不同体细胞评分奶牛血清和乳清中TNF-α、Il-6的检测

本试验探讨了细胞因子含量的变化与体细胞数的关系,确定其变化是否由乳房炎引起,为今后乳房炎的诊治提供参考依据。依据奶牛生产性能测定体细胞数的检测结果,将82头泌乳奶牛分为低体细胞组（体细胞评分≤2分）、中体细胞组（29〈体细胞评分≤6分）和高体细胞组（体细胞评分〉6分）,分别检测各组奶牛血清和乳清中细胞因子TNF-a、IL-6的含量,对结果采用SPSS分析。结果显示,随着体细胞数的增加,血清和乳清中TNF—a的含量呈上升趋势;乳清样本各组间TNF-a含量差异显著,高体细胞组显著高于低体细胞组（P〈0．05）,中体细胞组TNF—a的含量极显著高于低体细胞组（P〈0．01）。血清样本中IL-6的含量差异显著,中体细胞组血清中IL-6的含量显著高于低体细胞组（P〈0．05）,高体细胞组与低体细胞组血清中IL-6的含量差异接近显著（P值为0．059）。     

体细胞数过高对乳制品品质的影响

本文主要阐述了体细胞数过高对乳制品营养价值、风味、加工特性以及贮藏特性等方面的不利影响。体细胞数过高,则乳脂率和酪蛋白含量降低;牛乳中盐类比例失调,牛乳热稳定性降低,凝固型酸奶的凝乳松散易碎裂,乳清易析出;过氧化物酶含量升高,乳品风味欠佳;脂肪氧化酶增加,其氧化产物游离脂肪酸含量上升,乳易酸败,缩短乳品保质期;蛋白水解酶尤其是血纤维蛋白溶酶含量和活性增加,造成乳蛋白大量水解,降低干酪产量;牛乳中有害微生物含量增加,抗生素残留的风险增加,降低乳制品食用安全。     

α_1-酸性糖蛋白与奶牛隐性乳房炎的.相关性分析

为了分析奶牛隐性乳房炎的不同发病阶段与乳清中α_1-酸性糖蛋白含量变化之间的关系,本试验选取10头健康奶牛和30头不同发病程度(轻、中、重)隐性乳房炎患牛作为试验动物,采用α_1-酸性糖蛋白ELISA检测试剂盒测定各组乳清样品中α_1-酸性糖蛋白的含量,对α_1-酸性糖蛋白与奶牛隐性乳房炎的相关性进行分析。结果显示,隐性乳房炎组奶牛乳清中α_1-酸性糖蛋白的含量显著或极显著高于健康组奶牛(P0.01或P0.05),且随着奶牛隐性乳房炎病情的加重及乳中体细胞数的增加,乳清中α_1-酸性糖蛋白的含量呈现出递增趋势。研究结果提示,乳清中α_1-酸性糖蛋白的含量变化与奶牛隐性乳房炎的发病程度具有一定的相关性,乳腺炎症引发的乳腺损伤及乳中体细胞数增加与乳清中α_1-酸性糖蛋白的含量呈正相关。     

ACE 2在奶牛乳腺中的表达定位及其抗炎性损伤作用的研究

本研究旨在通过体内外试验,明确ACE 2在奶牛乳腺中的表达定位,并对其在高精料饲喂致内源性奶牛乳房炎中的抗损伤作用进行初步探讨。体外试验分别选用牛乳腺组织样品和牛乳腺上皮细胞(Mac-T细胞),RTPCR和Western blotting法检测ACE 2在奶牛乳腺组织中的mRNA和蛋白表达;免疫荧光法测定ACE 2蛋白在Mac-T细胞中的定位。体内试验,选用6头健康泌乳期荷斯坦奶牛,随机分为对照组和高精料饲喂组,饲喂20周后,活体采集乳腺组织及乳。测定乳中LPS含量、体细胞数及相关炎性指标;制作乳腺组织学切片;分析乳腺组织中ACE、AT1、ACE2、MasR mRNA表达水平,ELISA法检测Ang II、Ang1-7含量。体外试验结果表明,奶牛乳腺中ACE2在基因和蛋白水平上均有表达,细胞学定位在细胞的胞浆和胞膜。体内试验结果显示,高精料长期饲喂,奶牛乳中体细胞数和LPS含量均明显升高(P0.01);乳中NAGase和AKP酶活力均显著高于正常对照组(P0.05),MPO活力两组之间无明显差异;乳腺组织学表现出一定炎性损伤变化;其中Ang1-7含量显著增高(P0.05),Ang II的含量显著降低(P0.05);ACE、AT 1、ACE 2、MasR mRNA表达量均显著上升((P0.05)),ACE2/ACE mRNA比值高于对照组。本研究首次证实奶牛乳腺组织中有ACE 2的存在。在高精料长期饲喂造成奶牛乳房炎性损伤时,乳腺组织中RAS处于激活状态,ACE/ACE2比例失衡,以ACE 2-Ang1-7-MasR轴的活力处于优势状态,即ACE 2的抗损伤作用占优势。ACE 2可能通过降解AngII,产生Ang1-7发挥抗损伤作用,对乳腺组织炎性损伤具有一定的保护作用。     

正常和隐形乳房炎状态下围产期娟姗奶牛与荷斯坦奶牛能量状态、脂溶性维生素、急性期蛋白质的变化研究

通过一项严格控制条件的观察试验,建立了判定临产期能量负平衡、血脂、脂溶性维生素浓度以及急性期蛋白质含量与亚临床乳房感染之间的相关性。根据奶牛品种进行分组,并预计分娩日期,自奶牛断奶后观察8周。如果能在产后乳腺内分离到与预产期的前9周不同的病原菌,则判定为新形成的乳房感染。在前9周时奶牛的体况评分为3.71±0.12。共有15头娟姗奶牛与荷斯坦奶牛符合本文的标准。与正常奶牛相比,新的亚临床乳房炎奶牛具有较高的体况评分、体重和体重损失。处于新的亚临床乳房炎的娟姗牛临产期时,其血浆β-胡萝卜素含量比正常娟姗牛要高,同时高于同种状态下的荷斯坦奶牛。然而,与正常的娟姗牛相比,亚临床乳房炎的娟姗牛其血浆中β-胡萝卜素含量上升的较迟。正常奶牛在临产期体内血浆α-生育酚,乳清蛋白和维生素A结合蛋白浓度较高。新的亚临床乳房炎奶牛,其乳蛋白含量、乳糖含量以及乳尿N比正常奶牛要低,但体细胞数要高。如果临产期时奶牛组织能量贮备较高,且血浆蛋白、β-胡萝卜素以及血浆α-生育酚含量降低,则该奶牛在该时期患乳房感染的几率较高。     

电导率诊断奶牛隐性乳房炎的方法

奶牛隐性乳房炎(H idden Mastitis)也称为亚临床乳房炎(SubclinicalMastitis),特点是肉眼患牛的乳房和乳汁无异常,但乳汁培养有细菌,乳汁体细胞数增加,增加的多少可反映炎症的程度。奶牛乳房组织感染后,由于炎症的发生,乳腺合成脂肪、蛋白质和乳糖能力下降,渗透性降低,血液成分中的白细胞、Na 、C l-、HCO3-、蛋白质等成分渗出而进入乳腺泡,使乳汁成分发生改变。发生隐性乳房炎的奶牛,乳汁的生理生化指标如体细胞数、电导率、pH值、各种酶等发生较大幅度的变化。因此,可以根据牛乳中生理生化指标的变化间接诊断隐性乳房炎。以下主要研究…     

不同音乐对奶牛产奶性能影响的研究

为了研究民族音乐、轻音乐、流行音乐对奶牛产奶性能的影响,试验选取年龄、胎次、产奶量接近、饲养管理水平完全相同的荷斯坦泌乳牛32头,随机分成2组,每组16头。试验分预试期7 d,正试期60 d。预试期开始给试验组奶牛播放音乐,对照组常规饲喂,每10 d测定单产并采集奶样1次。结果表明:0~60 d,民族音乐组平均产奶量较对照组低12.61%,体细胞数较对照组高45.14%,差异极显著(P0.01)。轻音乐组平均产奶量较对照组高10.26%,差异极显著(P0.01);奶牛乳体细胞数较对照组低41.24%,差异显著(P0.05)。流行音乐组平均产奶量较对照组低0.73%;体细胞数、乳脂、乳糖、乳蛋白分别较对照组高0.94%、0.27%、0.18%、0.63%,且差异均不显著(P0.05)。说明民族音乐可显著降低奶牛产奶量并提高奶牛体细胞数,对乳糖、乳脂和乳蛋白含量影响不大;轻音乐有提高奶牛产奶量和降低奶牛体细胞数的作用,对牛奶乳成分含量的影响不大;流行音乐有提高奶牛产奶量和降低奶牛体细胞数的作用,但其作用时间和作用效果有限,对乳成分含量的影响作用不大。     

热应激对牛奶中离子平衡的影响

对比热应激期和非热应激期奶牛乳清中阴阳离子含量变化和电荷总量,发现热应激期牛奶胶体体系中阳离子不足而阴离子过剩,以致全乳PH值显著降低。同时,全乳中体细胞数显著升高表明热应激对奶牛乳腺组织有一定程度的损伤。     

生化黄腐酸对奶牛乳体细胞数及生产性能影响的研究

通过对奶牛饲喂生化黄腐酸,研究其对奶牛生产性能、血液生化指标及乳体细胞数的影响。选择50头泌乳奶牛,进行分组试验。结果表明,添加生化黄腐酸的试验组奶牛产奶量较对照组提高了5.99%,乳脂率提高1.97%,乳体细胞数下降了40.09%,乳蛋白率变化不明显;奶牛血清中SOD含量提高了3.6%,GSH-Px含量提高了7.72%,LDH含量降低9.3%,MDA变化不明显,奶牛白细胞维持正常,两组各项指标差异均不显著(P0.05)。综合指标分析表明:饲喂生化黄腐酸具有提高奶牛泌乳性能,减少奶牛乳体细胞数,增强机体抗病力的效果。     

stat5高效表达对奶牛乳腺上皮细胞泌乳能力的影响

本研究旨在检验构建的stat5表达载体对奶牛乳腺上皮细胞泌乳能力的影响。构建真核表达载体pcD-NA3.1+-stat5-αS1,稳定转染到奶牛乳腺上皮细胞中。利用细胞活力分析仪、HPLC、Real-time PCR和WesternBlotting技术检测乳腺上皮细胞转染前后stat5基因和蛋白的表达量、细胞活力及乳糖和酪蛋白分泌情况。结果表明,与空白细胞和空白载体组相比,非磷酸化STAT5蛋白和stat5基因的表达量增加(P<0.01),乳糖含量提高(P<0.05),细胞活力和增殖能力增强(P<0.01),酪蛋白和磷酸化STAT5(pSTAT5)表达增多(P<0.05)。结果提示,构建的载体pcDNA3.1+-stat5-αS1在乳腺上皮细胞中高效表达,显著提高乳腺上皮细胞的泌乳能力。     

利用乳汁体细胞研究共轭亚油酸钙对奶牛乳腺基因表达的作用

8头泌乳中期的奶牛被随机分为2组，分别是对照组（每头牛：基础日粮＋棕榈酸钙200g／d）和试验组（每头牛：基础日粮＋共轭亚油酸钙200g／d），试验期14d，检测了奶产量、乳成分，分析奶牛的血液变化，并采用荧光定量PCR对乳汁体细胞中脂蛋白脂酶（LPL）、乙酰辅酶A羧化酶（ACACA）的基因表达进行检测。结果显示，与对照组相比，试验组奶牛的乳产量、乳蛋白、乳糖和乳汁体细胞含量没有显著影响，但是显著降低了乳脂肪含量（P〈0．05），对照组和试验组奶牛乳脂肪含量分别为0．0326g／mL和0．0244g／mL。检测血液指标发现，共轭亚油酸钙显著升高了奶牛血液中高密度脂蛋白的含量（P〈0．05）。基因分析发现，试验组奶牛乳汁体细胞中LPL、ACA—CA的基因表达显著下调，表明共轭亚油酸钙抑制了奶牛乳腺细胞脂肪酸合成酶的基因表达。     

两种微生态制剂对荷斯坦牛生产性能的影响

2008年7月份至12月份在新疆呼图壁种牛场选择397头年龄相近、泌乳量为28.23±4.26kg的中国荷斯坦牛,随机分成三组。第一组为对照组(CT),第二组每天饲喂50g"益康XP",第三组每天饲喂24g"PM发酵粉";试验期6个月,每10d测日产奶量,每月数据汇总处理,每月底采集乳样,检测其乳脂、乳蛋白、乳糖、乳非脂固形物含量及体细胞数、pH值。结果表明:与CT组相比,XP组与PM组明显提高奶牛产奶量和乳脂率;与CT组相比,XP组和PM组均能降低乳体细胞数(P0.05);此外,与CT组相比,XP组和PM组对乳糖、乳非脂固形物含量和pH值影响并不显著(P0.05)。     

生物抗氧化剂对原料奶体细胞数的影响

原料奶中体细胞是间接反应奶牛乳房是否健康的一个有力数据。同时过高的体细胞也将直接影响到原料奶的质量和价格。因此,本试验选择年龄、胎次、产奶量、泌乳天数相近的中国荷斯坦奶牛80头,探讨日粮添加34g生物抗氧化剂对原料奶中体细胞的影响。结果表明,生物抗氧化剂对奶牛产奶量及乳成分无显著影响。但与对照组相比,试验组原料奶中体细胞数呈显著低于对照组（P〈0.05）。因此,本研究表明,生物抗氧化剂能够有效降低原料奶中体细胞数,提高原料奶质量。     

Effects of intramammary infection and parity on calf weaning weight and milk quality in beef cows

The objectives of this study were to determine 1) the effect of intramammary infection on calf weaning weight, milk somatic cell count, and milk composition, and 2) the effect of parity on percentages of infected cows, infected quarters, and blind quarters. The number of infected quarters, milk somatic cell counts, milk components, and intramammary infection were studied at weaning in 164 beef cows. The percentage of infected cows ranged from 61.9% at first parity to 66.7% at fifth to ninth parities. Cows with three or four infected quarters had higher (P < .01) milk somatic cell counts than cows with zero, one, or two infected quarters. Among bacterial isolates, Staphylococcus aureus-infected quarters had the highest (P < .01) milk somatic cell count. Percentages of butterfat and lactose were lower (P < .01) in milk from infected quarters than from uninfected quarters. Infections by S. aureus and coagulase-negative staphylococci were the most common and accounted for 67 to 78% of the infections. Percentages of infected quarters and infections caused by S. aureus increased with parity (P < .01). Intramammary infections did not affect (P > .10) calf weaning weight. In conclusion, intramammary infection had no effect on calf weaning weight but increased milk somatic cell count and decreased the percentage of protein, lactose, solids-not-fat, and butterfat. The number of infected and blind mammary quarters increased with parity.     

Effect of oral administration of colostrum on inflammation in the udders of dairy cows suffering from mastitis

The present study was undertaken to examine whether oral administration of colostrum to mastitic cows reduced inflammation in the udder. Fifty milliliters of a colostrum whey product was administered orally daily for 3 days to cows suffering from mastitis. Milk was collected on day 0 and 7 of colostrum administration. For Experiment 1, milk from 11 udder quarters with high somatic cell counts (SCC) in four cows was used. SCC in milk decreased significantly after colostrum administration, whereas colostrum administration increased sodium and IgA concentrations significantly compared with those before administration. In Experiment 2, cows with clinical mastitis were divided into two groups, with and without colostrum administration, whereas all cows with subclinical mastitis were administered colostrum. Antibiotics were infused into the mammary gland from the first day of colostrum administration for 2–4 days. There was no significant decrease in SCC after colostrum administration in any group. However, udder firmness in both clinical mastitis groups was reduced after administration regardless of colostrum administration. IgA concentration in both clinical mastitis groups was significantly increased after colostrum administration compared to that before administration, although there was no significant difference between them. These results suggest the possibility that oral administration of colostrum attenuates inflammation of the mammary gland. Further studies are required to examine the effect of colostrum more precisely using cows with subclinical and chronic mastitis and longer duration of colostrum administration.     

果香味剂对奶牛乳腺上皮细胞培养液中乳成分含量及风味影响的研究

试验旨在研究果香味剂对奶牛乳腺上皮细胞培养液中乳成分含量及培养液风味的影响。试验选用自制的奶牛乳腺上皮细胞,试验设5个处理组,果香味剂的添加剂量分别为0、5、10、15和20μg/ml。结果表明:①当培养基中果香味剂添加量为15μg/ml时,乳腺上皮细胞培养液中总蛋白水平、甘油三酯及乳糖含量均达到最高,其中对脂肪含量影响显著(P<0.05),而对蛋白和乳糖含量影响不显著(P>0.05),之后呈下降趋势,说明果香味剂可能会诱导奶牛乳腺上皮细胞乳蛋白、乳脂和乳糖分泌水平的升高;②运用PT/GC-MS分析乳腺培养液中的风味成分,与对照组相比,各试验组中除具有原有乳腺培养液的风味外,还有乙酸异丁酯、乙酸异戊酯、丙酸异戊酯、丙酸戊酯、丁酸异丁酯、丁酸戊酯、丁酸乙酯、邻苯二甲酸二异丁酯等物质成分,而这些物质成分正好是果香味剂中进入到乳腺培养液中的风味物质,且当添加剂量为15μg/ml时,各物质成分含量为最高(P<0.05),之后呈下降趋势。果香味剂能显著影响奶牛乳腺上皮培养液中乳成分含量和风味。     

Possible involvement of selenium in Staphylococcus aureus inhibition in cow's whey

Previous investigations have shown that selenium supplementation inhibits growth of mastitis pathogens in cow's milk. The present study was performed to clarify the role of selenium in defence mechanisms of mammary gland. We have examined the effects of selenium supplementation on Staphylococcus aureus growth inhibiting activity in whey. Six selenium-supplemented and six non-supplemented Estonian dairy cows were used for this study. Selenium-supplemented cows received 4 mg organic selenium in the form of selenium yeast in their daily diet for 8-week period. Cows from non-supplemented group received the same amount of yeast free of selenium in their diet. All cows had initially low blood glutathione peroxidase (GPx) activity (相似文献   

Climatic Changes and Emerging Diseases

The relationships between welfare and udder health indicators were investigated in 120 midlactation Comisana ewes over a 90-day period. The welfare indicators monitored were the humoral response to chicken egg albumin (OVA), the cell-mediated immune response to phytohemagglutinin, and the plasma cortisol levels. Changes in milk components, in somatic cell count (SCC) and in bacterial count, in leukocyte populations and in anti-OVA IgG concentration were used to monitor the ewe udder health. Correlations between welfare and udder health indicators were then tested. The skinfold thickness, representative of the cell-mediated immune response, was correlated positively with the percentage of neutrophils in milk and negatively with the chloride content, the percentage of lymphocytes and anti-OVA IgG concentrations in milk. The plasma antibody titres to OVA, representative of the humoral immune response, correlated positively with the anti-OVA IgG levels in milk and negatively with the lactose content and to the percentage of neutrophils. Plasma cortisol levels correlated positively with the chloride content in milk. Our study demonstrates that information about the immune condition of animals can be successfully achieved by monitoring the immunological responses of the mammary gland. The detection of reliable indicators of animal welfare in milk can help in reducing the stress from animal handling and blood sampling from lactating animals.     

Daily rhythmicity in nutrient content of asinine milk

Asinine (donkey) milk has been proposed as an alternative to bovine (cow) milk for consumption by human infants who are allergic to bovine milk proteins. To expand the current knowledge of asinine lactation, we investigated daily rhythmicity in the concentration of major constituents of asinine milk. We observed no daily rhythmicity in somatic cell count and pH but observed robust rhythmicity in lipid, lactose, and protein content (robustness greater than 70%, p < 0.01). Lipid and lactose content peaked during the night, whereas protein content peaked during the day. Lipid content of asinine milk was lower than that of human milk, and asinine milk resembled human milk better than bovine milk regarding sugar and protein content.     

放养密度对泌乳奶牛氧化应激状态和乳腺通透性的影响

研究旨在探讨放养密度对早期泌乳奶牛氧化应激状态和乳腺通透性的影响。试验选择32头泌乳期奶牛,根据奶次和产奶量随机为为2组,每组16头牛,每个重复1头牛。奶牛采用两种放养方式,即75%的放养密度和100%放养密度,试验共开展8周,且试验期间两组奶牛饲喂相同的饲料。结果显示:75%较100%放养密度组显著提高了泌乳量、能量校正乳和4%脂肪校正乳产量(P<0.05),同时75%放养密度组显著降低了乳中尿素氮含量(P<0.05),显著提高了整个试验期间乳中蛋白质含量(P<0.05),而100%放养密度组较75%放养密度组显著提高了奶牛乳中体细胞数量(P<0.05)。75%放养密度组血清乳糖含量显著低于100%放养密度组(P<0.05),75%放养密度组较100%放养密度组显著提高了血清SOD和T-AOC活力(P<0.05)。75%放养密度组血清胰岛素及胰岛素与胰高血糖素比值最低(P<0.05),但催乳素和生长激素最高(P<0.05)。结论:泌乳早期奶牛在75%放养密度条件下氧化应激水平较低,而100%放养密度导致氧化应激水平升高,同时乳腺通透性较高。因此建议泌乳早期奶牛的放养密度应该维持在较低水平,以防止氧化应激。