Effects of stable dust on farm animals--a review

The relationship between air quality--its dust content--and respiratory diseases of animals in the food industry and otherwise is examined. The correlation between dust content and incidence of disease in farm animals is also discussed. Lesions caused either directly or indirectly by dust-transported microorganisms are reviewed. Effects of dust on animal performance are included. This review is an attempt to compile available information on the natural occurrence of stable dust and the possibilities for its measurement and control.     

Coxiella burnetii associated reproductive disorders in domestic animals-a critical review

The bacterium Coxiella burnetii has been detected in the fetal membranes, birth fluids and vaginal mucus, as well as in the milk and other excretions of several domestic mammals. The finding of C. burnetii in association with abortion, parturition and in the postpartum period has led to the hypothesis that C. burnetii causes a range of reproductive diseases. This review critically evaluates the scientific basis for this hypothesis in domestic mammals.The review demonstrates a solid evidence for the association between C. burnetii infection and sporadic cases of abortion, premature delivery, stillbirth and weak offspring in cattle, sheep and goats. C. burnetii induced in-herd epidemics of this complete expression of reproductive failure have been reported for sheep and goats, but not for cattle. The single entities occur only as part of the complex and not as single events such as generally increased stillbirth rate. Studies show that C. burnetii initially infects the placenta and that subsequent spread to the fetus may occur either haematogenous or by the amniotic-oral route. The consequences for the equine, porcine, canine and feline conceptus remains to the elucidated but that infection of the conceptus may occur is documented for most species. There is no solid evidence to support a hypothesis of C. burnetii causing disorders such as subfertility, endometritis/metritis, or retained fetal membranes in any kind of domestic animal species.There is a strong need to validate non-pathology based methods such as polymerase chain reaction for their use in diagnostic and research in relation to establishing C. burnetii as the cause of abortion and to adapt an appropriate study design and include adequate control animals when linking epidemiological findings to C. burnetii or when evaluating effects of vaccination in production herds.     

Circulation of prions within dust on a scrapie affected farm

Prion diseases are fatal neurological disorders that affect humans and animals. Scrapie of sheep/goats and Chronic Wasting Disease (CWD) of deer/elk are contagious prion diseases where environmental reservoirs have a direct link to the transmission of disease. Using protein misfolding cyclic amplification we demonstrate that scrapie PrP^Sc can be detected within circulating dusts that are present on a farm that is naturally contaminated with sheep scrapie. The presence of infectious scrapie within airborne dusts may represent a possible route of infection and illustrates the difficulties that may be associated with the effective decontamination of such scrapie affected premises.     

Exposure of workers to dust and bioaerosol on a poultry farm

Poultry houses are known for generating excessive dust, which originates from bedding materials, fiberglass insulations, feed, dried fecal materials, and feather particles. Dust may contain microorganisms, including endotoxins, fungi, and bacteria, that may affect living things when inhaled. Dust that contains living organisms is referred to as bioaerosol, and its particle size may range from 0.5 to 100 µm. Respirable dust, which has an aerodynamic diameter of less than or equal to 4 µm, can travel to and be deposited in the gas-exchange region of the human respiratory system. This is of particular concern because of the greater health hazard that it poses. The concentrations of respirable dust and bioaerosol measured with samplers attached to the workers (worker-exposure concentrations) were more than 3 (0.82 vs. 0.26 mg/m³) and one-and-a-half times (58.46 vs. 33.79 cfu/m³) higher, respectively, than the concentrations measured with stationary samplers indoors. The respirable dust is still below the permissible exposure limit (5 mg/m³) set by the Occupational Safety and Health Administration, but beyond the limit for animal buildings suggested by other researchers.     

益生素联用对蛋鸭养殖场水体水质的影响

饲养蛋鸭时,分别在池水和饮水器中添加光合菌和枯草芽胞杆菌2种益生素,旨在研究益生素联合作用对养殖场水体水质的净化作用。试验采用同一日龄、健康的缙云麻鸭300只随机分成5组,每组3栏,每栏20只。15 d预试期和54 d正试期。试验组Ⅰ:不添加任何微生态制剂;试验组Ⅱ:仅在池水中加20 mg/L光合菌;试验组Ⅲ:饮水中添加125 mg/L枯草芽孢杆菌,池水中添加20 mg/L光合菌;试验组Ⅳ:饮水中添加250 mg/L枯草芽孢杆菌,池水中添加20 mg/L光合菌;试验组Ⅴ:饮水中添加375 mg/L枯草芽孢杆菌,池水中添加20 mg/L光合菌,其中试验组Ⅰ、Ⅱ作为对照组。结果表明:在动物饲养的同时,益生素联用能够在一定程度上降低水中总有机碳、无机碳、总碳、总氮以及总磷的含量,且随饲养时间的增加而增强,而光合菌单独处理的作用效果不佳;无论是单独添加光合菌还是益生素联用对水体中碳氮比的影响较小;试验还表明:益生素联用对水中有机质的降解能力有限,不能有效降解畜禽养殖过程中的粪便持续排放。     

Air hygiene in stables. 1: Effects of stable design, ventilation and management on the concentration of respirable dust

The concentration of fungal spores, the main constituents of respirable dust in stables, is determined by rates of release from fodder and bedding and rate of clearance, principally by ventilation. This paper outlines the principles that govern the application of natural ventilation to the control of air hygiene in barns and individual boxes for horses. When release rates are low, ventilation rates over four air changes per hour are satisfactory. Ventilation was satisfactory in individual boxes but usually unsatisfactory in barns and specific recommendations are made for improvement. Preliminary observations in stables with clean, well-managed bedding revealed only small differences between straw, wood shavings and paper. In these circumstances hay tended to be the major source of respirable spores.     

Sustainability in farm animal breeding: a review

The paper examines the notion of sustainable farm animal breeding. A brief explanation of why sustainability matters is offered first. After this, the historical development of the concept of sustainability is charted. The authors then turn to review published literature with a bearing on sustainable farm animal breeding. Little has been written directly on the subject: the requirements of sustainable farm animal breeding await serious clarification. The paper looks at SEFABAR (Sustainable European Farm Animal Breeding and Reproduction), a project designed to identify sustainable practices in farm animal breeding which ran for nearly 3 years from 2000. In this project commercial breeders and breeding scientists were required, with the professional assistance of bioethicists, economists, social scientists and NGO representatives, to develop a definition of sustainable farm animal breeding. The authors describe initial attempts to carry out this task. They then describe a general method of building a definition of sustainability—the so-called concern-criteria-indicators method—that was used in SEFABAR to good effect. They note the progress that was made once this method was introduced. Finally, the importance of communication is explained. The authors suggest that the concept of sustainability can be effectively used to organise and facilitate dialogue between stakeholders, including the breeding industry and society as a whole.     

Role of leptin in farm animals: a review

The discovery of hormone leptin has led to better understanding of the energy balance control. In addition to its effects on food intake and energy expenditure, leptin has now been implicated as a mediator of diverse physiological functions. Recently, leptin has been cloned in several domestic species. The sequence similarity suggests a common function or mechanism of this peptide hormone across species. Leptin receptors are expressed in most of tissues, which is consistent with the multiplicity of leptin functions. The main goal of this review was to summarize knowledge about effect of leptin on physiology of farm animals. Experiments point to a stimulatory action of leptin on growth hormone (GH) secretion, normal growth and development of the brain. Surprisingly, leptin is synthesized at a high rate in placenta and may function as a growth factor for fetus, signalling the nutritional status from the mother to her offspring. Maturation of reproductive system can be stimulated by leptin administration. Morphological and hormonal changes, consistent with a major role of leptin in the reproductive system, have also been described, including the stimulation of the release of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin. Leptin has a substantial effect on food intake and feeding behaviour in animals. Administration of leptin reduces food intake. Its level decrease within hours after initiation of fasting. Leptin also serves as a mediator of the adaptation to fasting, and this role may be the primary function for which was the molecule evolved.     

胞外多糖pullulan处理养猪场污水效果分析

用pullulan处理养猪场污水 ,结果表明 :污水的稀释倍数与pullulan的添加量对处理效果有极显著的影响。当Pullulan在 2倍稀释污水中的添加量达到 3mg/kg时 ,污水的生物需氧量 (BOD)、化学耗氧量 (COD)、总P、N的去除率达到 90 %以上 ;大肠杆菌的去除率达到 95 %以上 ,透过率也从 8%上升到 92 %。     

Effects of aerosolized feedyard dust that contains natural endotoxins on adult sheep

OBJECTIVE: To determine the clinical, clinicopathologic, and histologic effects of aerosolized feedyard dust that contains natural endotoxins on adult sheep. ANIMALS: Eighteen 3-year-old Saint Croix sheep. PROCEDURE: A prospective randomized controlled study was conducted. There were 2 treatment groups (dust-endotoxin group, n = 9; control group, 9). Aerosolized feedyard dust was provided continuously during a 4-hour period for each application (once in week 1, 3 times in week 2, and 7 times in week 3) to sheep in a semiairtight tent. All sheep were euthanatized and necropsied 8 hours after the treatment group received the last dust treatment. Variables measured before and after each dust treatment were rectal temperature, total WBC count, and concentrations of fibrinogen and haptoglobin. RESULTS: Mean amount of dust administered during each treatment was 451 g/4 h. Filter collection indicated 51 mg of dust/m3 and 7,423 ng of endotoxin. Mean rectal temperature at 8 hours (40.4 C) and mean WBC counts 12 and 24 hours after dust treatment were significantly higher for the treated group than the means of the respective variables for the control group. Similar responses were observed with repeated dust-endotoxin treatments; however, with each subsequent treatment, there was a diminished response. Sheep in the treatment group had generalized alveolar septal thickening and hypercellularity. CONCLUSIONS AND CLINICAL RELEVANCE: Feedyard dust induced a temporary febrile response and leukocytosis in sheep in the treatment group. Exposure to dust that contains endotoxins may be a stressor preceding acute infectious respiratory tract disease of marketed sheep.     

Effects of inhalation of dust and endotoxin on respiratory tracts of pigs.

OBJECTIVE: To assess the effects of inhalation of feed flour dust and dustborne endotoxin on respiratory tracts of pigs. ANIMALS: 29 healthy Belgian Landrace pigs. PROCEDURE: Pigs housed in an environmental chamber were exposed for 6 days to feed flour dust (1 to 15 mg/m3) and dustborne endotoxins (50 to 2,500 ng/m3). Effects were evaluated by measuring albumin concentration, lactate dehydrogenase (LDH) activity, cell composition of nasal lavage (NL) and bronchoalveolar lavage (BAL) fluids and blood, and percentages of CD4+ and CD8+ T lymphocytes in blood and lavage fluids. Dustborne endotoxin was obtained by mixing endotoxins from Escherichia coli (serotype O127:B8) with feed flour before spraying the flour in the environmental chamber. RESULTS: Exposure did not affect cell composition of NL fluid or blood. Total cell counts of BAL fluids were increased in all groups exposed to dust. Macrophage counts were increased in pigs exposed to inhalable dust concentrations as low as 4.4 mg/m3, and lymphocyte counts were increased in groups exposed to high dust concentrations. Percentages of CD4+ and CD8+ T lymphocytes in blood and lavage fluids were unchanged. In all dust-exposed groups, albumin content of BAL fluid was increased, whereas LDH activity was unaffected. Macrophage and lymphocyte infiltration and edema in the bronchi were identified by light microscopy. Effects attributable to E. coli endotoxin exposure were not identified. CONCLUSIONS: Inhalation of feed flour dust did not affect nasal mucosa but did induce bronchial airway inflammation. Dustborne endotoxins did not have effects attributable to endotoxin alone.     

The dust and microbial content in a horse stable during the use of a dust-binding agent

Dust in horse barns is assumed to contribute to pulmonary disease, it is attempted to reduce the airborne dust by soaking or sprinkling the hay before feeding. Both means cause considerable efforts and increase the relative humidity of the air. This is why a commercial dust-binding agent (Revesto pur) was used in a pilot investigation which was carried out during 2 weeks - one week for control and one week using the agent - in a private horse barn where three horses were regularly stable. The airborne dust was measured by a continuously working instrument. Once a day (7.00 a.m.) the number of airborne germs was estimated. The dust is reduced to 0.03 mg/m3 during the night, (8.00 p.m. to 6.00 a.m.), as compared to the control (0.05 mg/m3). However, the total dust content during 24 h increases after spraying with the aid of the instruments supplied by the manufacturer to 0.12 mg/m3 (control 0.07 mg/m3). The airborne germs show a decreasing tendency after application of the agent. The use of the sprayers is very time-consuming, their use inside of the barn obviously increases the particles in the air. Thus, it seems advisable to spray outside of the stable. Further investigations are necessary in order to evaluate whether the reduction of the dust during night which was indicated in this study may have a positive clinical effect.     

Halal slaughtering,welfare, and empathy in farm animals: a review

Pre-slaughter and slaughter stressors are considered major concerns in animal welfare. Halal slaughtering method is considered one of the slaughtering stressors in livestock. This method seems to cause fear followed by stress in animals mainly due to inhuman handling. In this review, empathy and animal welfare are discussed in light of Islamic sharia and has further linked with animal’s physiology and behavioral responses during slaughtering. Islam as a religion forbids slaughtering an animal in front of another animal as through optic, olfactory, and cochlear senses animals can perceive the stress state of conspecifics. This suggests and strengthens the hypothesis that animals being slaughtered in front of each other may produce stress in them. This argument further leads to a claim that animals can experience empathy of each other through olfaction of semiochemicals (stress pheromones) emitted from animals slaughtered in the stressful condition that can be detected by other animals in abattoirs. Hence, research is needed to find out these specific stress pheromones and legislation needs to be adopted in slaughterhouses to isolate the areas of butchery from slaughtering lines to ensure proper guidelines of Halal slaughtering in slaughterhouses.     

养殖场的消毒管理

近几年来,在养殖业蓬勃发展的同时,畜禽疾病也在呈现区域性的频发,为了有效地控制畜禽疾病,除了利用疫苗、药物防治以外,合理地利用消毒药也是控制畜禽疾病一个很好的措施,因为消毒药可以直接对病原微生物进行杀灭.怎样算是合理利用消毒药,笔者根据实践提出几点想法.