畜禽钼中毒

对于钼中毒，国外早有报道。1938年Ferguson等人首先发现，英国Somerset地区流行了上百年的一种原因不明的“腹泻病”是由该地区天然高钼牧草引起的。随后世界各地许多学者报道了天然或使用钼肥导致的高钼牧草引起家畜中毒。国内对于本病的研究起步较晚。1981年，樊璞等人报道，赣南大     

牛钼中毒的防治

１病因本病是由于在钼矿及其冶炼厂附近地区，因排放含钼废水的污染，形成高钼土壤，生产高钼饲料，牛采食了这类饲料而引起中毒。２症状病牛主要表现有色被毛褪色、下痢、跛行、受胎率下降、红细胞减少等症状。有色被毛褪色：这是最引人注目的症状，主要是有色被毛白色化，９２％的病牛有这种变化，黄色被毛变成棕色，到处可见脱毛部位，奶牛在眼圈周围特别明显，看起来像戴眼镜似的。拿一根褪色部位的毛观察，发现白色和黑白部分交替，白色部分较细易折断。下痢：出现下痢症状的占发病牛的８０％，其症状的程度因个体差异而不同，一般育成…     

耕牛钼中毒的研究初报

我省某地区,由于钨钼选矿废水——尾砂水——的污染,形成高钼土壤,生产高钼饲草。耕牛因摄取高钼饲料和含钼饮水而发生钼中毒。临床上以持续性腹泻、皮肤发红和被毛褪色为特征。每年7月呈爆发流行。水牛比黄牛更为易感。水牛的发病率在95％以上,死亡率约为33％;黄牛发病率约为50％,死亡率约为10％。口服硫酸铜进行防治,效果良好。     

家畜钼营养研究进展

自从Ferguson(1938)报道了高钼饲料与反刍动物(腹泻病)的关系以后,Richert等(1953)又发现了钼作为黄嘌呤氧化酶和醛氧化酶的成分是一种必需的营养因子,同时还发现钼是亚硫酸盐氧化酶的成分,也是瘤胃微生物的促进剂。随后,相继有人报道了反刍动物钼中毒,鸡和火鸡的钼缺乏症。我国也于1981年首次报道了耕牛的钼中毒,并已开始了这方面的研究。在人的营养方面,国内已有不少报道。本文对近十年来有关钼营养研究所取得的进展作一简要综述。一、钼的生物学作用 1.钼的主要生化功能是形成三种重要的酶:黄嘌呤氧化酶、醛氧化酶和亚硫酸盐氧化     

钼及钼铜联合对小鼠肝脏、肾脏、睾丸细胞微核率的影响

为探讨高钼条件下钼对小鼠组织的损伤作用和铜对钼中毒的保护作用,实验采用昆明ICR系健康雄性小白鼠36只,随机分成6组,分别自由饮用含有0 mg/l Mo、200 mg/l Mo、400 mg/l Mo、20 mg/lCu2+、20 mg/l Cu2++200 mg/l Mo和20 mg/l Cu2++400 mg/l Mo的水溶液(以Na2MoO4.2H2O和CuSO4形式)16周。实验期末将小鼠处死,取肝脏、肾脏和睾丸,研磨涂片,计算微核率。实验结果表明:钼暴露组中,随着钼剂量的增加,肝脏、肾脏和睾丸细胞微核率都呈增大的趋势,且显著高于对照组(P<0.05);钼补铜组与钼暴露组相比较发现,钼补铜组微核率低于钼暴露组,但差异不显著(P>0.05)。因此,高钼暴露可引起小鼠肝脏、肾脏和睾丸细胞的损伤,而补铜可在一定程度上减轻这种损伤。     

钼的毒性与反刍动物钼中毒

本文综述了微量元素钼对反刍动物毒性的研究结果,如:钼的化学特性、钼在饲料与反刍动物体内的含量与分布、钼的生物学作用、钼在反刍动物体内的吸收、代谢及与其它元素间的互作等。最后阐述了反刍动物钼营养需要量、饲料中钼的最大允许量及反刍动物钼中毒的防治。     

牛、羊钼中毒的病因分析、诊断和防治

钼是一种能形成钼酶的必需微量营养元素,它对所有动物的健康起着重要作用。反刍动物从日粮中摄入过量钼,部分动物可引起继发性低铜症。大剂量摄入钼引起的钼中毒较罕见。反刍动物比非反刍动物对钼毒性更敏感,其他种类的动物对钼的抵抗力相对较强。现分析牛、羊钼中毒的病因、症状,并提出诊断要点及防治方法。     

家畜钼中毒的病因、症状与诊治

1病因分析 土壤高钼可使生长的牧草钼含量过高，动物采食后引起钼中毒，见于腐植土和泥炭土。另外，植物中的钼含量还与土壤的酸碱度有关，碱性土壤中可溶性钼较多，容易被植物吸收，在含钼较低的碱性土壤上生长的植物钼含量也较高，而在强酸性富钼土壤上生长的牧草，其钼含量则较低。应用过量钼肥及石灰可增加植物对钼的吸收，动物容易发生与高钼有关的铜缺乏。     

钼与家畜营养

一、钼在家畜营养中的意义 钼在动物体内的生物化学机制除与铜反应外,它和黄嘌岭氧化酶、醛氧化酶以及亚硫酸盐氧化酶的形成与所具有的特异活性相关。钼还参与嘌呤氧化酶同细胞色素C的反应,促进被醛氧化酶催化的细胞色素C的还原。在动物体组织中,这种酶的浓度与采食日粮中钼的含量有关。     

绵羊实验性钼中毒研究——Ⅰ.绵羊钼中毒动物模型的建立

20只成年绵羊按体重随机分成5组,每组4只。Ⅰ、Ⅱ、Ⅲ组每只羊日给钼量分别按60、30、15mg/kg体重计,以钼酸铵水溶液经口投服;Ⅳ组羊日给钼量同Ⅲ组,另加喂7g硫酸钠;Ⅴ组不作处理。实验期限150d。结果表明,健康绵羊日投钼高于30mg/kg体重或15mg/kg体重并加喂7g硫酸钠方能产生中毒效应。临床特征是体况不佳、跛行、腹泻、脱毛、增重缓慢或消瘦。病理学特征是中毒性肝病和代谢性骨病。加喂硫酸盐能加剧钼中毒效应。在超高钼摄入时,钼对心脏和骨骼等靶器官有直接损害作用。未见中毒羊存在钼诱导的继发性铜缺乏。     

饮用天然高钼水诱发的钼中毒耕牛主要生物酶测定

本研究对高钼饮水诱导钼中毒的耕牛及对照牛的血浆及组织（肝脏、肺脏、肾脏、脾脏、心脏、肌肉）中超氧化物歧化酶（ＳＯＤ）、黄嘌呤氧化酶（ＸＯＤ）及谷胱甘肽过氧化物酶（ＧＳＨ－ＰＸ）等３种生物酶活性进行了对比分析测定。结果表明，血浆和组织中ＳＯＤ、ＸＯＤ及ＧＳＨ－ＰＸ均随着钼中毒的加重其活性显著下降。这３种生物酶是钼中毒比较灵敏且相关较大的生化指标，对钼中毒具有一定诊断价值；测定ＳＯＤ。ＸＯＤ、ＧＳＨ－ＰＸ可作为钼中毒监测的重要手段。     

对畜禽粪便污染治理的一些看法

本文认为我国水环境污染难以根本改善的原因是只重视工业废水和生活污水的治理而忽视了畜禽粪尿污染水环境的治理。指出大中城市及人口稠密地区要把畜禽养殖的环保工作放在重要位置来抓。同时提出了畜禽粪尿治理工作的指导思想和工作步骤。     

Substances with pharmacological effects including hormonally active substances in the environment: identification of tetracyclines in soil fertilized with animal slurry

Many drugs used in human medicine are detectable in surface waters from the low to the very low microgram/L concentration range. In drinking waters only some of these substances were detected, the concentrations are usually an order of magnitude below the concentrations found in surface waters. A risk assessment of long time effects caused by a permanent intake of these low concentrations of drug residues cannot be done at this time. Hormonally active substances in surface waters may present an ecotoxicological risk, there are many investigations currently under way to assess this problem. Our investigations show for the first time that residues of the commonly used veterinary drugs tetracycline and chlortetracycline can be detected in the surface of soil (0-40 cm) fertilized with animal slurry. The maximum concentrations found were 32.3 micrograms/kg and 26.4 micrograms/kg respectively. Leaching of these compounds into seeping water sampled at a depth of 80-140 cm could not be detected with the methods employed. The significance of the detected antibiotic residues in soil samples for the quality of food of animal origin or any ecotoxicological consequences needs further investigations. The knowledge about the concentrations of veterinary drug residues resulting from animal husbandry in the environment is the first step for such a risk assessment.     

Anthrax outbreak in a Swedish beef cattle herd - 1st case in 27 years: Case report

After 27 years with no detected cases, an outbreak of anthrax occurred in a beef cattle herd in the south of Sweden. The outbreak was unusual as it occurred in winter, in animals not exposed to meat-and-bone meal, in a non-endemic country.The affected herd consisted of 90 animals, including calves and young stock. The animals were kept in a barn on deep straw bedding and fed only roughage. Seven animals died during 10 days, with no typical previous clinical signs except fever. The carcasses were reportedly normal in appearance, particularly as regards rigor mortis, bleeding and coagulation of the blood. Subsequently, three more animals died and anthrax was suspected at necropsy and confirmed by culture and PCR on blood samples.The isolated strain was susceptible to tetracycline, ciprofloxacin and ampicillin. Subtyping by MLVA showed the strain to cluster with isolates in the A lineage of Bacillus anthracis.Environmental samples from the holding were all negative except for two soil samples taken from a spot where infected carcasses had been kept until they were picked up for transport.The most likely source of the infection was concluded to be contaminated roughage, although this could not be substantiated by laboratory analysis. The suspected feed was mixed with soil and dust and originated from fields where flooding occurred the previous year, followed by a dry summer with a very low water level in the river allowing for the harvesting on soil usually not exposed. In the early 1900s, animal carcasses are said to have been dumped in this river during anthrax outbreaks and it is most likely that some anthrax spores could remain in the area.The case indicates that untypical cases in non-endemic areas may be missed to a larger extent than previously thought. Field tests allowing a preliminary risk assessment of animal carcasses would be helpful for increased sensitivity of detection and prevention of further exposure to the causative agent.     

Melioidosis in intensive piggeries in south eastern Queensland

The epidemiology of melioidosis was investigated in 8 intensive piggery units which used water from the same river in south eastern Queensland. In 3 consecutive years cases of disease followed heavy rainfall and flooding. Although Pseudomonas pseudomallei was not isolated from water or soil samples the water supply was suspected as the source of infection. Affected pigs were detected at slaughter by the presence of abscesses most commonly in the bronchial lymph nodes (40%) and spleen (34%). One hundred and fifty nine cases were observed at slaughter from a total of 17,397 animals at risk. Infection by inhalation of water aerosols derived from nipple drinkers, hose sprays and a water misting cooler was considered to be responsible for the bronchial lymph node lesions. These outbreaks occurred outside the area in which melioidosis is generally regarded as being endemic.     

PCR技术检测饲料中沙门氏菌的应用研究

用聚合酶链反应(PCR)技术检测饲料中沙门氏菌,对已知被沙门氏菌污染的动物饲料培养物均能检出阳性,说明本方法对检测饲料中沙门氏菌具有特异性高、灵敏、快速等特点,适用于快速、准确地检测饲料中沙门氏菌的需要。     

松嫩草原中南部退化羊草草地生态恢复与重建中大型土壤动物群落生态特征

选取吉林省大安市姜家甸草场清塘羊草草地、三年生人工碱茅草地和一年生人工碱茅草地为研究样地,2002年分7月、8月和10月3次对样地野外采样.共捕获大型土壤动物4 190只,分别隶属3门7纲16目18类.土壤动物群落间个体密度有一定的差异,鞘翅目在各生境中都有较高个体密度分布,显示其是该草原地带大型土壤动物的特征性类群.土壤动物类群和个体数垂直分布表聚程度群落间有较大不同.土壤动物群落生物多样性存在空间分异和明显季节间波动,人为水肥干预可以增加土壤动物群落的生物多样性.DG多样性指数更适合表达不同演替阶段土壤动物群落的差异,大型土壤动物群落生物多样性能够指示退化草地生态系统恢复与重建过程.     

柱花草硼、钼微肥施用效果的研究

在热带地区土壤中硼、钼微量元素缺乏较为普遍.采用田间试验的方法,针对柱花草(Stylosanthes guianensis)喷施硼、钼微肥效果进行研究.结果表明,在土壤缺硼、钼的情况下,适量喷施钼、硼肥均能增加柱花草的产量.其中喷施钼增产效果较明显,其次为硼肥.与对照相比较,喷施钼肥和硼肥柱花草产量分别增加了2 475...     

Nocardial infections of animals in New Zealand, 1976–78

Nocardiaspecies that are common in the soil environment can cause disease in man and animals. These infections are usually considered rare, and there have been only four cases of animal disease previously reported in the New Zealand literature. A limited survey, with the co-operation of staff from animal health laboratories, revealed a further 34 cases of Nocardia infection between 1976–78, and this figure is likely to be conservative. Twenty-six cases were mastitic infections and one was an isolate from a bovine placenta; the majority of infected animals were reported from the South Auckland and Waikato regions. The remaining cases were fatal infections of cats, dogs and a seal. Diagnostic tests on the causative organisms from 27 cases for which cultures were available all proved to be N. asteroides strains. Improved epidemiological data may help relate occurrence of disease in animals to the distribution of Nocardia in nature, but this is dependent on recognition of the organism by the specialists involved in the field and laboratory. Without epidemiological data, it will not be possible to evaluate the effects on animals of increasing the multiplication of Nocardia, for example by adding sewage sludge to soil.     

Food safety achieved through herd management

Most animal-derived food products originate from production chains consisting of a series of well-defined, separate production steps. Undesired events affecting food safety can principally occur at any point within the production chain. The principle of integrated food safety assurance from stable to table has therefore been established. The livestock holding has thus to be understood as a fix element of the production chain, and the producer has to accept a part of the responsibility for food safety. On a farm, food safety can be negatively affected by animal feed (microbiological or toxicological contamination), management (hygiene, stocking density, cleaning and disinfecting), veterinary treatments (use of antibiotics) and recycling of slurry. Most relevant practices can be summarised under the standard of "good farming practice". HACCP programmes as they are applied in the processing industries could in principle also be used at the farm level. Influential management steps would need to be identified and controlled. This approach is, however, still in its infancy at present. Using the current monitoring systems, microbiological and toxicological problems in food are difficult to be identified before the end of the production chain. As the cause of a problem can be found at the farm level, traceability of products through the production chain is essential. In Switzerland, traceability of animals is realised using compulsory animal identification and the animal movement database. Using this link, information on the health status of a herd could be made available to the slaughterhouse in order to classify animals into food-safety risk categories. This principle is a key element in the ongoing discussion about visual meat inspection in Europe and elsewhere.