大豆异黄酮对奶牛产奶量及乳成分的影响

为研究大豆异黄酮对奶牛产奶量和乳成分的影响,选用32头产奶水平相近的荷斯坦奶牛,随机分成A、B两组。试验分为两个阶段,第一阶段A组在基础日粮中添加Da400mg·kg^-1,B组饲喂基础日粮,持续15d。第一阶段试验结束后,两组均饲喂基础日粮,持续20d。第二阶段A组奶牛饲喂基础日粮（A’组）,B组奶牛在基础日粮中添加Da200mg·kg^-1（B＇组）,持续15d。结果显示,A组奶牛产奶量略高于B组,表明饲喂大豆异黄酮在一定程度上能提高产奶量;但A’组奶牛产奶量极显著低于B组（P〈0．01）,可能由于添加Da剂量过大导致内源性激素水平下降所引起的。同时与A’组相比,B’组乳蛋白略有提高,脂肪含量极显著升高（P〈0.01）。     

日粮中添加过瘤胃脂肪对奶牛产奶量和乳汁成分的影响

为了解过瘤胃脂肪对奶牛产奶量和乳汁成分的影响,选取24头试验奶牛,分为4组,每组6头。3个处理组每头每天的过瘤胃脂肪添加量分别为：Ⅰ组200g,Ⅱ组300g,III组400g,IV组为对照组。结果表明,Ⅲ组产奶量提高了21.9%,显著高于对照组（P〈0.05）;乳脂率未见显著变化（P〉0.05）;乳蛋白含量有下降的趋势,与对照组差异不显著（P〉0.05）。这表明,泌乳早期添加过瘤胃脂肪能提高奶牛产奶量,对奶牛乳汁成分的影响不显著。     

奶牛产奶量与乳成分的多元回归分析

通过SAS 8.2软件分析了20头胎次相同、泌乳期相近荷斯坦泌乳牛产奶量与乳成分中乳蛋白质率、乳脂率、干物质、体细胞数和乳中尿素氮的多元回归分析。结果表明:从产奶量与乳成分的单项指标回归分析表明,产奶量与乳脂率、体细胞数和干物质含量呈显著性的负相关,而与乳蛋白率和乳中尿素氮差异不显著;从产奶量与乳成分的多元回归分析表明,乳蛋白率、乳脂率和干物质含量对产奶量的影响高于体细胞数和乳中尿素氮,同时乳蛋白率、乳脂率、体细胞数和乳中尿素氮与产奶量成反比。     

中国荷斯坦奶牛产奶量与乳品质互作关系探讨

以一个奶牛场的336头泌乳牛为研究对象,选取了降低产奶量前、降低产奶量期间、恢复产奶量期间和提高产奶量期间4个阶段,研究了每个阶段的产奶量与乳品质一些指标间的相关性。经分析,产奶量、乳蛋白质率、乳脂肪率、非脂乳固体含量、乳糖含量这5个指标相互之间均有极显著的正相关性。     

Bacillus subtilis Co-transfected with a Lysine-rich and a Methionine-rich Protein Gene and Its Effect on Cow Milk Production

The probiotic Bacillus subtilis(B. subtilis) was widely applied in animal production as feed additive. Lysine(Lys) and methionine(Met) were the two most important limiting amino acids in livestock animal feed. Raising Lys and Met contents in B. subtilis would provide better effects for animal production and save Lys and Met supplements. We still didn't know whether Lysrich and Met-rich protein genes from plants could be transfected into B. subtilis and expressed at a high level so as to improve animal production, such as milk production as an additional diet. The Lys-rich protein gene(Cflr) and Met-rich 10 ku-δ Zein were cloned from pepper anther and maize endosperm, respectively. Then they were constructed into plasmids individually and successfully cotransfected into B. subtilis. Upon IPTG induction, m RNAs and protein expressions could be observed. Lys and Met contents in the fermentation broth were raised by 65.92% and 46.39%, respectively. After feeding 200 g and 400 g · cow~(-1) · d~(-1), transgenic B. subtilis fermentation broth, the milk yield, milk protein and milk fat contents all significantly increased. The Lys-rich protein gene(Cflr) and Met-rich 10 ku-δ Zein were successfully transfected into B. subtilis. Contents of Lys and Met in the transgenic B. subtilis obviously raised and the fermentation broth of the transgenic bacteria could effectively improve milk yield and quality.     

Effects of Rumen Protected Methionine on Milk Yield and Milk Composition in Earlier Lactating Cow

A total of 12 mature healthy Holstein dairy cows of the nearly body weight （580±30） kg, milk yield （22.5±2.8） kg in the early stages of lactation were selected in this experiment. The cows were randomly divided into 2 groups, every group had 6 cows, every group had 6 repeats, and every repeat had 1 cow. Added 20 g protected methionine in earlier lactating cow food every day. The results showed that protected methionine increased milk yield by 10.83%, testing group milk yield was significantly different than that of control （P〈0.05）; protected methionine increased milk fat by 5.98%, testing group milk fat was significantly different than that of control （P〈0.05）; Milk protein increased by 2.15%, but bad insignificantly different （P〉0.05）; dry matter of milk had the tendency of decrease, but had insignificant difference （P〉0.05）.     

催乳灵对奶牛产奶性能影响的试验研究

在日粮的配合精料中添加中草药添加剂—“催乳灵”, 用这些饲料饲喂泌乳牛, 研究其对荷斯坦泌乳牛产奶性能的影响。经过60天的饲养试验, 结果表明: 添加催乳灵的试验组与没加催乳灵的对照组相比, 试验组奶牛日产奶量平均提高了3 56kg, 乳脂率提高了0 17个百分点, 经济效益达2 04元/头日。     

西宁市市售鲜牛乳质量状况的检测

[目的]了解西宁市市售鲜牛乳的质量状况。[方法]从西宁市随机抽取45份市售鲜牛乳,对奶样的比重、脂肪、固形物、杂质度、酸度、尿素和抗生素含量进行检测。[结果]在45份奶样中,检测出2份掺尿素乳、12份掺盐乳7、份掺碱乳、5份抗生素残留奶、12份酸度超标样品2、8份比重不达标样品3、7份脂肪含量不合格样品4、2份固型物不合格样品。抗生素阳性率为11.11%,比往年高得多,呈逐年增长的趋势。西宁市售鲜牛乳存在较大的质量问题,如普遍掺水现象导致了比重、固型物含量和脂肪含量不达标。[结论]应采取实施牛奶产量配额制度、加强牛奶质量定点检测和通过宣传培训提高奶农素质等措施,以避免牛奶掺假现象。     

奶牛血液及乳几项生化指标与泌乳性能的关系

黑白花奶牛血糖、血清清蛋白，乳ｃＡＭＰ，ｃＧＭＰ、α－乳清蛋白和Ｆｅ含量与日产奶量及３０５ｄ产奶量呈正相关；而血清异柠檬酸脱氢酶（ＮＡＤＰ－ＩＣＤＨ）和乳葡萄糖－６－磷酸脱氢酶（Ｇ－６－ＰＤＨ）含量与日产奶量呈负相关。     

复合微量元素缓释丸对奶牛产奶量及奶品质影响的研究

以产奶的黑白花奶牛２０头,分为两组,每组１０头。在同一日粮和饲养管理条件下,一组投丸,为试验组;另一组不投丸,为对照组。预试期１０ｄ,正试期３２ｄ。试验结果,试验组日平均产奶量１７．７６ｋｇ,对照为１６．３０ｋｇ。试验组比对照组提高８．９５％;校正为４％乳脂率的标准乳的日产奶量,试验组为１５．９９ｋｇ,对照组为１３．９４ｋｇ,试验组比对照组提高１４．７１％;     

酒精阳性牛乳脂肪球不稳定机理的研究

本文从牛乳脂肪球的结构特点出发,从不同角度分析探讨了牛乳脂肪球的稳定性及其影响因素,为探讨酒精阳性乳的形成机理提供了理论依据。     

奶牛泌乳调节剂研发SWOT分析

目前我国奶牛平均单产奶量仅为4 100 kg·年-1,乳蛋白质率为2.95％～3.0％,而世界奶牛平均单产能达到5 500 kg·年-1,乳蛋白质率为3.2％～4.0％.奶牛单产水平和乳蛋白质含量低成为制约我国奶牛养殖业发展的重要问题,提高奶品质和产奶量是奶业重大行业问题和技术瓶颈,这就为奶牛泌乳调节剂的研发提供了市场前景.奶牛泌乳调节剂是将活性益生菌发酵液应用于奶牛饲料中而制得的低相对分子质量发酵肽,是一种益生菌添加剂.为研究奶牛泌乳调节剂的研发前景,采用SWOT分析方法,从优势、劣势、机遇、威胁4个方面对产品发展环境进行分析.     

瘤胃稳定性脂肪对产后奶牛产奶量和血液生化指标的影响

40头荷斯坦高产奶牛采用配对分组设计分为对照组和试验组,每组各20头。试验组奶牛自分娩当日起在基础日粮中添加400g瘤胃稳定性脂肪,至产后90日龄时结束。统计奶产量,并分别于产后0、15、30、45、60、75和90d经尾静脉采血,检测血浆总蛋白、白蛋白、球蛋白、葡萄糖、尿素氮和非酯化脂肪酸(NEFA)浓度。结果:补充瘤胃稳定性脂肪后牛奶产量显著升高(P<0.05),对血浆总蛋白、白蛋白、球蛋白、葡萄糖、尿素氮无显著影响,但引起血浆非酯化脂肪酸(NEFA)产后30d内显著升高(P<0.05)。本研究结果表明在奶牛产后日粮中添加瘤胃稳定性脂肪可提高产奶量,并可能在短期内促进脂肪代谢,但对血液蛋白质和葡萄糖含量无显著影响。     

不同泌乳阶段和产奶水平对奶牛淋巴细胞凋亡的影响

选择48头奶牛,分为6组,每组8头,分别为泌乳盛期,泌乳中期和泌乳末期,每个泌乳期设高产组和低产组,研究不同泌乳阶段和产奶水平下奶牛外周血淋巴细胞凋亡情况。结果表明:随着泌乳阶段的延长淋巴细胞凋亡率显著升高,其中泌乳末期最高为2.95%,显著高于泌乳盛期(P0.05),泌乳中期淋巴细胞凋亡和各阶段差异不显著;在泌乳盛期和泌乳中期,高产奶牛的外周血淋巴细胞凋亡率极显著地高于低产奶牛(P0.01),泌乳末期低产组淋巴细胞凋亡率升高为3.02%,高产组低产组,但差异不显著(P0.05)。由此可见,随着泌乳时间的延长,奶牛外周血淋巴细胞的凋亡率逐渐上升,并且高产奶牛更易于发生淋巴细胞的凋亡。     

影响荷斯坦奶牛305d产奶量的因素分析

[目的]探讨各因素对荷斯坦奶牛305 d产奶量的影响.[方法]采用SAS8.1软件对影响305 d产奶量的因素进行最小二乘方差分析.[结果]不同年度对305 d产奶量的影响极显著(P<0.01);不同产犊季节对305 d产奶量有极显著的影响(P<0.01),冬季产奶量最高,夏季产奶量最低;不同胎次对305 d产奶量有极显著的影响(P<0.01),305 d产奶量随着奶牛胎次的增加产奶量也逐渐增加,5胎后开始下降;不同初产月龄对305 d产奶量有极显著的影响(P<0.01),当初产年龄在24-26月龄间产奶量最高.[结论]年度、产犊季节、胎次和初产月龄均是影响荷斯坦奶牛305 d产奶量的主要因素.     

Effect of Different Roughages on Milk Protein and Milk Fat Synthesis in Dairy Cows

The main purpose of this study was to determine the effect of a corn straw or mixed diet on milk production, milk composition and the expression of genes associated with lactation in mid-lactation Chinese Holstein cows. In this study, 10 healthy Chinese Holstein cows were randomly assigned to two groups and fed with different diets respectively, corn straw(CS) or mixed forage(MF) diet. CS group was fed roughage consisting of 53.8% corn straw only and the forge to concentrate(F : C) ratio [dry matter(DM)] was about 40: 60. MF group was fed roughage consisting of 3.7% Chinese wildrye and 23.4% alfalfa hay, the forge to concentrate(F : C) ratio(DM) was 70: 30. All the cows were fed 8 weeks and body weight, dry matter intake, body condition score, fat, protein, lactose, milk yield, total solid and somatic cell count(SCC) were recorded. Quantitative real-time PCR(q RT-PCR) was used to analyze cow mammary gland samples representing two different diets. The results suggested that different diet types had significant effects on milk yield, lactose, milk fat, milk protein, dry matter intake and somatic cell count in dairy cows, and cows fed MF diet improved milk production and lactation performance clearly(P0.05). In addition, m RNA expression of genes ACC, m TOR, STAT5, CSN2, PPARγ, FABP3 and PTEN in MF group was extremely significantly higher than that in CS group(P0.05). m RNA expression of AKT1, FAS, SCD and SREBP1 c in MF group was significantly higher than that in CS group(P0.01). In summary, the milk yield and composition in mixed forage group were significantly improved than those in corn straw group.     

苜蓿青贮对奶牛产奶量、乳品质及养殖效益的影响

[目的]为苜蓿青贮在奶牛养殖中的推广和应用提供科学依据。[方法]以苜蓿青贮替代苜蓿干草,进行饲喂效果比较,探讨苜蓿青贮对产奶量及乳品质的影响。[结果]试验组日均产奶量、乳脂率、乳蛋白率、非脂乳固体率、乳糖率分别比对照组高9.13%、1.73%、0.57%、0.42%、0.38%。[结论]在奶牛日粮中适量添加苜蓿青贮,可以有效提高奶牛的产奶量,同时降低饲料成本,从而提高养殖经济效益。     

准噶尔双峰驼驼乳营养与功能成分与荷斯坦牛乳的差异比较分析

【目的】分析比较准噶尔双峰驼乳和荷斯坦牛乳的差异,为研究驼乳的营养价值和生物学功能提供科学基础。【方法】使用乳成分分析仪、电感耦合等离子体光度发射光谱法、气相色谱和ELISA检测乳的主要营养成分、理化特性、脂肪酸和主要生物活性物质含量。【结果】准噶尔双峰驼乳中乳蛋白、乳糖、钙、灰分、干物质显著高于荷斯坦牛乳(P<0.05)。乳密度也显著高于荷斯坦牛乳(P<0.05)。乳脂中花生酸、二十一碳酸、棕榈油酸和α-亚麻酸显著高于荷斯坦牛乳(P<0.05)。而准噶尔双峰驼乳的电导率、酸碱度、水分显著低于荷斯坦牛乳(P<0.05)。顺-8,11,14-二十碳三烯酸、己酸、辛酸、癸酸和月桂酸显著低于荷斯坦牛乳(P<0.05)。但两乳中所检测的生物活性成分含量无显著差异(P> 0.05)。【结论】准噶尔双峰驼乳相较于荷斯坦牛乳存在诸多显著性差异。     

荷斯坦奶牛产奶量遗传力的估计

[目的]探究新疆呼图壁种牛场荷斯坦奶牛主要经济性状的遗传力.[方法]收集呼图壁种牛场1996～2010年15年间荷斯坦牛泌乳期的生产性能记录,其中包括9 901条奶产量记录.采用SAS(8.1)最小二乘分析过程分析场、年度、季节、胎次四个非遗传因素对新疆呼图壁种牛场荷斯坦牛产奶量的影响.[结果]场、年度、季节、胎次四个非遗传因素对产奶量均有极显著影响(P＜0.01).[结论]根据各因素的显著情况进行了固定效应划分,利用MTDFREML软件对荷斯坦牛进行遗传参数估计,估计了产奶量的方差组分和遗传力,产奶量的遗传力为0.4.     

高产奶牛日粮中苜蓿干草适宜添加量的研究

选用30头2～4胎的荷斯坦奶牛随机分为3组,各组产奶量、体重、胎次、泌乳天数(DIM)差异不显著。3组奶牛日粮中苜蓿干草的添加量分别为2kg(对照)、4kg和6kg,相应的日粮干物质(DM)中粗蛋白含量分别为15.6%,17.2%和18.8%,各组间中性洗涤纤维(NDF)和产奶净能(NE)含量相同,分别为37.4%和6.9MJ·kg-1DM。结果表明:在以苜蓿干草为主的奶牛日粮中,提高粗蛋白含量能显著提高产奶量(P<0.05);干物质采食量(DMI)变化不显著(P>0.05),但有增加的趋势;乳脂率、乳蛋白、乳糖以及干物质含量没有显著变化(P>0.05),在奶牛日粮中大量使用苜蓿干草并没有增加日粮成本,但可以大幅度提高经济效益,6kg组与对照相比纯增效益最高。因此苜蓿干草在奶牛日粮中的适宜添加量为6kg。