保护性蛋氨酸对中国荷斯坦奶牛血浆代谢产物及生产性能的影响

选择25头中国荷斯坦奶牛,分成对照组,试验一组(添加30 g DL-蛋氨酸),试验二组(添加45 g保护性蛋氨酸),试验三组(添加30 g DL-蛋氨酸+50 g L-赖氨酸)和试验四组(添加45 g保护性蛋氨酸+50 g L-赖氨酸)进行饲养试验。试验表明:试验四组和试验二组产奶量显著(P<0.05)高于对照组,分别提高6.31 %和6.73 %,其他组差异不显著(P>0.05);试验四组和试验二组乳脂率显著(P<0.05)高于对照组,分别提高6.25 %和6.55 %;并且试验四组和试验二组乳脂率也显著(P<0.05)高于试验一组。乳蛋白、体细胞数、全脂固形物和非脂固形物各组间差异不显著(P>0.05)。试验四组和试验二组血浆白蛋白和总蛋白显著高于对照组(P<0.05),其它各组差异不显著(P>0.05)。试验二组血浆尿素氮(PUN)显著低于对照组和试验一组(P<0.05),其他各组差异不显著(P>0.05)。血浆游离脂肪酸和总氨基酸浓度各组差异不显著(P>0.05)。由此得出结论:一方面,保护性蛋氨酸(RPMet)的一部分能避免瘤胃微生物的降解,以保护性Met的形式提供给瘤胃后Met;另一方面,保护性蛋氨酸的降解部分改善了瘤胃的发酵,促进瘤胃微生物的合成,这两方面的作用提高了奶牛的产奶量和乳成分。     

高碘日粮对奶牛产奶量和乳碘含量的影响

选30头经产2~4胎、产期相近、产奶量相近的奶牛随机分成3组,其中2组饲喂高碘日粮。结果表明:在奶牛日粮精料中添加1.0 mg/kg和2.0 mg/kg碘对牛奶的乳脂、乳蛋白、乳糖和SNF无影响;添加2.0 mg/kg碘能显著提高产奶量,而添加1.0 mg/kg碘则无显著影响;添加1.0 mg/kg和2.0 mg/kg碘均极显著提高血碘和乳碘的含量,而且两者存在线性相关(r=0.427,n=30)。     

过瘤胃蛋氨酸对奶牛产奶量、乳成分以及血液氨基酸的影响

选用16头泌乳中期荷斯坦奶牛按拉丁方设计进行试验,研究饲粮中补充0、8、12和16 g.d-1过瘤胃蛋氨酸对奶牛产奶量、乳成分以及血液氨基酸含量的影响。结果表明,与对照组相比,补饲过瘤胃蛋氨酸能够提高奶牛乳蛋白、乳脂率和酪蛋白水平。补饲过瘤胃蛋氨酸对产奶量较高(>22 kg.d-1)的奶牛有增加产奶量的趋势,对产奶量低的奶牛没有积极作用,能提高高产奶牛乳蛋白和乳脂肪量。选用9头泌乳中期荷斯坦奶牛,在补饲过瘤胃蛋氨酸和普通蛋氨酸前后连续采血44 h,探索蛋氨酸的吸收变化曲线,发现奶牛补饲过瘤胃蛋氨酸后12~16 h达到吸收高峰,过瘤胃蛋氨酸能显著提高奶牛血清蛋氨酸水平,而补饲普通蛋氨酸则无明显影响。补饲过瘤胃蛋氨酸和普通蛋氨酸对血清总氨基酸水平均无显著影响。     

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。     

玉米蒸汽压片和活性酵母添加对奶牛产奶性能及血液指标的影响

本试验旨在研究蒸汽压片处理和添加活性酵母对奶牛产奶性能及血液指标的影响。选用30头健康荷斯坦奶牛平均分为3个组,各处理组精料中分别添加普通玉米(对照)、蒸汽压片玉米(处理1)和添加了活性酵母的蒸汽压片玉米(处理2),正式试验期8周。结果表明:处理1和处理2显著改善了奶牛产奶性能,其中处理2产奶量和乳蛋白率均显著高于对照,分别提高了5.0%和3.7%(P<0.05),且产奶量较处理1提高4.5%(P>0.05);处理1乳蛋白率显著高于对照组,提高了5.4%(P<0.05),产奶量也高于对照组0.5%。在血液指标方面,处理2血液总胆固醇和低密度脂蛋白水平显著高于处理1(P<0.05),而胰岛素水平显著低于对照组(P<0.05),也低于处理1;处理2奶牛血液中异常红细胞、血红蛋白以及红细胞比积含量低于处理1,且显著低于对照组(P<0.05)。总体显示,饲喂蒸汽压片玉米和添加活性酵母的蒸汽压片玉米对于提高奶牛产奶性能和改善乳品质方面效果明显,可能与其促进奶牛能量代谢、改善血液指标和增强机体免疫力有关。     

烟酸和烟酸铬对热应激奶牛产奶性能和血液激素水平的影响

用36头泌乳中期的荷斯坦奶牛按配对原则分为对照组、烟酸组和烟酸铬组,进行65 d的饲养试验。对照组为基础混合精料,烟酸组在混合精料中添加800 mg/kg的烟酸,烟酸铬组在混合精料中添加10 mg/kg的烟酸铬。结果表明:在夏季热应激条件下,烟酸和烟酸铬使奶牛的粗饲料采食量增加,产奶量分别比对照组提高4.86%和12.02%(P<0.05);烟酸铬组提高乳脂5.0%、乳蛋白2.8%、非脂固形物1.8%;烟酸和烟酸铬使血清PRL、T3、T4激素水平上升(P<0.05),对GLU影响不明显(P>0.05);烟酸对血清COR水平无显著影响,烟酸铬使血清COR水平降低8.80%(P<0.05)。     

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）.     

轻微至中度热应激对荷斯坦奶牛生理指标及产奶性能的影响

随机选用16头中国荷斯坦泌乳牛,研究轻微至中度热应激对其生理指标及产奶性能影响。结果表明：（1）泌乳牛在轻微热应激期（THI 74.5±1.0）的生理常数指标与非热应激期（THI 65.2±4.1）差异均不显著（P>0.05）;中度热应激期（THI 84.0±2.4）的各项生理常数指标均显著高于非热应激期（P<0.05）。从非热应激至中度热应激,THI每升高1,直肠温度上升0.04℃;从轻微至中度热应激,THI每升高1,泌乳牛的呼吸频率增加3.4次/min,脉搏增加2.6次/min。（2）在轻微和中度热应激期泌乳牛产奶量分别下降13.8%和26.9%（P<0.01）,产奶量与THI呈极显著负相关（P<0.01）（R= -0.82）,THI每上升1,产奶量下降1.9％。     

日粮精粗比对泌乳奶牛瘤胃纤维降解酶活性及血液指标的影响

选择4头安装有瘤胃瘘管的泌乳奶牛,按4×4拉丁方设计,研究日粮精粗质量比约为30∶70的“高低质粗料型”日粮、30∶70的混合型高青贮日粮、50∶50的精粗料比例相当的日粮及65∶35的高精料日粮等4种不同精粗比日粮对瘤胃纤维降解酶活性及血液指标的影响。结果显示,奶牛采食4种精粗比不同的日粮,均能达到满足纤维降解及纤维分解菌生长要求的瘤胃pH值;日粮精粗比对微晶纤维素、羧甲基纤维素酶、纤维二糖酶和木聚糖酶等瘤胃纤维降解酶活性的影响差异不显著(P>0.05),对奶牛颈静脉血中血浆葡萄糖浓度和血清生长激素、胰岛素、胰高血糖素浓度亦无显著(P>0.05)影响。说明4种精粗比日粮对奶牛瘤胃纤维降解酶活性及上述血液指标没有影响。     

复合包膜甜菜碱对夏季奶牛产奶性能及血液生化指标的影响

选取36头泌乳中期的荷斯坦奶牛,随机分为3组,即基础对照组、试验Ⅰ和Ⅱ组,分别添加10、20和30 g.d-1复合包膜甜菜碱于奶牛全混合日粮中.于试验前、中期和后期在牛尾静脉采集血液,测定血液指标,研究复合包膜甜菜碱对夏季奶牛的产奶性能及血液指标的影响.结果表明:三组奶牛的产奶量差异不显著(P>0.05),Ⅰ和Ⅱ组的产奶量分别比基础对照组提高0.58和1.17 kg.d-1;三组奶牛乳脂含量、乳蛋白含量和体细胞数的变化均不明显,各组之间的差异均不显著(P>0.05);试验期间,三组奶牛血浆中的葡萄糖浓度较试验前均有增加,血浆中的乳酸脱氢酶、肌酸磷酸激酶和碱性磷酸酶活性均下降后上升;试验中期,Ⅱ组奶牛血浆中的总蛋白含量显著低于基础对照组(P<0.05);试验末期,Ⅰ和Ⅱ组奶牛血浆中的总蛋白和白蛋白含量低于基础对照组(P>0.05),Ⅰ组血浆中的尿素氮含量高于基础对照组(P>0.05),Ⅱ组尿素氮含量低于基础对照组(P>0.05).由于试验缺乏空白对照组,因此不同添加量的复合包膜甜菜碱对奶牛的产奶性能及与能量代谢有关的血液指标无显著影响,但Ⅱ组产奶量较高;与Ⅰ和Ⅱ组相比,基础对照组有积累血浆中总氮的趋势.     

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％。     

荷斯坦牛leptin基因exon 2突变与泌乳性能的关联分析

leptin蛋白是leptin基因在脂肪组织表达的一种蛋白质,经证实,其基因单核苷酸多态性与奶牛的繁殖力、能量平衡及乳蛋白含量相关。本研究运用PCR-RFLP方法,对荷斯坦牛leptin基因外显子2序列E2JW和E2FB位点进行了突变检测,并分离了基因型,然后应用SAS 8.2软件分析了两个位点突变对泌乳性能的影响。结果发现,E2JW SNP不同基因型对乳脂率(P=0.02)、305d产奶量(P=0.03)的影响显著;E2FB SNP不同基因型对乳蛋白率的影响显著(P=0.04);在分析E2JW SNP和E2FB SNP联合基因型对305 d产奶量的影响中,AB/CC基因型与AA/CC、AA/CD、AA/DD、AB/CD、AB/DD之间存在显著性差异,在对乳脂率的影响中,AA/CD基因型与AB/CD基因型之间存在显著性差异;因此,荷斯坦牛leptin基因E2JW和E2FB位点可以作为影响泌乳性能的两个标记。     

The Effects of Graded Abomasal Glucose Infusion on Milk Yield and Composition in Lactating Goats

Four non-pregnant multiparous lactating goats were used in a 4 × 4 latin square experiment in the present study. The four treatments were abomasal infusion of 0, 50, 100, and 150 g d^-1 glucose. The results showed that graded glucose infusion increased milk yield （P 〈 0.01）. The highest milk yield was observed when 50 g d^-1 glucose was infused. An infusion of glucose at 100 or 150 g d^-1 failed to increase milk yield further and milk yield of the 100 g d ^-1 glucose infusion treatment was even significantly lower than that of the 50 g d^-1 treatment （P 〈 0.01）. Though milk fat content was gradually decreased by graded glucose infusions and milk fat yield of the 100 and 150 g d 1 treatments were lower than that of the control （P 〈 0.01）; milk fat yield of the 50 g d i treatment was not depressed and was higher than that of the control （P 〈 0.01）. Graded glucose infusion did not change the contents of milk protein and non-fatty solids. Yields of milk protein （P 〈 0.05）, lactose （P 〈 0.01）, non-fat solids （P 〈 0.01）, and lactose content （P 〈 0.01） of the 50 g d^-1 treatment were higher than those of the control but had no difference among the other three treatments. Contents of those de novo synthesized fatty acids in milk fat remained unchanged or increased and those preformed fatty acids remained unchanged or decreased by graded glucose infusion. Glucose infusion decreased the total yields of C16 ＋ C16：1 and 〉 C16 fatty acids and had no influence on the yield of C4-C14：1 fatty acids （P 〈 0.05）. Results of the present study implied that increased glucose supply had positive effects on the production of milk, milk protein, milk fat, and lactose only when glucose was a limiting factor for milk synthesis. Excessive glucose supply had no further beneficial effects and might depress milk fat synthesis.     

饲料中添加N-羟甲基蛋氨酸钙对泌乳期奶牛血清生化指标的影响

为研究饲料中添加不同比例N-HMM-Ca对泌乳期奶牛血清生化指标的影响,试验选用胎次、产奶量和泌乳天数相近身体健康的荷斯坦奶牛30头,完全随机区组分为5组,每组6头。对照组饲喂基础日粮;试验组分别饲喂在基础日粮中以干物质基础添加0.15%、0.30%、0.75%和1.50%的N-HMM-Ca,预试期14d,正试期42d。结果表明:1)泌乳期奶牛日粮中添加0.75%N-HMM-Ca使血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)浓度显著升高。2)在第14天时,1.50%组甘油三酯(TG)浓度显著高于其他各处理组(P0.01)。血清中高密度脂蛋白(HDL)水平有所提高,但差异不显著(P0.05);随着N-HMM-Ca添加量的增加血清中非酯化脂肪酸(NEFA)的浓度逐渐降低(P0.05);对β-羟丁酸(β-OHB)来说,随着日粮中N-HMM-Ca添加量的增加浓度逐渐升高(P0.05)。3)0.15%、0.30%和0.75%组血清IgA浓度呈现增加的趋势,而且在第42天时尤为显著(P0.01)。4)在第28天时,泌乳期奶牛日粮中分别添加0.15%和0.30%的N-HMM-Ca使过氧化氢酶(CAT)浓度显著高于其他各处理组(P0.01)。综上所述,泌乳期奶牛日粮中添加0.15%的N-HMM-Ca有利于改善机体健康。     

小肽制剂和过瘤胃产品对奶牛产奶性能及奶品质的影响

为了研究过瘤胃脂肪、过瘤胃蛋氨酸和小肽制剂对奶牛产奶性能及奶品质的影响,选取20头中国荷斯坦奶牛,随机分成4组,每组5头,其中对照组饲喂基础日粮;试验组Ⅰ每天饲喂基础日粮 过瘤胃脂肪(450g/头);试验组Ⅱ每天饲喂基础日粮 过瘤胃蛋氨酸(15 g/头);试验组Ⅲ每天饲喂基础日粮 小肽制剂(21g/头)。结果表明,试验Ⅰ组、试验Ⅱ组、试验Ⅲ组产奶量较对照组分别提高31.90%、12.19%和15.17%;乳脂率和乳蛋白率均较对照发生改变,但乳脂率改变幅度更大。     

The effects of step-wise improvement of forage combination in total mixed rations on fatty acid profile in the rumen and milk of Holstein cows

Five lactating Holstein cows in a 5×5 Latin square experiment were fed five high-concentrate total mixed rations(TMRs) to investigate the effects of step-wise improvement of forage combination on ruminal and milk fatty acid profiles. The ratio of concentrate to forage was fixed as 61:39, and the step-wise improvement of forage combination was applied as: TMR1, a ration containing corn stover; TMR2, a ration containing corn stover and ensiled corn stover; TMR3, a ration containing ensiled corn stover and Chinese wild ryegrass hay(Leymus chinensis); TMR4, a ration containing the ryegrass hay and whole corn silage; TMR5, a ration containing the ryegrass hay, whole corn silage and alfalfa hay. The TMRs were offered to the cows twice daily at 0700 and 1900 h. The entire experiment was completed in five periods, and each period lasted for 18 days. Diurnal samples of rumen fluids were collected at 0100, 0700, 1300 and 1900 h(day 16); 0300, 0900, 1500 and 2100 h(day 17); and 0500, 1100, 1700 and 2300 h(day 18). The step-wise improvement of forage combination increased energy and crude protein contents and decreased fibre content. As a result, the step-wise improvement of forage combination increased dry matter intake and milk yield(P0.05). The step-wise improvement increased dietary content of linolenic acid(C18:3 n-3), but did not alter dietary proportions of palmitic acid(C16:0), stearic acid(C18:0), oleic acid(C18:1 cis-9), linoleic acid(C18:2 n-6) and arachidic acid(C20:0). In response to the forage combination, ruminal concentration of C16:0, C18:2 n-6 and C18:3 n-3 linearly increased against their dietary intakes(P0.10). The step-wise improvement increased milk contents of C10:0, C12:0, C14:0, C16:0, C18:2 n-6 and C18:3 n-3(P0.10) and decreased milk contents of C18:0 and C18:1 cis-9(P0.05). Milk yields of C16:0, C18:1 cis-9, C18:2 n-6 and C18:3 n-3 were linearly increased by the increase of these fatty acids in the rumen(R2≥0.79, P0.05), and milk yields of C18:2 n-6 and C18:3 n-3 were also positively correlated with dietary intake of these fatty acids(R2≥0.85, P0.05). The step-wise improvement increased the transfer efficiencies from feed to milk for C18:2 n-6 from 11.8 to 14.2% and for C18:3 n-3 from 19.1 to 22.3%. In a brief, along with the step-wise improvement of forage combination, more dietary linoleic and linolenic acids might escape microbial hydrogenation in the rumen and consequently accumulated in milk fat though these fatty acids were present in low concentrations in ruminal fluids. The step-wise improvement of forage combinations could be recommended as a dietary strategy to increase the transfer efficiency of linoleic and linolenic acids from feed to milk.     

荷斯坦奶牛初乳与常乳代谢物差异分析

【目的】基于非靶向代谢组学技术,对荷斯坦奶牛初乳和常乳中的代谢物进行鉴定与分析。【方法】选择年龄、体况及预产期相近、胎次相同的健康围产期经产荷斯坦奶牛12头,分别于分娩后1 h和21 d采集乳汁,离心并收集乳清,依次记为初乳组（C_0）和常乳组（C_21）。采用代谢组学技术对初乳组和常乳组乳清进行分析,结合正交偏最小二乘判别分析（OPLS-DA）和学生t检验,以变量投影重要度(variable importance in the projection,VIP)＞1,P＜0.05为标准筛选差异代谢物,并对筛选出的差异代谢物进行聚类分析、显著差异代谢物筛选和KEGG通路分析。【结果】在荷斯坦奶牛初乳组（C_0）和常乳组（C_21）共筛选到97种差异代谢物,通过聚类热图可以看出,大多数代谢物在初乳组的含量高于常乳组;差异代谢物随机森林图显示,排名靠前的9种显著差异代谢物分别为乌头酸、柠康酸、龙胆酸、泛酸、牛磺酸、氧戊二酸、柠檬酸、6’唾液酸乳糖和精胺。KEGG通路富集分析显示,8条主要的代谢通路分别为酮体的合成与降解、牛磺酸与次黄嘌呤代谢、丙酮酸代谢、嘌呤代谢、嘧啶代谢、氨基糖与核苷酸糖代谢、三羧酸循环和丁酸代谢。【结论】荷斯坦奶牛初乳中脂质、氨基酸和核苷酸代谢物的含量高于常乳,而常乳中糖类代谢物含量高于初乳,初乳与常乳中代谢物水平的差异为后续代谢物机制的研究奠定了理论基础。     

泌乳奶牛向环境中氮排泄量的预测

采用4×4拉丁方试验设计,以全收粪尿的方法,研究了饲喂粗料相同而精料不同的泌乳奶牛乳液中尿素氮浓度与总氮排泄量(粪氮 尿氮)关系。结果表明,乳尿素氮浓度与奶牛总氮排泄量密切相关,说明乳尿素氮可以用来监测奶牛向环境中排泄氮的总量。     

Pilot study to monitor body temperature of dairy cows with a rumen bolus

A bolus containing a mote (temperature sensor, processor and radio) was placed in the rumen of a fistulated cow to monitor body temperature. Rumen temperature was measured every minute and stored in the internal buffer of the mote. The measured temperature was also transmitted to a base station by the mote every minute. A relay mote mounted on the cows’ left front leg assisted transmission of the information from rumen to the base station. Cow behaviour affected the success rate of data transmission. The base station received more than 50% of the transmitted data when the cow was standing. Success rate was lower than 40% when the cow was lying down. Rumen temperature varied diurnally with night-time temperatures higher than day-time temperatures. Drinking events resulted in distinct decreases of the rumen temperature. It is concluded that for the application of internal sensor motes wireless communication through the body and living environment of the animal works but improvements are possible. Research should also focus on the interpretation of sensor data on mote level for optimizing data recording frequency and transmission of data to dairy management practice.     

不同水平肌醇对黑白花奶牛乳成分的影响

以 40头黑白花奶牛为实验动物 ,随机分成 3个试验组和 1个对照组 ,各试验组分别添加 0 .1,0 .2 ,0 .3g/ (头· d)肌醇 ,研究其对奶牛产奶量、采食量以及乳成份的影响。结果表明 :试验 组中产奶量、采食量、乳脂、乳蛋白、乳糖、无脂固形物和总固形物的增加量最大 ,分别为 3.76 kg/ d,3.36 kg/ d,0 .90 g/ kg,0 .91g/ kg,0 .73g/ kg,1.0 4g/ kg和 1.0 0 g/ kg。证明在奶牛日粮中添加 0 .2 g/ (头· d)肌醇对提高产奶量 ,采食量以及乳成份最好。