Comparison of basic nutrients, mineral and heavy metal contents of herby dairy products

The aim of this study was to determine basic nutrients, some minerals and heavy metal contents of herby cheese, cacik and lor. Herby cheese is a cheese made from cow and/or sheep milk mixed with some herb. Herby cacik is a dairy product manufactured from light yoghurt (non-fat), ayran (liquid yoghurt) and/or a small amount of cheese whey. Herby lor cheese is a product traditionally made in Turkey, produced from cheese whey and occasionally some whole milk added. These dairy products are mixed with wild herb species (Allium sp., Chaerophyllum macropodum, Antriscus nemorosa, Ferula sp., Prangos sp., Silene vulgaris, Tymus sp. and Mentha sp.). In this study, herby cacik, cheese and lor samples were analysed for some physicochemical, mineral and heavy metal contents. The dry matter, protein, fat, salt and ash contents among herby dairy products were found significantly different (P < 0.05). There were significant differences in Ca, P, Na, Mg, Fe, Cu and Mn content of herby dairy products (P < 0.05). Zn, Co, Cr, Ni and Cd contents of analysed samples were not significantly different (P > 0.05).     

Phenotypic and genetic analysis of milk and serum element concentrations in dairy cows

Enhancing micronutrient (i.e., mineral and vitamin) concentrations within milk and serum from dairy cows is important for both the health of the cow and the nutritive value of the milk for human consumption. However, a good understanding of the genetics underlying the micronutrient content in dairy cattle is needed to facilitate such enhancements through feeding or breeding practices. In this study, milk (n = 950) and serum (n = 766) samples were collected from Holstein-Friesian dairy cows (n = 479) on 19 occasions over a 59-mo period and analyzed for concentrations of important elements. Additionally, a subset of 256 milk samples was analyzed for concentrations of vitamin B₁₂. Cows belonged to 2 genetic lines (average and highest genetic merit for milk fat plus protein yield) and were assigned to 1 of 2 diets based on either a by-product or homegrown ration. Univariate models accounting for repeated records were used to analyze element and vitamin B₁₂ data and investigate the effect of genotype and feeding system as well as derive estimates of variance components and genetic parameters. Bivariate models were used to study correlations both within and between milk and serum. Only concentrations of Hg in milk were seen to be affected by genotype, with higher concentrations in cows with high genetic merit. In contrast, element concentrations were influenced by feeding system such that cows fed the homegrown diet had increased milk concentrations of Ca, Cu, I, Mn, Mo, P, and K and increased serum concentrations of Cd, Cu, Fe, Mo, and V. Cows on the by-product diet had increased milk concentrations of Mg, Se, and Na and increased serum concentrations of P and Se. Heritability (h²) estimates were obtained for 6 milk and 4 serum elements, including Mg (h²_milk = 0.30), K (h²_serum = 0.18), Ca (h²_milk = 0.20; h²_serum = 0.12), Mn (h²_milk = 0.14), Cu (h²_serum = 0.22), Zn (h²_milk = 0.24), Se (h²_milk = 0.15; h²_serum = 0.10), and Mo (h²_milk = 0.19). Significant estimates of repeatability were observed in all milk and serum quantity elements (Na, Mg, P, K, and Ca) as well as 5 milk and 7 serum trace elements. Only K in milk and serum was found to have a significant positive genetic and phenotypic correlation (0.52 and 0.22, respectively). Significant phenotypic associations were noted between milk and serum Ca (0.17), Mo (0.19), and Na (−0.79). Additional multivariate analyses between measures within sample type (i.e., milk or serum) revealed significant positive associations, both phenotypic and genetic, between some of the elements. In milk, Se was genetically correlated with Ca (0.63), Mg (0.59), Mn (0.40), P (0.53), and Zn (0.52), whereas in serum, V showed strong genetic associations with Cd (0.71), Ca (0.53), Mn (0.63), Mo (0.57), P (0.42), K (0.45), and Hg (−0.44). These results provide evidence that element concentrations in milk and blood of dairy cows are significantly influenced by both diet and genetics and demonstrate the potential for genetic selection and dietary manipulation to alter nutrient concentration to improve both cow health and the healthfulness of milk for human consumption.     

比浊法测定饲料添加剂中重金属限量的研究

采用不同试样预处理方法,并以硫代乙酰胺溶液和硫化钠溶液作为显色剂,研究饲料添加剂中重金属限量试验的制定方法.经试验验证,以硫代乙酰胺为显色剂的比浊法和以硫化钠为显色剂比浊法的目视检出限分别为4μg/管和3μg/管;2种比浊方法,铅含量在0～40μg/管与吸光度值均呈良好的线性关系(r>0.99),对添加重金属的不同试样...     

Correlations of milk and serum element concentrations with production and management traits in dairy cows

The present study investigated the potential consequences, positive or negative, that selection for favorable production-related traits may have on concentrations of vitamin B₁₂ and key chemical elements in dairy cow milk and serum and the possible impact on milk healthiness, and associated benefits, for the dairy product consumer. Milk and serum samples (950 and 755, respectively) were collected from Holstein-Friesian dairy cows (n = 479) on 19 occasions over a 59-mo period, generating 34,258 individual records, and analyzed for concentrations of key trace and quantity elements, heavy metals, and milk vitamin B₁₂. These data were then matched to economically important production data (milk, fat, and protein yield) and management data (dry matter intake, liveweight, and body condition score). Multivariate animal models, including full pedigree information, were used to analyze data and investigate relationships between traits of interest. Results highlighted negative genetic correlations between many quantity and trace elements in both milk and serum with production and management traits. Milk yield was strongly negatively correlated with the milk quantity elements Mg and Ca (genetic correlation between traits, r_a = ?0.58 and ?0.63, respectively) as well as the trace elements Mn, Fe, Ni, Cu, Zn, and Mo (r_a = ?0.32, ?0.58, ?0.52, ?0.40, ?0.34, and ?0.96, respectively); and in serum, Mg, Ca, Co, Fe, and Zn (r_a = ?0.50, ?0.36, ?0.68, ?0.54, and ?0.90, respectively). Strong genetic correlations were noted between dry matter intake with V (r_a = 0.97), Fe (r_a = ?0.69), Ni (r_a = ?0.81), and Zn (r_a = ?0.75), and in serum, strong negative genetic correlations were observed between dry matter intake with Ca and Se (r_a = ?0.95 and ?0.88, respectively). Body condition score was negatively correlated with serum P, Cu, Se, and Pb (r_a = ?0.45, ?0.35, ?0.51, and ?0.64, respectively) and positively correlated with Mn, Fe, and Zn (r_a = 0.40, 0.71, and 0.55, respectively). Our results suggest that breeding strategies aimed at improving economically important production-related traits would most likely result in a negative impact on levels of beneficial nutrients within milk for human consumption (such as Mg, Ca, Fe, Zn, and Se).     

Radioactivity and heavy metal concentrations in food samples from Rize, Turkey

BACKGROUND: Rize in Turkey was contaminated by the Chernobyl accident in 1986. A comprehensive study was planned and carried out to determine the radioactivity levels and heavy metal concentrations in four food categories collected in Rize in 2008, 2009 and 2010. RESULTS: Tomato showed the highest concentration of ²³⁸U, at 9.43 ± 0.128 Bq kg^?1, whereas the lowest concentration of 0.20 ± 0.02 Bq kg^?1 was measured in aubergine samples. The highest concentration of ²³²Th was measured at 3.22 ± 0.29 Bq kg^?1 in grape samples. ⁴⁰K was found to contribute the highest activity in all the food samples. The highest activity concentration of ¹³⁷Cs was 10.20 ± 4.19 Bq kg^?1, for parsley. The average contribution range of each of the heavy metals to the dietary intake was 0.13–9.14, 0.27–34.63, 0.05–3.62, 0.11–14.97, 0.78–8.51 and 0.01–1.57 mg, respectively, for Mn, Fe, Cu, Zn, Ni and As. CONCLUSION: The range of radioactivity levels in food samples of the present study is of no risk to public health. Heavy metal concentrations of Mn, Fe, Cu, Zn, Ni and As obtained were far below the established values by FAO/WHO limits. Copyright © 2011 Society of Chemical Industry     

Effect of monensin in lactating dairy cow diets at 2 starch concentrations

The objective of this study was to determine the effects of monensin (M) supplementation on lactation performance of dairy cows fed diets of either reduced (RS) or normal (NS) starch concentrations as total mixed rations. One hundred twenty-eight Holstein and Holstein × Jersey cows (90 ± 33 d in milk) were stratified by breed and parity and randomly assigned to 16 pens of 8 cows each in a randomized controlled trial. Pens were then randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement of treatments. A 4-wk covariate adjustment period preceded the treatment period, with all pens receiving NS supplemented with 18 g of monensin/t of dry matter (DM). Following the 4-wk covariate adjustment period, cows were fed their assigned treatment diets of NS with M (18 g of monensin/t), NS with 0 g of monensin/t (C), RS with M, or RS with C for 12 wk. Actual starch concentrations for the RS and NS diets were 20.4 and 26.9% (DM basis), respectively. Mean dry matter intake (DMI; 27.0 kg/d) was unaffected by the treatments. Feeding M compared with C and NS compared with RS increased milk yield by 1.3 and 1.5 kg/d per cow, respectively. Milk protein percentage and yield and lactose yield were increased and milk urea nitrogen was decreased for NS compared with RS. Feeding M increased actual and component-corrected milk feed efficiencies (component-corrected milk yield/DMI) and lactose yield and tended to increase milk urea nitrogen compared with C. Milk protein percentage was decreased for M compared with C, but milk fat percentage and yield, protein yield, and lactose percentage were unaffected by M. We observed a tendency for a starch × monensin interaction for milk feed efficiency (actual milk yield/DMI); M tended to increase efficiency more for NS than for RS. Starch and monensin had minimal effects on milk fatty acid composition and yields. Feeding RS decreased milk and protein yields, but component-corrected milk yields and feed efficiencies were similar for RS and NS. Monensin increased feed efficiency and lactation performance for both dietary starch concentrations.     

Results of a producer survey regarding crossbreeding on US dairy farms

Comprehensive surveys were sent to 528 US dairy producers who are currently practicing crossbreeding in their herds. Fifty usable surveys were returned, and the resulting data included qualitative responses regarding facilities, milk recording plans, milk pricing, crossbreeding goals, breed selection, advantages, disadvantages, and future plans. Quantitative variables included producer scores on a 1 to 5 scale for questions regarding ability to fit into the free stalls and milking parlor, milk volume, component percentages, involuntary culling rate, conception rate, calving difficulty, calf mortality, and prices for breeding stock, cull cows, market steers, and bull calves. The most common first generation crosses involved Jersey and Brown Swiss bulls mated to Holstein cows, and backcrosses to one of these parental breeds were most common in the next generation. Producers who responded to this survey desired, and indicated that they achieved, improvements in fertility, calving ease, longevity, and component percentages through crossbreeding. Respondents indicated that crosses involving the Jersey and Brown Swiss breeds had a clear advantage in longevity relative to purebred Holsteins, and conception rates for crosses of Jersey or Brown Swiss sires on Holstein cows were similar to the (high) conception rates typically achieved in purebred Jersey matings. Respondents also indicated that milk composition was improved in the crossbred cattle, but producers cited some difficulties in marketing crossbred breeding stock and bull calves, and noted that the lack of uniformity within the milking herd created management challenges. Based on results of this survey, it appears that crossbreeding can improve the health, fertility, longevity, and profitability of commercial dairy cattle. However, further research is needed regarding specific heterosis estimates for functional traits in crosses involving each of the major dairy breeds, and improvements are needed in systems for recording the ancestry and breed composition of crossbred animals.     

Feeding strategies on certified organic dairy farms in Wisconsin and their effect on milk production and income over feed costs

The purposes of this study were (1) to analyze and categorize certified organic Wisconsin dairy farms based on general farm characteristics and feeding strategies during the course of 2010, and (2) to evaluate herd milk production and income over feed costs (IOFC). An on-site survey containing sections on farm demographics, feeding, grazing, and economics was conducted on 69 farms (12.6% survey response rate). A nonhierarchical clustering method using 9 variables related to general farm characteristics, feed supplementation, and grazing was applied to partition the farms into clusters. A scree plot was used to determine the most appropriate number of clusters. Dry matter intake was approximated based on farmer-reported total amounts of feed consumed (feed offered less refusals). Milk production was evaluated using reported milk rolling herd averages (RHA). Income over feed costs was calculated as milk sales minus feed expenses. The farms in clusters 1 (n = 8) and 3 (n = 32), the large and small high-input farms, respectively, included more feed ingredients in their lactating cow diets and relied more heavily on concentrates than farms in other clusters. Cows on these farms were predominantly Holstein. Clusters 1 and 3 had the highest RHA (6,878 and 7,457 kg/cow per year, respectively) and IOFC ($10.17 and $8.59/lactating cow per day, respectively). The farms in cluster 2 (n = 5) were completely seasonal, extremely low-input farms that relied much more heavily on pasture as a source of feed, with 4 out of the 5 farms having all of their operated land in pasture. Farms in cluster 2 relied on fewer feeds during both the grazing and nongrazing seasons compared with farms in the other clusters. These farms had the lowest RHA and IOFC at 3,632 kg/cow per year and $5.76/lactating cow per day, respectively. Cluster 4 (n = 24), the partly seasonal, moderate-input, pasture-based cluster, ranked third for RHA and IOFC (5,417 kg/cow per year and $5.92/lactating cow per day, respectively). Breeds other than Holstein were used more prevalently on farms in clusters 2 and 4. Results indicated extreme variation in animal breed, structure, and feeding strategies among Wisconsin organic dairy farms. Feeding strategies appeared to be major determinants of RHA and IOFC. These findings may serve current organic and transition farmers when considering feeding management changes needed to meet organic pasture rule requirements or dealing with dietary supplementation challenges.     

A survey analysis of farmer practices and perceptions of zero-grazing on Irish dairy farms

Zero-grazing (ZG; the mechanical harvesting and feeding of fresh grass) is increasingly used in grass-based milk production systems alongside conventional grazing. It allows farmers to supply fresh grass from land parcels that are outside of the main grazing block during seasonal shortages and periods when climatic conditions limit animal grazing opportunities. The objective of this study was to establish an understanding of current ZG practices on Irish dairy farms, to capture farmer perceptions on the implementation of this management practice, and to identify farmer knowledge requirements on ZG. An online survey was distributed and completed by 130 dairy farmers who use or have used ZG. Zero-grazing was used alongside conventional grazing by 92% of respondents. These farms were particularly fragmented, with between 1 and 14 separate land blocks. Respondents felt ZG helped them overcome fragmentation, increase grass use, and extend grass feeding in spring and autumn. However, extra cost and time input associated with ZG were recognized as key challenges. The majority of respondents rated current technical information available on ZG in the Republic of Ireland as “poor” or “very poor,” and knowledge deficits were identified in the areas of cost analysis, grass management and productivity, cow productivity, cow health and nutrition, and soil fertility.     

Ammonia emissions from dairy production in Wisconsin

Ammonia gas is the only significant basic gas that neutralizes atmospheric acid gases produced from combustion of fossil fuels. This reaction produces an aerosol that is a component of atmospheric haze, is implicated in nitrogen (N) deposition, and may be a potential human health hazard. Because of the potential impact of NH₃ emissions, environmentally and economically, the objective of this study was to obtain representative and accurate NH₃ emissions data from large dairy farms (>800 cows) in Wisconsin. Ammonia concentrations and climatic measurements were made on 3 dairy farms during winter, summer, and autumn to calculate emissions using an inverse-dispersion analysis technique. These study farms were confinement systems utilizing freestall housing with nearby sand separators and lagoons for waste management. Emissions were calculated from the whole farm including the barns and any waste management components (lagoons and sand separators), and from these components alone when possible. During winter, the lagoons’ NH₃ emissions were very low and not measurable. During autumn and summer, whole-farm emissions were significantly larger than during winter, with about two-thirds of the total emissions originating from the waste management systems. The mean whole-farm NH₃ emissions in winter, autumn, and summer were 1.5, 7.5, and 13.7% of feed N inputs emitted as NH₃-N, respectively. Average annual emission comparisons on a unit basis between the 3 farms were similar at 7.0, 7.5, and 8.4% of input feed N emitted as NH₃-N, with an annual average for all 3 farms of 7.6 ± 1.5%. These winter, summer, autumn, and average annual NH₃ emissions are considerably smaller than currently used estimates for dairy farms, and smaller than emissions from other types of animal-feeding operations.     

加工精度对稻谷籽粒中重金属含量的影响

研究了稻谷籽粒不同的组织结构中Cd、Pb、As的含量分布,以及不同加工精度对重金属去除率的影响。结果表明,研究样品中Pb的浓度最高,米糠层重金属含量最高。随着加工精度的增加,重金属去除率也随之增加,当碾米120 s后,As总去除率最高,为42.57%,而Cd和Pb的去除率分别为24.38%和41.38%。因此通过砻谷和提高碾米精度,可以去除稻谷中部分重金属。     

AAS法测定重金属含量的不确定度分析

根据纺织品重金属检测的新标准GB/T 17953.1-2006<纺织品重金属的测定第1部分:原子吸收分光光度法>操作规程,酸性汗液条件下萃取出游离重金属,在原子分光光度仪石墨炉上测定其含量,以铅、镉、铬为例,对整个测试过程中各不确定度的分量进行了评定、合成,最后给出了合成不确定度和扩展不确定度,以及不确定度的主要来源.     

A survey on antibiotic usage in dairy herds in Pennsylvania

A survey was conducted (July 2001 to June 2002) on antibiotic usage of 113 dairy herds from 13 counties in Pennsylvania. Fifty percent of dairy farms surveyed maintained antibiotic treatment records. Only 21% of dairy producers had written plans for treating sick animals. Thirty-two percent of dairy producers sought veterinarian advice before administering antibiotics and on most farms (93%), antibiotics were administered by the owner/manager or designated herdsman. Twenty-four percent of the dairy producers said they always completed the course of antibiotic treatment. Any extra-label use of antibiotics was administered only on the guidelines of a veterinarian on majority of the farms. Comprehensive records from 33 dairy farms indicated that antibiotic usage was largest for calves with enteritis (36%) followed by pneumonia in calves (25%) and foot rot in cattle (16%). Twenty-four antibiotics including beta-lactams, spectinomycin, florfenicol, and tetra-cyclines were used on these farms. Beta-lactam antibiotics were used mostly for dry cow therapy, clinical mastitis, and on some farms for pneumonia and metritis. On 18% of the dairy herds surveyed, ceftiofur was used in an extra-label manner to treat mastitis in lactating cattle. On 70% of farms, calves were fed medicated milk replacers containing oxytetracycline and neomycin. The results of this study suggest that antibiotics are used extensively on dairy herds for both therapeutic and prophylactic purposes. Beta-lactams and tetracyclines were the most widely used antibiotics. There is considerable variation in the management practices associated with antibiotic use on dairy farms. It is anticipated that the findings of this survey will permit developing new strategies for prudent use of antibiotics on dairy herds.     

土壤重金属污染现状及其对蔬菜重金属残留影响的研究进展

人类活动与自然条件的共同作用,使得土壤遭受了不同程度的重金属污染,由于食物链的富集作用,对人类健康构成了威胁。"水俣病"和"骨痛病"的发生,引起了世界各国对重金属污染问题的兲注。重金属主要包括生物毒性显著的镉、铬、铅等物质,土壤是蔬菜重金属污染最主要的来源之一。本文主要从土壤重金属污染入手,分析不同地区适宜种植以及需要加强监管的蔬菜种类,幵对重金属的危害迚行总结分析,着重评述了2000～2018年以来,全国部分城市的蔬菜中重金属污染物的含量,幵针对不同富集程度的蔬菜迚行对比。为全国不同地区的蔬菜质量安全监管提供参考,幵指出现阶段存在的问题以及今后的监管方向。     

不同打顶方式对烤烟吸收重金属的影响

为探讨烤烟重金属的调控措施,采用大田试验方法,研究了在土壤重金属复合污染的条件下,不同打顶方式对烤烟吸收重金属的影响.结果表明,处理B初花打顶正常留叶对叶部Cd、Pb、Cr(下部叶和中部叶)调控效果较好.在重金属复合污染条件下,烟株体内重金属Cd、Pb和Hg含量随叶位的升高而增加,Cr含量随叶位的升高而降低,根部含量最...     

进口俄罗斯食品重金属含量检测分析

目的:了解进口俄罗斯食品中多种重金属的污染状况。方法:对黑龙江省两个对俄口岸进口的10类921批俄罗斯食品参照国家标准方法对重金属含量进行了检测分析。结果:除矿泉水外所有样品中均检出铅,检出率为93%(921批),镉的检出率为73.3%(258批),砷的检出率为39.6%(889批),红茶粉和咖啡粉中铜检出率达到了100%,矿泉水中有三批样品钡超过限量标准(0.7 mg/L)。单样本t检验结果显示所检食品的铅、砷、钡水平都低于限量值,腌渍马哈鱼的镉、咖啡粉中的铜水平超标(p<0.05)。结论:大部分进口俄罗斯食品中重金属的含量符合我国的国家标准,部分存在重金属超标问题,建议设立专项监测计划,以提高食品安全性。      

不同重金属胁迫蔬菜产生金属硫蛋白的同源性检测

目的 对不同重金属胁迫蔬菜产生金属硫蛋白(金属硫组氨酸三甲基内盐)进行同源性检测。方法 用Cd-MT免疫家兔产生IgG后, 用不同浓度硫酸铜、乙酸铅、氯化钴、氯化汞等重金属胁迫萝卜幼苗、油白菜和油麦菜诱导产生金属硫蛋白, 通过免疫印迹检测其同源性。结果 Cd-MT与重金属胁迫三种蔬菜所产生的金属硫蛋白具有同源性; 不同浓度的重金属对幼苗中MTs表达量有影响。结论 Cd-MT诱导家兔产生的IgG可用于农产品中重金属污染的检测。     

重金属铅酶联免疫检测方法的研究

制备铅离子多克隆抗体,并建立间接竞争ELISA检测方法。利用双功能螯合剂ITCBE将Pb2+与载体蛋白KLH和BSA偶联在一起,制备免疫抗原与检测抗原;通过免疫新西兰大耳白免成功制备铅多克隆抗体,建立间接竞争ELISA检测方法,并与ICP-MS检测结果进行比较。标准曲线IC50为3.48ng/mL,IC15为0.32ng/mL,与ICP-MS法检测结果的总符合率超过97%。     

养殖鱼体中重金属污染状况评价

对上海郊区两个团头鲂(Megalobrama amblycephala)和鲫鱼(Carassius auratus)标准化养殖场水产品中重金属污染现状展开研究,就其养殖鱼肌肉中的Cu、Pb、Cd、Cr、As和Hg进行测定和分析,利用单项污染指数和综合污染指数法评价养殖水产品重金属污染程度,定量剖析各种重金属的富集情况。实验发现,团头鲂和鲫鱼肌肉中Cu、Pb、Cd、Cr和Hg含量符合《无公害水产品安全要求》,As含量也符合《食品中污染物限量》标准,表明养殖品种并未受到Cu、Pb、Cd、Cr、As和Hg的污染,属于清洁水平。团头鲂和鲫鱼对Cu、Pb、Cd、Cr、As和Hg都有较强的富集能力,其富集系数分别为459、14、17、263、1、24和755、3、8、185、6、23,其中两种鱼对Cu的富集能力最强,其次是Cr。团头鲂对Pb、Cd、Cr和Hg的富集能力要强于鲫鱼,对Cu和As的富集能力弱于鲫鱼。