过瘤胃胆碱和有机铬对围产期奶牛免疫及抗氧化功能的影响

【目的】试验通过研究饲粮中添加过瘤胃胆碱和有机铬对围产期奶牛免疫及抗氧化功能的影响,旨在为过瘤胃胆碱和有机铬在围产期奶牛饲粮中的科学应用提供理论依据。【方法】选取40头健康、经产（平均胎次1~2）的中国荷斯坦奶牛,随机分为4组（每组10头牛）：对照组（T_O）,基础饲粮;胆碱组（T_C）,基础饲粮＋30 g/d过瘤胃胆碱;有机铬组（T_A）,基础饲粮＋8 g/d蛋氨酸铬;混合组（T_CA）,基础饲粮＋30 g/d过瘤胃胆碱＋8 g/d蛋氨酸铬。试验处理从产前20 d至产后20 d,记录奶牛产后4周内日均产奶量,分别于产前第20、10天和产犊日、产后第10、20天,于晨饲前采集血样,测定血清抗氧化（谷胱甘肽过氧化物酶（GSH-Px）、过氧化氢酶（CAT）和超氧化物歧化酶（SOD））及免疫（白介素-1（IL-1）、白介素-6（IL-6）和肿瘤坏死因子（TNF-α））功能指标。【结果】与对照组相比,3个试验组奶牛产后4周内日均产奶量均显著提高（P<0.05）;产前各组奶牛血清GSH-Px、CAT含量无显著差异（P>0.05）,但试验组奶牛血清SOD含量显著降低（P<0.05）;产犊日至产后第10天,胆碱组和有机铬组奶牛血清GSH-Px、CAT和SOD含量均显著高于对照组（P<0.05）;产后第20天,胆碱组血清GSH-Px、CAT含量均显著低于高于对照组、有机铬组和混合组,而血清SOD含量却显著降低（P<0.05）;整个试验周期内,胆碱组奶牛血清IL-1含量显著低于对照组及有机铬组和混合组（P<0.05）,IL-6和TNF-α含量却显著提高（P<0.05）。【结论】综上所述,本试验条件下,饲粮中单独添加30 g/d过瘤胃胆碱或8 g/d有机铬可明显降低围产期奶牛机体氧化应激水平,提高产奶量和机体免疫力,改善奶牛健康状况,联合添加过瘤胃胆碱和有机铬与单独添加效果差异不明显。     

半胱胺对夏季水牛泌乳性能、抗氧化性能和瘤胃微生物多样性的影响

本试验旨在研究水牛饲粮中添加半胱胺对水牛泌乳性能、瘤胃发酵参数、抗氧化性能和瘤胃微生物组成的影响。选取体重（615 kg±21 kg）、胎次（3~5胎）和产奶量（6 kg/d±1 kg/d）相近的健康泌乳中期尼里-拉菲奶水牛20头,采用单因素随机区组设计,分为4组,每组5头水牛。在基础饲粮中分别添加0（对照组）、15、30和45 g/d半胱胺。预饲期1周,试验期4周。结果表明：与对照组相比,①添加半胱胺对水牛体表温度、直肠温度和呼吸频率均无显著影响（P>0.05）。②添加30和45 g/d半胱胺显著提高了水牛干物质采食量（DMI）和酸性洗涤纤维（ADF）表观消化率（P<0.05）。③添加半胱胺显著提高了水牛产奶量、4%乳脂校正乳产量、乳蛋白率、乳总固形物和乳非脂固形物含量（P<0.05）。④添加45 g/d半胱胺显著提高了水牛瘤胃微生物蛋白（MCP）含量（P<0.05）;添加半胱胺对水牛瘤胃液细菌和真菌数量无显著影响（P>0.05）;添加15 g/d半胱胺显著降低了原虫数量（P<0.05）,而半胱胺添加剂量为30 g/d时瘤胃液原虫数量则显著增加（P<0.05）。⑤添加半胱胺能显著降低乳中C14：1n5、C18：3n6含量,显著增加乳中C18：1n9t、C19：0、C20：3n6含量（P<0.05）。添加30 g/d半胱胺显著降低乳中C16：0、C18：0和饱和脂肪酸（SFA）含量（P<0.05）;添加30和45 g/d半胱胺显著降低乳中C20：4n6（ARA）和不饱和脂肪酸（UFA）含量（P<0.05）。⑥添加半胱胺组水牛血清总抗氧化能力（T-AOC）显著提高（P<0.05）;15和30 g/d半胱胺组水牛血清丙二醛（MDA）含量显著降低（P<0.05）;30和45 g/d半胱胺组谷胱甘肽过氧化物酶（GSH-Px）活性、总蛋白、球蛋白水平显著增加（P<0.05）;15和45 g/d半胱胺组皮质醇（Cor）显著降低（P<0.05）;30 g/d半胱胺组谷草转氨酶（AST）活性显著增加（P<0.05）。综合试验结果,饲粮中添加半胱胺能够提高泌乳中期水牛泌乳性能与抗氧化能力,影响水牛瘤胃发酵、乳脂脂肪酸含量和瘤胃原虫数量。在本试验条件下,建议半胱胺在水牛饲粮中的适宜添加量为30 g/d。     

过瘤胃葡萄糖和缓释尿素对热应激绵羊生产性能及瘤胃发酵功能的影响

【目的】 本试验旨在研究饲粮中添加缓释尿素（SRU）和过瘤胃葡萄糖（RPG）对热应激绵羊生产性能和瘤胃发酵功能的影响。【方法】 选取40只健康、体重相近的3月龄湖羊公羔,按初始体重随机分成4个处理组（n=10）,分别为对照组（CON组,饲喂基础饲粮）、缓释尿素组（SRU组,基础饲粮中添加缓释尿素15 g/d）、过瘤胃葡萄糖组（RPG组,基础饲粮中添加过瘤胃葡萄糖10 g/d）和联合添加组（UG组,基础饲粮中添加缓释尿素15 g/d+过瘤胃葡萄糖10 g/d）,预饲期15 d,正饲期50 d。在正饲期的最后一天晨饲前,分别采集血液和瘤胃液,测定血样中免疫球蛋白A （IgA）、免疫球蛋白M （IgM）、免疫球蛋白G （IgG）、肿瘤坏死因子-α（TNF-α）、白细胞介素-2（IL-2）的含量,并测定瘤胃液pH、氨态氮、微生物蛋白及挥发性脂肪酸等指标。【结果】 与CON组相比,①饲粮中添加缓释尿素、过瘤胃葡萄糖均显著降低热应激绵羊的呼吸频率（P<0.05）,UG组热应激绵羊的直肠温度显著降低（P<0.05）。②SRU组、RPG组、UG组热应激绵羊的终末体重和平均日增重均显著提高（P<0.05）,料重比显著降低（P<0.05）。③RPG组和UG组热应激绵羊血清中IgG和IgM的含量均显著提高（P<0.05）,血清中TNF-α和IL-2的含量显著降低（P<0.05）。④各处理组热应激绵羊瘤胃内乙酸与丙酸的比值均显著提高（P<0.05）,SRU组瘤胃内乙酸、异丁酸、异戊酸比例和总挥发性脂肪酸的浓度均显著提高（P<0.05）,RPG组瘤胃液pH和异戊酸比例均显著提高（P<0.05）,瘤胃内氨态氮、丙酸、丁酸的比例均显著降低（P<0.05）,UG组瘤胃内乙酸、总挥发性脂肪酸及微生物蛋白的含量均显著提高（P<0.05）。【结论】 饲粮中添加缓释尿素、过瘤胃葡萄糖显著提高了热应激绵羊的生产性能,改善瘤胃发酵,维持瘤胃内环境的稳定,可有效缓解绵羊热应激。     

瘤胃发酵产物乙酸和丙酸比对奶牛生产性能及乳成分影响的荟萃分析

本研究旨在探讨瘤胃发酵产物乙酸、丙酸以及乙酸和丙酸比对奶牛干物质摄入量（DMI）、产奶量（MY）和乳成分的影响。通过回顾已发表文献，使用荟萃分析的方法构建模型并进行相应的回归分析和相关性分析。试验整理了关于奶牛生产性能的中文及英文相关文献51篇，共计181个处理，研究不同的饲料原料、营养成分、饲料添加剂对不同生理阶段泌乳奶牛瘤胃发酵指标及生产性能的影响。基于此51项试验的荟萃分析结果表明，与瘤胃内乙酸和丙酸产量相比，奶牛的产奶量（R²=-0.426，P<0.01）、乳脂率（R²=0.359，P<0.01）、乳脂产量（R²=-0.257，P<0.01）、挥发性脂肪酸（VFA）（R²=-0.226，P<0.05）和干物质采食量（DMI）（R²=-0.485，P<0.01）与瘤胃发酵产物乙酸和丙酸比有更强的相关性；瘤胃乙酸和丙酸比与奶牛的产奶量、乳脂率、乳脂产量和DMI存在极显著的一元线性回归关系（P<0.01），其比值的增加会导致DMI、产奶量、乳脂产量极显著降低（P<0.01），乳脂率极显著升高（P<0.01），瘤胃乙酸和丙酸的比值每增加1，乳脂率增加0.26%，奶牛的干物质摄入量、产奶量分别减少2.34和4.99 kg。通过荟萃分析发现，乙酸与丙酸的比值可以更科学地预测乳脂在乳中的占比且准确反应牛奶乳脂率的变化，为饲粮的选取及调控乳品质提供了参考价值。     

全株甘蔗的奶牛瘤胃降解特性及其替代奶牛饲粮苜蓿、燕麦草及精料的应用研究

本试验旨在探究全株甘蔗的奶牛瘤胃降解特性及其替代奶牛饲粮中苜蓿、燕麦草及精料对奶牛瘤胃发酵、营养物质表观消化率、血液生化指标及生产性能的影响,为其替代奶牛饲粮中价格日益攀升的苜蓿和精饲料,并用作奶牛粗饲料资源开辟新途径。试验一采用半体内试验即瘤胃尼龙袋技术,探究了全株甘蔗、国产羊草与国产苜蓿各营养成分的瘤胃降解特性;试验二采用重复3×3拉丁方试验设计,选择体重、胎次、泌乳天数和产奶量相近并装有永久瘤胃瘘管的荷斯坦奶牛进行消化试验,探究全株甘蔗替代饲粮25%或50%的美国进口苜蓿对奶牛营养物质消化率、瘤胃发酵特性和血液生化指标的影响;试验三选取60头胎次、产奶量和泌乳天数相近的荷斯坦奶牛进行生产试验,探究了全株甘蔗分别替代饲粮30%苜蓿干草、50%燕麦草或10%精料对奶牛生产性能、血液生化指标和牧场经济效益的影响。结果发现：1）全株甘蔗干物质（DM）和酸性洗涤纤维（ADF）的有效降解率显著高于国产羊草（P<0.05）,中性洗涤纤维（NDF）和有机物（OM）的有效降解率显著高于国产羊草和国产苜蓿（P<0.05）。2）用全株甘蔗替代饲粮25%或50%美国进口苜蓿对奶牛瘤胃pH、氨态氮（NH₃-N）（除25%组4 h外）和挥发性脂肪酸（VFA）含量无显著影响;对奶牛干物质采食量（DMI）及饲粮DM、粗蛋白质（CP）、OM和ADF消化率无显著影响,而全株甘蔗替代饲粮50%美国进口苜蓿组的NDF消化率显著升高（P<0.05）;全株甘蔗替代饲粮中50%美国进口苜蓿组2和8 h血清尿素氮含量显著低于25%组和对照组（P<0.05）,且各处理组不同时间点血液β-羟丁酸含量、瘤胃各VFA和总VFA含量均无显著差异。3）用全株甘蔗替代高产奶牛饲粮中50%燕麦草、30%苜蓿干草或10%精料对奶牛血液中的葡萄糖、尿素氮、β-羟丁酸和非酯化脂肪酸（NEFA）等含量及产奶量均无显著影响,且综合产奶量和饲料成本两方面的因素,各替代组分别比对照组每头奶牛的经济效益增加3.28、7.48和1.62元·d^-1。由此可知,全株甘蔗是一种可供奶牛食用的消化率较高的优质粗饲料,且用其替代饲粮中的25%或50%美国进口苜蓿不影响奶牛的瘤胃发酵特性和营养物质表观消化率;用其替代30%苜蓿干草、50%燕麦草或10%精料不会影响奶牛的血液生化指标及生产性能,还会提高牧场的经济效益。     

中草药添加剂对围产期奶牛血液生化指标及生产性能的影响

本研究旨在研究中草药添加剂对围产期奶牛血液生化指标及生产性能的影响。试验选择36头体况、预产期和胎次相近的荷斯坦奶牛,采用完全随机试验设计,分为3组,每组12头奶牛。3组奶牛在基础日粮中分别添加0、150和300 g/d的中草药添加剂,预饲期1周,正饲期6周。奶牛产后每周采集1次饲料样、血样和奶样,测定其干物质采食量、血液生化指标及乳成分等指标。结果表明,随着中草药添加剂饲喂量的增加,围产期奶牛产后产奶量表现出一定的升高趋势,产奶量分别增加5.1%和10.6%,但与对照组相比差异不显著（P>0.05）,围产期奶牛饲喂中草药添加剂对干物质采食量没有显著影响（P>0.05）。与对照组相比,随着中草药添加剂饲喂量的增加,乳中体细胞数显著降低（P<0.05）,分别下降62.7%和76.6%,但对乳中其他常规指标没有显著的影响（P>0.05）。与对照组相比,随着中草药添加剂饲喂量的增加,奶牛血清中非酯化脂肪酸（NEFA）含量显著降低（P<0.05）,降低水平分别为29.0%和35.1%,血清中其他常规指标没有显著变化（P>0.05）。综上所述,在本试验条件下,推荐围产期奶牛中草药添加剂添加量为300 g/d,可以显著降低乳中体细胞数和血中NEFA含量,改善奶牛健康状况,提高奶牛产后生产性能。     

妊娠后期补充β-胡萝卜素对母猪乳成分和肠道菌群的影响

试验旨在探究妊娠后期饲粮中添加β-胡萝卜素对母猪初乳、常乳成分及肠道菌群的影响,并揭示肠道菌群与乳成分之间的相关性。选取胎次相近的妊娠后期二元杂交母猪48头,随机分为3组,每组16个重复,分别饲喂添加0、30和90 mg/kg β-胡萝卜素的饲粮,试验从妊娠第90天开始到分娩后第14天结束。分娩当天采集母猪初乳和粪便样品,哺乳第14天采集母猪常乳样品。对初乳中免疫球蛋白（Ig）水平以及常乳中乳成分进行测定,粪便样品通过16S rRNA测序技术进行分析。结果显示：与对照组相比,饲粮添加β-胡萝卜素有提高母猪初乳中IgM的趋势（P=0.173）,降低IgG的趋势（P=0.155）;添加30 mg/kg β-胡萝卜素显著提高了常乳中乳蛋白和尿素氮含量（P<0.05）,同时降低了乳糖含量（P<0.05）,而添加90 mg/kg β-胡萝卜素降低了常乳中总固体含量（P<0.05）。对粪便菌群进行分析发现,β-胡萝卜素上调了Eubacterium brachy group、Ruminococcaceae UCG009、Ruminococcaceae UCG014等菌群的丰度,下调了Candidatus Soleaferrea、Coprococcus 3、Lachnospiraceae NK4B4 group等菌群的丰度。相关性分析表明,Coprococcus 3与初乳中IgM水平呈显著负相关（P<0.05）,Fibrobacter与初乳中IgG、IgM水平呈显著正相关（P<0.05）;Lachnospiraceae NK4B4与常乳中乳蛋白和总固体含量呈显著正相关（P<0.05）;Ruminococcaceae UCG009与初乳中IgG水平呈显著负相关（P<0.05）。以上结果表明,β-胡萝卜素可通过调节肠道菌群影响母猪初乳及常乳的成分组成。     

氨基酸平衡日粮对奶牛生产性能、血清生化指标及经济效益的影响

试验旨在研究氨基酸平衡日粮对奶牛生产性能、血清生化指标及经济效益的影响。选择36头体况良好的泌乳初期的健康荷斯坦奶牛,平均泌乳天数(DIM)为(39.69±12.48) d、平均胎次为(3.02±0.64)胎。采用单因素随机试验设计,按年龄、产奶量、胎次相同或相近的原则,将36头荷斯坦奶牛区组配对后随机分为3组,每组12头奶牛,其中对照组奶牛饲喂仅添加有瘤胃保护性蛋氨酸(HMBi)的TMR日粮;试验1、2组日粮在对照组的基础上分别添加2种水平的瘤胃保护性赖氨酸,以平衡日粮中的氨基酸。结果表明,①与对照组相比,试验1、2组奶牛饲料转化率分别提高10.60%和11.26%(P>0.05),而干物质采食量没有显著变化(P>0.05),平均每日4%校正乳产量分别显著提高了8.65%和10.58%(P<0.05),并可显著或极显著增加乳脂和乳蛋白产量(P<0.05;P<0.01);饲喂氨基酸平衡日粮对奶牛繁殖性能、健康状况无显著影响(P>0.05)。②饲喂氨基酸平衡日粮60 d时,奶牛血清中葡萄糖、总氨基酸含量显著升高(P<0.05),尿素氮含量显著降低(P<0.05)。③与对照组相比,试验1、2组奶牛经济效益分别增加了15.09和16.36元/(头·d)。综上所述,饲喂氨基酸平衡日粮能显著提高奶牛的生产性能,具有改善奶牛代谢状况的趋势。     

日粮不同钴水平对奶牛泌乳性能、营养物质消化率和血液生化指标的影响

本研究旨在确定日粮中添加不同水平碳酸钴对奶牛泌乳性能、营养物质消化率和血液生化参数的影响。试验选用30头泌乳中期荷斯坦奶牛,随机分为5组,分别饲喂基础日粮（对照组）和试验日粮（4个试验组）,试验日粮为在基础日粮中以碳酸钴（CoCO₃）的形式,分别添加钴0.15、0.30、0.75和1.50 mg·kg^-1 DM。试验期56 d,其中适应期14 d,正试期42 d。测定每日采食量和产奶量,并采集奶样测定乳成分含量,采集饲料和粪样测定营养物质表观消化率,采集血样测定血液生化指标。结果表明,与对照组相比,日粮中添加不同水平的碳酸钴后,奶牛干物质采食量（DMI）和乳成分含量均无显著差异（P>0.05）。但添加钴0.30和0.75 mg·kg^-1 DM提高了产奶量（P<0.05）;与对照组相比,添加钴0.75 mg·kg^-1 DM组显著提高了酸性洗涤剂纤维（ADF）和粗蛋白（CP）的消化率（P<0.05）。此外,添加钴1.50 mg·kg^-1 DM组的血浆葡萄糖含量和谷草转氨酶（AST）活性降低（P<0.05）,日粮添加钴0.75 mg·kg^-1 DM降低了谷丙转氨酶（ALT）和碱性磷酸酶（ALP）的活性（P<0.05）;红细胞（RBC）、血红蛋白（HGB）含量和红细胞压积（HCT）随日粮碳酸钴水平升高而升高且呈二次曲线变化（P<0.05）。综上,泌乳中期的荷斯坦奶牛日粮Co水平推荐在0.30~0.75 mg·kg^-1 DM,最适添加水平是0.73 mg·kg^-1 DM。     

葛根素对饲喂氧化大豆油肉鸡小肠黏膜屏障功能及抗氧化能力的影响

本试验旨在研究葛根素对饲喂氧化大豆油饲粮黄羽肉鸡小肠黏膜形态结构、紧密连接蛋白基因表达及抗氧化能力的影响。试验采用2×2因子设计,因子包括油脂质量（新鲜大豆油和氧化大豆油）和葛根素添加水平（0、750 mg·kg^-1）。选取健康1日龄雌性黄羽肉鸡360只,随机分成4个处理组,分别为新鲜大豆油饲粮组、新鲜大豆油+葛根素（750 mg·kg^-1）饲粮组、氧化大豆油饲粮组和氧化大豆油+葛根素（750 mg·kg^-1）饲粮组,每组6个重复,每个重复15羽。在28和56日龄时,每个重复随机选取1只鸡,取十二指肠、空肠、回肠检测小肠形态结构和测定小肠黏膜紧密连接蛋白基因表达及抗氧化指标。结果表明：1）饲喂氧化大豆油显著降低28日龄肉鸡十二指肠的绒毛高度和绒毛高度/隐窝深度（V/C）、回肠V/C和claudin-1 mRNA表达量以及56日龄肉鸡3个肠段的绒毛高度及V/C （P<0.05）,显著升高56日龄3个肠段的隐窝深度（P<0.05）。饲粮中添加葛根素显著提高28日龄肉鸡空肠绒毛高度和V/C、回肠闭合小环蛋白1（ZO-1） mRNA表达量和56日龄肉鸡十二指肠V/C、空肠和回肠的绒毛高度及V/C （P<0.05）,显著降低3个肠段的隐窝深度（P<0.05）。2）饲喂氧化大豆油显著升高28日龄十二指肠还原型谷胱甘肽（GSH）含量和空肠还原型谷胱甘肽过氧化物酶（GSH-Px）活性（P<0.05）,并显著降低28日龄回肠GSH含量、超氧化物歧化酶（SOD）活力和总抗氧化能力（T-AOC）（P<0.05）。饲粮中添加葛根素显著提高28日龄肉鸡十二指肠GSH-Px活性（P<0.05）。饲喂氧化大豆油显著降低56日龄回肠SOD活性和T-AOC （P<0.05）,饲粮中添加葛根素显著提高56日龄肉鸡十二指肠SOD和回肠SOD、GSH-Px活性（P<0.05）,显著降低56日龄肉鸡空肠GSH含量、SOD活性、T-AOC和回肠T-AOC （P<0.05）。综上所述,饲喂氧化大豆油破坏肠道黏膜形态结构、降低紧密连接蛋白基因的表达量和抗氧化能力,添加葛根素可提高肉鸡小肠黏膜紧密连接蛋白基因的表达量,改善氧化损伤条件下肠道黏膜形态结构,提高抗氧化酶的活性而提高其抗氧化能力。     

不同季节添加复合水溶性维生素对奶牛生产性能、血液生理生化和抗氧化性能的影响

本试验旨在研究复合水溶性维生素对春、夏季奶牛生产性能、血液生理生化指标和抗氧化性能的影响。采用2×2因子随机区组设计,选取胎次、体重相近的健康成年奶牛80头,随机分为4个处理,即Ⅰ、Ⅱ、Ⅲ、Ⅳ组,4组均饲喂基础日粮,Ⅲ、Ⅳ处理在春季补充复合水溶性维生素,Ⅱ、Ⅳ处理组在夏季补充复合水溶性维生素,各组添加量均为0.02%(日粮干物质为基础),预试期7 d,正式期70 d。结果表明:在春季添加复合水溶性维生素极显著提高奶牛的平均日采食量和日产奶量(P<0.01);在夏季显著提高奶牛的平均日采食量(P<0.05),极显著提高日产奶量(P<0.01);均能极显著提高乳脂率(P<0.01),极显著降低体细胞数(P<0.01);均能显著影响淋巴细胞总数(P<0.05)。在夏季补充复合水溶性维生素能极显著增加血清总抗氧化能力、总超氧化物歧化酶(P<0.01),极显著降低乳酸脱氢酶、白蛋白、总蛋白、高密度脂蛋白、低密度脂蛋白和磷酸肌酸激酶含量(P<0.01)。综上所述,复合水溶性维生素可以提高奶牛的生产性能,增强奶牛非特异性免疫,改善奶牛抗氧化性能,减少夏季热应激。     

Effects of Supplemental Complex Water Soluble Vitamin on Production Performance,Blood Biochemical Parameters and Oxidation Resistance of Dairy Cows

The objective of the study was to investigate the effects of supplemental complex water soluble vitamins on production performance, blood biochemical parameters and oxidative resistance of dairy cows in spring and summer.The experiment was designed by 2×2 factorial randomized blocks design.Eighty healthy dairy cows with similar parity and body weight were randomly divided to four groups, with 7 days of adaptation and 70 d experimental phase.The dairy cows in group Ⅲ and Ⅳ were fed a basal diet supplemented with complex water soluble vitamins in spring.The dairy cows in group Ⅱ and Ⅳ were fed a basal diet supplemented with complex water soluble vitamins in summer.The results showed that the ADFI and daily milk yield of dairy cows receiving water soluble vitamin in spring were extremely significantly higher (P<0.01);The ADFI of dairy cows receiving water soluble vitamin was significantly higher in summer (P<0.05) and daily milk yield were extremely significantly higher (P<0.01);The butterfat rate was extremely significantly increased and SCC was extremely significantly decreased in spring and summer (P<0.01);Supplementation of water soluble vitamin was also significantly increased LYM (P<0.05).In summer, T-AOC, T-SOD were extremely significantly increased (P<0.01), and TP, CK, LDH, TP, HDL and ALB were extremely significantly decreased (P<0.01) by water soluble vitamin supplementation than that of control group.In conclusion, complex water soluble vitamins could increase the production performance and non-specific immune function, improve the oxidative resistance and relieved the heat stress of the dairy cows.     

The Rumen Degradation Characteristics of Whole Sugarcane for Dairy Cows and Its Application in Substituting Alfalfa,Oat Hay and Concentrate in Dairy Cows' Diets

The purpose of this experiment was to investigate the rumen degradation characteristics of whole sugarcane of dairy cows and its effects of using it replacing alfalfa, oat hay and concentrates in dairy cows' diet on the rumen fermentation, nutrient apparent digestibility, blood biochemical indexes and production performance of dairy cows, in order to open up new ways to replace the increasing prices feedstuff such as alfalfa, oat hay and concentrate in dairy cows' diets with whole sugarcane. In experiment one, the in-situ test, namely the rumen nylon bag test was used to investigate the rumen degradation characteristics of various nutrients of whole sugarcane, leymus chinensis and alfalfa. Experiment two was in vivo test,repeat 3 ⅹ 3 Latin square design was conducted and Holstein dairy cows with similar body weight, parities and milk yield and permanent rumen fistula were chosen to investigate the effect of using whole sugarcane replacing 25% or 50% of imported alfalfa from the Unites States in dairy cows' diet on nutrient digestibility, rumen fermentation characteristics and blood biochemical indexes of dairy cows. In experiment three, 60 Holstein dairy cows with similar parity, milk yield and milk in lactation were selected to perform production test, which aimed to explore the effects of using whole sugarcane replacing 30% alfalfa hay, 50% oat hay or 10% concentrate on the production performance, blood biochemical indexes of dairy cows and the economic benefits of dairy farms. The results showed that：1) The effective degradation rates of dry matter (DM) and acid detergent fiber (ADF) of whole sugarcane were significantly higher than leymus chinensis (P<0.05), and the effective degradation rates of neutral detergent fiber (NDF) and organic matter (OM) were significantly higher than leymus chinensis and alfalfa (P<0.05). 2) There was no significant effect on rumen pH, NH₃-N (except 25% group at the 4 h time point) and volatile fatty acid (VFA) concentrations of dairy cows when using 25% and 50% whole sugarcane to replace imported alfalfa from the Unites States in the diet. There was also no significant effect on DMI and digestibility of DM, CP, OM and ADF, while the digestibility of NDF in the 50% group was significantly increased (P<0.05). In 50% group, the content of serum urea nitrogen in 2 and 8 h was significantly lower than 25% group and control group (P<0.05) and there was no significant difference in the blood content of β-hydroxybutyric acid, rumen VFA and total VFA in each group at different time points. 3) After using 50%, 30% and 10% of whole sugarcane to replace oat hay, alfalfa hay and concentrate, respectively, no significant difference was detected in blood glucose, urea nitrogen, β-hydroxybutyric acid, the esterification of fatty acid (NEFA), and milk yield. Besides, combined with milk yield and feed cost, the economic benefits of each cow in the substitution groups increased by 3.28, 7.48 and 1.62 yuan per day. respectively, compared with control group. It can be seen that the whole sugarcane is a kind of high-quality roughage that can be used by dairy cows with high digestibility, and using it to replace 25% or 50% of imported alfalfa from the Unites States in dairy cows' diet does not affect the rumen fermentation characteristics and rumen apparent digestibility of nutrients of dairy cows. And using whole sugarcane replacing 30% alfalfa hay, 50% oat hay or 10% concentrate will not affect the blood biochemical indicators and production performance of dairy cows, and will also increase the economic benefits of the dairy farm.     

Effect of Compound Enzyme and Compound Enzyme Probiotics Preparation on Degradation Rate of Diet in vitro and Milk Production Performance of Dairy Cows at Different Lactation Stages

The purpose of this experiment was to study the effect of compound enzyme and compound enzyme bacteria preparation on the degradation rate of diet in vitro and milk production performance of dairy cows at different lactation stages.In in vitro experiment,the basic diet (group Ⅰ) and the basic diet added with compound enzyme (group Ⅱ) and compound enzyme probiotics preparation (group Ⅲ) were used as fermentation substrate respectively.After 72 h of culture in vitro,the dry matter degradation rate (DMD) and crude protein degradation rate (CPD) of the diet were measured at different time (6,12,24,36,48 and 72 h).In feeding experiment,24 dairy cows with similar body weight,parity and condition were divided into three groups at early lactation (30 d±5 d),middle lactation (100 d±5 d) and late lactation (250 d±5 d),respectively.The cows in control group (group Ⅰ) were fed with TMR,in compound enzyme group (group Ⅱ) and the compound enzyme probiotics group (group Ⅲ) were fed with the TMR added with 1 kg/t compound enzyme and compound enzyme probiotics respectively.The trial period was 74 days,including 14 days of pre trial period and 60 days of normal trial period.`The results showed that:①In vitro DMD and CPD of the two groups increased with the prolongation of treatment time.At each time point,the values of DMD and CPD in group Ⅲ were higher than those in group Ⅱ,the difference of DMD was significant at 6 and 72 h (P<0.05),CPD was significant at 36 and 72 h (P<0.05),and there was no significant difference at other time points (P>0.05).②In the early stage of lactation,the average daily milk production of groups Ⅱ and Ⅲ increased by 3.68% and 4.10% respectively compared with group Ⅰ,the difference was significant (P<0.05),and the difference between groups Ⅱ and Ⅲ was not significant (P>0.05).In mid-lactation,the average daily milk production of groups Ⅱ and Ⅲ increased by 7.53% and 10.66% respectively compared with group Ⅰ (P<0.05),and the difference between groups Ⅱ and Ⅲ was not significant (P>0.05).In the later stage,the average daily milk production of groups Ⅱ and Ⅲ increased by 7.06% and 5.16% respectively compared with group Ⅰ (P<0.05),and the difference between group Ⅱ and Ⅲ was not significant (P>0.05).In conclusion,both compound enzymes and compound enzyme probiotics preparations could improve the in vitro DMD and CPD of the diet and the milk production of dairy cows in different periods to a certain extent.Among them,the compound enzyme preparation had a better effect on increasing milk production of dairy cows in the late lactation,while the compound enzyme probiotics preparation has a better effect on increasing milk production in mid-lactating dairy cows.     

复合酶与复合酶菌制剂对日粮体外降解率及不同泌乳阶段奶牛产奶性能的影响

本试验旨在研究复合酶及复合酶菌制剂对奶牛日粮体外降解率及不同阶段奶牛产奶性能的影响。在体外试验中,分别以基础日粮（Ⅰ组）及基础日粮中分别添加复合酶制剂（Ⅱ组）、复合酶菌制剂（Ⅲ组）的日粮作为发酵底物,体外培养72 h,测定不同时间点（6、12、24、36、48、72 h）日粮干物质降解率（DMD）和粗蛋白质降解率（CPD）。在饲养试验中,分别选取体重、胎次、体况相近的泌乳前期（30 d±5 d）、泌乳中期（100 d±5 d）和泌乳后期（250 d±5 d）奶牛各24头,平均分成3组,其中对照组（Ⅰ组）奶牛饲喂全混合日粮（TMR）,复合酶制剂组（Ⅱ组）和复合酶菌制剂组（Ⅲ组）奶牛在TMR中分别添加1 kg/t的复合酶制剂和复合酶菌制剂。每期试验持续74 d,其中预试期14 d,正试期60 d,每天记录产奶量。结果显示：①体外试验中,Ⅱ、Ⅲ组的DMD、CPD均随处理时间的延长而增加。在各个时间点,Ⅲ组的DMD、CPD均高于Ⅱ组,其中DMD在6、72 h时差异显著（P<0.05）,CPD在36、72 h时差异显著（P<0.05）,在其他时间点差异均不显著（P>0.05）。②在泌乳前期,Ⅱ、Ⅲ组的平均日产奶量与Ⅰ组相比分别提高了3.68%和4.10%,差异显著（P<0.05）,Ⅱ、Ⅲ组之间差异不显著（P>0.05）;泌乳中期,Ⅱ、Ⅲ组的平均日产奶量与Ⅰ组相比分别提高了7.53%和10.66%,差异显著（P<0.05）,Ⅱ、Ⅲ组之间差异不显著（P>0.05）;泌乳后期,Ⅱ、Ⅲ组的平均日产奶量与Ⅰ组相比分别提高了7.06%和5.16%,差异显著（P<0.05）,Ⅱ组、Ⅲ组之间差异不显著（P>0.05）。综上,复合酶与复合酶菌制剂均能在一定程度上提高日粮体外DMD和CPD以及奶牛在不同时期的产奶量,其中,复合酶制剂对提高泌乳后期奶牛产奶量效果更好,复合酶菌制剂对提高泌乳中期奶牛产奶量效果更好。     

Effect of Amino Acid Balance Diet on Production Performance,Serum Biochemical Indexes and Economic Benefits in Dairy Cows

This experiment was conducted to study the effect of amino acid balance diet on production performance,serum biochemical indexes and economic benefits in dariy cows.36 healthy Holstein cows in the early lactation period were selected,the average number of lactation (DIM) was (39.69±12.48) d,the average parity was 3.02±0.64.Principle of experiments using single factor randomized experimental design accroding to age,milk yield,parity identical same or similar,the 36 Holstein cows were assigned by random block design to 3 groups,and each group were 12 cows.The control group cows were fed with TMR diets only adding rumen-protected methionine (HMBi);Diets of group 1 and 2 were on the basis of control group,respectively adding two kinds of rumen-protected lysine levels in order to balance the amino acid in diet.The results showed as follows:① Compared with control group,the feeding conversion ratio in groups 1 and 2 were increased by 10.60% and 11.26% (P>0.05),respectively,while the dry matter intake had no significantly changed (P>0.05),the 4% average daily milk yield in groups 1 and 2 were significantly increased by 8.65% and 10.58% (P<0.05),respectively,and the milk fat and milk protein yield in groups 1 and 2 were significantly or extremely significantly increased (P<0.05;P<0.01),respectively.Adding amino acid balance diet had no significantly effects on reproductive performance and health conditions in dariy cows (P>0.05).② When feeding the amino acid balance diets for 60 days,the contents of GLU and TAA in serum of dairy cows were significantly increased (P<0.05),while the BUN content was significantly decreased (P<0.05).③ Compared with control group,the economic benefits of groups 1 and 2 were increased by 15.09 and 16.36 yuan/(head·d).The results indicated that feeding the amino acid balance diets could significantly improve production performance of dairy cows,and there was a tendency to improve metabolic conditions.     

Effect of Supplementation of Ligustrum lucidum Ait on Production Performance and Blood Biochemical Indices in Dairy Cows

The objective of the experiment was to investigate the effect of supplementation of Ligustrum lucidum Ait on production performance and blood biochemical indices in dairy cows.Forty eight mid-lactation Holstein dairy cows were randomly assigned to four groups with twelve individuals in each group.The control group was fed a TMR diet,groups N1 to N3 were fed the TMR diets supplemented with 150,300,450 g/d Ligustrum lucidum Ait,respectively.The pre-test period lasted for 1 week and the trial period lasted for 7 weeks.The results showed that compared with control group,the supplementation of 450 g/d Ligustrum lucidum Ait significantly increased 4% FCM (P<0.05),the supplementation of 150 g/d Ligustrum lucidum Ait significantly increased milk fat content (P<0.05).Dietary supplementation of Ligustrum lucidum Ait had no effects on DMI,milk yield,milk protein,total solids (TS) and somatic cell counts (SCC) (P>0.05).Compared with control group,the supplementation of Ligustrum lucidum Ait significantly decreased blood TG content (P<0.05),and had no effects on other blood biochemical indices (P>0.05).In conclusion,dietary supplementation of Ligustrum lucidum Ait could improve milk quality and yield,and the lipid metabolism of dairy cows.