发酵黄芪粉对奶牛抗氧化性能及血液代谢的影响

研究发酵黄芪粉对奶牛抗氧化性能及血液代谢的影响。对照组奶牛饲喂基础日粮,试验Ⅰ、Ⅱ和Ⅲ组奶牛分别饲喂含10、20和30g/(头·d)发酵黄芪粉的基础日粮。结果表明:与对照组相比,添加适量发酵黄芪粉可显著降低奶牛血清丙二醛含量,提高血清总抗氧化能力、超氧化物歧化酶和谷胱甘肽过氧化物酶的活性,降低奶牛血清尿素氮含量;但对奶牛血清葡萄糖和白蛋白影响不显著。发酵黄芪粉以20g/(头·d)的添加量效果较好。     

过瘤胃氨基酸-脂肪复合物添加水平对崂山奶山羊产奶量及乳成分的影响

研究过瘤胃氨基酸-脂肪复合物对崂山奶山羊产奶量及乳成分的影响,对照组饲喂常规饲粮;Ⅰ、Ⅱ和Ⅲ组为试验组,试验组饲粮在常规饲粮基础上分别添加过瘤胃氨基酸-脂肪复合物60、120和180 g/(d·头).结果表明:与对照组相比,不同添加水平过瘤胃氨基酸-脂肪复合物均可提高崂山奶山羊产奶量、乳脂率和乳蛋白质,但对非脂乳作用效果不明显;其中添加水平为120 g/(d·头)对提高崂山奶山羊产奶性能的效果较佳.     

玉米粉碎粒度对产后奶牛瘤胃发酵及生产性能的影响

旨在研究玉米粉碎粒度对泌乳早期奶牛瘤胃发酵、产奶量及乳成分的影响。试验选择4头泌乳天数为14 d,日产奶量25 kg左右,体重550 kg左右的经产(二胎)中国荷斯坦泌乳奶牛,随机分为两组,对照组奶牛日粮添加10%的破碎玉米,将对该比例破碎玉米由细粉碎玉米代替,作为试验组。试验采用2×2交叉试验设计,每期21 d。结果表明:试验组奶牛瘤胃液pH值显著低于对照组(P0.05);与对照组相比,试验组奶牛瘤胃液乙酸、丙酸与对照组相比有所增加,乙丙比例降低,丁酸具有增高的趋势,与对照组相比提高了17.77%,但差异均不显著(P0.05)。试验组奶牛瘤胃液微生物蛋白与对照组比较有增加的趋势,合成效率与对照组比较无显著性差异(P0.05);试验组奶牛瘤胃液氨态氮的含量显著低于对照组(P0.05)。试验组奶牛产奶量高于对照组,乳脂率与对照组相比有所降低,但差异均不显著(P0.05);随着玉米粉碎粒度的降低,奶牛乳中乳蛋白率有增高趋势,与对照组相比提高了7%;试验组奶牛乳中尿素氮显著低于对照组(P0.05)。说明在本试验条件下,细粉碎玉米替代日粮中部分破碎玉米,可以提高奶牛瘤胃的发酵功能,使奶牛乳中乳蛋白率有增高趋势。     

复方产品对热应激泌乳奶牛生产性能及经济效益的影响

为研究复方产品对热应激奶牛采食量、产奶量的影响,选择荷斯坦泌乳奶牛56头,按随机区组方式分为对照组与试验组,每组28头。对照组不做任何处理,试验组添加复方产品200 g/(头·d),试验周期为30 d。试验期间,每天统计各组干物质采食量与产奶量,每周采集一次奶样用于检测乳指标。结果显示,在试验组中添加200 g/(头·d)复方产品,可提高奶牛干物质采食量0.71 kg/d,产奶量增加1.51 kg/d,且停止使用1月内试验组产奶量仍比对照组高2.26 kg/d。试验期内,试验组比对照组每头每天增加净收益0.21元;试验后一个月内,试验组比对照组每头每天增加净收益7.68元。试验结果表明,该复方产品对缓解奶牛夏季热应激、提高奶牛生产性能、增加经济收益有积极作用。     

果寡糖对泌乳早期奶牛瘤胃发酵及生产性能的影响

为研究果寡糖对泌乳早期奶牛瘤胃发酵及生产性能的影响,采用两阶段交叉设计,将4头泌乳天数20 d,产奶量30 kg/d,体质量(550±35)kg健康经产(二胎)中国荷斯坦泌乳奶牛随机分为两组,分别为试验组、对照组,试验组添加果寡糖。结果表明:日粮中添加60 g/(d·头)的果寡糖,对奶牛瘤胃中总挥发性脂肪酸、氨态氮影响极显著(P0.01),对丁酸影响差异显著(P0.05),但是对于乙酸、丙酸来说影响不显著(P0.05),与对照组相比,试验组的总挥发性脂肪酸量提高35.9%,氨态氮降低15.5%,丁酸提高33%。对奶牛生产性能进行分析,乳脂率影响差异显著(P0.05),体细胞影响差异极显著(P0.01),与对照组相比,试验组乳脂率提高4.7%,体细胞降低68.5%,而产奶量、乳蛋白、乳中尿素氮浓度均无显著影响(P0.05)。综上所述,日粮中添加果寡糖能够改变瘤胃发酵模式,提高奶牛的乳脂率。     

纳米多维对荷斯坦奶牛产奶性能的影响

为研究纳米多维对荷斯坦奶牛产奶量、乳品质和体细胞数的影响,试验选择94头荷斯坦奶牛,采用随机分组的方法分为对照组和试验组,对照组正常饲喂,试验组在饮水中添加纳米多维,测定其对奶牛产奶性能的影响。结果表明,试验组荷斯坦奶牛产奶量、乳脂含量、乳蛋白含量和干物质含量均高于对照组,试验组牛奶中体细胞数低于对照组,说明纳米多维可有效改善牛奶的产奶性能和降低奶牛的体细胞数,显著提高经济效益。     

谷朊粉酶解物对小鼠免疫功能的影响

研究了酶解谷朊粉小肽对小鼠免疫功能的影响.空白组饲粮中不添加谷朊粉或谷朊粉酶解物,对照组饲粮中添加未酶解的谷朊粉1 000 mg/(kg饲粮·d);Ⅲ、Ⅳ、Ⅴ组为试验组,饲粮中分别添加酶解谷朊粉500、750和1 000 mg/(kg饲粮·d),饲喂28 d后进行免疫指标测定.结果表明:Ⅳ组与其它各组相比,小鼠的SOD、GSH-PX、GLU、GPT、IgG、IgM、IL-2和IGF-I均提高显著,但IgA降低显著.添加酶解谷朊粉750 mg/(kg饲粮·d)对提高小鼠的免疫功能效果最佳.     

乳酸菌制剂对奶牛泌乳量及乳成分的影响

选择27头经产,产犊30～45d,产奶量相近,胎次相近,体重相近,健康无病的高产奶牛。随机分为3组,1组为基础对照组,2组（A组和B组）为试验组,试验组在基础日粮的水平上添加10g不同型号的乳酸菌制剂,预试期2周,正试期为6周。结果表明,两种乳酸菌对奶牛产奶量和奶成分有不同程度的影响,其中A组奶牛的产奶量比对照组有所增加,且差异显著（P〈0．05）,B组则有所下降;不同型号的乳酸菌制剂对牛乳成分也有不同程度的影响。A组奶牛除乳糖率与对照组相比有所降低外,其他乳成分（乳脂率、蛋白率和非脂固形物）相比对照组均有显著增长（P〈0．05）;B组奶牛其乳脂率呈上升趋势,日蛋白产量及日乳糖产量较对照组有所下降,对其他乳成分无显著影响。乳酸菌A能显著减少乳体细胞数（p〈0.05）。两种乳酸菌所生产牛奶的比重、冰点、酸度与对照组无显著差异。     

麦蓝菜对奶牛产奶量及乳成分的影响

选用15头体质量、胎次、产奶量均相近中国荷斯坦奶牛,随机分为A、B、C三组(n=5)∶A组(对照组)饲喂基础日粮;B组(试验组1)饲喂基础日粮+50 g麦蓝菜种子;C组(试验组2)饲喂基础日粮+150 g麦蓝菜植株.试验周期24 d,每天测定各组奶牛产奶量及乳成分,研究麦蓝菜对奶牛产奶量及乳成分的影响.结果表明:B组较A组产奶量提高了15.56％ (P＜0.01),牛奶乳蛋白和干物质分别提高了11.9％和5.1％(P＜0.01),乳脂率提高了9.4％(P＜0.05),A、B两组间乳糖含量差异不显著;C组较A组产奶量提高了3.48％(P＜0.01),牛奶乳蛋白和干物质体分别提高了6.3％和4.9％(P＜0.01),乳脂率和乳糖分别提高了9.1％和6.6％(P＜0.05).研究表明,基础日粮中添加麦蓝菜植株和种子均可以显著提高奶牛产奶量和乳品质.     

几种酵母菌添加剂对奶牛产奶量及乳成分的影响

将54头高产中国荷斯坦奶牛随机分为6组，1组基础对照组，5组（A，B，C，D，E）试验组，试验组在基础日粮的水平上添加15g不同型号的酵母菌制剂，预试期2周，正试期为6周。结果表明：不同型号的酵母菌对奶牛产奶量和奶成分有不同程度的影响，其中C和E组奶牛的产奶量分别比对照组有所增加，B和D组的产奶量与对照组相比增加显著（P〈0．05），A组则有所下降；不同型号的酵母菌制剂对牛乳成分也有不同程度的影响，试验组B，D，E组乳脂日产量比对照组有增加，并且差异显著（P〈0．05）；E组乳脂率增加，差异显著；蛋白质日产量除A组无显著性差异（P〉0．05），B，C，D，E组相比对照组都有所增加，其中C和E组相比对照组，差异显著（P〈0．05）；试验组的乳糖、非脂固形物产量与对照组没有显著差异（P〉0．05）；各试验组的所生产牛奶的比重、冰点、酸度与对照组无显著差异，但试验组的酸度除D组外均比对照组有所提高，乳中体细胞数均比对照组低，其中酵母菌C和D能显著减少乳中体细胞数（P〈0．05）。     

山羊奶与牛奶和人奶营养成分的比较

对山羊奶、牛奶和人奶中蛋白质、脂肪、维生素、矿物质等主要营养成分进行了比较,分析了3种奶中主要营养成分的差别。通过比较发现,山羊奶在总体营养成分方面优于牛奶,更接近人奶。但山羊奶存在铁、叶酸和维生素B12含量较低以及羊奶膻味的问题,应在营养上对这方面加以重视。     

Calibration of infrared milk analyzers: modified milk versus producer milk

Mid-infrared (MIR) milk analyzers are traditionally calibrated using sets of preserved raw individual producer milk samples. The goal of this study was to determine if the use of sets of preserved pasteurized modified milks improved calibration performance of MIR milk analyzers compared with calibration sets of producer milks. The preserved pasteurized modified milk sets exhibited more consistent day-to-day and set-to-set calibration slope and intercept values for all components compared with the preserved raw producer milk calibration sets. Pasteurized modified milk calibration samples achieved smaller confidence interval (CI) around the regression line (i.e., calibration uncertainty). Use of modified milk calibration sets with a larger component range, more even distribution of component concentrations within the ranges, and the lower correlation of fat and protein concentrations than producer milk calibration sets produced a smaller 95% CI for the regression line due to the elimination of moderate and high leverage samples. The CI for the producer calibration sets were about 2 to 12 times greater than the CI for the modified milk calibration sets, depending on the component. Modified milk calibration samples have the potential to produce MIR milk analyzer calibrations that will perform better in validation checks than producer milk-based calibrations by reducing the mean difference and standard deviation of the difference between instrument values and reference chemistry.     

免疫学检测羊乳中掺入牛乳成分

由于营养、价格和原料等原因，市场上在羊乳中掺入牛乳的现象常有发生。针对这种乳源性掺假陆续产生了多种检测方法，本文主要综述了以ELISA为主的免疫学快速检测方法。     

Effects of milk powders in milk chocolate

The physical characteristics of milk powders used in chocolate can have significant impact on the processing conditions needed to make that chocolate and the physical and organoleptic properties of the finished product. Four milk powders with different particle characteristics (size, shape, density) and "free" milk fat levels (easily extracted with organic solvent) were evaluated for their effect on the processing conditions and characteristics of chocolates in which they were used. Many aspects of chocolate manufacture and storage (tempering conditions, melt rheology, hardness, bloom stability) were dependent on the level of free milk fat in the milk powder. However, particle characteristics of the milk powder also influenced the physical and sensory properties of the final products.     

模拟母乳及婴儿配方奶粉的研究

介绍了人乳中的主要功能因子及其对婴儿的生长发育所具有的生理意义。比较、分析了现阶段婴儿配方奶粉与人乳成分中存在的差别及不足，并针对婴儿的生长特点及现阶段生产技术，对婴儿配方奶粉的生产及发展进行了叙述。     

Decreased milk yield is associated with delayed milk ejection

To determine whether individual cow milking vacuum (within the short milk tube and the liner mouthpiece) could be substituted for milk flow technology to identify delayed (bimodal) milk ejection, and the possible relationship between bimodal milk flow and milk yield, we recorded milking data from 663 Holstein cows on a 3,600-cow Michigan dairy that milked 3 times per day. Overall, delayed milk ejection occurred in 45.6% of the milkings, and 98% of the cows with delayed milk ejection also had bimodal flow. Multivariable analysis revealed that milk yield during each individual cow milking was positively associated with increasing lactation number but negatively associated with increasing days in milk and delayed milk ejection. As the time between unit attachment and the estimated milk letdown (the lag period) increased, milk yield decreased; relative to a lag of <30 s, milk yield decreased by 1.8 and 3.1 kg for lags of 30–59 and ≥60 s, respectively. The final multivariate model had an adjusted coefficient of determination of 0.27. The negative association between delayed milk ejection and decreased milk yield in this study suggested that milking vacuum parameters from individual cows could serve as a useful tool to qualitatively estimate milk flow within a herd and that this information may be used to enhance herd productivity.     

奶啤的研制

以牛奶、麦芽和酒花为主要原料,通过二次生物发酵研制出具有奶香和啤酒风味的奶啤饮料。通过实验确定奶啤的最佳配方及生产工艺流程并对奶啤的稳定性进行探讨,从而研制出即有啤酒的低酒精度、泡沫丰富和适度的二氧化碳,又具有酸乳饮料的酸甜可口、营养全面的奶啤饮料。     

Effect of leaving milk trucks empty and idle for 6 h between raw milk loads

The US Pasteurized Milk Ordinance (PMO) allows milk tanker trucks to be used repeatedly for 24 h before mandatory clean-in-place cleaning, but no specifications are given for the length of time a tanker can be empty between loads. We defined a worst-case hauling scenario as a hauling vessel left empty and dirty (idle) for extended periods between loads, especially in warm weather. Initial studies were conducted using 5-gallon milk cans (pilot-scale) as a proof-of-concept and to demonstrate that extended idle time intervals could contribute to compromised raw milk quality. Based on pilot-scale results, a commercial hauling study was conducted through partnership with a Pacific Northwest dairy co-op to verify that extended idle times of 6 h between loads have minimal influence on the microbiological populations and enzyme activity in subsequent loads of milk. Milk cans were used to haul raw milk (load 1), emptied, incubated at 30°C for 3, 6, 10, and 20 h, and refilled with commercially pasteurized whole milk (load 2) to measure cross-contamination. For the commercial-scale study, a single tanker was filled with milk from a farm known to have poorer quality milk (farm A, load 1), emptied, and refilled immediately (0 h) or after a delay (6 h) with milk from a farm known to have superior quality milk (farm B, load 2). In both experiments, milk samples were obtained from each farm's bulk tank and from the milk can or tanker before unloading. Each sample was microbiologically assessed for standard plate count (SPC), lactic acid bacteria (LAB), and coliform counts. Selected isolates were assessed for lipolytic and proteolytic activity using spirit blue agar and skim milk agar, respectively. The pilot-scale experiment effectively demonstrated that extended periods of idle (>3 h) of soiled hauling vessels can significantly affect the microbiological quality of raw milk in subsequent loads; however, extended idle times of 6 h or less would not measurably compromise milk quality in subsequent loads in commercial tankers. Current tanker sanitation practices appear to be sufficient for maintaining raw milk SPC, LAB, and coliform levels, which are important measures of milk quality.     

含24种乳抗体免疫乳的制备

以24株人肠道病原菌（包括病原性大肠杆菌12株、沙门氏菌8株、志贺氏菌3株、小肠结肠炎耶尔森氏菌1株）作为抗原，对乳牛进行系统免疫，免疫乳与非免疫乳乳中IgG含量无显著差异。系统免疫并不增加乳中IgG的含量，但IgG的抗体特异性大大增强，所得的免疫初乳中乳抗体对24种不同病原菌的凝集价为2^8-2^12，为普通初乳中乳抗体凝集价的32－256倍；免疫常乳中乳抗体对24种不同病原菌的凝集价为2^5-2^8，为普通乳中乳抗体凝集价的8－128倍。     

Invited review: Corrected milk: Reconsideration of common equations and milk energy estimates

Corrected milk equations were developed in attempts to bring milk weights to a standardized basis for comparison by expressing the weight and composition of milk as corrected to the energy content of milk of a specific composition. Expressed as milk weights familiar on farm and in commerce, this approach integrates energy contributions of the dissimilar components to make the mass units more comparable. Such values are applied in evaluating feed efficiency, lactation performance, and global milk production, as functional units for lifecycle assessments, and in translation of research results. Corrected milk equations are derived from equations relating milk gross energy to milk composition. First, a milk energy equation is used to calculate the energy value of the milk composition to correct to (e.g., 0.695 Mcal/kg for milk with 3.5% fat, 3.05% true protein, and 4.85% lactose). That energy value is divided into the energy equation to give the corrected milk equation. Confusion has arisen, as different equations purport to correct to the same milk composition; their differences are based on uses of different energy equations or divisors. Accuracy of corrected milk equations depends on the accuracy of the energy equations used to create them. Energy equations have evolved over time as different milk component analyses have become more available. Inclusion of multiple milk components more accurately predicts milk energy content than does fat content alone. Omission of components from an equation requires the assumption that their content in milk is constant or highly correlated with an included component. Neither of these assumptions is true. Milk energy equations evaluated on a small data set of measured milk values have demonstrated that equations that incorporate protein, fat, and lactose contents multiplied by the gross energy of each component more closely predict milk energy than equations containing fewer components or regression-derived equations. This provides a tentative recommendation for using energy equations that include the 3 main milk components and their gross energy multipliers for predicting milk energy and deriving corrected milk equations. Accuracy of energy equations is affected by the accuracy of gross energy values of individual components and variability of milk composition. Lactose has consistent reported gross energy values. In contrast, gross energy of milk fat and protein vary as their compositional profiles change. Future refinements could assess accuracy of milk fat and protein gross energy and whether that appreciably improves milk energy predictions. Fat gross energy has potential to be calculated using the milk fatty acid profile, although the influence on gross energy may be small. For research, direct reporting of milk energy values, rather than corrected milk, provides the most explicit, least manipulated form of the data. However, provision of corrected milk values in addition to information on components can serve to translate the energy information to a form familiar to and widely used in the field. When reporting corrected milk data, the corrected milk equation, citation for the energy equation used, and composition and energy contents of the corrected milk must be described to make clear what the values represent.