A standard procedure for measuring rodent bedding particle size and dust content

Hardwood dust can cause dermatitis, respiratory disease, allergies and nasal cancer in humans. A major concern with animal hardwood bedding is its dust content and its possible effects on animals and animal technicians. Previous reports on the quality control of rodent bedding did not specify sample size or shake time for measuring bedding particle size and dust content. These variables could alter particle size analyses. In an effort to more accurately characterize bedding particle size and dust content, 50g and 100g samples of hardwood bedding were shaken for 0.5, 1, 2, 3, 4, or 5 minutes in a portable sieve shaker containing U.S. standard sieves (Nos. 8, 20, 30 and 50) to determine optimum sample size and shake time. Significant differences (P less than 0.05 or greater) were observed in the percent of bedding retained on a No. 8 sieve when 50g and 100g samples were taken for 30 seconds or for 1 minute. Samples shaken for 2 or more minutes did not show any statistical differences in the percent of bedding which was retained on or passed through the different sieves. Major differences occurred in the percent of bedding which was retained or passed through the different sieves, when the shake time was varied from 0.5 to 5 minutes. These results indicated that 0.5 or 1 minute was definitely not enough time to accurately measure bedding particle size and dust content and that the sample size and shake time must be consistent in order to accurately compare the particle size and dust content of different shipments of bedding or to compare bedding from different vendors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rats' preferences for corn versus wood-based bedding and nesting materials

Corn by-products can be used as bedding and nesting products. Corn-cob bedding resists ammonia build-up and corn-husk nesting material resists dampness. It is not clear whether these advantages are at the expense of animal comfort. Corn cob was compared to aspen chip bedding, and corn husk to paper strip nesting material. Data from 20 rats with differential early bedding experience suggested that they prefer aspen chip, but are also biased towards the bedding they were raised on. Data from 10 rats with no prior nesting material experience suggested that paper strip was preferred over cornhusk. Thus, corn-cob products are not recommended except in situations where air quality and/or flooding are significant problems.     

实验动物垫料的标准化

垫料与实验动物关系密切,是对实验动物产生直接作用和影响的环境因素.本文从实验动物垫料的种类和消毒、垫料质量控制与评价体系的建立、垫料的商品化等方面的问题进行探讨.为实验动物垫料的研发和完善实验动物国家标准提供重要参考依据.     

Technological advances in temperate hardwood tree improvement including breeding and molecular marker applications

Hardwood forests and plantations are an important economic resource for the forest products industry worldwide and to the international trade of lumber and logs. Hardwood trees are also planted for ecological reasons, for example, wildlife habitat, native woodland restoration, and riparian buffers. The demand for quality hardwood from tree plantations will continue to rise as the worldwide consumption of forest products increases. Tree improvement of temperate hardwoods has lagged behind that of coniferous species and hardwoods of the genera Populus and Eucalyptus. The development of marker systems has become an almost necessary complement to the classical breeding and improvement of hardwood tree populations for superior growth, form, and timber characteristics. Molecular markers are especially valuable for determining the reproductive biology and population structure of natural forests and plantations, and the identity of genes affecting quantitative traits. Clonal reproduction of commercially important hardwood tree species provides improved planting stock for use in progeny testing and production forestry. Development of in vitro and conventional vegetative propagation methods allows mass production of clones of mature, elite genotypes or genetically improved genotypes. Genetic modification of hardwood tree species could potentially produce trees with herbicide tolerance, disease and pest resistance, improved wood quality, and reproductive manipulations for commercial plantations. This review concentrates on recent advances in conventional breeding and selection, molecular marker application, in vitro culture, and genetic transformation, and discusses the future challenges and opportunities for valuable temperate (or “fine”) hardwood tree improvement.     

Escherichia coli O157:H7 in environments of culture-positive cattle

Outbreaks of Escherichia coli O157:H7 disease associated with animal exhibits have been reported with increasing frequency. Transmission can occur through contact with contaminated haircoats, bedding, farm structures, or water. We investigated the distribution and survival of E. coli O157:H7 in the immediate environments of individually housed, experimentally inoculated cattle by systematically culturing feed, bedding, water, haircoat, and feed bunk walls for E. coli O157:H7 for 3 months. Cedar chip bedding was the most frequently culture-positive environmental sample tested (27/96 or 28.15%). Among these, 12 (44.0%) of positive bedding samples were collected when the penned animal was fecal culture negative. Survival of E. coli O157:H7 in experimentally inoculated cedar chip bedding and in grass hay feed was determined at different temperatures. Survival was longest in feed at room temperature (60 days), but bacterial counts decreased over time. The possibility that urine plays a role in the environmental survival of E. coli O157:H7 was investigated. Cedar chip bedding moistened with sterile water or bovine urine was inoculated with E. coli O157:H7. Bedding moistened with urine supported growth of E. coli O157:H7, whereas inoculated bedding moistened with only water yielded decreasing numbers of bacteria over time. The findings that environmental samples were frequently positive for E. coli O157:H7 at times when animals were culture negative and that urine provided a substrate for E. coli O157:H7 growth have implications for understanding the on-farm ecology of this pathogen and for the safety of ruminant animal exhibits, particularly petting zoos and farms where children may enter animal pens.     

Bacterial concentrations in bedding and their association with dairy cow hygiene and milk quality

Comparison of bacterial counts (BCs) among common bedding types used for dairy cows, including straw, is needed. There is concern that the microbial content of organic bedding is elevated and presents risks for dairy cow udder health and milk quality. The objectives of this study were to investigate: (1) % DM and BCs (Streptococcus spp., all gram-negatives and specifically Klebsiella spp.) in different types of bedding sampled, and to investigate housing and farm management factors associated with % DM and BCs; (2) if bedding type was associated with hygiene of cow body parts (lower-legs, udder, upper-legs and flank) and housing and management factors associated with hygiene and (3) bedding types associated with higher BCs in cow milk at the farm level and bulk tank milk and management factors that were associated with highest BCs. Seventy farms (44 free-stall and 26 tie-stall) in Ontario, Canada were visited 3 times, 7 days apart from October 2014 to February 2015. At each visit, composite samples of unused and used bedding were collected for % DM determination and bacterial culture. Used bedding samples were collected from the back third of selected stalls. Data were analyzed using multivariable linear mixed models. Bedding classification for each farm were: new sand (n = 12), straw and other dry forage (n = 33), wood products (shavings, sawdust; n = 17) and recycled manure solids (RMSs)-compost, digestate (n = 8). In used bedding, across all bedding samples, sand was driest, compared to straw and wood, and RMS; higher % DM was associated with lower Streptococcus spp. count. Streptococcus spp. and all Gram-negative bacteria counts increased with increasing days since additional bedding was added. Gram-negative bacteria counts in used bedding varied with type: RMS = 16.3 ln colony-forming units (cfu)/mL, straw = 13.8 ln cfu/mL, new sand = 13.5 ln cfu/mL, and wood = 10.3 ln cfu/mL. Klebsiella spp. counts in used bedding were lower for wood products (5.9 ln cfu/mL) compared to all other bedding types. Mean cow SCC tended to be higher on farms with narrower stalls. Farms with mattress-based stalls had a higher prevalence of cows with dirty udders compared to those using a deep bedding system (often inorganic sand). Wider stalls were associated with lower bulk milk bacteria count. Lower % DM of used bedding was associated with higher bulk milk bacteria count. In conclusion, bedding management may have a profound impact on milk quality, bacterial concentrations in the bedding substrates, and cow hygiene.     

Microbial cell wall product contamination of bedding may induce pulmonary inflammation in rats

To test the hypothesis that airborne microbial cell wall components could induce an inflammatory response in the lungs, measurements were made of the amounts of bacterial endotoxin and (1-->3)-beta-D-glucan in laboratory animal bedding materials. Groups of rats were exposed by inhalation to airborne endotoxin, (1-->3)-beta-D-glucan or a combination of the two for 5 weeks. The results demonstrated that measurable amounts of endotoxin and (1-->3)-beta-D-glucan could be detected in the different bedding materials. In contrast to animals at delivery, those kept on bedding for 5 weeks showed moderate inflammatory reactions in the lung. These were most pronounced among animals exposed to endotoxin and (1-->3)-beta-D-glucan. The results suggest that further studies need to be undertaken to elucidate the role of microbial cell wall products in the development of inflammatory lung responses among research animals.     

Use of soft hydrothermal processing to improve and recycle bedding for laboratory animals

Cage bedding for laboratory rodents can influence animal wellbeing and thus the experimental data. In addition, a large amount of used bedding containing excrement is discharged as medical waste from life science institutes and breeding companies. We developed a ground-breaking system to improve fresh bedding and recycle used bedding by applying a soft hydrothermal process with high-temperature and high-pressure dry steam. The system removes both harmful organic components and aromatic hydrocarbons that can affect animals' metabolism. The purpose of the present study was to evaluate the chemical and physical properties of the improved fresh bedding and the recycled used bedding treated by the system. The results showed that 68-99% of the predominant aromatic hydrocarbons were removed from fresh bedding treated at 0.35 MPa and 140 degrees C for 120 min ('improved bedding'). In addition, 59.4-99.0% of predominant harmful organic compounds derived from excrement were removed from used bedding treated at 0.45 MPa and 150 degrees C for 60 min ('recycled bedding'). The soft hydrothermal treatment increased the number of acidic functional groups on the bedding surface and gave it the high adsorptive efficiency of ammonia gas. Harmful substances such as microorganisms, heavy metals and pesticides decreased below the detection limit. The results clearly showed that the improved and recycled bedding is safer for laboratory rodents and has the potential to ameliorate conditions in primary and secondary enclosures (e.g. cages and animal rooms) used for maintaining laboratory animals. This process may be one of the most advanced techniques in providing an alternative to softwood and other bedding, economizing through the recycling of used bedding and reducing bedding waste from animal facilities.     

Preferences of group-housed female mice regarding structure of softwood bedding

Bedding influences various parameters in the housing of laboratory mice, such as health, physiology and behaviour (often considered as being integral parts of welfare). Notwithstanding existent studies about bedding preferences of individually tested mice, data about group-housed mice are still lacking. The aim of this study was to find out the structure preference for softwood bedding of group-housed mice. One hundred and eight 8-week-old female mice (C57BL6/JOlaHsd and BALB/cOlaHsd) were housed in groups of three and were given one-week free access to two different bedding structures at a time. In three test combinations, softwood shaving bedding was tested versus softwood chip bedding products of three different particle sizes (fine/medium/coarse-grained). The preference test was performed in a DoubleCage system composed of two Makrolon type IIL cages, connected by a perspex tunnel. This validated system was able to detect the crossings of each individual animal with correct crossing time and direction. On the basis of these data, dwelling times on the particular bedding structures were statistically analysed as a parameter for bedding preferences. In all three test combinations, a highly significant shaving preference was detected. On average, mice spent 70% of their dwelling time on the shavings. This preference was more explicit during the light period and in C57BL/6J mice. The relative ranking of the bedding structures was: shavings > coarse-grained chips > medium chips = fine chips. By means of these results, a shaving structure as bedding can be recommended for laboratory mice, whereas fine chip structures should be avoided.     

The bedding of laboratory animals as a source of airborne contaminants

In work environments with laboratory animals, the bedding of animals binds the excreta as well as other compounds originating from the animals and their environment. These may be generated into the ambient air when the personnel handle bedding in different procedures. This study compares the dustiness of different types of six clean and four soiled beddings from rat or mouse cages. The dust generation of clean bedding varied from <1 to 25 mg/m(3). When used in the cages of rats or mice for 4 days, the dust concentration of the beddings decreased, increased or stayed the same, depending on the type of bedding and animal species. A decrease in dustiness was, however, more common. The levels in the soiled beddings varied from <1 to 8.6 mg/m(3). In the case of the aspen chip bedding, the contents of bedding used in mouse, rat or rabbit cages were analysed for mesophilic bacteria and fungi, mycobacteria and endotoxins. All of these contaminants were variably found in the bedding samples, the maximal concentrations for bacteria were >6 500 000 colony-forming units (cfu)/g, for fungi 212 000 cfu/g, and for endotoxins 6500 ng/g (81 000 EU/g). The results showed that the bedding of laboratory animals may contain biologically effective compounds, and that these may be distributed into the ambient air depending on the characteristics of the bedding material. The dustiness of different bedding types is an important factor affecting the amount and quality of the occupational exposure of the personnel to airborne contaminants.     

Escherichia coli O157:H7 in Environments of Culture-Positive Cattle

Outbreaks of Escherichia coli O157:H7 disease associated with animal exhibits have been reported with increasing frequency. Transmission can occur through contact with contaminated haircoats, bedding, farm structures, or water. We investigated the distribution and survival of E. coli O157:H7 in the immediate environments of individually housed, experimentally inoculated cattle by systematically culturing feed, bedding, water, haircoat, and feed bunk walls for E. coli O157:H7 for 3 months. Cedar chip bedding was the most frequently culture-positive environmental sample tested (27/96 or 28.15%). Among these, 12 (44.0%) of positive bedding samples were collected when the penned animal was fecal culture negative. Survival of E. coli O157:H7 in experimentally inoculated cedar chip bedding and in grass hay feed was determined at different temperatures. Survival was longest in feed at room temperature (60 days), but bacterial counts decreased over time. The possibility that urine plays a role in the environmental survival of E. coli O157:H7 was investigated. Cedar chip bedding moistened with sterile water or bovine urine was inoculated with E. coli O157:H7. Bedding moistened with urine supported growth of E. coli O157:H7, whereas inoculated bedding moistened with only water yielded decreasing numbers of bacteria over time. The findings that environmental samples were frequently positive for E. coli O157:H7 at times when animals were culture negative and that urine provided a substrate for E. coli O157:H7 growth have implications for understanding the on-farm ecology of this pathogen and for the safety of ruminant animal exhibits, particularly petting zoos and farms where children may enter animal pens.     

Characteristics of black rhinoceros (Diceros bicornis) bedding sites

Black rhino numbers have decreased greatly since the early 1970s, primarily as a result of poaching. A recent strategy to protect rhinos in Kenya has been to establish fenced sanctuaries. This has increased the rhino population and that of other species, but problems have emerged because of limited dispersal and rising animal densities. Unfortunately, how rhino utilize habitat, especially areas called bedding sites, is not well understood. These areas provide shade and may be a critical component of rhino habitat. We measured habitat variables at bedding sites located in bedding plots and compared them with control plots at Sweetwaters Reserve, Kenya. Euclea divinorum was the most common tree in the bedding site comprising 64.3% of the vegetation. Elephant dung was significantly more likely to be found in bedding plots than in control plots which suggests that elephants and rhinos use overlapping habitats. Elephants may be causing damage to the tree species that are important for bedding sites. Resource competition between large herbivores in small reserves is likely to negatively affect the tree species. Black rhino habitat, particularly bedding sites, may be at risk and rhino numbers may decrease.     

Matrix context and patch quality jointly determine diversity in a landscape‐scale experiment

The biodiversity of a habitat patch is predicted to be driven in part by interactions between patch quality and landscape context (i.e. type of regional matrix), but these interactions are rarely explored experimentally. Understanding the interaction between patch quality and matrix context can provide insight into the kind of dynamics that best describe a metacommunity and help predict how the diversity of a patch will respond to environmental change at different scales. We conducted a landscape‐scale experiment to examine how regional and local aspects of the terrestrial matrix interact to affect biodiversity within artificial ponds designed to mimic generic features of freshwater ephemeral ponds. We manipulated both the kind of matrix surrounding ponds (open canopy grassland, pine forest, and hardwood forest) and pond quality (three different types of leaf litter substrate). Ponds were left open to natural colonization for three months by aquatic insects and amphibians. The terrestrial matrix had consistent and strong effects on biodiversity throughout the experiment: ponds in open canopy areas had more animal morphotypes than ponds in pine or hardwood forests. Leaf litter type affected biodiversity during the experiment, with more animal morphotypes in ponds with higher quality litter than ponds with lower quality litter, and this effect was stronger in open canopy areas. The effect of leaf litter, however, disappeared by the end of the experiment. Our results suggest that the matrix surrounding patches has strong effects on community dynamics and biodiversity within patches, and conservation efforts aimed at maintaining biodiversity requires simultaneous consideration of both matrix habitats and habitat patches.     

Consequential life cycle assessment of miscanthus livestock bedding,diverting straw to bioelectricity generation

Straw is an important livestock bedding material facing increasing demand for alternative uses in Europe and is often transported long distances from arable to livestock regions. Alternative bedding materials cultivated directly on livestock farms could potentially avoid this transport and competition for use. For the first time, we applied consequential life cycle assessment (LCA) to account for the direct and indirect implications of miscanthus bedding production on livestock farms, considering displacement of fodder or livestock, and substitution of fossil fuels with straw in electricity generation. We modelled the effect of substituting straw with ‘home‐grown’ miscanthus bedding across seven beef and sheep farms. The consequences of displacing grass forage (or animal) production with home‐grown miscanthus bedding cultivation were evaluated via three farmer decision scenarios: buy extra concentrate feed (D₁), utilize remaining pasture areas more efficiently (D₂) and buy grass silage (D₃). Electricity generated from displaced straw (bedding) substituted either natural gas or coal electricity. Sensitivity analyses were undertaken using 34 scenario permutations to represent combinations of feed and electricity substitution, miscanthus fertilization rates and yields, and the quality of displaced pasture. Consequential LCA indicates that miscanthus bedding production could be environmentally beneficial, under scenarios involving D₂ and D₃. However, greenhouse gas emissions and wider environmental burdens may be increased under D₁ scenarios, owing to the environmental cost of additional concentrate feed production, and possible indirect land use change, outweighing the benefits from: (a) fossil electricity substitution with straw bioelectricity; (b) reduced animal emissions via improved digestibility of concentrate feed; (c) avoided straw transport. The ratio of the yield of miscanthus to replaced grass was found to be a critical determinant of D₁ environmental outcomes. We conclude that if grass forage production can be better managed, the use of miscanthus as a bedding material on livestock farms provides environmental benefits via diversion of straw to bioenergy use.     

Biotechnological efforts for preserving and enhancing temperate hardwood tree biodiversity,health, and productivity

Hardwood tree species in forest, plantation, and urban environments (temperate regions of the world) are important biological resources that play a significant role in the economy and the ecology of terrestrial ecosystems, and they have aesthetic and spiritual value. Because of these many values of hardwood tree species, preserving forest tree biodiversity through the use of biotechnological approaches should be an integral component in any forestry program in addition to large-scale ecologically sustainable forest management and preservation of the urban forest environment. Biotechnological tools are available for conserving tree species as well as genetic characterization that will be needed for deployment of germplasm through restoration activities. This review concentrates on the biotechnological tools available for conserving, characterizing, evaluating, and enhancing hardwood forest tree biodiversity. We focus mainly on species grown for lumber and wood products, not species grown mainly for fiber (pulp and paper production). We also present a brief summary of the importance of non-wood forest products from temperate hardwood tree species (a research area that needs further development using biotechnological techniques) and a few case studies for preserving forest tree biodiversity.     

Direct and chemosignal-mediated effects of immune activation on behavior,glucocorticoid level,and body temperature in male mice during social conflict

Behavioral and physiological effects mediated by activation of immune system response to the injection with sheep red blood cells (SRBC) have been established to be mediated by chemosignal modification to a considerable extent while conducting experiments on BALB/cLac and C57Bl/6j male mice. Control mice of both strains have been characterized by the same increase of plasma coricosterone concentrations caused by territorial conflict between the control and SRBC-treated males; hence, the quality of bedding did not have an effect on hormonal response. The greatest level of plasma corticosterone in SRBC-treated mice was detected after dyadic tests of social conflict in the case of provided bedding from the control mice. The bedding odor also determined the agonistic behavior of more aggressive male BALB/cLac mice. Dyadic tests staged on bedding from SRBC-treated males led to a decrease in the amount of direct aggression in comparison to tests on bedding from control males; moreover, the number of aggressive demonstrations positively correlated with the increase of the rectal temperature, which might be considered a manifestation of the emotional reaction to territorial conflict.     

Influence of bedding type on mucosal immune responses

The mucosal immune system interacts with the external environment. In the study reported here, we found that bedding materials can influence the intestinal immune responses of mice. We observed that mice housed on wood, compared with cotton bedding, had increased numbers of Peyer's patches (PP) visible under a dissecting microscope. In addition, culture of lymphoid organs revealed increased production of total and virus-specific IgA by PP and mesenteric lymph node (MLN) lymphocytes from mice housed on wood, compared with cotton bedding. However, bedding type did not influence serum virus-specific antibody responses. These observations indicate that bedding type influences the intestinal immune system and suggest that this issue should be considered by mucosal immunologists and personnel at animal care facilities.     

Shifts in microbial community,pathogenicity-related genes and antibiotic resistance genes during dairy manure piled up

The uncomposted faeces of dairy cow are usually stacked on cow breeding farms, dried under natural conditions and then used as cow bedding material or they may be continuously piled up. However, no information is available to evaluate variations in the human and animal pathogen genes and antibiotic resistance during the accumulation of fresh faeces of dairy cow to manure. Here, we present the metagenomic analysis of fresh faeces and manure from a dairy farm in Ning Xia, showing a unique enrichment of human and animal pathogen genes and antibiotic resistance genes (ARGs) in manure. We found that manure accumulation could significantly increase the diversity and abundance of the pathogenic constituents. Furthermore, pathogens from manure could spread to the plant environment and enphytotic pathogens could affect the yield and quality of crops during the use of manure as a fertilizer. Levels of virulence genes and ARGs increased with the enrichment of microbes and pathogens when faeces accumulated to manure. Accumulated manure was also the transfer station of ARGs to enrich the ARGs in the environment, indicating the ubiquitous presence of environmental antibiotic resistance genes. Our results demonstrate that manure accumulation and usage without effective manure management is an unreasonable approach that could enrich pathogenic microorganisms and ARGs in the environment. The manure metagenome structure allows us to appreciate the overall influence and interaction of animal waste on water, soil and other areas impacted by faecal accumulation and the factors that influence pathogen occurrence in products from dairy cows.     

Countering the Broadleaf Invasion: Financial and Carbon Consequences of Removing Hardwoods during Longleaf Pine Savanna Restoration

The once widespread Longleaf pine (Pinus palustris)–dominated ecosystems of the southeastern coastal plain of the United States have been greatly reduced in extent, and many of the remaining stands are being degraded by hardwood invasion due to fire suppression. The first step toward pine savanna restoration is often hardwood removal, a costly process due to their large volumes and low market values. Despite these problems, by marketing a wide range of hard‐ and softwood products, the costs of 13 restoration projects in northern Florida were substantially reduced. Ten different products were sold to 19 different buyers. Fuel chips represented 71–100% of all biomass removed (8.2–81.1 Mg/ha). Although landowners were charged modest amounts for removing biomass harvested as fuel chips, other marketed products yielded revenues. Overall, four projects earned net profits of $29–$383/ha, and four projects generated sufficient revenue to pay 17–99% of the cost of hardwood removal as fuel chips. A carbon accounting of a second set of projects demonstrated that carbon harvested as fuel chips far exceeded that consumed in harvest and transport, yielding net carbon offsets of 451–1,320 Mg C/project (3.3–13.9 Mg C/ha). Using fuel consumption results of this second set of projects, carbon offsets for the 13 restoration projects were estimated as 89–1,524 Mg (3.8–37.9 Mg C/ha). Restorationists should monitor traditional forest product markets as well as developing carbon markets for price fluctuations that could provide significant revenues to restoration projects.