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。     

不同水平瘤胃保护赖氨酸对奶牛产奶性能的影响

选用32头泌乳奶牛配对分为4组,对照组饲喂基础日粮,试验Ⅰ、Ⅱ和Ⅲ组在基础日粮中分别添加瘤胃保护赖氨酸(RPLys)10、20、30 g/头.d。研究结果表明:相对于对照组,饲喂RPLys组的产奶量与乳蛋白质率都有所提高,其中试验Ⅲ组的产奶量增幅最大,试验Ⅲ组与对照组的乳蛋白质率差异显著(P0.05);添加RPLys对乳脂率、乳糖、非脂总固形物含量没有显著影响(P0.05)。     

烟酸对热应激奶牛生产性能、血清生化指标的影响

选择健康泌乳后期的中国荷斯坦奶牛3头,采用3×3拉丁方设计,在基础日粮中分别添加0、8、15 g/(头.d)的烟酸,试验期63 d,研究了日粮中添加不同水平的烟酸对热应激奶牛生产性能、血清生化指标的影响。结果表明:烟酸对热应激状态的奶牛直肠温度和呼吸频率影响未达显著水平;日粮中添加8、15 g/(头.d)烟酸奶牛的产奶量分别比对照组提高29.9%、22.0%(P<0.05),4%标准乳产量比对照组分别提高了28.5%和21.5%(P<0.05),且不同添加水平间无显著差异(P>0.05),添加烟酸对奶牛的乳蛋白、乳脂和乳糖含量影响未达到显著水平;2个试验组都能够维持奶牛血清皮质醇水平的基本恒定,降低了胆固醇和甘油三酯的水平,但与对照组相比差异不显著(P>0.05)。综合分析表明,给热应激奶牛补饲烟酸有助于缓解热应激,烟酸适宜添加量为8 g/d。     

CB酵母对泌乳早期奶牛产奶量及乳成分的影响

在奶牛日粮中每头添加50g·d-1CB酵母(Candida tropicalis Berkhout)。结果表明,CB可提高产奶量11.2%,试验组产奶量与对照组产奶量差异显著(P<0.05);乳蛋白含量提高5.13%,试验组与对照组乳蛋白差异显著(P<0.05);乳中乳脂率含量有所提高,但差异不显著(P>0.05);乳中干物质含量有增加趋势,但差异不显著。     

酒糟和大豆皮非饲草纤维替代泌乳奶牛日粮中玉米淀粉的效果

试验采用完全随机设计,2周为协变量期、6周为试验期,选择40头荷斯坦奶牛,评估玉米可溶性干酒糟(DDGS)和大豆皮(SH)部分替代日粮中由玉米提供淀粉的效果。给奶牛提供淀粉含量下降的日粮:淀粉29%不含DDGS、淀粉26%含DDGS7%、淀粉23%含DDGS14%、淀粉20%含DDGS21%。日粮由玉米青贮27%、苜蓿干草22%、混合精料51%配合而成,含粗蛋白17%、脂肪4.7%、中性洗涤纤维23%(来自饲草)。试验结果表明,在日粮中添加DDGS和大豆皮,提高了中性洗涤纤维总量。在日粮中添加大豆皮和DDGS替代豆粕和压榨豆粕,可保持日粮相似的粗蛋白含量,干物质采食量下降;随着淀粉被非饲草纤维替代,饲料转化率趋于线性提高。对奶牛产奶量、乳脂率、乳蛋白率、乳脂量、乳蛋白量无显著影响,日粮之间的乳脂肪酸含量相似,乳脂肪校正奶4%、总固形物、乳中尿素氮等不受日粮处理的影响,日粮之间的瘤胃挥发性脂肪酸浓度无差别,日粮之间的血糖浓度和β-羟基丁酸浓度相似。研究结果表明,来自DDGS的非饲草纤维可部分替代奶牛日粮中的玉米淀粉而不会影响产奶量和乳成分。对日粮的经济分析表明,用DDGS和大豆皮替代玉米是有成本效益的。试验结果表明,DDGS和大豆皮可作为替代玉米降低饲料成本的能量来源。     

热应激期日粮添加酵母铬对奶牛产奶性能及血液生化指标的影响

根据胎次、泌乳期和产奶量,按随机单位组方法将44头泌乳120 d,日均产奶量为27.70 kg的奶牛分为4组,每组11头.预饲期15 d,正试期45 d,试验期温湿指数为81.5.对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组在基础日粮中添加酵母铬(精料中,Cr的质量分数分别为0.40、0.80、1.20 mg.kg-1),研究热应激期日粮添加酵母铬对奶牛产奶性能及血液生化指标的影响.结果表明:试验组奶牛产奶量较对照组均有不同程度提高,其中以试验Ⅱ组效果最佳,提高6.26%(P<0.05),试验Ⅰ、Ⅲ组有升高的趋势,但差异不显著(P>0.05);试验Ⅱ、Ⅲ组血清游离三碘腺原氨酸(FT3)含量和FT3与游离甲状腺素(FT4)的比值(FT3/FT4)较对照组极显著降低(P<0.01);试验Ⅰ组血清胰岛素活性较对照组显著升高(P<0.05),试验Ⅱ、Ⅲ组有升高的趋势,但差异不显著(P>0.05);试验Ⅰ组日粮干物质进食量(DM I)较对照组显著提高(P<0.05),但随着Cr含量的增加,DM I提高的趋势逐渐减弱;各试验组奶样中Cr含量符合NY5045-2001卫生标准.     

益生素对奶牛泌乳性能及乳品质影响的研究

选取共36头健康黑白花奶牛,随机分为3组,每组各12头,对照组饲喂基础日粮;试验I组饲喂添加啤酒糟的日粮,试验Ⅱ组饲喂含益生素的日粮,将3组的奶产量、乳品质及抗病能力进行比对分析.结果表明,产奶量、乳脂率、乳蛋白率试验Ⅱ组与对照组、试验I组相比,差异极显著(P<0.01).而试验I组与对照组相比差异不显著(P>0.05);乳糖率试验Ⅱ组与对照组、试验I组相比差异不显著(P>0.05),而试验I组与对照组相比差异不显著(P>0.05).在试验期间试验Ⅱ组12头受试奶牛均未发生乳房炎和子宫内膜炎,而试验I组有1头奶牛发生乳房炎,发病率为8.33%.结果表明合理地使用益生素,可明显提高奶牛产奶量和牛奶的品质,降低奶牛乳房炎和子宫内膜炎的发病率.     

日粮蛋白水平对泌乳奶牛生产性能及牛乳中尿素氮含量的影响

日粮营养水平是影响奶牛产奶量和乳成分的重要因素之一,其中日粮蛋白质水平是奶牛营养学研究的热点。研究不同蛋白质水平对泌乳奶牛生产性能及牛乳中尿素氮含量的影响,可为奶牛养殖中调整日粮蛋白质水平提供依据,达到既满足奶牛生产性能的需要,又减少饲料浪费,还可以提高日粮蛋白质利用率的目的。选用体质健康且产奶量、胎次和泌乳天数基本一致的泌乳期荷斯坦奶牛20头,随机分为2组（每组10头）,分别饲喂蛋白质含量为12.2%（对照组）和10.6%（试验组）的日粮,均采用全混合日粮饲喂90 d,自由采食。在试验开始时测定奶牛的产奶量;试验开始后每个月（泌乳第56 d、86 d、116 d）分别测定1次产奶量、乳成分和牛乳中的尿素氮含量。结果表明：将日粮蛋白水平由12.2%降低到10.6%,对奶牛产奶量、乳脂率和乳蛋白含量影响均不显著（P〉0.05）,但可以显著降低奶牛乳中的尿素氮含量（P〈0.05）。对于产奶量在20～25 kg/d的奶牛,蛋白质水平为10.6%的日粮完全可以满足奶牛泌乳的需要,且有利于提高奶牛的繁殖性能和降低养殖成本。     

复合生物预混剂对奶牛生产性能和乳品质的影响

为探讨相同日粮条件下添加复合生物预混剂对奶牛生产性能和乳品质的影响,选取 20 头年龄、胎次、泌乳日龄、妊娠期、产奶量、体重基本相似且身体健康的荷斯坦奶牛随机分为2组,每组10头。分别饲喂对照组（普通型预混剂）和试验组（项目组研制的5%的复合生物预混剂）日粮,两种日粮基础配方相同,含预混剂不同,经74 d试验期显示：整个试验期对照组与试验组每头日平均产奶量差异显著（P<0.05）;随着泌乳期的延长,试验组乳脂肪率增加125%,显著高于对照组（P<0.05）;两组乳蛋白率和乳中总固形物含量有增加趋势,差异不显著（P＞0.05）。表明奶牛日粮中添加复合生物预混剂可以显著提高奶牛产奶性能、改善乳品质。     

盐藻粉对奶牛生产性能的影响研究

[目的]为盐藻粉在反刍动物中的应用提供理论依据。[方法]选择40头中国荷斯坦奶牛随机分为4组,分为对照组(基础日粮)、试验Ⅰ组、试验Ⅱ组及试验Ⅲ组,分别在基础日粮的基础上添加4.5、9和13.5 g/d盐藻粉,研究其对奶牛生产性能的影响。[结果]试验Ⅰ组、试验Ⅱ组、试验Ⅲ组奶牛产奶量比对照组分别提高了2.98%、5.24%和6.59%,但差异均不显著(P>0.05);试验Ⅰ组、试验Ⅱ组、试验Ⅲ组乳脂率、乳蛋白、乳糖、非脂乳固形物含量与对照组差异均不显著(P>0.05);3个试验组牛奶中的体细胞数分别比对照组降低了15.7%、29.4%和33.5%。[结论]添加盐藻粉有提高奶牛产奶量、降低牛奶中的体细胞数和改善乳品质量的趋势。     

Application of Protein Feed Processed by Microbial Fermentation to Dairy Cow

Methionine(Met)and lysine(Lys)have been reported as the first two limiting amino acids(AA)for maximum milk yield and milk protein production.Supplying these AA may improve microbial protein synthesis and therefore improve milk production without adding excess N to the environment.This observation utilized fermented soybean meal(SBM),cottonseed meal(CSM),rapeseed meal(RSM)and corn by Bacillus subtilis 168 and Leuconostoc mesenteroides as core feedstuffs to produce special biological protein feed for dairy cow.The results showed that the milk production,milk protein percentage,milk fat percentage and milk DM percentage of test groups in trial period were significantly more than those of the control group(P<0.01),the results showed that adding fermenting protein feed in dairy cow diets could significantly improve milk yield,milk protein and milk fat content.The economic benefits of actual application were analyzed,the group of 0.5%was the best compared with the other groups.     

全棉籽替换TMR中部分精料对泌乳后期奶牛生产性能的影响

[目的]探讨全棉籽替换TMR(全价混合日粮)中精料对奶牛生产性能的影响.[方法]试验选用产奶量、膘情、胎次相近、泌乳后期健康的荷斯坦奶牛30头,褐牛25头.采用自身对照,对照期按牛场常规TMR饲喂奶牛,试验期在TMR中用2kg全棉籽替换等量的精料饲喂奶牛,与对照期相比较.[结果]试验期乳脂率、乳糖率极显著地高于对照期(P＜0.01),荷斯坦奶牛和褐牛的乳脂率提高了9.09;和8.70;;荷斯坦奶牛和褐牛的乳糖率提高了2.82;和7.98;;试验期奶牛产奶量、干物质采食量、乳蛋白都有增高的趋势,但与试验期相比差异不显著(P＞0.05).[结论]在奶牛泌乳后期,用2kg全棉籽替换TMR中等量(2kg)精料可以提高奶牛的乳脂率和乳糖率,但对体细胞数及其它乳成分的影响差异不显著(P＞0.05).     

Effect of oilseeds rich in linoleic and linolenic acids on milk production and milk fatty acid composition in dairy cows

Nine multiparous cows averaging 93±13 days in milk production (DIM) were used in a triple 3×3 Latin square design to determine the effects of feeding them whole roasted flaxseed, cracked roasted soybean and fresh alfalfa in the diet on milk production, milk fatty acid profiles and the digestibility of nutrients. Each experimental period lasted 30 d and a sample collection was performed during the last 7 d. The cows were fed on the control basal diet (CON) or diets containing whole roasted flaxseed (FLA) or cracked roasted soybean (SOY). All diets were fed as a total mixed ration (TMR) and had similar concentrations of crude protein (CP), Net Energy Lactation (NEL), acid detergent fibre (ADF) and neutral detergent fibre (NDF). The dry matter intake (DMI) was not significantly different (P>0.05), but tended to increase in FLA and SOY diets compared with the control (P>0.05). Cows in all treatments had a similar milk yield, although 4% fat corrected milk (FCM) yield was higher on the FLA and SOY diets than on the CON diet. Milk fat percentage (3.45%) increased in the FLA diet compared with the control (3.31%) and SOY diets (3.39%). Milk protein percentages were similar among the diets (P>0.05). There were similar digestibilities of DM, CP and ADF among the treatments and lower digestibilities of NDF and ether extract in the SOY diet compared with the CON diet. Feeding various oilseeds significantly increased the concentrations of C_18:1, C_18:3 and conjugated linoleic acid (CLA). The FLA diet decreased the ratio of omega-6 to omega-3 fatty-acids in the milk, which would improve the nutritive value of the milk.     

南方地区中国荷斯坦牛DGAT1基因多态性与泌乳性状的关联分析

 【目的】探索南方地区中国荷斯坦牛DGAT1基因多态性与泌乳性状的相关性。【方法】以上海光明乳业集团金山奶牛场30个公牛家系的605头中国荷斯坦牛为试验材料,采用PCR-SSCP法分析DGAT1基因K232A位点遗传多态性,采用混合动物模型分析DGAT1基因K232A位点突变对测定日产奶量、乳脂率、乳蛋白率、305 d校正产奶量、乳脂量、乳蛋白量及体细胞评分7个泌乳性状的影响。【结果】共检测到KK、KA和AA三种基因型,频率分别为0.7918、0.1917和0.0165,等位基因K和A的频率分别为0.8876和0.1124。该位点突变对测定日产奶量、乳脂率、乳蛋白率、305 d校正产奶量、乳蛋白量的影响达到极显著水平(P＜0.01),对乳脂量的影响达到显著水平(P＜0.05),对乳中体细胞评分影响不显著(P＞0.05)。多重比较表明,KK和KA型测定日产奶量、305 d校正产奶量和乳蛋白量极显著高于AA型(P＜0.01),AA型乳脂率和乳蛋白率极显著高于KK和KA型(P＜0.01)。【结论】DGAT1基因K232A位点突变对中国荷斯坦牛泌乳性状有较大的遗传效应,可用于其泌乳性状的分子标记辅助选择。     

氢醌在奶牛饲养中的应用研究

将泌乳量、胎次、泌乳月相近的 18头黑白花奶牛分为 3组 ,分别饲以精料补充料Ⅰ ,Ⅱ ,Ⅲ。精料补充料I含有11%的豆饼 ,在等能等氮分别添加 0 .l%和 0 .0 2 %氢醌 (脲酶抑制剂 )的前提下 ,用尿素取代精料补充料I中全部豆饼构成精料补充料Ⅱ和Ⅲ。结果表明 :3组试牛泌乳量、乳脂率、血液尿素氮、日增重和体增重校正标准乳差异均不显著(P >0 .0 5 ) ,但Ⅰ组试牛日增重和体增重校正标准乳有提高趋势 ,而Ⅱ ,Ⅲ组试牛泌乳量有上升趋势。因此 ,在奶牛饲养中适当应用氢醌尿素对泌乳量无负效应 ,而且可节约蛋白质饲料资源     

十二指肠灌注α-亚麻酸对奶牛养分消化率及生产性能的影响

为观察泌乳奶牛十二指肠灌注游离亚麻酸(LNA)对干物质采食量、养分表观消化率和乳成分的影响,选用4头安装有十二指肠和瘤胃瘘管的中国荷斯坦奶牛,用灌注游离α-亚麻酸(LNA)处理和空白对照交叉试验设计,每期试验持续5周;期间2头牛进行LNA增量灌注(0、30、60、90和120g/d),每个剂量灌注1周,另外2头奶牛只灌注乳化载体。结果表明:灌注LNA对奶牛干物质采食量和养分表观消化率无显著影响(P>0.05);随LNA灌注剂量的增加(0、30、60、90和120g/d)乳产量趋于降低(18.54、17.17、16.94、15.93和16.28kg/d(P=0.08));但4%(质量分数)脂肪校正乳产量无降低趋势;乳脂肪含量随LNA灌注剂量的增加呈线性升高趋势(4.01、4.12、3.96、4.32和4.41g/100g(P=0.09)),乳脂产量无变化;乳糖含量(4.56、4.60、4.68、4.59和4.57g/100g)和乳产量(0.85、0.79、0.79、0.73和0.74kg/d)随LNA灌注量的增加呈现二次式降低(P<0.05),乳蛋白含量和产量无变化。结果显示,增加泌乳奶牛小肠游离亚麻酸的供给量...     

不同水平DDGS对奶牛乳产量和乳成分的影响

选择18头荷斯坦奶牛,设置3个处理,每个处理6个重复,每个重复1头奶牛。分别在饲料中添加15％（Ⅰ组）、25％（Ⅱ组）和35％（Ⅲ组）的DDGS,研究不同添加水平的DDGS对奶牛产奶量和乳成分的影响。试验结果表明：①试验Ⅱ组平均产奶量为10．99kg·d^-1,比Ⅰ组提高了4．67％,差异不显著（P〉0．05）;比Ⅲ组提高了9．03％,差异显著（P〈0．05）;②不同处理间的乳脂率差异不显著（P〉0．05）;对于乳糖和乳蛋白含量,Ⅱ组与Ⅰ组和Ⅲ组差异不显著（P〉0．05）;对于乳干物质,试验第15天时,Ⅱ组比Ⅰ组提高了4．39％（P〈0．05）,比Ⅲ组提高了1．19％（P〉0．05）。根据上述生产性能指标综合评定,建议奶牛配合饲料中DDGS适宜添加量为25％。     

Relationship of Somatic Cell Count with Milk Yield and Composition in Chinese Holstein Population

The objective of this study was to analyze the relationship of somatic cell count （SCC） with milk yield, fat and protein percentage, fat and protein yield using analysis of variance and correlation analysis in Chinese Holstein population. The 10 524 test-day records of 568 Chinese Holstein Cattle were obtained from 2 commercial herds in Xi＇an region of China during February 2002 to March 2009. Milk yield, fat percentage, fat and protein yield initially increased and then dropped down with parity, whereas protein percentage decreased and SCC increased. Analysis of variance showed highly significant effects of different subclasses SCC on milk yield and composition （P〈 0.01）. Compared with milk yield with SCC ≤ 200 000 cells mL-1, milk yield losses with SCC of 200 000-500 000 cells mL-1, 501000-1 000 000 cells mL-1, ≥ 1 000 000 cells mL-1 were 0.387, 0.961 and 2.351 kg, respectively. The highly significant negative correlation coefficient between somatic cell score （SCS） and milk and protein yield, milk yield and fat and protein percentage, protein percentage and fat yield were -0.084, -0.037, -0.061, -0.168, and -0.088, respectively （P〈 0.01）. The highly significant positive correlation coefficients between SCS and fat yield and fat and protein percentage, milk yield and fat and protein yield, fat percentage and protein percentage and fat yield, protein yield and protein percentage and fat yield were 0.041, 0.177, 0.105, 0.771, 0.865, 0.122, 0.568, 0.318, and 0.695, respectively （P〈 0.01）. There was no significant relationship between fat percentage and protein yield （P 〉 0.05）. The results of the present study first time provide the relevant base-line data for assessing milk production at Xi＇an region of China.     

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.