮条件下，采用In sacco法测定了不同温度和时间烘烤加工处理的玉米在奶牛瘤胃内干物质和淀粉的降解规律。结果表明，玉米经过不同温度和时间的烘烤处理，干物质和淀粉的瘤胃降解率都有不同程度的降低，随着温度逐渐升高、作用时间逐渐延长，干物质和淀粉的降解率也逐渐降低。在所有处理组中，140℃35min处理组可以明显降低玉米的瘤胃淀粉降解率（P〈O．05），比未处理玉米组降低了15．26％。淀粉在瘤胃中降解的影响因素最主要的是淀粉的快速可溶部分和降解速率。     

不同温度挤压膨化玉米在泌乳奶牛瘤胃内干物质和淀粉降解规律的研究

本试验选用3头安装有永久性瘤胃瘘管的泌乳前期荷斯坦奶牛为试验动物,在精粗比为55∶45的日粮条件下,采用尼龙袋法测定了不同温度挤压膨化加工处理的玉米在奶牛瘤胃内干物质和淀粉的降解规律。试验结果表明,玉米经过挤压膨化加工处理,能明显提高干物质和淀粉在泌乳奶牛瘤胃中的降解率(P<0.05)。随着挤压膨化温度的不断升高,干物质和淀粉的瘤胃降解率线性下降。     

用绵羊小肠液冻干粉测定饲料过瘤胃淀粉小肠消化率方法的研究

本试验旨在以玉米为样本筛选用绵羊小肠液冻干粉测定精饲料瘤胃非降解残渣淀粉小肠消化率的最佳培养条件。分别研究了小肠液冻干粉用量(0.2、0.3、0.4、0.5和0.6g)对16h玉米瘤胃非降解残渣干物质和淀粉小肠消化率的影响;离体培养时间(4、8、12、16、20和24h)对16h玉米瘤胃非降解残渣干物质和淀粉小肠消化率的影响。结果表明,在本试验条件下,绵羊小肠液冻干粉测定玉米瘤胃非降解残渣淀粉小肠消化率的最佳用量为0.45g小肠液冻干粉/0.56g玉米瘤胃非降解残渣,最佳培养时间为12h。利用绵羊小肠液冻干粉测定常用饲料过瘤胃残渣淀粉小肠消化率的方法是可行的。     

不同加工方式玉米的干物质和淀粉瘤胃降解率及过瘤胃淀粉含量的测定

为测定三种不同加工方式玉米的干物质及淀粉的瘤胃降解率并计算各自的过瘤胃淀粉含量,以3头安装有永久性瘤胃瘘管的利木赞×鲁西黄牛杂交阉牛为试验动物,采用尼龙袋法对常用的破碎玉米、膨化玉米、蒸汽压片玉米瘤胃降解率进行测定,并计算出三种不同加工方式玉米的过瘤胃淀粉含量.结果破碎玉米、膨化玉米和蒸汽压片玉米的干物质瘤胃有效降解率(%)依次为48.11、77.16和72.72,淀粉瘤胃有效降解率(%)依次为64.37、87.05和82.76;过胃淀粉含量(g/kg)依次为216.22、89.13和121.50.     

不同比例的湿玉米纤维饲料对奶牛瘤胃降解规律与表观消化率的影响

采用尼龙袋试验和消化试验研究在日粮中添加不同比例的湿玉米纤维饲料对奶牛瘤胃降解规律和表观消化率的影响。选用体重为550 kg左右、装有永久性瘤胃瘘管的成年荷斯坦奶牛4头,采用4×4拉丁方试验设计,对照组饲喂基础饲粮,试验组湿玉米纤维饲料分别占基础饲粮干物质重的5%、10%和15%。结果表明:15%试验组干物质(DM)的有效降解率显著高于其他试验组(P0.05);10%和15%试验组的粗蛋白(CP)的有效降解率显著高于其他试验组(P0.05);饲喂湿玉米纤维饲料对瘤胃酸性洗涤纤维(ADF)降解率没有影响,但显著降低了瘤胃中性洗涤纤维(NDF)的有效降解率(P0.05),其中15%试验组最低。随着湿玉米纤维饲料饲喂比例的增加,对日粮表观消化率没有显著影响(P0.05)。综上所述,饲喂湿玉米纤维饲料虽一定程度上降低了瘤胃NDF的有效降解率,但有效提高了瘤胃DM和CP的有效降解率,维持了瘤胃ADF有效降解率和日粮表观消化率的稳定,因此本试验中15%试验组是最适组。     

5种青贮饲料在奶牛瘤胃中的淀粉降解特性

本试验旨在研究苜蓿青贮、全株小麦青贮、燕麦青贮和全株玉米青贮（2种）共5种青贮饲料的淀粉瘤胃降解特性，对其有效降解率与实时降解率进行分析，以期能根据单个时间点的淀粉降解率来估算青贮饲料的淀粉降解率，并为《奶牛营养需要和饲养标准》的更新提供相关数据。选用4头装有永久性瘤胃瘘管的荷斯坦奶牛为试验动物，采用尼龙袋法评定淀粉的动态降解率和有效降解率，将装有待测饲料样品的尼龙袋在奶牛瘤胃中分别培养4、8、12、24、30、36、48和72 h，每头牛每个时间点设4个平行。结果显示：①随着在瘤胃内培养时间的延长，各青贮饲料的淀粉瘤胃降解率均呈现逐步上升的趋势，且在24 h后趋于稳定；全株小麦青贮的淀粉有效降解率最高，与依次降低的燕麦青贮、苜蓿青贮和全株玉米青贮差异显著（P < 0.05）。②试验所选用的青贮饲料的8 h淀粉降解率与其有效降解率相关性最强，R²为0.9876。由此可知，采用8 h淀粉降解率估测青贮饲料在奶牛瘤胃中的淀粉降解率是可行的，本试验结果可为科学配制奶牛日粮提供数据参考。     

不同加工处理玉米的干物质和淀粉在奶牛瘤胃中降解规律的研究

选择4头荷斯坦奶牛,利用尼龙袋法测定不同的物理加工处理(膨化、制粒、压扁、烘炒)的玉米干物质(DM)和淀粉在奶牛瘤胃中的降解率。各组玉米DM和淀粉的有效降解率从大到小依次为:膨化玉米>颗粒玉米>压扁玉米>对照玉米>烘炒玉米(P>0.05)。DM和淀粉的有效降解率P值的显著改变可能是在水分、热量和压力的作用下,玉米籽实的结构发生了变化,导致各组玉米的瘤胃降解率也不同。     

秦川肉牛5种常用精饲料的瘤胃降解特性研究

试验旨在研究秦川肉牛常用饲料的瘤胃降解特性,为秦川肉牛的科学养殖提供理论支持。试验选用3头装有永久性瘤胃瘘管的秦川肉牛(公牛),采用尼龙袋法评定秦川肉牛常用饲料的干物质(DM)、有机物(OM)和粗蛋白质(CP)的瘤胃降解率和有效降解率。DM的瘤胃有效降解率为麸皮玉米豆粕棉粕菜籽粕(P0.05)。OM瘤胃有效降解率依次为:麸皮玉米豆粕,各饲料间差异显著(P0.05),而菜籽粕与棉粕的有效降解率最低,两者之间差异不显著(P0.05)。CP有效降解率麸皮最高,玉米次之,豆粕最低,各饲料间差异显著(P0.05)。棉粕和菜籽粕均比豆粕高,且两者较为接近(P0.05)。结果表明:不同种类饲料瘤胃的有效降解率与饲料原料的养分组成有关。在5种饲料中,豆粕的CP含量最高,玉米的OM含量最高。麸皮的CP瘤胃有效降解率高于玉米,棉粕和菜籽粕的DM、OM、CP的瘤胃有效降解率均相似。     

新尼龙袋使用前瘤胃浸泡处理对饲料瘤胃降解特性的影响

本试验旨在研究瘤胃尼龙袋法中新尼龙袋使用前瘤胃浸泡处理对饲料瘤胃降解特性的影响.以8只装有永久性瘤胃瘘管的云南半细毛羊公羊为试验动物,随机分为2组(每组4只),分别采用预浸泡的尼龙袋(试验组)和未浸泡的尼龙袋(对照组)对玉米、豆粕、麦秸、黑麦干草4种常用饲料干物质(DM)和粗蛋白质(CP)的瘤胃降解特性进行研究.结果显...     

常规与非常规粗饲料在奶牛瘤胃中的降解特性研究

旨在探讨非常规粗饲料(玉米芯、毛豆荚壳)与奶牛常用粗饲料(苜蓿干草、玉米青贮)在奶牛瘤胃中的降解规律,试验选用3只装有永久性瘤胃瘘管的荷斯坦奶牛,采用尼龙袋法测定4种粗饲料的干物质(DM)、粗蛋白(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的瘤胃降解规律。结果表明:1)苜蓿干草和毛豆荚壳的CP含量分别为17.55%和11.10%,且苜蓿干草显著高于毛豆荚壳(P<0.05);玉米芯和玉米青贮的CP含量分别为2.97%和8.41%,且玉米芯显著低于玉米青贮(P<0.05);玉米芯的NDF和ADF含量显著高于其他3种粗饲料(P<0.05),达到79.98%和43.35%。2)苜蓿干草的DM有效降解率最高(P<0.05),由高到低依次为苜蓿干草、毛豆荚壳、玉米青贮和玉米芯。毛豆荚壳的CP有效降解率显著高于其他3种粗饲料(P<0.05),由高到低依次为毛豆荚壳、苜蓿干草、玉米青贮和玉米芯。苜蓿干草的NDF有效降解率显著高于毛豆荚壳(P<0.05),玉米青贮和毛豆荚壳无显著差异(P>0.05);玉米芯的ADF有效降解率最高(P<0.05),苜蓿干草、玉米青贮和毛豆荚壳无显著差异(P>0.05)。综上所述,玉米芯和毛豆荚壳可作为非常规粗饲料资源加以开发利用。     

Relationship between ruminal starch degradation and the physical characteristics of corn grain

The objectives of this study were to determine the range of variation in the rate and extent of in situ ruminal starch degradation of 14 corns differing in vitreousness and to predict ruminal starch degradability by physical characteristics of corn grains. This study was conducted with eight dent and six flint corns. Ruminal starch degradability was determined by an in situ technique on 3-mm ground grains. Physical characteristics of corn grain were measured: hardness by grinding energy and particle size distribution, apparent and true densities, and specific surface area. Ruminal DM and starch degradabilities averaged 50 and 55.1% and varied from 39.7 to 71.5% and from 40.6 to 77.6%, respectively. Ruminal starch degradability averaged 61.9 and 46.2% in dent and flint types, respectively. The proportion of coarse particles (61.9 vs. 69.6% for dent and flint, respectively), the apparent density (1.29 vs. 1.36 g/cm3 for dent and flint, respectively), and the specific surface area (.13 vs. .07 m2/g for dent and flint, respectively) varied with the vitreousness. Ruminal starch degradability could be predicted accurately by vitreousness (r2 = .89) or by the combination of apparent density and 1,000-grain weight (R2 = .91), a measurement faster than the vitreousness determination.     

6种常用饲料原料在肉牛瘤胃内降解规律的研究

选用3头体重相近的安装有永久性瘤胃瘘管的科尔沁肉牛,采用尼龙袋法测定玉米面、压片玉米、啤酒糟、玉米酒糟、蚕豆和豌豆壳6种饲料原料在肉牛瘤胃内干物质(DM)、粗蛋白(CP)、淀粉的瘤胃降解率。结果显示:6种饲料原料的DM、CP的肉牛瘤胃有效降解率,压片玉米与玉米面显著高于蚕豆、豌豆壳、玉米酒糟和啤酒糟(P<0.05),压片玉米与玉米面差异不显著(P>0.05);淀粉的肉牛瘤胃有效降解率大小顺序依次为蚕豆、压片玉米、玉米面、豌豆壳、玉米酒糟和啤酒糟。试验表明,蚕豆和压片玉米、玉米面的瘤胃降解率较高,玉米酒糟与豌豆壳居中,啤酒糟相对较差。     

Effects of source and level of dietary neutral detergent fiber on feed intake, ruminal fermentation, ruminal digestion in situ, and total tract digestion in beef cattle fed pelleted concentrates with or without supplemental roughage.

The effects of source and level of dietary NDF on intake, ruminal digestion in situ, ruminal fermentation, and total tract digestion were evaluated in Hereford steers using a replicated 5 x 5 Latin square design. Diets contained 62 to 64% TDN and included 1) 80% control concentrate (contained pelleted ground grains) and 20% timothy hay (traditional diet), 2) 80% control concentrate and 20% alfalfa cubes, 3) 90% control concentrate and 10% cubes, 4) a completely pelleted diet using corn cobs as the primary NDF source, and 5) 80% textured (rolled instead of ground grains) concentrate and 20% hay. Dry matter intake differed (P less than .05) between the traditional and cube diets due to limited acceptance of alfalfa cubes. Increased (P less than .05) ruminal osmolality, total VFA, and NH3 N and lower (P less than .01) ruminal pH in steers fed corn cob and cube diets relative to steers fed the traditional diet were due to preferential consumption of concentrate over supplemental roughage and the resultant rapid fermentation of concentrates. Potentially degradable DM in the traditional diet exceeded (P less than .06) all other diets, resulting in the increased (P less than .10) extent of DM disappearance despite a slower (P less than .05) rate of DM disappearance. Rate of NDF disappearance and all in situ starch disappearance parameters were similar between the traditional, corn cob, and cube diets. All ruminal digestion parameters involving NDF disappearance were similar between hay diets and between cube diets, whereas rate and extent of starch disappearance differed (P less than .05) between hay diets. Although formulation of diets with different sources of dietary NDF did not affect total tract digestion of nutrients, nutrient availability and ruminal fermentation were altered due to dietary differences in sources of dietary NDF and preferential selection of feedstuffs by steers.     

奶牛常用粗饲料的瘤胃降解规律

本试验旨在研究 ２种苜蓿［黑龙江公农 １号苜蓿、美国安德森（Ａｎｄｅｒｓｏｎ）一级苜蓿］、黑龙江 ２种含杂量不同羊草（杂草率分别为 １０％、３４％）、全株玉米青贮、玉米秸秆青贮和玉米秸秆共 ７种粗饲料的瘤胃降解特性。试验选用 ８头装有永久性瘤胃瘘管的荷斯坦奶牛,采用尼龙袋法评定其干物质（ＤＭ）、粗蛋白质（ＣＰ）和中性洗涤纤维（ＮＤＦ）的瘤胃降解率和有效降解率。结果表明,美国安德森一级苜蓿、全株玉米青贮和黑龙江公农 １号苜蓿三者 ７２ｈＤＭ 降解率差异不显著（Ｐ＞０．０５）,并显著高于其他 ４种粗饲料（Ｐ＜０．０５）,而 ＤＭ有效降解率以美国安德森一级苜蓿最高,并与依次降低的黑龙江公农 １号苜蓿、全株玉米青贮和玉米秸秆青贮差异显著（Ｐ＜０．０５）,羊草与玉米秸秆的 ＤＭ有效降解率显著低于其他粗饲料（Ｐ＜０．０５）。７２ｈＣＰ降解率及有效降解率以美国安德森一级苜蓿最高,且降解率与依次降低的黑龙江公农 １号苜蓿、全株玉米青贮、玉米秸秆青贮、杂草率为 １０％的羊草、玉米秸秆和杂草率为 ３４％的羊草间差异显著（Ｐ＜０．０５）。全株玉米青贮、玉米秸秆青贮 ７２ｈＮＤＦ降解率显著高于其他粗饲料（Ｐ＜０．０５）;而有效降解率以 ２种苜蓿较高,其次为玉米秸秆青贮与全株玉米青贮;降解率和有效降解率最低的均为杂草率为 ３４％的羊草。因此,从 ７种粗饲料在奶牛瘤胃的消化特性来看：１）美国安德森一级苜蓿营养价值最高,杂草率为 ３４％的羊草与玉米秸秆营养价值较低;２）羊草的品质受杂草率的影响;３）青贮能改善玉米秸秆的品质。     

Effect of a saponin-based surfactant and aging time on ruminal degradability of flaked corn grain dry matter and starch

The objectives of this study were to investigate the effect of a saponin-based surfactant, Grain Prep surfactant (GP), and hot flake aging time on starch characteristics and ruminal DM and starch degradability of steam-flaked corn grain. In 2 experiments, the moisture content of incoming corn was automatically adjusted using the Grain Prep Auto Delivery System to 19.8% (Exp. 1) and 18.5% (Exp. 2). The application rate of GP was 22 mg/kg (as-is basis). Control corn was treated with water alone. Processed corn in Exp. 2 was stored in insulated containers for 0, 4, 8, or 16 h. Flaked corn samples were incubated in the rumen of lactating dairy cows for 0, 2, 4, 6, 16, or 24 h. In Exp. 1, GP increased, compared with the control, the soluble fraction and effective degradability (ED) of DM by 17.2 and 8.6%, respectively. The ED of cornstarch was increased by 6.7%. In Exp. 2, the concentration of soluble DM and starch were increased by GP by 15 and 24% compared with the control. The ED of DM and starch were also increased by 3 and 4%, respectively. No differences in gelatinization temperatures were observed due to treatment, except that GP-treated grain had a slightly greater mean gelatinization enthalpy in Exp. 2. In a pilot study, DM degradability parameters were not affected by germination of the corn kernels. Aging of the hot flakes for up to 16 h resulted in a quadratic decrease in DM and starch ruminal degradability. The aging process affected starch gelatinization enthalpy values of flaked grain in a manner opposite to that observed for ruminal DM and starch degradation. This phenomenon was most likely explained by increased starch intramolecular associations or crystallinity associated with starch annealing, or both. This study confirmed our previous observations that Grain Prep surfactant increases flaked corn DM and starch degradability in the rumen. Because the rate of degradation was not affected by the surfactant, the increase in degradability was attributed mainly to increases in DM and starch solubility.     

Site and extent of starch and neutral detergent fiber digestion as affected by source of calcium and level of corn

Five steers (385 kg) fitted with permanent abomasal cannulae were used to compare Ca source (limestone or dicalcium phosphate) and corn level on site and extent of digestion. Diets contained 50, 70 or 90% corn, with corn silage and supplement to provide .70% Ca from either limestone or dicalcium phosphate. Limestone did not affect ruminal digestion, but postruminal starch and neutral detergent fiber (NDF) digestion were higher (P less than .05) for limestone compared with dicalcium phosphate, which suggests that starch utilization may be increased postruminally by a compound with buffering capacity. As a percentage of total starch intake, total tract and ruminal starch digestion increased (linear, P less than .01) while postruminal starch digestion decreased (linear, P less than .01) with corn level. Neutral detergent fiber digested in the rumen decreased (linear, P less than .01) and postruminal NDF digestion increased (linear, P less than .01) when level of corn in the diet increased. Effects of corn level were not different when organic matter and starch intake were included as covariates.     

Effects of physicochemical and structural properties of single and double feedstuffs derived from different botanic sources on in vitro starch digestion and glucose release kinetics

Starch is the largest constituent in animal diets. The aims of this study were as follows: (a) to assess the variability of basic physicochemical properties and in vitro starch digestion of starchy feedstuffs and investigate relationship between physicochemical properties and starch digestion of the feedstuffs, and (b) to explore the effects of different sources of starchy feedstuffs on starch digestion and glucose release. In this study, we determined the inherent molecular structure and granular structure of starch and chemical compositions of seven starchy feedstuffs, as well as starch digestion in single feedstuff and different feedstuffs combined with corn. Scanning electron microscope (SEM) results revealed significant difference between granule shape and size of starch of different feedstuffs. Fourier transforms infrared (FTIR) spectra for barley and wheat had lower (p < 0.05) absorbance band at areas A_860 and A_928 than other feedstuffs, yet rice starch had the lowest value for ratio (R) (1047/1022). Moreover, digestion rate ranged from 0.0157/min for resistant starch (sorghum) to 0.029/min for rapidly starch (broken rice). The principle component analysis (PCA) showed that predicted glycaemic index (pGI) was positively related to A_1022, glucose and rapidly (RDS) content and negatively related to A_995, A_1047, R (1047/1022), resistant starch (RS) and amylose content. Most of the feedstufss with corn combination had no effect on rate of starch digestion. In addition, different starchy feeds and corn combination changed the rate of starch digestion, when barley, however, sorghum combined with corn seemed to affect rate of starch digestion. To sum up, different sources differed in basic physicochemical and structural properties, which would influence the digestion rate of starch and the release of glucose. Combination of different feedstuffs particular sorghum with corn has interactive effect on starch digestion and the release of glucose.     

Effect of diet composition and feed intake level on diet digestibility and ruminal metabolism in growing lambs.

Lambs (29 +/- 2.5 kg) were fed three diets at various intakes to determine whether diet composition or level of intake was reflected in changes in diet digestibility or ruminal fluid characteristics. In Exp. 1, a 90% concentrated, pelleted diet or a whole shelled corn diet with a pelleted protein supplement was fed at three levels of intake: ad libitum and 92.5 and 85% of ad libitum (n = 15). Exp. 2 compared the 90% concentrate diet with diets in which the energy density was diluted to 55 or 72.5% concentrate by including alfalfa hay as a possible method of restricting energy intake (n = 6). Lambs were adapted to diets for 13 d; feces were collected for 6 d and ruminal fluid was collected 0, 3, and 6 h after feeding on the day following fecal collection. Restricting intake in Exp. 1 did not affect DM digestibility or digestibility of CP or starch. Digestibility of ADF was increased (P less than .10) by restricting intake. Ruminal fluid pH, ammonia concentration and VFA concentrations were affected little by either restricted intake level. Digestibility of DM was 4% higher (P less than .001) and starch 5% higher (P less than .001) for the whole shelled corn diet than for the pelleted, high-concentrate diet. Ruminal pH of lambs fed the whole shelled corn diet was higher and fluctuated less than the ruminal pH of lambs fed the high-concentrate, pelleted diet. In Exp. 2, diet digestibility was reduced (P less than .01) and ruminal pH was increased (P less than .002) by addition of hay. Restricted feeding of lambs did not seem to increase diet digestibility or alter ruminal conditions.