Perchlorate in the feed-dairy continuum of the southwestern United States

Perchlorate has the potential to cause thyroid dysfunction by inhibiting iodide uptake by the sodium iodide symporter. Perchlorate-contaminated waters may lead to human exposure through drinking water and food chain transfer in crops by way of irrigation water. Perchlorate has been found in dairy milk collected nationally and internationally. This study was conducted to evaluate perchlorate in the feed-dairy continuum in the southwestern United States. All feed products collected at dairies in this study had detectable levels of perchlorate as analyzed by ion chromatography-tandem mass spectrometry. The calculated total perchlorate intake across dairies ranged from 1.9 to 12.7 mg/cow per day. The variation in total perchlorate intake across dairies was largely associated with variation in forage and silage products. Alfalfa products were the single most important source of perchlorate intake variability among dairies. The estimated perchlorate intake from drinking water ranged from 0.01 mg per cow per day and was generally less than 2% of the total perchlorate intake. The perchlorate content of milk ranged from 0.9 to 10.3 microg/L and was similar to levels reported by the Food and Drug Administration's Total Diet Study. The perchlorate content of milk was significantly related to the presence of perchlorate in feed but the variation of perchlorate in milk could not be explained by feed intake alone.     

基于全混合日粮饲喂技术的精饲料精确饲喂模式

为了提高奶牛产量、降低生产成本,奶牛精细饲喂是重要的实现途径,该文对奶牛精饲料精确饲喂与配套饲喂模式进行了研究。该文以个体奶牛为饲养管理单位对200头和500头牛群进行了"TMR（total mixed ration,全混合日粮）+精饲料精确饲喂"饲喂模式的牛舍内和奶厅外饲喂研究,试验结果表明：牛舍内饲喂采用牛颈枷间距1.2 m,装备行进速度0.45 m/s时,识别系统对奶牛的识别率100%,识别准确率不小于96%,抢食率不大于4%,系统响应时间不大于2 s,每百头奶牛饲喂时间不大于0.4 h;奶厅外饲喂采用牛颈枷间距1.4 m,装备行进速度0.7 m/s时,识别系统对奶牛的识别率100%,识别准确率不小于99%,抢食率为0,系统响应时间不大于2 s,每百头奶牛饲喂时间不大于0.35 h;同时试验期间比2011年同期传统"TMR+人工补饲精饲料"饲喂模式平均单产提高0.8 kg/d,并减轻了劳动强度。研究结果可为奶牛饲喂与养殖模式相关研究、牛场建设与改造等提供参考。     

Tissue distribution, elimination, and metabolism of sodium [36Cl]perchlorate in lactating goats

Perchlorate has contaminated water sources throughout the United States but particularly in the arid Southwest, an area containing large numbers of people and few water sources. Recent studies have demonstrated that perchlorate is present in alfalfa and that perchlorate is secreted into the milk of cows. Studies in lactating cows have indicated that only a small portion of a perchlorate dose could be accounted for by elimination in milk, feces, or urine. It was hypothesized that the remainder of the perchlorate dose was excreted as chloride ion. The purpose of this study was to determine the fate and disposition of (36)Cl-perchlorate in lactating dairy goats. Two goats (60 kg) were each orally administered 3.5 mg (16.5 muCi) of (36)Cl-perchlorate, a dose selected to approximate environmental perchlorate exposure but that would allow for adequate detection of radioactive residues after a 72 h withdrawal period. Blood, milk, urine, and feces were collected incrementally until slaughter at 72 h. Total radioactive residue (TRR) and perchlorate concentrations were measured using radiochemical techniques and liquid chromatography mass spectrometry (LC-MS-MS). Peak blood levels of TRR occurred at 12 h ( approximately 195 ppb) postdose; peak levels of parent perchlorate, however, occurred after only 2 h, suggesting that perchlorate metabolism occurred rapidly in the rumen. The serum half-life of perchlorate was estimated to be 2.3 h. After 24 h, perchlorate was not detectable in blood serum but TRR remained elevated (160 ppb) through 72 h. Milk perchlorate levels peaked at 12 h (155 ppb) and were no longer detectable by 36 h, even though TRRs were readily detected through 72 h. Perchlorate was not detectable in skeletal muscle or liver at slaughter (72 h). Chlorite and chlorate were not detected in any matrix. The only radioactive residues observed were perchlorate and chloride ion. Bioavailability of perchlorate was poor in lactating goats, but the perchlorate that was absorbed intact was rapidly eliminated in milk and urine.     

苹果酸对泌乳早期奶牛泌乳性能和代谢产物的影响

选用28头经产奶牛,根据泌乳期、上一泌乳期305d的产奶量和预产期,采用随机区组设计分为4组,研究苹果酸(07、0、140和210g/d)对泌乳早期奶牛采食量、泌乳性能、血液代谢产物和尿酮浓度的影响。结果表明:日粮添加苹果酸对奶牛的采食量、乳脂率、乳蛋白率、乳糖率和乳干物质率无显著影响,140g/d组和210g/d组产奶量和饲料转化效率显著高于对照组(P<0.05)。添加苹果酸后,140g/d组和210g/d组血浆葡萄糖浓度显著高于对照组(P<0.05),而血浆游离脂肪酸和β-羟丁酸浓度显著低于对照组(P<0.05);140g/d组和210g/d组尿酮浓度显著低于对照组和70g/d组(P<0.05)。根据试验结果,苹果酸适宜添加量为140g/d。     

Aroma compounds of fresh milk from New Zealand cows fed different diets

Volatile compounds were extracted from fresh milk produced by New Zealand cows using the newly developed solvent-assisted flavor evaporation (SAFE) technique. The two samples that were used came from cows that had been fed on different diets and represented the considerably different flavors of Northern hemisphere and New Zealand milk. Using gas chromatography-olfactometry (GC-O), 71 aroma compounds were found from the milk extracts, 66 of which were identified. Nearly all of the aroma compounds were common to both extracts, despite the two milk samples having quite different flavors. Only one compound, gamma-12:2 lactone, was significantly odor-active for the extract of milk from cows fed a supplement diet, but was not found for the extract of milk from cows fed a pasture diet. Thus, differences in milk flavor are primarily caused by concentration differences of a common set of flavor compounds, rather than by the occurrence of compounds uniquely associated with a particular feed.     

奶牛隐性乳房炎便携式计算机视觉快速检测系统设计与试验

为解决奶牛隐性乳房炎难以防治的问题,构建了一种基于计算机视觉技术的快速检测系统。通过电脑与USB摄像头采集牛奶p H测试纸图像,提出了一种融合颜色特征与形态学处理的分割方法,分割化学反应区并获取RGB值,使用Foss5000牛乳体细胞分析仪得到牛奶体细胞实测值,采取幂回归法建立RGB值与牛奶体细胞数的预测模型,并基于Android技术开发了便携式移动终端设备。牛场实测20组数据试验结果显示,牛奶体细胞数估测值与实测值相关系数为0.970,估测平均相对误差为3.67%,标准差为1.88%。系统估测牛奶体细胞数较为准确,可用于奶牛隐性乳房炎快速检测。     

应用RIA测定奶中孕酮含量诊断奶牛卵巢机能性疾病

正常奶牛一个发情周期由卵泡期、黄体期、黄体生长期和黄体消解期所组成。根据30头正常奶牛的临床观察和测定各个时期的奶中孕酮含量表明,卵泡期奶中孕酮含量为≤5ng/ml,持续时间为4.5±1.5天;黄体期奶中孕酮含量为≥11ng/ml,持续时间为13±2天;黄体生长期奶中孕酮含量为>5ng/ml—<11ng/ml,持续时间为2±1天;黄体消解期奶中孕酮含量为<11ng/ml—75ng/ml,持续时间为1±0.5天.根据这些指标并结合奶牛的临床表现对奶牛的卵巢机能性疾病进行了诊断,获得了较好的结果,提高了诊断的准确率。     

奶牛乳房炎自动检测技术研究进展

奶牛乳房炎是影响奶牛健康的主要疾病之一,发病率高、发病范围广、经济损失严重。目前奶牛乳房炎的检测大多是采集奶牛乳汁进行理化性质检测,该方法对检测环境有着较高要求,且检测周期长。随着信息技术的迅速发展,奶牛乳房炎的自动检测技术取得了较好的研究成果。该研究根据数据的传感器类型,从视觉传感器、自动挤奶系统与其他传感器3个方面阐述了奶牛乳房炎自动检测的研究进展。基于视觉传感器的奶牛乳房炎自动检测方法包括基于乳房热红外图像和基于乳汁图像的检测方法,该方法较大程度上保障了动物福利,但检测精度有待提升;基于自动挤奶系统（automatic milking systems, AMS）的奶牛乳房炎自动检测方法利用AMS获取乳汁信息,然后构建乳房炎检测模型,该方法检测误差较小,但成本较高;基于其他传感器的奶牛乳房炎检测方法采用独立研发的传感器获取乳汁数据,预测乳房炎发病情况,该方法操作简便,但使用不同传感器构建的检测模型精度差异较大。该文还探讨了目前奶牛乳房炎自动检测领域存在的精度低、实时性差、自动化不足等问题,并展望了该领域未来的发展趋势,以期为开展奶牛乳房炎自动检测技术与方法研究提供参考。     

Laboratory and on-farm studies on the bioaccumulation and elimination of dioxins from a contaminated mineral supplement fed to dairy cows

A dioxin-contaminated mineral supplement was used to study the bioaccumulation and elimination of dioxins in two dairy cows. The supplement was mixed into the total maintenance ration and fed to the cows for 40 days after which unfortified diets were fed for 40 additional days. Dioxins and coplanar polychlorinated biphenyls (PCBs) were measured twice a week in the milk and in selected tissues of the cows, one at death (day 10 of withdrawal) and one at slaughter (day 40 of withdrawal). The dioxins and PCBs were readily transferred into the milk, and at steady state, total toxic equivalents were concentrated 6-fold into the milk fat from the diet. Bioaccumulation was inversely related to chlorination number. The elimination of dioxins and PCBs in milk was biphasic. With the exception of 1,2,3,4,6,7,8-heptachlorodioxin and both octachlorinated congeners, dioxin and furan half-lives in milk were approximately 3-5 days for the alpha-phase and 35-50 days for the beta-phase. PCB-169 had a longer half-life: 11 (alpha) and 200 days (beta). When milk and feed samples from Minnesota farms that had used similar contaminated mineral supplements were analyzed, no elevated dioxin levels were found in milk. It appeared that although the dioxins from the mineral supplements have the potential to bioaccumulate, dilution into the total diet was sufficient to prevent a significant rise in the dioxin concentrations in the milk at these farms.     

Residue depletion study and withdrawal period for flunixin-N-methyl glucamine in bovine milk following intravenous administration

The objective of this study was to establish a withdrawal period for flunixin in milk by quantifying 5-hydroxyflunixin, the marker residue, in bovine milk as a function of time, following intravenous treatment of lactating dairy cows with flunixin-N-methyl glucamine (Banamine or Finadyne). Lactating dairy cows were dosed on three consecutive days at 2.2 mg of flunixin free acid/kg of body weight/day. Milk was collected twice daily and assayed using a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) procedure. The method was validated at concentrations in the range 0.5-250 ppb. The concentrations for 5-hydroxyflunixin measured 12 h after the last administration of drug ranged from 1.56 to 40.6 ppb for all cows. Milk concentrations for 5-hydroxyflunixin were used to establish withdrawal periods of 36 h using guidelines established by the U.S. Food and Drug Administration/Center for Veterinary Medicine and 24 h using guidelines established by the European Medicinal Evaluation Agency/Committee on Veterinary Medicinal Products.     

Disposition of doramectin milk residues in lactating dairy sheep

Doramectin (DRM) is a broad spectrum macrocyclic lactone antiparasitic drug not approved for use in dairy animals. However, DRM and other endectocide compounds are widely used extra-label to control endo- and ectoparasites in dairy sheep. The plasma disposition kinetics and the pattern of DRM excretion in milk were characterized following its subcutaneous administration to lactating dairy sheep. DRM concentration profiles were measured in plasma and milk samples after validation of a specific HPLC-based methodology. DRM was detected between 1 h and 30 days post-treatment. DRM concentrations of 0.48 ng.mL(-1) (plasma) and 1.03 ng.mL(-1) (milk) were measured at 30 days post-treatment. DRM was extensively distributed from the bloodstream to the mammary gland, and large concentrations were excreted in milk. The peak concentrations and total amount of DRM recovered in milk (expressed as area under the concentration versus time curve) were 3-fold higher than those measured in plasma; 2.44% of the total DRM dose was excreted in milk. The long persistence of DRM milk residues should be seriously considered before its extra-label use in dairy animals is recommended.     

挤奶机真空度对牛奶体细胞数和牛乳头末端壁厚的影响

为了研究挤奶机系统真空度不同时的挤奶效果,解决目前挤奶机使用中系统真空度缺乏科学设定依据的问题,该文以12头高产泌乳牛(单产(7.4±0.4)t)为试验对象,以体细胞数(somatic cell count,SCC)、乳头末端壁厚变化率以及挤奶量等作为挤奶效果评价指标参数,在系统真空度分别为44、46以及48 kPa时,研究了系统真空度对泌乳牛挤奶过程不同阶段的内套真空度和挤奶杯口真空度的影响,量化了系统真空度对挤奶效果评价指标的影响程度。研究表明,当系统真空度从44 kPa增加至48kPa时,挤奶量、挤奶时间以及平均奶流量均无显著差异,但体细胞数的对数(P0.05)和乳头末端壁厚变化率(P0.05)均显著增加。研究认为试验挤奶机用44 kPa的系统真空度比用46或48 kPa时的效果更好。该文为中国挤奶机使用中系统真空度的优化设置提供技术支持。     

Safety and animal handling practices among women dairy operators

This article presents suggestions toward safer animal handling utilizing the results of a qualitative study of women dairy farmers in Finland. A major proportion of injuries (43%) occur in livestock-related work in Finnish agriculture. An even greater proportion of women's farm injuries (77%) is related to animals. We investigated the working conditions often women dairy farmers. Data were collected by observing farm work and performing semi-structured interviews. The study farms represented different milk production technologies with an average farm size of 106 ha (262 acres) of cultivated land, 51 ha (126 acres) of forest, and 45 dairy cows. Farm-related injuries were frequent; eight respondents out often had suffered one or several injuries during the previous two years. The women considered farm animals as the greatest hazard, and unexpected animal behavior was viewed as the most significant work-related injury risk. Dangerous situations often resulted from stress in cows caused by unpleasant circumstances or making animals fearful of people. Experiences from some farms suggested that dairy farm work can be relatively safe and that improving the trust between the cows and their handlers plays a key role in safety. We synthesized our findings into four animal handling strategies that can potentially reduce the risk of injury among stockpersons. We developed practical guidelines on how to gradually build a good cow-handler relationship based on our findings and the literature on cattle handling strategies and animal welfare science.     

基于热红外图像的奶牛乳区温度分布与乳房炎识别方法

乳房炎是影响奶牛健康与牛奶品质的主要疾病之一,是健康养殖的监控重点,该研究提出了一种基于热红外图像的奶牛乳区温度分布测量与乳房炎识别方法.通过现场采集的健康与患病共189头荷斯坦奶牛挤奶前后的后乳区热红外图像样本,提出了左右后乳区自动识别方法,确定了后乳区的特征区域及识别乳房炎的数据最佳采集时间为挤奶前.通过线剖法获取...     

Soil Nutrient Load and Drain Water Quality in Seepage Fields Receiving Milk House Wastewater

The large volume of wastewater generated on dairy farms from the cleaning of milk pipelines and milking equipment contains nutrients and microorganisms that could pollute waterways if discharged without treatment. The objective of this study was to evaluate a modified septic tank-seepage field system for disposing of milk house wastewater, by measuring the accumulation of nutrients in the soil and monitoring the water drained from the seepage field. The study was conducted on two small dairy farms (40–50 milking cows) in south-west Québec, Canada. After passing through a sediment and milk fat trap and then the septic tank, the milk house wastewater was drained into a 0.45 ha experimental seepage field under pasture or arable cropped land. Much larger than a conventional seepage bed (0.025 ha), the experimental seepage field was designed to remain recycle the wastewater nutrients and water, while preventing soil saturation. Annual nutrient loading from milk house wastewaters were, on average, 60 kg total N ha^?1, 50 kg total P ha^?1 and 80 kg total K ha^?1. The concentrations of plant-available nutrients increased when milk house wastewater entered the seepage field, but the magnitude of change was farm-specific, due to the unique topography and soil characteristics offered by each farm. For instance, the P concentration was unchanged on one farm, but there was rapid and significant accumulation of P in the 20–60 cm depth of the soil profile on the second farm. There was an increase in Ca and Mg concentrations in the soil profile on both farms, but soil salinity remained <4 dS m^?1 during this study. Water drained from the experimental seepage fields was similar in quality to that drained from a control area, indicating that the seepage fields were sufficiently large to adsorb and treat the nutrients contained in milk house wastewater in the short-term. Assessment of the cation and anion adsorption capacity of soils on these farms will be necessary to verify the treatment capacity and effective lifespan of the seepage fields.     

Real-time TaqMan polymerase chain reaction detection and quantification of cow DNA in pure water buffalo mozzarella cheese: method validation and its application on commercial samples

Mozzarella cheese obtained from buffalo (Bubalus bubalis) milk is a typical Italian product certificated by means of the European Protected Designation of Origin (PDO). Mozzarella cheese can also be obtained from bovine milk or bovine/buffalo milk mixtures, but in this case, it cannot be sold as PDO product, and its label must report the actual ingredients. However, bovine milk in PDO products was frequently detected in the past, suggesting fraudulent addition or accidental contamination. Several methods based on end-point polymerase chain reaction (PCR) have been profitably applied in a large number of tests to detect the presence of undeclared ingredients, also in dairy products. In the present study we report a real-time PCR method able to quantify bovine milk addition to pure buffalo cheese products. We validated a normalized procedure based on two targets: bovine mitochondrial cytochrome b (cyt b) to detect and quantify the bovine DNA and nuclear growth hormone (GH) gene used as a universal reference marker. With the use of this real-time PCR assay, 64 commercial mozzarella di bufala cheese samples purchased at local supermarkets, dairy shops, or directly from cheese manufacturers were analyzed. The results obtained demonstrate that most of the commercial samples were contaminated with bovine milk. Therefore, this assay could be conveniently employed to carry out routine and accurate controls aimed not only to discourage any fraudulent behavior but also to reduce risks for consumer health.     

Kinetics of abamectin disposition in blood plasma and milk of lactating dairy sheep and suckling lambs

Abamectin (ABM) has been used worldwide as an anthelmintic drug in veterinary medicine and as an agricultural pesticide. Its pharmacokinetics and permeation into milk was evaluated in dairy sheep after subcutaneous administration. ABM elimination half-lives and mean residence times were 1.7 and 3.7 days for blood plasma and 1.9 and 3.8 days for milk, respectively. The ABM milk to plasma concentration ratio (0.89) primarily depends on milk fat content. Transfer of ABM residues to suckling lambs was evaluated by determination of ABM concentration time courses in lambs' plasma. Mean maximal concentration in lambs was 1.6 microg L(-1) at 3.3 days, and elimination half-life was 2.7 days. In ewes' plasma and milk, ABM was detected up to 23 days. Because of different pharmacokinetics, ABM exposure in lambs was almost 10% of the exposure in ewes, although the amount excreted in milk was only 1.0% of the dose.     

Survey of dioxin-like compounds in dairy feeds in the United States

The United States Environmental Protection Agency (USEPA) has completed a survey of dioxin-like compounds (including 17 dioxin and furan (CDD/F) congeners and 12 coplanar polychlorinated biphenyl (PCBs) congeners) in dairy feeds from 10 dairy research facilities around the United States, sampling the overall mixtures and the major and minor feed components. Low levels of dioxin were found in all feed mixtures with an average concentration of 0.05 pg/g (ppt) toxic equivalent (TEQ) dry weight. This is lower than previously found in dairy feeds by about a factor of 4. While it is possible that generally lower levels of dioxins in the environment in recent years may explain this result, examinations of the data suggest that the oven drying used to prepare the wet feed samples could have resulted in a loss of dioxins from the feed materials. The percentage of the total TEQ due to CDD/Fs was about four times that of PCBs. Leafy vegetations in the feed (the silages and the hays) had concentrations about twice as high as nonleafy, protected vegetation of the feeds (the ground or meal corn, cottonseed, and others). Minor components did not significantly influence the final feed mixture concentration of dioxin TEQ. However, in one of the feed mixtures, a minor component with a high concentration of 38.5 ppt TEQ effectively doubled the concentration of the overall feed mixture.     

Physical and sensory properties of dairy products from cows with various milk fatty acid compositions

Dairy products from milk of cows fed diets rich in polyunsaturated fatty acids have a more health-promoting fatty acid composition and are softer but often have oxidized flavors. Dairy products made from cow's milk that has more- or less-unsaturated fatty acid compositions were tested for differences in texture and flavor from those made from bulk-tank milk. The milk was manufactured into butter, vanilla ice cream, yogurt, Provolone cheese, and Cheddar cheese. The products were analyzed for fatty acid composition, physical properties, and flavor. Milk of cows with a more monounsaturated fatty acid composition yielded products with a more monounsaturated fatty acid composition that were softer and had a satisfactory flavor. Thus, selection of cows for milk fatty acid composition can be used to produce dairy products that are probably more healthful and have a softer texture.     

高氯酸盐与铬复合污染对水稻幼苗生长的影响

通过营养液沙培盆栽试验,研究了水稻幼苗的根长、株高和鲜重对高氯酸盐（ClO4^-）、六价铬（Cr^6＋）及其复合污染（ClO4^-＋Cr^6＋）胁迫的响应。结果表明,随着污染物处理浓度的提高,ClO4^-、Cr^6＋和ClO4^-＋Cr^6＋对水稻幼苗主要生长指标根长、株高和鲜重的抑制作用越明显,呈现出明显的浓度-效应关系;在同一浓度下,ClO4^-、Cr^6＋和ClO4^-＋Cr^6＋对水稻幼苗根长、株高和鲜重的抑制率呈明显的时间-效应关系,处理时间越长,抑制率越高;复合污染对水稻生长的抑制效应大于其中任一污染物在同浓度条件下的单一污染的影响,且随着浓度和时间的增加,抑制作用也越明显;复合污染对水稻幼苗生长的交互作用类型因处理时间和浓度组合的不同而更趋复杂。