酮病对泌乳早期乳牛体内代谢和内分泌的影响

随机选取某奶牛场10头患临床酮病乳牛和10头同期健康对照组乳牛，检测了2组乳牛血液10项指标，阐明了酮病对泌乳早期乳牛体内代谢和内分泌的影响。结果显示，酮病乳牛血糖浓度极显著降低（P〈O．01），血浆NEFA和BHBA的浓度明显增高（P〈O．01）；酮病乳牛血浆Ins、LP、NPY、E2的浓度和Ins／Gn比值均明显降低（P〈O．05），而血浆Gn浓度未明显升高，P4未明显降低（P〉0．05）。表明，酮病乳牛体内某些激素协调作用紊乱会妨碍酮病乳牛能量负平衡的缓解，并将对产后生殖机能产生不良影响。     

酮病治疗对奶牛总抗氧化能力的影响

为探究奶牛酮病治疗对机体总抗氧化能力的影响,本研究选取南宁市某规模化养殖场的65头围产期奶牛作为研究对象,经血浆酮体定量检测,从中选取5头健康牛作为健康对照组,将检出的10头酮病患牛分为治疗组(5头)和阳性对照组(5头)。试验期间,对治疗组进行药物治疗,阳性对照组和健康对照组不做任何治疗。对各组奶牛分别于治疗前和停药后清晨空腹颈静脉采血,测定血浆酮体(改良水杨醛比色法)、血糖(氧化酶-过氧化物酶法)和TAC(铁还原比色法)水平。结果显示,治疗后,治疗组奶牛的血酮含量较治疗前极显著下降,血糖和总抗氧化能力含量极显著升高。阳性对照组和健康对照组的血酮和血糖含量、总抗氧化能力治疗前后变化不大,差异均不显著。结果表明,酮病治疗可提高奶牛血浆TAC水平,提示TAC的提高与酮病痊愈有关。     

亚临床酮病对泌乳早期奶牛繁殖性能和血液生化指标的影响

试验旨在探究围产期亚临床酮病与泌乳早期奶牛繁殖性能、卵泡发育之间的关系,并检测试验牛血液生化指标的变化。试验在黑龙江某大型集约化牛场开展,根据产后血酮水平确定亚临床酮病组(SCK)和健康组(C)奶牛共60头,根据试验牛产后50 d内发情状况,将SCK组再分为发情组(SCKE,16头)和乏情组(SCKA,14头),C组也同样分为发情组(CE,25头)和乏情组(CA,5头)。所有试验牛在产后50 d通过直肠检查和B超检查了解子宫复旧及卵泡发育状况,记录繁殖性能数据,并进行血液生化指标分析。结果表明:与健康组发情奶牛相比,亚临床酮病发情奶牛产后首次发情日期推迟约10 d(P0.05);产后50 d卵泡直径差异极显著(差值约4 mm)(P0.01)。亚临床酮病乏情奶牛子宫复旧延迟发生率显著高于健康组发情奶牛(P0.05);亚临床酮病奶牛血浆中胰岛素样生长因子-1(IGF-1)含量显著低于健康奶牛(P0.05),而泌乳量极显著提高(P0.01)。与发情奶牛相比,乏情奶牛血浆中甘油三酯(TG)含量显著升高(P0.05);葡萄糖(Glu)、胰岛素(Ins)、雌二醇(E_2)、孕酮(P_4)含量显著或极显著降低(P0.05;P0.01)。综合以上试验结果,奶牛患亚临床酮病而导致能量代谢指标异常是引起奶牛乏情、产后卵泡发育受阻和繁殖障碍的主要因素,进而导致奶牛繁殖力下降。     

乳牛产后气虚血瘀证与血浆一氧化氮含量变化关系的初步观察

选用产后健康乳牛18例和产后气虚血瘀证乳牛9例，于产后1、2、4、7、10、15和30d采血分离血浆，用硝酸还原酶法测定一氧化氮（NO）含量。结果，血浆NO含量在产后2、4和7d气虚血瘀证组高于产后健康组，两组呈极显著性差异（P＜0．01）；产后10d气虚血瘀证组亦高于产后健康组，两组呈显著差异 （P＜0．05）；其余时间两组差异不显著（P＞0．05）。因此乳牛产后气虚血瘀证NO自由基含量增加，可能是产后气虚血瘀证发病的病理基础之一。     

围产期酮病奶牛血液生化指标特征分析

试验随机选取产前奶牛29头,跟踪采集产前2周、产前1周、分娩当天及产后3,7,14,21 d的血浆样品,检测血浆相关生化指标变化特征,并记录泌乳量。任意采集时间点血浆β-羟丁酸(BHBA)≥1.2 mmol/L则为酮病组, BHBA<1.2 mmol/L则为对照组。结果显示:随机选取的牛群中酮病发病率为58.6%,酮病主要发生在产后7～14 d;酮病组奶牛产前血液相关生化指标与对照组相比无显著性差异;与对照组相比,酮病组奶牛分娩当天血钾水平升高,血磷水平显著降低;产后3 d酮病组奶牛血浆甘油三酯、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、BHBA、泌乳量显著高于对照组奶牛;产后7,14,21 d血浆BHBA、非脂化脂肪酸(ENFA)、TC、HDL-C、低密度脂蛋白胆固醇(LDL-C)水平极显著高于对照组奶牛,血糖水平显著低于对照组奶牛。二元Logistic回归分析显示:产后3 d血液TC、HDL-C、K、BHBA、泌乳量与奶牛酮病的发生显著相关。将显著性相关指标利用Logistic回归建模,最终建立了基于血液HDL-C、BHBA、泌乳量的奶牛酮病早期诊断模型,即y=17.95-9.81×HDL-C-2.71×BHBA-0.20×泌乳量,当y<0时存在发生酮病风险,模型早期预测奶牛酮病的准确率82.8%、灵敏度81.3%、特异性84.6%。     

奶牛隐性酮病的研究

奶牛酮病,也称为乳牛酮血症,最早由Landel于1894年提出。曾用名有乳牛醋酮血病、酮尿病、母牛热、慢热、产后消化不良、低血糖性酮病、牛产后狂燥病等。该病是由于日粮中碳水化合物和生糖物质不足造成脂肪代谢紊乱,使组织中酮体的浓度增高所致一种代谢病。     

亚临床酮病对泌乳早期奶牛繁殖性能和血液生化指标的影响

试验旨在探究围产期亚临床酮病与泌乳早期奶牛繁殖性能、卵泡发育之间的关系,并检测试验牛血液生化指标的变化。试验在黑龙江某大型集约化牛场开展,根据产后血酮水平确定亚临床酮病组（SCK）和健康组（C）奶牛共60头,根据试验牛产后50 d内发情状况,将SCK组再分为发情组（SCKE,16头）和乏情组（SCKA,14头）,C组也同样分为发情组（CE,25头）和乏情组（CA,5头）。所有试验牛在产后50 d通过直肠检查和B超检查了解子宫复旧及卵泡发育状况,记录繁殖性能数据,并进行血液生化指标分析。结果表明：与健康组发情奶牛相比,亚临床酮病发情奶牛产后首次发情日期推迟约10 d（P<0.05）;产后50 d卵泡直径差异极显著（差值约4 mm）（P<0.01）。亚临床酮病乏情奶牛子宫复旧延迟发生率显著高于健康组发情奶牛（P<0.05）;亚临床酮病奶牛血浆中胰岛素样生长因子-1（IGF-1）含量显著低于健康奶牛（P<0.05）,而泌乳量极显著提高（P<0.01）。与发情奶牛相比,乏情奶牛血浆中甘油三酯（TG）含量显著升高（P<0.05）;葡萄糖（Glu）、胰岛素（Ins）、雌二醇（E₂）、孕酮（P₄）含量显著或极显著降低（P<0.05;P<0.01）。综合以上试验结果,奶牛患亚临床酮病而导致能量代谢指标异常是引起奶牛乏情、产后卵泡发育受阻和繁殖障碍的主要因素,进而导致奶牛繁殖力下降。     

亚临床酮病对泌乳早期奶牛繁殖性能的影响

为探究围产期亚临床酮病与泌乳奶牛繁殖性能及卵泡发育之间的关系,本试验选择了黑龙江省某大型集约化牛场开展试验,根据产后血酮水平确定亚临床酮病组和健康组奶牛共80头,该牛场亚临床酮病发生率为71%;两组奶牛跟踪到产后50 d进行直肠检查和B超检查了解卵泡发育状况,并记录繁殖性能数据。结果显示:与健康组奶牛相比,亚临床酮病组奶牛产后首次发情天数延长10 d,产后60 d内发情次数少0.58次;产后50 d子宫复旧不全高15%,与亚临床酮病呈显著正相关(R^2=8.74);产后60 d卵泡直径小3 mm(P<0.05)。结论:该牛场奶牛亚临床酮病发病率较高,是引起奶牛产后繁殖障碍的风险因素,也是造成卵泡发育受阻的不良因素,会导致奶牛繁殖力下降。     

富硒益生菌和亚硒酸钠对羔羊生产性能和抗氧化及IL-6水平的影响

本试验旨在对比富硒益生菌和亚硒酸钠对羔羊生产性能、抗氧化和血浆IL-6水平的影响。将30只健康羔羊随机均分成对照组、富硒益生菌组和亚硒酸钠组:对照组饲喂基础饲粮,富硒益生菌组、亚硒酸钠组分别在基础饲粮中添加富硒益生菌和亚硒酸钠,其剂量以硒计均为0.1 mg/kg饲粮,试验期56 d。试验过程中记录生产性能相关指标;试验0、28、56 d测定血浆总抗氧化(T-AOC)水平、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和白细胞介素6(IL-6)水平。结果表明:富硒益生菌组羔羊平均增重显著高于对照组和亚硒酸钠组(P0.05),而富硒益生菌组羔羊饲料增重比显著低于对照组和亚硒酸钠组(P0.05)。28 d和56 d时,富硒益生菌组和亚硒酸钠组羔羊血浆T-AOC水平和SOD活性均显著或极显著高于对照组(P0.05或P0.01);而富硒益生菌组和亚硒酸钠组羔羊血浆T-AOC水平和SOD活性之间均无显著差异(P0.05)。28 d和56 d时,富硒益生菌组羔羊血浆MDA含量均极显著或显著低于对照组和亚硒酸钠组(P0.01或P0.05),而亚硒酸钠组羔羊血浆MDA含量较对照组也极显著降低(P0.01)。28 d时,富硒益生菌组羔羊血浆IL-6浓度显著高于对照组(P0.01);56 d时,富硒益生菌组和亚硒酸钠组羔羊血浆IL-6浓度均极显著或显著高于对照组(P0.01或P0.05);而富硒益生菌组羔羊血浆IL-6浓度也显著高亚硒酸钠组(P0.05)。由此可见,富硒益生菌能够提羔羊生产性能、抗氧化能力和血浆IL-6水平,效果优于亚硒酸钠。     

奶牛酮病的危害及防治措施

正奶牛酮病也称奶牛醋酮血症、乳牛酮血症、母牛热,最早于1894年提出并描述。奶牛酮病属于营养代谢性疾病,主要发病原因是机体脂肪代谢、碳水化合物代谢紊乱。该病多发于产后泌乳奶牛,尤其是高产奶牛。奶牛常于产犊后10~60 d内发病,持续数周甚至数月,临床上主要表现为低血糖,高血酮,尿、乳中出现酮体,病牛采食量减少,消化功能、产奶量、     

Prevalence of subclinical ketosis in dairy cattle in the Southwestern Iran and detection of cutoff point for NEFA and glucose concentrations for diagnosis of subclinical ketosis

Subclinical ketosis (SCK) is simply a condition marked by increased levels of circulating ketone bodies without the presence of the clinical signs of ketosis. Subclinical ketosis can cause economic losses through decreased milk production and association with preparturient diseases. Limited information is available regarding the prevalence of SCK in dairy herds in Southwestern Iran. The objectives of this study were (i) determination of the cutoff point of nonesterified fatty acids (NEFAs) and glucose concentrations for diagnosis of SCK using receiver operating characteristic (ROC) analysis, and (ii) determination of prevalence of subclinical ketosis in apparently healthy dairy cattle in Southwestern Iran. From October to December 2009, a total of 100 clinically healthy multiparous Holstein cows (3-8 years old) were randomly selected from 16 dairy herds around Kazerun, Fars Province, Iran. The cows had two-six lactations, with body weight ranging from 500 to 650 kg. Blood samples for each cow were taken at 2, 4 and 6 weeks post parturition and 3-4h after the morning feeding. The optimal cutoff point was set, by the ROC method, to >0.26 mmol/L for NEFA, and < 2.26 mmol/L for glucose with corresponding 82.54% sensitivity and 91.89% specificity for NEFA and 44.44% sensitivity and 78.38% specificity for glucose. Cows with BHB concentrations higher than 1200 μmol/L were classified as having SCK. In 2, 4 and 6 weeks post parturition 63%, 68% and 59% of the tested cows were subclinically ketotic. Overall, 97% of tested cows (97/100) were considered subclinically ketotic in at least one sample period. Thirty percent of tested cows (30/100) suffered from subclinical ketosis in all of the 2, 4 and 6 weeks postpartum. The results suggest that, a cut-off point of 0.26 mmol/L for NEFA concentrations can be used during early lactation for diagnosis of subclinical ketosis and making management decisions for prevention and treatment. Glucose cannot be a good criterion for diagnosis of SCK and it does not appear to be useful for monitoring subclinical ketosis.     

Subclinical ketosis in dairy cows

Subclinical ketosis is defined as a preclinical stage of ketosis. The peak prevalence of subclinical ketosis occurs during the fourth week of lactation. Herd-related factors, breed, parity, and season are other important determinants. Subclinical ketosis can be revealed by determining levels of plasma glucose, plasma NEFA and blood, and milk or urine ketone body concentration. There are theoretical and practical advantages of using milk ketone bodies. Most authors are agreed on approximate lower and upper borderlines for subclinical ketosis. The risk of an outbreak of clinical symptoms has been evaluated by some authors. Most authors have found significant negative relationships between energy balance and ketone body concentration. Some disagreement may be attributable to the fact that the diets used in different experiments can have different glucogenic potential, even if the energy content is the same. This affects the relationship between energy balance and ketone body concentration, as the ketone body level is influenced by both the energy balance and plasma glucose. Feeding silage with high butyric acid content increases the risk of subclinical ketosis. There are indications that cows with the highest milk yield directly after calving are at greatest risk for developing ketosis. Increased ketone body level secondarily reduces milk production, a decrease that has been quantified by some authors. Subclinical ketosis causes delayed reproductive functions return to normal after calving, increased intervals from calving to first and last service, and an increased frequency of ovarian cysts. The routine determination of milk acetone levels in control programs can be used to evaluate the status of individual cows, to indicate the energy feeding in early lactation at a herd level, and to evaluate sires for breeding. The heritability and the tendency toward a positive genetic correlation between milk acetone and milk yield have also been discussed, as have aspects of nutritional prevention. Factors such as energy- and protein-rich roughage, tasty high-energy concentrates, suitable feeding during the dry period, and division of the concentrates into at least four meals are considered to be important.     

Suppression of interferon response of bovine leukocytes during clinical and subclinical ketosis in lactating cows.

The influence of spontaneous ketosis on interferon alpha and gamma production in blood leucocytes and on PHA induced lymphocyte blastogenic response was investigated. Twenty three cows 4.13 +/- 2.8 weeks after calving were divided into three experimental groups on the basis of blood ketone bodies, glucose and free fatty acids concentrations. The leukocytes of cows with clinical symptoms and the highest concentration of ketones and free fatty acids in blood responded with the lowest levels of interferons alpha and gamma to three interferon inducers: Newcastle Disease Virus (NDV), phytohemagglutinin (PHA) and concanavalin A (ConA). Depression in interferon PHA stimulated synthesis correlated with a very low mitogenic response of blood lymphocytes. Blood leukocytes of cows with subclinical ketosis, characterized by mild clinical symptoms and a lower concentration of ketones in blood in comparison to cows with clinical ketosis, responded better to interferon and mitogenic stimulation; however, the interferon titer and blastogenesis were still lower than in leukocytes of healthy cows. Correlation between the stage of ketosis and the level of interferon production in milk leukocytes was also observed. A possible relationship between the suppression of interferon production in blood leukocytes and the increased concentration of ketone bodies in blood is discussed.     

Effects of long-term feeding of a diet supplemented with clinoptilolite to dairy cows on the incidence of ketosis, milk yield and liver function

Fifty-two clinically healthy Holstein cows were randomly assigned to one of three groups according to their age and parity. The first group (A) consisted of 17 cows that were fed a concentrate ration supplemented with 1.25 per cent clinoptilolite, the second group (B) consisted of 17 cows fed a ration supplemented with 2.5 per cent clinoptilolite, and the third group (C) consisted of 18 cows, which were fed the basal ration containing no clinoptilolite. The rations were fed from four weeks before the cows' expected parturition dates until the beginning of the next dry period. Blood samples were collected from each animal at the start of the experiment, on the day of calving and then monthly, and analysed for serum glucose, ketone bodies, liver enzymes, blood urea nitrogen (BUN) and total proteins. The milk yield of each cow was recorded monthly. The cows in group B had significantly fewer cases of clinical ketosis during the first month after calving and a higher total milk yield. Feeding the cows with clinoptilolite for a long period had no apparent adverse effects on their liver function, and did not significantly affect the concentrations of glucose, ketone bodies, BUN and total proteins in their serum.     

The effect of subclinical ketosis in dry cows on the composition of the colostrum and on health indicators in newborn calves

Subclinical ketosis of dry cows was studied as to its effect on the composition of colostrum and on the health condition and selected clinico-biochemical parameters in the new-born calves of these cows. The experimental group consisted of eight cows with ketonuria and their calves. The control group consisted of six cows without ketonuria and their new-born calves. Calves of both groups were reared in similar conditions. Colostrum samples were taken from the first milking and then from the milking 24 hours after parturition. The blood of the calves was sampled before the intake of colostrum and 24 hours after birth. The concentration of ketone bodies, particularly beta-hydroxybutyrate, was much higher in the colostrum of both groups of cows than in the blood (62.6 mg total ketone bodies per 1 litre of the first colostrum of the cows of the experimental group). The concentration of ketone bodies slightly increased after parturition. The cows with ketonuria secreted into colostrum a larger amount of oxidated ketone bodies. Colostrum quality was good in both groups. Decreased viability was not recorded during the clinical examination of the calves after birth. The level of total ketone bodies in the blood of pre-colostral calves in the experimental group was 10.4 mg per litre (a much lower concentration than in blood of their dams), and exhibited no appreciable change after taking in the colostrum. The blood of calves born to cows with ketonuria contained significantly higher amounts of oxidated ketone bodies. No correlation was demonstrated between the contents of ketone bodies in the blood of cows, in the blood of calves, and in the colostrum. The calves of the experimental group were found to have a significantly higher AST activity in plasma, as compared with the control group. Twenty-four hours after birth, the quantity of immunoglobulins in the blood serum was significantly lower in the calves of the experimental group. Thanks to good attendance and hygiene, the morbidity did not increase and no losses occurred.     

泌乳奶牛脂肪肝早期诊断的研究

为了寻找泌乳奶牛脂肪肝早期诊断方法,本研究从某千头奶牛场随机选取了30头乳酮阳性的奶牛,其中临床酮病牛10头,亚临床酮病牛20头,测定其肝脂含量以及血中代谢指标和肝功指标。试验结果表明,脂肪肝的奶牛存在能量负平衡现象,机体呈现高游离脂肪酸血症、高酮血症,肝脂浸润越重,能量代谢障碍越严重;乳酮阳性出现时间的早晚与脂肪肝的严重程度密切相关,乳酮阳性产后出现的越早,乳酮阳性越明显,肝脂浸润越重;随肝脂浸润程度的加重,肝功多个指标会出现异常,重度的脂肪肝会引发肝功能不全。本试验证明,酮粉法可以作为早期诊断奶牛脂肪肝的初选方法,肝功指标异常可作为诊断脂肪肝的辅助方法,两者结合可作为奶牛脂肪肝的实用、有效和准确的早期诊断方法,准确率可达80%。     

Stability of plasma metabolites and hormones in parturient dairy cows

Metabolic changes that accompany the transition from parturition to lactation in dairy cows were studied. To measure these changes, plasma samples were obtained from 20 mature Holstein-Friesian dairy cows 10 days before through 10 days after parturition. They were analyzed for glucose, free fatty acids (FFA), lactic acid, ketone bodies, glucocorticoids, insulin, and growth hormone concentration. Lactic acid and glucocorticoids remained constant during the experiment, except for the day of parturition itself. In the prepartum period, changes were not detected in concentrations of hormones (glucocorticoids, insulin, and growth hormone), whereas, plasma metabolites began changing prior to parturition. Most evident were prepartum increased in FFA, ketones, and glucose. Postpartum plasma glucose concentration rapidly returned to prepartum concentrations. Plasma concentration of FFA and ketone bodies remained elevated for longer periods.     

围产期奶牛干物质摄入水平与产后生产性能及血浆酮体浓度的关系

将围产期奶牛30头随机分为3组,每组10头。其中Ⅱ组为对照组,Ⅰ组和Ⅲ组分别为试验组;Ⅰ、Ⅱ、Ⅲ3组于产前28d开始分别饲喂NRC标准减少20%日粮(能量摄入80%组)、NRC标准日粮(能量摄入100%组)、NRC标准增加20%日粮(能量摄入120%组),产后各组奶牛均饲喂标准日粮,至产后56d结束,观察不同干物质摄入水平对奶牛血浆酮体浓度的影响。试验结果表明:奶牛产后干物质摄入量和产奶量均为Ⅰ组高于Ⅱ组、Ⅱ组又高于Ⅲ组,经统计分析组间差异极显著(P<0.01)或差异显著(P<0.05);此外,Ⅰ组体重消耗最小,Ⅲ组体重消耗最大,各组间差异极显著(P<0.01)。产后Ⅲ组血酮浓度显著高于Ⅰ组和Ⅱ组(P<0.05),而Ⅰ组和Ⅱ组之间差异不明显。可见,围产期奶牛不同干物质摄入量与产奶量、体重等生产性能及产后血酮浓度之间存在着密切的关系。     

产后酮病奶牛血液生化指征分析

为了比较产后一段时期内酮病奶牛与健康奶牛血液生化指标的差异,为奶牛酮病的防控及兽医临床诊治提供理论依据。本研究选取吴忠市某集约化奶牛场待产奶牛共30头进行为期3周的血液生化指标监测,根据β-羟丁酸（BHBA）的浓度将奶牛分为酮病组和对照组并进行比较研究。结果显示,酮病组与对照组在生产当天（0 d）各项检测指标未出现显著性差异;酮病组奶牛β-羟丁酸浓度在产后7 d时较对照组极显著升高（P<0.01）;天门冬氨酸氨基转移酶（AST）和总胆红素（T-bil）浓度在产后7 d和14 d时显著升高（P<0.05）;血糖（Glu）浓度在产后7 d时显著降低（P<0.05）,产后14 d时极显著降低（P<0.01）;钙（Ca）、磷（P）浓度无显著性差异,但均低于正常参考值范围,出现低血钙、低血磷症。经分析发现,本场奶牛所患酮病为Ⅱ型酮病,酮病牛高发胎次为3~6胎,产后低血钙、低血磷、低血糖现象严重,同时奶牛酮病引发了机体肝脏功能损伤,影响母牛生产性能。