围产期奶牛能量负平衡营养调控研究进展

随着我国畜牧养殖业的快速发展,奶牛养殖业得到了进一步的发展,市场需求量持续增加.奶牛产量不断提升,奶牛被动淘汰率持续增加.奶牛生产前,胎儿快速发育,为满足产奶需求奶牛乳房会快速发育,营养需要持续增加,母牛的采食量大幅度降低,导致营养摄入量无法满足于奶牛的生长所需,进而造成能量负平衡.     

围产期奶牛代谢与营养调控研究进展

围产期是奶牛泌乳周期中最为关键的阶段,该阶段奶牛代谢的最大特点是能量摄入减少而需求增加从而导致能量负平衡.改善围产期奶牛的营养条件,最大限度地缓解能量负平衡,对于充分发挥奶牛的生产性能至关重要.本文综述了围产期奶牛的代谢特点以及营养调控研究进展,旨在为提高奶牛的生产性能和健康水平提供新的思路.     

奶牛围产期阴离子日粮营养调控

奶牛围产期,各种感染性和代谢性疾病,如产乳热、酮中篱、胎衣滞留、子宫炎和真胃移位主要发生在这一阶段。在围产期的奶牛日粮中添加阴离子盐,使阴离子曰粮（DCAB）达到100～150mg当量,同时每天为奶牛提供120～150g钙,定期监测尿液pH值和采食量,能够避免低血钙症的出现,减少产乳热等疾病的发生,从而提高奶牛的产奶量。     

预防围产期奶牛脂肪肝的营养调控措施

奶牛围产期指产前2~3周到产后2~3周,这一时期是奶牛泌乳周期的重要时期,也是以围产期能量代谢障碍为病理学基础的脂肪肝高发时期。近年来,由于高产奶牛品种的陆续引进和培育,高能饲料的开发、利用,规模化饲养程度的提高而饲养管理水平又相对滞后等原因,使我国围产期奶牛脂肪肝的发病率呈现逐年上升的趋势。因此,考虑到脂肪肝对围产期奶牛的危害及给奶牛业带来的巨大经济损失,应采取科学、有效的营养调控措施来预防该病,以提高奶牛的健康水平和生产性能,促进奶牛业的健康和长远发展。本文就预防围产期奶牛脂肪肝的营养调控措施进行分析。     

奶牛干奶期和围产期的营养及其调控

奶牛的干奶期约为60 d,围产期是指分娩前3周和分娩后2～3周.这个时期由于进食量及体内养分的沉积和动用有很大的变化,从而对奶牛的健康和产奶有明显的影响,因此,研究其代谢规律及营养调控对奶牛健康和产奶的影响,是饲养技术的重要基础.     

奶牛围产期低血钙症的发生及营养调控措施

文章介绍了围产期奶牛的生理状况及低血钙症的发生机理、危害、影响因素等,提出通过营养调控手段预防奶牛围产期疾病发生、改善奶牛健康状况的措施.通过合理的营养调控手段可以降低奶牛围产期低血钙症的发生几率,促进奶牛健康,提高奶牛养殖的经济效益.     

奶牛围产期营养与疾病

奶牛不同生理时期的营养需要有很大差异。围产期的营养管理是奶牛泌乳、繁殖和控制围产期疾病发生的关键。围产期疾病是一组与营养代谢有关的、互相关联的代谢相关性疾病，其中营养不平衡造成的低钙血症是引起围产期相关疾病的根本原因。在保证围产期其它营养需要的同时，根据离子平衡理论给予阴离子盐调节离子差(DCAD)为-10～-15meq／DMI 110g，尿的pH为6．0～6．5时，体液偏酸性，可有效动员骨钙，使血钙浓度上升，从而减少围产期疾病的发生。     

围产期奶牛的代谢特点及其营养调控

围产期是奶牛泌乳周期中最为关键的阶段,该阶段奶牛代谢最大的特点是能量摄入减少而需求增加从而导致能量负平衡。探寻缓解围产期奶牛能量负平衡的调控措施是减少奶牛疾病发生率的重要基础。本文对近年来围产期奶牛能量负平衡的营养调控研究进行了归纳和总结,旨在为寻找提高奶牛健康水平和生产性能的途径提供新的思路。     

围产期奶牛NEFA的营养调控研究进展

非酯化脂肪酸（NEFA）升高是围产期奶牛能量负平衡的标志，也是导致奶牛发生脂肪肝和酮病的直接原因。在过去的30余年里人们对围产期奶牛NEFA营养调控的方法和机制进行了大量研究，文章就该方面的研究进展作一综述。     

甘露寡糖对围产期奶牛瘤胃微生物区系的影响

试验旨在研究饲粮中添加不同水平的甘露寡糖(MOS)对荷斯坦奶牛围产后期瘤胃微生物区系的影响.选取60头荷斯坦奶牛,随机分4组,每组15头.对照组饲喂基础饲粮,低、中、高剂量组分别在基础饲粮基础上添加5、10、15 g/(头·d)MOS.结果 显示,随着MOS添加量的增加,奶牛产后21 d瘤胃液中微生物蛋白含量、总挥发性...     

围产期饲粮中添加外源能量饲料对奶牛泌乳性能的影响

试验研究围产期奶牛日粮中添加瘤胃脂肪粉、葡萄糖及丙二醇外源能量饲料对奶牛泌乳性能的影响.试验选取40头处于围产前期、体况相近的中国荷斯坦奶牛,随机分成4组,每组5个重复,每个重复2头牛,处理组日粮在对照组基础日粮中分别添加200 g/d的过瘤胃脂肪粉(脂肪组)、葡萄糖(葡萄糖组)和丙二醇(丙二醇组),试验期30 d.结...     

Seasonal variation of the lying and standing behavior indexes of dairy cattle at different daily time periods in free‐stall housing

The lying and standing behavior of dairy cattle reveal whether dairy cattle housing is appropriate to cow comfort. Lying and standing behavior indexes, such as cow comfort index (CCI), cow stress index (CSI) and stall usage index (SUI) are often used as an indication of animal welfare. This study was performed to determine the seasonal and hourly variation of cow behavioral indexes at different daily time periods (DTP) and evaluate appropriate DTP better representing daily behavioral activity of dairy cattle in free‐stall housing (FHS) in Konya, Turkey. Animal behaviors were videotaped for a total of 24 days (576 h) over four seasons in a FHS at a commercial dairy farm from November 2007 to March 2009 using continuous video data (24 h per day). The behaviors of cows in the barn were evaluated using 60‐min scan sampling. All phenotypes were evaluated on an hourly basis during the experimental period. The results show how these indexes can be accurately evaluated by analyzing video recordings taken on DTP between 08.00–15.00 and 19.00–24.00 hours for autumn and summer and 10.00–12.00 and 20.00–22.00 hours for spring, instead of continuous observation (r > 0.93, P < 0.01). Consequently, the evaluated method provides saving time and labor to accurately analyze cow behavior instead of observations over a long time.     

Hyperglycaemia in transition dairy cows: Effects of lactational stage and conjugated linoleic acid supplementation on glucose metabolism and turnover

Supplementing conjugated linoleic acid ( CLA ) is supposed to spare glucose due to the milk fat‐depressing effect of the trans ‐10, cis ‐12 CLA isomer, and allows repartitioning nutrients despite an energy deficiency in early lactation. However, there is still a lack of knowledge in terms of the dynamic pattern of the glucose turnover in transition dairy cows. We hypothesized that dairy cows supplemented with CLA have an altered rate of glucose turnover and insulin sensitivity during early lactation. We conducted three consecutive hyperglycaemic clamps (HGC ) in weeks ?2, +2 and +4 relative to parturition in Holstein cows supplemented daily either with 70 g of lipid‐encapsulated CLA (6.8 g trans ‐10, cis ‐12 and 6.6 g of the cis ‐9, trans ‐11 CLA isomer; CLA ; n  = 11) or with 56 g of control fat ( CON ; n  = 11). From week ?3 up to week +4 relative to parturition, milk yield and dry matter intake (DMI ) were recorded daily, while body weight (BW ) and milk composition were obtained once weekly. Blood samples were taken once weekly and every 30 min during the HGC . Plasma was analysed for concentrations of glucose, fatty acids (FFA ), beta‐hydroxybutyrate (BHB ), insulin, triglycerides and cholesterol. The CLA supplementation did not affect performance and metabolic parameters except for BHB and cholesterol. Furthermore, insulin concentrations and insulin sensitivity were affected by treatment. During the HGC in early lactation, insulin response was lower and decrease in FFA and BHB greater compared with the HGC in week ?2 although glucose target concentration achieved during the steady‐state period was similar for all three HGC . Our findings in terms of insulin and cholesterol suggest that body reserves are preserved through CLA feeding without restraining animal's performance. Furthermore, CLA effects on cholesterol and triglyceride concentrations indicated beneficial effects on hepatic lipid export contributing to an improved efficiency of prevailing metabolites in circulation.     

Glucose transport and milk secretion during manipulated plasma insulin and glucose concentrations and during LPS‐induced mastitis in dairy cows

In dairy cows, glucose is essential as energy source and substrate for milk constituents. The objective of this study was to investigate effects of long‐term manipulated glucose and insulin concentrations in combination with a LPS‐induced mastitis on mRNA abundance of glucose transporters and factors involved in milk composition. Focusing on direct effects of insulin and glucose without influence of periparturient endocrine adaptations, 18 dairy cows (28 ± 6 weeks of lactation) were randomly assigned to one of three infusion treatments for 56 h (six animals each). Treatments included a hyperinsulinemic hypoglycaemic clamp (HypoG), a hyperinsulinemic euglycaemic clamp (EuG) and a control group (NaCl). After 48 h of infusions, an intramammary challenge with LPS from E. coli was performed and infusions continued for additional 8 h. Mammary gland biopsies were taken before, at 48 (before LPS challenge) and at 56 h (after LPS challenge) of infusion, and mRNA abundance of genes involved in mammary gland metabolism was measured by RT‐qPCR. During the 48 h of infusions, mRNA abundance of glucose transporters GLUT1, 3, 4, 8, 12, SGLT1, 2) was not affected in HypoG, while they were downregulated in EuG. The mRNA abundance of alpha‐lactalbumin, insulin‐induced gene 1, κ‐casein and acetyl‐CoA carboxylase was downregulated in HypoG, but not affected in EuG. Contrary during the intramammary LPS challenge, most of the glucose transporters were downregulated in NaCl and HypoG, but not in EuG. The mRNA abundance of glucose transporters in the mammary gland seems not to be affected by a shortage of glucose, while enzymes and milk constituents directly depending on glucose as a substrate are immediately downregulated. During LPS‐induced mastitis in combination with hypoglycaemia, mammary gland metabolism was more aligned to save glucose for the immune system compared to a situation without limited glucose availability during EuG.     

宁夏利通区产奶期奶牛铜盈缺状况调查

对宁夏吴忠市利通区4个奶牛场和10户农户进行奶牛产奶期铜营养状况进行了调查,分别测定了奶牛盛乳期、产奶中期、产奶后期血清和毛铜的含量和血清中铜蓝蛋白、SOD的活性.结果表明:在盛乳期、产奶后期,散户(产奶后期)、中户奶牛血液铜、毛铜含量偏低,但未出现明显缺乏症状,处于亚临床缺乏状态;产奶中期各户奶牛各项指标均在正常范围之内,混合料中的铜符合标准.各期小户奶牛各项指标基本正常,饲喂状况良好.产奶各期血液铜蓝蛋白、SOD的活性变化范围较小,处于正常范围之内.     

黑龙江省主要栽培的禾本科牧草对奶牛的营养价值评价

通过对常见的13种栽培禾本科牧草的常规营养成分测定及用尼龙袋法测定的干物质在瘤胃72 h降解率(RDMD)的测定,结果表明:l)用营养成分和RDMD等指标进行评定,2个冰草Agropyron cristatum品种营养价值最高,猫尾草Phleum pratense次之,3个披碱草Puccinellia tenuiflora品种居中,羊草Leymuschinensis和墨西哥玉米Zea mays较差,谷莠子Setaria anceps和稗草Echinochloa crusgalli最差。2)禾本科牧草RDMD与ADF、ADL含量呈极显著负相关(P<0.05)。利用回归方程可以用ADF、ADL含量来预测禾本科牧草的RDMD。3)应用干物质采食量(DMI)、产奶净能(NEL)估测模型计算了各种禾本科牧草的分级指数(GI)值,并参照豆科和禾本科牧草质量分级标准对研究测定的禾本科牧草等级进行划分,其结果是:符合优质牧草等级的有高冰草、中间冰草,符合中等牧草等级标准的有无芒雀麦Bromus inermis、垂穗披碱草、东北羊草、吉生羊草、百特猫尾草、猎犬披碱草、润宝高丹草Sorghum×Sudan。属于劣质牧草的有粗穗披碱草Elymus dahuricus、墨西哥玉米、稗草、谷莠子。4)用单一的营养指标如化学成分、干物质降解率不能准确地评价牧草的营养价值。只有综合考虑DMI、养分含量、消化率和有效能才能对牧草的营养价值做出正确的评价。使用GI值能明显区分养分含量差异很小的不同种类牧草,这说明分级指数是评价牧草营养价值的最权威指标。     

2010年至2011年奶牛养殖中碳减排的研究概况

碳排放是关于温室气体排放的总称或简称.在全球气候变化背景下,碳排放空间将逐渐成为经济发展关键的资源约束,农业的低碳排放亦势在必行.在政府间气候变化委员会(IPCC)发布的温室气体排放清单中,反刍动物肠胃发酵甲烷排放与粪便管理系统中的甲烷和一氧化二氮的排放均是农业温室气体的主要排放源,奶牛生产作为反刍动物生产的主要形式之一加之其巨大的粪污排放量,如何实现奶牛生产中温室气体减排对于奶牛生产实现环境友好型发展至关重要.本文从营养调控、减少粪便中碳排放、奶牛业碳减排模型、温室气体减排技术与减排规律等方面对2010年至2011年国内外致力于减少奶牛生产中碳排放的相关研究进行了综述,期望为奶牛生产实现低碳、生态型转变提供帮助.     

苹果发酵物对奶牛产奶性能和疾病的影响

将有益微生物接种到以苹果渣为主的培养基中进行有氧和无氧培养,制成颗粒状苹果培养物。对高产奶牛进行饲喂试验表明,用苹果发酵物代替等量的甜菜或苹果发酵物和甜菜粕同时使用,奶牛分别增产鲜奶1.89和1.90千克/头·日,同时乳脂、乳蛋白质、乳固体物都有上升趋势,奶牛发病率明显下降。苹果发酵物是一种新型反刍动物饲料。     

The importance of the oxidative status of dairy cattle in the periparturient period: revisiting antioxidant supplementation

Dairy cows are especially vulnerable to health disorders during the transition period, when they shift from late pregnancy to the onset of lactation. Diseases at this stage affect not only the animals' well‐being, but also cause a major economic impact in dairy farms, because apart from treatment costs, affected cows will not reach their peak milk‐producing capacity. The overproduction of reactive oxygen species (ROS) leads to oxidative stress, which has been identified as an underlying factor of dysfunctional inflammatory responses. Supplementation with vitamins and trace elements attempts to minimize the harmful consequences of excessive ROS production, thereby trying to improve animals' health status and to reduce disease incidence. However, results regarding the effects of supplementing antioxidants on dairy cows' health and performance have been inconsistent, because in most cases, the antioxidant potential of the animals was not assessed beforehand and the nutritional strategy planned accordingly. Therefore, reviewing the physiological and harmful effects of ROS production, along with the different options available for assessing the redox balance in dairy cattle and some of the key findings of different supplementation trials, could bring one step forward the on‐farm application of determinations of oxidative status for establishing nutritional strategies early enough in the dry period that could improve transition cow health.