奶牛蛋白质和氨基酸营养研究综述

提高饲料氮的利用率一直以来都是动物营养学家们致力于蛋白质营养研究的初衷。本文从饲料粗蛋白、非蛋白氮及瘤胃氨的利用、尿素循环、牧草中的蛋白、限制性氨基酸平衡以及牛奶尿素氮六个方面入手,对1917年美国《Journal of Dairy Science》(乳业科学)杂志创办以来奶牛营养学家们所做的探索和发现进行了概述,以期为进一步提高奶牛饲料氮的利用率提供参考。     

The diagnostic value of plasma proteins and non-protein nitrogen substances in birds

This paper summarises current knowledge of the diagnostic value of avian plasma proteins and non-protein nitrogen substances. Reference values for total protein, the albumin: globulin ratio, uric acid, creatinine, and urea for various avian species are presented. The importance of the albumin:globulin ratio and the urea:uric acid ratio is emphasised.     

不同产奶量和乳蛋白率奶牛的血液生化和激素水平分析

试验旨在探究奶牛自身生理代谢与产奶量(MY)和乳蛋白率(MP)的关系。从饲喂相同日粮的287头经产、泌乳中期荷斯坦奶牛中分别选取高、低MY牛各20头,高、低MP牛各20头,探究血液生化参数和激素水平的差异;结合287头奶牛的MY、MP与血液生化参数、激素的关联结果,挖掘影响MY和MP的关键生理代谢。结果表明:高MY牛血液中总蛋白、白蛋白和总胆固醇浓度高于低MY牛(P<0.05),而血尿素氮、胰高血糖素、胰岛素样生长因子-1和瘦素浓度低于低MY牛(P<0.05);高MP牛的血尿素氮和白蛋白浓度高于低MP牛(P<0.05),高低MP牛的血清激素无显著差异;关联分析显示,上述差异指标中总胆固醇与MY正相关(P<0.01),血尿素氮与MY负相关(P<0.05);血尿素氮与MP正相关(P<0.05),总蛋白与MP负相关(P<0.01)。综上,在相同的日粮和管理条件下,氮代谢在奶牛MY、MP合成中均发挥重要作用,并且MY可能受能量供应和奶牛自身分泌激素的调控。     

影响反刍动物氮素利用效率和排放的营养实践

涉及奶牛生产系统和粪肥应用的总氨氮排放参数是影响农业源氨氮排放的最敏感的参数,如何通过精细饲养来提高奶牛的氮素泌乳转化效率,降低奶牛生产系统的氮素排放,对于缓解奶牛生产系统面临的经济与环保双重压力具有重要意义。本文从饲粮的氮素水平、碳水化合物类型、氨基酸补饲、饲料添加剂、饲粮精粗比以及新型饲料原料等方面对影响反刍动物氮素排放的研究进行了综述,同时介绍了康奈尔净碳水化合物-蛋白质体系(CNCPS)模型及其改进对奶牛场氮排放估测的影响以及尿素转运蛋白对反刍动物氮素代谢的影响。     

疾病对奶牛繁殖性能的影响及其研究进展Ⅲ:营养代谢性疾病

现代规模化、集约化奶牛养殖生产模式下,不断供给高营养水平日粮是维持后备牛快速生长发育和泌乳母牛高泌乳性能的物质基础。然而,在遗传品质到达"瓶颈期"后,尽管随着日粮营养浓度的不断提高和干物质采食量（DMI）的增加,奶牛单产水平可以继续维持在一定的高水平状态,但是高产奶牛的营养代谢性疾病的发病率也呈现快速增长趋势,特别是围产期能量负平衡（negative energy balance,NEB）引起的酮病,高精日粮引发的酸中毒、高蛋白质日粮引起的血液中尿素氮升高等营养代谢性疾病,负调控奶牛繁殖性能,造成奶牛产后发情不明显,配种率和受胎率下降等,直接影响奶牛生产群的更新速度、优质牛群泌乳性能正常发挥以及奶牛养殖的经济效益。作者详细介绍了近年来国内外不同营养代谢性疾病对奶牛繁殖性能影响的相关研究资料,重点分析了酮病、低血钙、瘤胃酸中毒等围产期高发的营养代谢性疾病影响奶牛繁殖性能的分子机制,并对营养代谢性疾病与高产奶牛繁殖性能今后研究的方向提出了展望和思考,以期为提高中国规模化牧场高产奶牛群繁殖效率和母牛围产期营养管理水平提供一定的借鉴和理论依据。     

N-羟甲基蛋氨酸钙水平对泌乳期奶牛血清含氮物和游离氨基酸的影响

为研究N-羟甲基蛋氨酸钙（N-hydroxymethyl methionine calcium,N-HMM-Ca）对荷斯坦奶牛血清含氮物和游离氨基酸的影响,试验选用胎次、产奶量和泌乳天数相近的30头健康荷斯坦奶牛,随机分为5组。对照组饲喂基础日粮,试验组分别在基础日粮中添加0.15%、0.30%、0.75%和1.50% N-HMM-Ca,预试期14 d,正试期42 d。结果显示：①日粮中补充N-HMM-Ca对奶牛血清中总蛋白、白蛋白、球蛋白含量无显著影响（P>0.05）。第14天,1.5%组血清肌酐浓度显著低于对照组（P<0.05）;第42天,1.5%组尿素氮浓度显著低于对照组（P<0.05）,而0.75%组尿酸浓度极显著高于其他组（P<0.01）。②第14天,0.15%组血清中谷氨酸、丝氨酸、精氨酸、亮氨酸、异亮氨酸、赖氨酸及总游离氨基酸浓度最高,与对照组相比差异显著或极显著（P<0.05;P<0.01）;试验第42天,0.15%组血清中精氨酸、胱氨酸及总游离氨基酸浓度最高。0.30%组血清中谷氨酸、丝氨酸、酪氨酸、蛋氨酸、缬氨酸、赖氨酸浓度最高,与对照组相比差异显著或极显著（P<0.05;P<0.01）。综上所述,在基础日粮中添加0.15%、0.30% N-HMM-Ca对泌乳期奶牛血清含氮物含量无显著影响（P>0.05）,且添加0.15% N-HMM-Ca能够显著提高泌乳期奶牛血清游离氨基酸含量,综合考虑,N-HMM-Ca的添加量以0.15%为宜。     

Effects of Diseases on Reproductive Performance in Dairy Cattle Ⅲ: Nutritional Metabolic Diseases

Under the modern large-scale and intensive dairy farming production mode,the continuous supply of feed with high nutrition level is the material basis for maintaining the rapid growth and development of reserve cows and the high lactation performance of lactating cows.However,after the genetic quality reaches the "bottleneck period",although the milk yield of dairy cow can continue to maintain a certain high level with the continuous improvement of the nutrient concentration of feed and the increase of dry matter intake (DMI),the incidence of nutritional metabolic diseases of high-yield dairy cows also shows a rapid growth trend,especially ketosis caused by the negative energy balance in perinatal period,acidosis caused by high-precision diet and the increase of blood urea nitrogen caused by high-protein diet,negatively regulate the reproductive performance of dairy cows,resulting in inconspicuous postpartum estrus,decreased mating rate and conception rate of dairy cows,which directly affect the update speed of dairy cows production groups,the normal performance of high-quality cattle and the economic benefits of dairy farming.In this paper,the author introduced in detail the relevant research on the current situation and its mechanism influence of different nutritional metabolic diseases on the reproductive performance of dairy cows in recent years,and focused on analyzing the molecular mechanism of nutritional and metabolic diseases with high perinatal incidence such as ketosis,low blood calcium and moderate gastric acid,and put forward the prospect and thinking on the future research direction of nutritional and metabolic diseases and reproductive performance of high-yielding dairy cows,in order to provide some reference and theoretical basis for improving the reproductive efficiency of high-yielding dairy cows in large-scale pastures in China and the perinatal nutrition management level of dairy cows.     

饲喂高淀粉饲粮时不同瘤胃降解淀粉水平对奶牛泌乳性能、营养物质表观消化率和氮平衡的影响

本试验旨在研究饲喂高淀粉饲粮时不同瘤胃降解淀粉水平对奶牛泌乳性能、营养物质表观消化率和氮平衡的影响。选用10头荷斯坦经产奶牛[平均泌乳天数为(214±38)d,平均乳产量为(26.2±2.4)kg/d,平均体重为(727±65)kg]作为试验动物,随机分成2组,每组5头。试验设计2种不同瘤胃降解淀粉水平的试验饲粮,分别为瘤胃降解淀粉水平为62.3%(占总淀粉的百分比)的低瘤胃降解淀粉水平饲粮(L-RDS)和瘤胃降解淀粉水平为72.1%(占总淀粉的百分比)的高瘤胃降解淀粉水平饲粮(H-RDS)。采用交叉试验设计,试验分为2期,过渡期7 d,每期试验21 d,其中适应期14 d,采样期7 d。结果显示:1)相比L-RDS组,H-RDS组有机物和淀粉的表观消化率显著升高(P0.05),中性洗涤纤维和酸性洗涤纤维的表观消化率显著降低(P0.05),干物质表观消化率有升高趋势(P=0.07),蛋白质表观消化率无显著差异(P0.05)。2)相比L-RDS组,H-RDS组尿素氮及它们占摄入氮比例有降低趋势(P=0.09),摄入氮、乳氮、粪氮、尿氮和沉积氮及它们占摄入氮比例无显著变化(P0.05),尿中总嘌呤衍生物排出量和微生物蛋白产量亦无显著变化(P0.05)。3)饲粮瘤胃降解淀粉水平对奶牛干物质采食量、乳产量和乳成分均无显著影响(P0.05)。综合以上结果可知,饲喂高淀粉饲粮时不同瘤胃降解淀粉水平影响饲粮营养物质的表观消化率,对泌乳性能和氮平衡无显著影响。     

Effects of N-hydroxymethyl Methionine Calcium Supplementation Levels on Serum Nitrogenous Compounds and Free Amino Acids of Lactating Dairy Cows

To study the effects of N-hydroxymethyl methionine calcium (N-HMM-Ca) supplementation levels on serum nitrogenous compounds and free amino acids of lactating dairy cows. 30 lactating Holstein dairy cows with similar parities,milk yield and days in milk were randomly assigned into 5 groups. The control group was fed with basal diet,test groups were fed with basal diet supplemented with 0.15%,0.30%,0.75% and 1.50% N-HMM-Ca,respectively. The experiment was lasted for 56 d,including 14 d of adaptation period and 42 d of experimental period. The results showed as follows:①Comparing with control group,the total protein,albumin and globulin in experimental groups were not significantly affected (P>0.05).On the 14th day,serum creatinine concentration in 1.5% level group was significantly lower than control group (P<0.05);On the 42th day,urea nitrogen concentration in 1.5% level group was significantly lower than control group (P<0.05),while the concentration of uric acid in 0.75% level group was extremely significantly higher than that in other groups (P<0.01).②On the 14th day,the concentration of serum Glu,Ser,Arg,Leu,Ile,Lys and total free amino acids in 0.15% level group was highest,which were significantly or extremely significantly higher than control group (P<0.05;P<0.01).On the 42th day,serum Arg,Cys and the total free amino acids in 0.15% level group were the highest. And serum Glu,Ser,Tyr,Met,Val and Lys in 0.30% level group were highest,which were significantly or extremely significantly higher than the control group (P<0.05;P<0.01). In summary, adding 0.15% or 0.30% N-HMM-Ca on diet of lactating dairy had no significant effect on serum nitrogen content (P>0.05),but adding 0.15% N-HMM-Ca could increase the concentration of serum free amino acids. Considering all the facts,the recommended amount of N-HMM-Ca on diet of lactating dairy cows was 0.15%.     

不同饲养模式下乳牛粪尿中氮磷排放量的研究

试验通过对规模化养殖场、奶农合作组织两种不同养殖模式下乳牛粪便中氮、磷含量进行抽样测定,旨在研究不同养殖模式对乳牛氮和磷污染物排放量的影响。结果表明:规模化奶牛场和奶农合作组织粪尿中总氮的排泄量占摄入量的比例从低到高的排序均为产奶牛、干奶牛、育成牛;规模化奶牛场奶牛不同生理阶段磷排泄量占摄入量的比例从低到高的排序为育成牛、产奶牛、干奶牛;奶农合作组织奶牛不同生理阶段磷排泄量占摄入量的比例从低到高的排序为产奶牛、育成牛、干奶牛。     

Feed‐derived volatile basic nitrogen increases reactive oxygen species production of blood leukocytes in lactating dairy cows

The present study investigated over 9 months the changes of fermentative quality of total mixed rations (TMR) containing grass silage (GS) as a major component, associated with changes in the volatile basic nitrogen (VBN) levels in an experimental dairy farm. Effects of VBN levels in TMR on metabolic parameters, reactive oxygen species (ROS) production by blood polymorphonuclear leukocytes (PMNs) and conception rates for dairy cows were analyzed. According to VBN levels in TMR during survey periods, three distinct phases were identified; phase A with low VBN; phase B with high VBN; and phase C with mid‐VBN. Metabolic parameters in blood were all within normal range. However, during phases B and C, nitrogen metabolic indices such as blood urea nitrogen and milk urea nitrogen showed higher levels compared to those in phase A, and a simultaneous increase in ROS production by blood PMNs and the load on hepatic function in metabolic parameters was observed in the cows with a lower conception rate. This suggests that feeding TMR with elevated VBN levels due to poor fermented GS results in stimulation of ROS production by PMNs by ammonia, and negatively affects metabolism and reproductive performance in lactating dairy cow.     

日粮能量水平对奶牛繁殖性能、血浆代谢产物和生殖激素的影响

为了解日粮能量水平对泌乳奶牛生殖机能的影响,选取年龄、体重、胎次、泌乳量相近的健康泌乳奶牛40头,按添加过瘤胃脂肪量分为高（H,400g/d/头）、中（M,300g/d/头）、低（L,200g/d/头）和对照组（不添加过瘤胃脂肪）四组,每组10头,试验期为产后30d至70d。产后30d、45d、60d、70d以及发情时记录试验奶牛采食量、体况分,记录繁殖性能,检测奶牛血浆GLU、BUN、ALB、TP、LH、FSH、E2、P4和PG浓度,结果显示：1）试验奶牛繁殖性能高低依次为H组、M组、L组和对照组。2）血浆GLU水平H组〉M组〉L组〉对照组;BUN水平L组〉M组〉H组;ALB和TP各组间无差异。3）血浆LH、FSH、E2水平随能量摄入增加而升高。这些结果提示：高能量摄入能缓解奶牛能量负平衡,促进卵泡正常性周期活动,从而提高奶牛繁殖性能。     

影响奶牛乳尿素氮的主要因素研究进展

牛奶中乳尿素氮(MUN)作为反映奶牛蛋白质营养状态和评价蛋白质利用效率的生物学指标已经被国内外研究人员广泛认可。综述了乳尿素氮的定义、检测方法、产生机制,以及影响乳尿素氮的营养和非营养性因素,以期为奶牛养殖生产提供参考。     

尿素在奶牛生产中的应用

尿素作为最常用的非蛋白质含氮化合物在奶牛生产中广泛应用,如何能更有效地代替蛋白质饲料对于实际生产中降低饲养成本、提高生产效率等具有重要意义。作者就尿素在奶牛实际生产中的相关应用研究进行综述,并对其应用前景进行探讨,以期为生产者提供帮助。     

低蛋白质氨基酸平衡饲粮对黄羽肉种鸡产蛋性能、蛋品质、孵化性能和氮排放的影响

本试验旨在研究低蛋白质氨基酸平衡饲粮对黄羽肉种鸡生产性能、蛋品质、孵化性能和氮排放的影响.选用30周龄健康的快大型岭南黄羽肉种母鸡288只,根据体重和产蛋率相近原则,随机分为4个组,每组6个重复,每个重复12只鸡.各组饲粮粗蛋白质(CP)水平分别为16％(对照组)、15％、14％、13％,各组的赖氨酸、蛋氨酸、色氨酸、...     

日粮添加益生菌对干乳期奶牛生长性能、瘤胃发酵及氮平衡的影响

本研究旨在评估全混合日粮添加益生菌对干乳期奶牛生长性能、瘤胃发酵及氮平衡的影响.试验将体重为(440.92±3.33)kg、平均干乳期为42?d的60头荷斯坦奶牛随机分为2组,每组5个重复,每个重复6头.对照组饲喂玉米-豆粕型全混合日粮,处理组饲喂基础全混合日粮+200?mg/kg益生菌(枯草芽孢杆菌含量:1×106?...     

过瘤胃氨基酸对泌乳早期奶牛生产性能、乳成分和血液生化指标的影响

为研究日粮添加过瘤胃氨基酸对泌乳早期奶牛生产性能、乳成分、血液生化指标和经济效益的影响,选择96头体况良好、健康的泌乳早期荷斯坦牛,泌乳天数为(65±15)天.采用单因素随机区组试验设计,按照年龄、胎次和产奶量相近的原则,将96头奶牛随机分为对照组和试验组,每组48头.对照组为基础日粮,试验组在对照组日粮的基础上添加过...     

非蛋白氮在家禽日粮中的应用

本文综述了家禽日粮中添加非蛋白氮(NPN)的效果,并分析影响使用效果的主要因素。家禽利用非蛋白氮的机理目前尚无定论,本文推测可能存在3种机制:利用非蛋白氮合成非必需氨基酸(NEAA)、代谢产物负反馈抑制原理和微生物转化利用。家禽日粮中添加非蛋白氮效果很不稳定,影响因素复杂,实际生产中难以把握,现阶段不宜推广使用。     

利用DHI报表对宁夏某奶牛场生产性能总体情况的分析

DHI测定是奶牛场精细化管理的工具,它不仅反映奶牛的产奶性能,饲养管理与健康水平,还能根据报表信息对奶牛场的育种与繁殖情况进行评价从而改进管理措施,利用好DHI报表信息可以提高奶牛场的技术管理水平和经济效益。本研究通过采集宁夏某奶牛场12个月的DHI报表数据,分析乳脂肪、乳蛋白、尿素氮、体细胞数、泌乳持续力等关键性指标,对该奶牛场的生产性能、经营管理、育种繁殖状况进行综合评定。结果表明：该牛场的泌乳高峰日到达较晚;牛群乳房炎在冬季发生率较高;群体尿素氮含量处于正常范围（10-18mg/dL）,对奶牛的繁殖性能影响较小;泌乳持续力较高、奶牛群体平均泌乳天数较长引起的繁殖问题较严重。针对测检和分析中发现的问题,提出了建议的改进措施。     

Use of every ten-day criteria for metabolic profile test after calving and dry off in dairy herds

The traditional metabolic profile test cannot be applied to peripartum dairy cows, because these cows are in a state of physiological abnormality making it difficult to interpret their blood components. This study aimed at establishing and evaluating the practicability of interpreting a metabolic profile test every 10 days (Ten-day criteria) during the dry and lactation periods in herds with high and no incidence of peripartum diseases. Data from 29,043 cows in 1,130 commercial dairy herds were used to establish standard values every 10 days, mean +/- 1.0 standard deviation for the metabolic profile test. The practicability of these criteria was evaluated in herds with peripartum diseases. In the ten-day criteria, the body condition score, albumin, blood urea nitrogen, glucose, total cholesterol, nonesterified fatty acids, gamma-glutamyl transpeptidase and aspartate aminotransferase, fluctuated during the dry and early lactation periods and there were very big changes in packed cell volume, blood urea nitrogen, total cholesterol and magnesium just after calving. The ten-day criteria were able to detect overconditioned cows, low levels of albumin, total cholesterol and magnesium, and high nonesterified fatty acids in herds with a high incidence of peripartum diseases. In conclusion, the ten-day criteria can be successfully applied to peripartum cows, and is recommended because it is able to detect metabolic abnormalities not only in the herd, but also in individual cows.