过瘤胃脂肪对泌乳奶牛生殖机能的影响

本研究旨在了解过瘤胃脂肪对奶牛产后发情的影响,为提高集约化牛场奶牛繁殖性能提供科学依据。选取年龄、体重、胎次及泌乳量相近的健康泌乳奶牛40头,按添加过瘤胃脂肪的量分为高（H,400g/d·头）、中（M,300g/d·头）、低（L,200g/d·头）和对照组（0g/d·头）四组,每组10头,试验期为产后30d至70d。在产后30d、45d、60d、70d以及发情时记录试验奶牛采食量、体况分及泌乳量,调查繁殖性能,检测血浆血糖、游离脂肪酸、雌激素和孕酮的浓度。结果显示,试验奶牛繁殖性能从高到低依次为H组、M组、L组和对照组;第一情期血浆葡萄糖浓度为H组〉M组〉L组〉对照组（P〉0.05）;第一情期间血浆雌激素水平随着能量摄入增加而升高,孕激素水平变化不大（P〉0.05）。M组奶牛产后发情最早,繁殖性能最高。本研究得出结论：集约化奶牛场奶牛日粮能量水平能明显地影响奶牛产后生殖机能。日粮能量摄入越低,奶牛配种率与受胎率越低,产犊间隔越长。产后30d每天饲喂300g过瘤胃脂肪能改善奶牛生殖机能,提高奶牛繁殖性能。     

能量负平衡对泌乳早期奶牛生产性能、繁殖性能和机体代谢的影响

在某一集约化牛场,随机选取年龄、胎次、泌乳量相近的奶牛60头,分别在产后1、14、28、42、56d和70d时颈静脉采血,根据血糖浓度在6个时间点分为能量负平衡组和对照组,同时调查和分析奶牛日粮营养水平(能量、CP、CF、CFb、Ca、P)、生产性能(BW、MY、DMI)、繁殖性能(首次配种间隔、情期受胎率、发情率、配种指数)、血液生化指标(Glu、BHBA、NEFA)和内分泌指标(Ins、Gn、Lp、E2、P4)。结果表明:奶牛泌乳早期存在不同程度的能量负平衡(NEB),产后14d最高。NEB能使奶牛产后血浆E2、P4水平降低,产后DMI、BW和MY均减少。能量负平衡奶牛血浆Ins、Gn和Lp浓度降低,表现低血糖、高血浆NEFA和BHBA生化特性,首次配种间隔延长,情期受胎率和发情率降低,配种指数增高。这些结果提示,奶牛泌乳早期易发能量负平衡,不仅与日粮能量水平低、泌乳量高、干物质摄入少和体重损失有密切关系,而且与机体内分泌未完全协调发挥作用有关。并且能量负平衡会降低奶牛生产性能和繁殖性能。     

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。     

改善高产奶牛泌乳初期能量供应的综合调控措施

由于能量采食量不能满足维持和产奶的能量需要,奶牛在泌乳初期常处于能量负平衡(NEB)状态。泌乳初期NEB的程度和恢复速度显著影响奶牛健康、繁殖和泌乳性能。本文总结了高产奶牛泌乳初期产生NEB的原因和评估方法,阐明了泌乳初期NEB对奶牛健康、繁殖和生产性能的影响,分析总结了干奶期和围产期的饲养管理和能量供应对奶牛产后NEB的调控作用,旨在为改善高产奶牛泌乳初期NEB提供理论指导。     

不同能量摄入水平对奶牛产乳性能及血液中Leptin和NPY浓度的影响研究

将30头围产期健康奶牛随机分为3组,每组均为10头,其中Ⅰ组为对照组,Ⅱ组和Ⅲ组为试验组;Ⅰ、Ⅱ、Ⅲ组分别于产前第28d开始饲喂标准日粮(能量摄入100%组)、标准日粮增加20%能量(能量摄入120%组)和标准日粮减少20%能量(能量摄入80%组),产后各组奶牛均饲喂标准泌乳日粮,至产后第56d结束,观察不同能量摄入水平对产后奶牛产乳性能及血液中瘦素(Leptin)和神经肽Y(NPY)浓度的影响。试验结果表明,产前饲喂低能日粮不仅提高了产后奶牛产乳性能,而且提高了产后奶牛血液中Leptin和NPY浓度。可见,奶牛不同能量摄入水平与产奶量及血液中Leptin和NPY浓度之间存在着密切的关系。     

能量水平对初产母牛围产期生产性能的影响

围产期奶牛历经了产犊与泌乳,其营养状况直接影响乳牛的生产性能。本试验就日粮能量水平对奶牛围产期干物质采食量、体重变化、产奶量、乳成分、体况及产后首次配种时间的影响进行了研究分析,评价其经济效益,探讨初产母牛围产期和泌乳前期合理的日粮能量水平配制,以期为夏季产犊奶牛的科学饲养提供理论依据和数据参考。     

高产奶牛日粮中添加脂肪的研究进展

高产奶牛有机体新陈代谢旺盛,通常在泌乳初期不能摄取到与产乳需要相适用的能量水平,以至于影响到产乳量甚至乳牛的健康。向饲粮中添加脂肪等能量添加剂是提高饲粮能量水平的有效途径。本文就近年来高产乳牛日粮中添加脂肪对奶牛生产性能影响进行了综述分析,以便更深入地研制和开发脂肪等能量添加剂,这对我国乳牛业的发展将具有重要意义。     

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。     

营养物质和饲养管理对母羊繁殖性能的影响

1 营养物质对母羊繁殖性能的影响 1.1 能量 母羊发情前后日粮能量水平高，可增加排卵率。如果母羊增重过快或消耗能量过多都会使受胎间隔延长。为了提高繁殖性能，对产后母羊应供应较高的能量，以避龟失重过多，但摄入的能量应该是逐渐增加的，否则会引起肥胖。能量的掇入量对泌乳和繁殖性能都很重要，泌乳母羊的乳汁合成对能量依赖极强。     

能量对奶牛繁殖力的影响

奶牛的繁殖力受日粮中能量水平的制约，能量不足和过剩都会对繁殖力产生影响。能量不足通常发生在饲料质量低劣、限制饲养、产后泌乳初期及高泌乳量等条件下．以产后初期最为常见，这是由奶牛产后的生理特点所决定的。奶牛在产后，产奶量逐步增加，使泌乳所需营养也逐步增加；牛在产后对采食量的反应应答迟缓．     

围产期高能日粮对奶牛产后乏情的影响

目的:观察高能日粮对集约化牛场奶牛产后乏情的防治效果.方法:围产期奶牛饲喂高能日粮(日粮干物质的摄入量:88.89%;脂肪:4.89%;粗纤维:19.39%;蛋白质:17.09%;钙:0.66%;磷:0.38%;能量:24.07 MJ/kg)后,检测血液中生殖激素的浓度和变化规律,并观察奶牛的发情情况.结果:饲喂高能日粮奶牛血浆中生殖激素浓度及规律符合发情奶牛标准.结论:高能日粮饲喂奶牛有利于奶牛产后的发情.     

日粮蛋白质水平对奶牛产后卵巢机能恢复及生殖激素的影响

[目的]本试验旨在探讨不同蛋白质水平日粮对奶牛产后卵巢机能恢复及生殖激素的影响,以确定奶牛日粮适宜蛋白质水平.[方法]采用单因素对比实验设计,根据生理状况和泌乳性能相近原则将72头中国荷斯坦牛,随机分成3组,每组24头,分别在围产期和泌乳盛期饲喂9.8%(A1)和13.8%(A2)、12.6%(B1)和16.2%(B2...     

An investigation into reduced milk production following dietary alteration on an Irish dairy farm

A nutritional evaluation of an Irish dairy herd indicated gross overfeeding of late lactation cows, over-conditioning of cows at parturition and a high rate of body condition loss in early lactation. Metabolisable-energy based nutritional modelling software was used to guide recommended dietary changes to prevent excessive condition gain in late lactation. Immediately following the implementation of the changes there was an unexpected reduction in performance affecting both milk yield and protein concentration. An investigation into the poor performance revealed underestimation of peak milk yield; over-estimation of maize silage quality; a large difference in the concentrate being fed compared to the concentrate recommended, and failure of the blend of concentrate ingredients to maintain the intended proportions in the in-parlour feeding system. The estimated maximum cumulative effect of these errors was to cause undersupply of energy and protein in the recommended diet of 16% and 3% respectively to cows in early lactation. Use of a net-energy nutritional model would have indicated a requirement for a higher energy supply in this case. This report highlights the challenges in obtaining accurate on-farm data for use in dairy cow nutritional models.     

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.     

Impact of dietary plane of energy during the dry period on lipoprotein parameters in the transition period in dairy cattle

The high energy demands of dairy cows during the transition period from late gestation into early lactation can place them at an increased risk for the development of metabolic and infectious diseases. Modification of the dry period diet has been investigated as a preventive means to minimize the detrimental aspects of metabolic shifts during the transition period. Studies investigating the impact of dry period diet on lipid parameters during the transition period have largely focused on markers of lipolysis and ketogenesis. Total cholesterol declines during the periparturient period and increases in early lactation. The impact total energy in the dry period diet has on the ability of the cow to maintain total serum cholesterol, as well as its natural high‐density lipoprotein‐rich status, during this metabolically challenging window is not clear. The impact of lipoproteins on inflammation and immune function may have a clinical impact on the cow's ability to ward off production‐related diseases. In this study, we hypothesized that the provision of adequate, but not excessive, total metabolizable energy, would better allow the cow to maintain total cholesterol and a higher relative proportion of HDL throughout the transition period. Cows were allocated to one of three dry period dietary treatment groups following a randomized block design. Total serum triglycerides, cholesterol and lipoprotein fractions were measured on a weekly basis from approximately 7 weeks pre‐calving to 6 weeks post‐calving. The cows on the high energy diet maintained total serum cholesterol as compared to the cows provided a lower energy diet, but there was no significant increase in the LDL fraction of lipoproteins between diet treatment groups.     

泌乳盛期和泌乳后期奶牛的采食行为和日粮营养物质表观消化率的对比分析

试验旨在研究不同泌乳阶段奶牛饲喂相同日粮对采食行为和日粮营养物质表观消化率的影响。选择体重、胎次相近的8头健康泌乳牛,其中4头处于泌乳盛期(泌乳盛期组),4头处于泌乳后期(泌乳后期组),2组奶牛饲喂相同日粮,预试期15 d,正试期15 d。结果表明:泌乳盛期组奶牛每天干物质采食量(24.0 kg)高于泌乳后期组(P<0.01),泌乳盛期组奶牛每千克干物质的采食时间、一昼夜总反刍时间、躺卧时间均低于泌乳后期组(P<0.01),;泌乳盛期组奶牛日粮中中性洗涤纤维和酸性洗涤纤维的表观消化率低于泌乳后期组(P<0.01)。由此可见,泌乳盛期奶牛采食时间极显著高于泌乳后期奶牛,泌乳盛期奶牛躺卧时间极显著少于泌乳后期。     

The relationship between feeding and fertility in dairy cattle]

The possible relationship between nutrition and fertility in dairy cows are reviewed. Study of the literature shows that opinions on the effect of the various nutrients differ markedly. The conclusion which can be made is that in countries where standards of dairy farming are high, nutrition only plays a minor role in the problem of herd subfertility. In the course of time deficiencies in a large number of minerals, trace elements and vitamins have been stressed as a cause of inadequate fertility. However cows are at present generally fed with a lot of well balanced concentrates and therefore deficiencies are very unlikely to occur. During early lactation every high producing dairy cow has a negative energy balance. In a number of cows this results in anoestrus and in a long interval from parturition to first insemination. Overfeeding during late lactation and the dry period does not adversely affect subsequent reproduction but may cause puerperal disorders. The relation between protein nutrition and fertility is complex. Protein effects on fertility are minor. Problems can arise if there is a combination of a high percentage of crude protein (greater than 18%), a high rumen degradability of the protein and a low energy content of the diet. The value of metabolic profile tests is minimal because they do not differentiate between normal herds and herds with fertility problems.     

简论高产奶牛的营养与饲养

本文从克服泌乳早期能量负平衡，日粮营养水平和增重速度的调控以及环境温度与营养水平的关系方面，提出高产奶牛的饲养措施，从而为奶牛生产提供了理论依据和可操作方法。