Biosecurity on dairy operations: hazards and risks

A survey of biosecurity and health management practices on Irish dairy farms engaged in contract-rearing

A survey was conducted to investigate potential differences in biosecurity and health management practices on Irish dairy farms that sent their heifers for contract-rearing (source dairy farms, SDF; n = 62) and those rearing their own heifers (control farms, CF; n = 50). Participating farmers were surveyed by postal questionnaire between September and November 2018. The overall response rate was 93%. Results show that structurally, SDF were larger, less fragmented, and more specialized than CF. Outsourcing of labor-intensive activities to external contractors was more common among SDF than CF, exposing them to potentially increased biosecurity risks associated with animal movements, use of shared equipment, and increased frequency of farm visitors. The majority of SDF sent heifers to a single-origin rearing facility (70%), with heifers most commonly arriving at the rearing unit between 2 and 4 mo (53%) and returning to the dairy farm between 18 and 21 mo of age (56%). Despite the increased biosecurity risk associated with contract-rearing, implementation of disease prevention measures was not superior on SDF compared with CF. For both farm types, there was scope for improvement to visitor biosecurity protocols, quarantine procedures, colostrum feeding practices, and hygiene of calving areas. This research provides an overview of the demographics and farm management practices implemented by dairy farmers engaged in contract-rearing of replacement heifers, and will serve to inform farmers, veterinary advisors, and policy makers.

COVID-19 Awareness and Preparedness of Minnesota and Wisconsin Dairy Farms

Dairy farms that had participated in previous and ongoing projects with the National Farm Medicine Center (NFMC), Migrant Clinicians Network (MCN), and Upper Midwest Agricultural Safety and Health Center (UMASH) were asked to participate in a 17-question survey by phone or email to investigate biosecurity principles on Minnesota and Wisconsin dairy farms in response to COVID-19 and the effects of the pandemic on the dairy industry. Three additional farms were recruited via a press release published in agricultural newsletters. Of 76 farms contacted, 37 chose to participate in this study from June to July 2020. In response to the COVID-19 pandemic, dairies have implemented or increased biosecurity measures and COVID-19 precautions. Dairies reported adequate personal protective equipment for their workers, though face masks were not required on most dairies (n = 32, 86%). Producers were concerned about the safety of their families, maintaining a healthy workforce, and keeping their farms profitable. Access to healthcare was not perceived to be an issue for their workers. One-quarter of dairies reported COVID-19 infections on their farms. Even though the majority had an isolation protocol in place if someone on the farm were to become ill, less than half of respondents felt their farm was protected against COVID-19. Two-thirds of producers have not had to decrease production, and a majority of operations have not furloughed or terminated employees due to COVID-19. Our data suggest that dairy farms in Minnesota and Wisconsin have implemented biosecurity and safety measures in response to COVID-19. These measures can be improved. Farms would benefit from additional guidance and education on implementation of personal protective measures and disease prevention strategies to keep workers employed and safe.

Molecular diversity of Staphylococcus aureus and the role of milking equipment adherences or biofilm as a source for bulk tank milk contamination

Staphylococcus aureus is one of the most frequent pathogens causing intramammary infections in dairy herds. Consequently, virulence factors, pathobiology, and epidemiology of Staphylococcus aureus strains have been widely assessed through the years. Nevertheless, not much has been described about the epidemiology of Staph. aureus strains from bulk tank milk (BTM) and adherences on milking equipment (AMES), even when these strains may play a role in the quality of milk that is intended for human consumption. The objective of this study was to assess the strain diversity of 166 Staph. aureus isolates collected from 3 consecutive BTM samples, and from AMES in contact with milk from 23 Chilean dairy farms. Isolates were analyzed and typed using pulsed-field gel electrophoresis. Diversity of strains, both within and among farms, was assessed using Simpson's index of diversity (SID). On farms where Staph. aureus was isolated from both AMES and BTM (n = 8), pulsotypes were further analyzed to evaluate the role of AMES as a potential source of Staph. aureus strains in BTM. Among all Staph. aureus analyzed by pulsed-field gel electrophoresis, a total of 42 pulsotypes (19 main pulsotypes and 23 subtypes) were identified. Among dairy farms, strain diversity was highly heterogeneous (SID = 0.99). Within dairy farms, Staph. aureus strain diversity was variable (SID = 0 to 1), and 18 dairy operations (81.8%) had one pulsotype that was shared between at least 2 successive BTM samples. In those farms where Staph. aureus was isolated in both AMES and BTM (n = 8), 7 (87.5%) showed a clonal distribution of Staph. aureus strains between these 2 types of samples. The overlapping of certain Staph. aureus strains among dairy farms may point out common sources of Staph. aureus among otherwise epidemiologically unrelated farms. Indistinguishable Staph. aureus strains between AMES and BTM across dairy farms suggest that Staph. aureus-containing AMES may represent a source for BTM contamination, thus affecting milk quality. Our study highlights the role of viable Staph. aureus in AMES as a source for BTM contamination on dairy farms, and also describes the overlapping and presence of specific BTM and AMES pulsotypes among farms.

Development of a quantitative risk assessment of bovine viral diarrhea virus and bovine herpesvirus-1 introduction in dairy cattle herds to improve biosecurity

A quantitative risk assessment model was developed to estimate the annual probability of introducing bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) at the farm level through animal movements. Data from 2017 official animal movements, biosecurity questionnaires, scientific literature, and expert opinion from field veterinarians were taken into consideration for model input parameters. Purchasing or introducing cattle, rearing replacement heifers offsite, showing cattle at competitions, sharing transport vehicles with other herds, and transporting cattle in vehicles that have not been cleaned and disinfected were considered in the model. The annual probability of introducing BVDV or BoHV-1 through infected animals was very heterogeneous between farms. The median likelihoods of BVDV and BoHV-1introduction were 12 and 9%, respectively. Farms that purchased cattle from within their region (i.e., local movements) and shared transport with other farms had a higher probability for BVDV and BoHV-1 introduction. This model can be a useful tool to support decision-making on biosecurity measures that should be prioritized to reduce the probability of introduction of these 2 diseases in dairy herds.

Exploring expert opinion on the practicality and effectiveness of biosecurity measures on dairy farms in the United Kingdom using choice modeling

Biosecurity, defined as a series of measures aiming to stop disease-causing agents entering or leaving an area where farm animals are present, is very important for the continuing economic viability of the United Kingdom dairy sector, and for animal welfare. This study gathered expert opinion from farmers, veterinarians, consultants, academics, and government and industry representatives on the practicality and effectiveness of different biosecurity measures on dairy farms. The study used best-worst scaling, a technique that allows for greater discrimination between choices and avoids the variability in interpretation associated with other methods, such as Likert scales and ranking methods. Keeping a closed herd was rated as the most effective measure overall, and maintaining regular contact with the veterinarian was the most practical measure. Measures relating to knowledge, planning, and veterinary involvement; buying-in practices; and quarantine and treatment scored highly for effectiveness overall. Measures relating to visitors, equipment, pest control, and hygiene scored much lower for effectiveness. Overall, measures relating to direct animal-to-animal contact scored much higher for effectiveness than measures relating to indirect disease transmission. Some of the most effective measures were also rated as the least practical, such as keeping a closed herd and avoiding nose-to-nose contact between contiguous animals, suggesting that real barriers exist for farmers when implementing biosecurity measures on dairy farms. We observed heterogeneity in expert opinion on biosecurity measures; for example, veterinarians rated the effectiveness of consulting the veterinarian on biosecurity significantly more highly than dairy farmers, suggesting a greater need for veterinarians to promote their services on-farm. Still, both groups rated it as a practical measure, suggesting that the farmer-veterinarian relationship holds some advantages for the promotion of biosecurity.

On-farm starling populations and other environmental and management factors associated with the presence of cefotaxime and ciprofloxacin resistant E. coli among dairy cattle in Ohio

Wild birds that forage around livestock facilities have been implicated as vectors of antimicrobial resistant organisms. Although antimicrobial resistant bacteria have been isolated from European starlings (Sturnus vulgaris), their role in the dissemination of antimicrobial resistant elements in livestock facilities needs further investigation. To determine whether on-farm starling density and other factors were associated with the presence of cefotaxime and ciprofloxacin resistant E. coli among dairy cows in Ohio, bovine fecal pats from 150 farms were tested for the presence of cefotaxime and ciprofloxacin resistant E. coli. Each farm was visited twice (during the summer and fall of 2007-2009). Multi-level logistic regression models with a random intercept to account for fecal pats collected within a specific visit to a farm were used to assess the associations. The percentage of samples with cefotaxime and ciprofloxacin resistant E. coli was 13.4% and 13.6%, respectively. The percentage of farms having at least one sample testing positive for cefotaxime and ciprofloxacin resistant E. coli was 56.7% and 48.7%, respectively. The odds of detecting cefotaxime and ciprofloxacin resistant E. coli in the samples was significantly higher in 2007 compared to 2008 and 2009, in fall compared to summer, and from farms closer than 60km to starling night roost sites compared to the farms further than 60km. The presence of starlings during the day had a negative association with the likelihood of detecting cefotaxime resistant E. coli. Presence of calves also had a negative association with the likelihood of detecting both cefotaxime and ciprofloxacin resistant E. coli. European starlings might play a role in the dissemination of antimicrobial resistant agents in livestock facilities related to their daily population movements rather than the specific density of birds on farm during the day.

Expert Opinion on the Perceived Effectiveness and Importance of On-Farm Biosecurity Measures for Cattle and Swine Farms in Switzerland

Biosecurity is crucial for safeguarding livestock from infectious diseases. Despite the plethora of biosecurity recommendations, published scientific evidence on the effectiveness of individual biosecurity measures is limited. The objective of this study was to assess the perception of Swiss experts about the effectiveness and importance of individual on-farm biosecurity measures for cattle and swine farms (31 and 30 measures, respectively). Using a modified Delphi method, 16 Swiss livestock disease specialists (8 for each species) were interviewed. The experts were asked to rank biosecurity measures that were written on cards, by allocating a score from 0 (lowest) to 5 (highest). Experts ranked biosecurity measures based on their importance related to Swiss legislation, feasibility, as well as the effort required for implementation and the benefit of each biosecurity measure. The experts also ranked biosecurity measures based on their effectiveness in preventing an infectious agent from entering and spreading on a farm, solely based on transmission characteristics of specific pathogens. The pathogens considered by cattle experts were those causing Bluetongue (BT), Bovine Viral Diarrhea (BVD), Foot and Mouth Disease (FMD) and Infectious Bovine Rhinotracheitis (IBR). Swine experts expressed their opinion on the pathogens causing African Swine Fever (ASF), Enzootic Pneumonia (EP), Porcine Reproductive and Respiratory Syndrome (PRRS), as well as FMD. For cattle farms, biosecurity measures that improve disease awareness of farmers were ranked as both most important and most effective. For swine farms, the most important and effective measures identified were those related to animal movements. Among all single measures evaluated, education of farmers was perceived by the experts to be the most important and effective for protecting both Swiss cattle and swine farms from disease. The findings of this study provide an important basis for recommendation to farmers and policy makers.

Associations between biosecurity and outbreaks of canine distemper on Danish mink farms in 2012-2013

Background

During 8 months from July 2012 to February 2013, a major outbreak of canine distemper involving 64 mink farms occurred on the Danish peninsula of Jutland. The canine distemper outbreak was associated with exposure of farmed mink to infected wild carnivores and could represent a deficit in biosecurity on the mink farms. The aim of this study was to investigate the extent and association of specific biosecurity measures with the outbreak. The study was carried out in an epidemiological case–control design. The case group consisted of the 61 farms, which had a confirmed outbreak of canine distemper from July 2012 to February 2013. The control group included 54 farms without an outbreak of canine distemper in 2012 or 2013, selected as the closest geographical neighbour to a case farm.

Results

The results showed that significantly more control than case farms had vaccinated their mink against canine distemper virus. Mortality was only assessed on the case farms, and there was a non-significantly lower mortality on vaccinated farms than on the non-vaccinated farms. Furthermore, the proportion of farms with observations of wild red foxes (Vulpes vulpes) inside the farm enclosures were larger for case farms, indicating that the control farms had a better biosecurity or were not equally exposed to canine distemper virus. Generally, all farms had very few specific precautions at the gate entrance in respect to human visitors as well as animals. The use of biosecurity measures was very variable in both case and control farms. Not using plastic boot covers, presence of dogs and cats, presence of demarcated area for changing clothes when entering and leaving the farm area and presence of hand washing facilities significantly lowered the odds of the farm having a canine distemper virus outbreak.

Conclusions

The results of the study indicate that consistent use of correct vaccination strategies, implementation of biosecurity measures and limiting human and animal access to the mink farm can be important factors in reducing the risk for canine distemper outbreaks.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-015-0159-2) contains supplementary material, which is available to authorized users.

A survey of management practices on Irish dairy farms with emphasis on risk factors for Johne's disease transmission

BACKGROUND

Johne's disease (JD) is a chronic granulomatous enteritis affecting ruminants. A number of farm management practices are associated with increased risk of JD transmission. The aim of the current study was to document JD-related management practices currently employed on Irish dairy farms. Survey questions focused on calving area (CA), calf and manure management. Independent variables (region, calving-season, enterprise type, herd size and biosecurity status) were used to examine influences on JD associated dependent variables (survey questions). Additionally general biosecurity practices were also examined.

RESULTS

Results showed management practices implemented by Irish dairy farmers pose a high risk of JD transmission. Of the farmers surveyed, 97% used the CA for more than one calving, 73.5% and 87.8% pooled colostrum and milk respectively, 33.7% never cleaned the CA between calving's, and 56.6% used the CA for isolating sick cows. Survey results also highlighted that larger herds were more likely to engage in high risk practices for JD transmission, such as pooling colostrum (OR 4.8) and overcrowding the CA (OR 7.8). Larger herds were also less likely than smaller herds to clean the CA (OR 0.28), a practice also considered of risk in the transmission of JD.

CONCLUSION

Many management practices associated with risk of JD transmission were commonly applied on Irish dairy farms. Larger herds were more likely to engage in high risk practices for JD transmission. Control programmes should incorporate educational tools outlining the pathogenesis and transmission of JD to highlight the risks associated with implementing certain management practices with regard to JD transmission.

Socioeconomic implications of biosecurity practices in small-scale dairy farms

BACKGROUND

Biosecurity plays a crucial role in preventing contagious diseases and in increasing farm productivity.

OBJECTIVE

To determine technical and economic biosecurity scores of farms, and to examine the associations between biosecurity practices (BP) and producers' socioeconomic characteristics.

METHODS

The study was conducted on a total of 50 small-scale dairy farms that were randomly selected in Hatay, Turkey. A checklist consisting of 19 biosecurity practices was addressed to the farms. The technical and economic scoring systems were developed by the authors according to presence and cost of the each of the biosecurity practices.

RESULTS

The mean of the technical and economic scores were found to be 9.30 and 17.04, respectively. 'Treatment of sick animals' (98%), 'vaccination against the most common contagious diseases' (90%), and 'barn lime' (86%) were found to be the most commonly used applications. 'Testing for the most common contagious diseases before buying' (10%) was used at the lowest rate. Significant differences were found among the groups regarding education level (<.05), income class (<.05), and herd size (<.01). Biosecurity scores were significantly positively correlated with herd size (<.05) and producers' education level (<.01). There were statistically significant associations between the producers' socioeconomic characteristics and some of the biosecurity practices.

CONCLUSION

Training programs should be arranged to change the attitudes and perception of small-scale producers concerning poor biosecurity practices. In order to encourage producers to increase biosecurity scores, regulations regarding financial support and penalties could be quite useful at both the regional and national levels.

Bioexclusion of diseases from dairy and beef farms: risks of introducing infectious agents and risk reduction strategies

Infectious disease represents a major threat to the productivity and welfare of cattle herds throughout the world. The introduction of infectious agents into dairy and beef farms may be through direct transmission (purchased cattle, reintroduced resident cattle and contact with contiguous cattle) or indirect transmission (fomites, visitors, other species, and biological materials) and this article reviews the evidence supporting these transmission routes. In the absence of eradication programmes for many endemic infectious diseases, bioexclusion is the key management process for risk reduction. Various ameliorative bioexclusion strategies have been recommended and the evidence supporting these protocols is considered.

Biosecurity on cattle farms: a study in north-west England

BACKGROUND

Few studies have considered in detail the range of biosecurity practices undertaken on cattle farms, particularly within the UK. In this study, 56 cattle farmers in a 100 km² area of north-west England were questioned regarding their on-farm biosecurity practices, including those relating to animal movements, equipment sharing and companies and contractors visiting the farms.

METHODOLOGY/PRINCIPAL FINDINGS

There was great variation between farms in terms of the type of, and extent to which, biosecurity was carried out. For example, the majority of farmers did not isolate stock bought onto the farm, but a small proportion always isolated stock. Many farmers administered treatments post-movement, primarily vaccinations and anthelmintics, but very few farms reported carrying out any health checks after moving animals on. In addition, there appeared to be much variation in the amount of biosecurity carried out by the different companies and contractors visiting the farms. Deadstock collectors and contracted animal waste spreaders, although likely to have a high potential for contact with infectious agents, were reported to infrequently disinfect themselves and their vehicles.

CONCLUSIONS/SIGNIFICANCE

These findings suggest that although certain biosecurity practices are undertaken, many are carried out infrequently or not at all. This may be due to many factors, including cost (in time and money), lack of proven efficacies of practices and lack of relevant education of veterinary surgeons, producers and other herd health specialists. Further research exploring the reasons for the lack of uptake is imperative if preventive medicine is to be utilised fully by the farming industry.

Invited review: The role of contagious disease in udder health

Contagious diseases are a threat to animal health and productivity, both nationally and at the farm level. This makes implementation of biosecurity measures to prevent their introduction and spread within countries and farms a necessity. Mastitis is the most common and costly contagious disease affecting dairy farms in the western world. The major mastitis pathogens are endemic in most countries, and biosecurity measures to prevent introduction and transmission must therefore be implemented at farm level. The 40-yr-old mastitis control plan remains a solid foundation to prevent the spread of contagious intramammary infections. Contagious diseases that do not affect the mammary gland directly may have an indirect effect on mastitis. This is true for list A diseases such as foot and mouth disease, for which biosecurity measures may need to be taken at national level, and for other infections with nonmastitis pathogens such as bovine viral diarrhea virus and Mycobacterium avium ssp. paratuberculosis. Maintaining a closed herd decreases the risk of introduction of pathogens that affect udder health directly or indirectly. If animals are purchased, their udder health history should be evaluated and they should be examined and tested for contagious diseases. Transmission of infections by and to humans and nonbovine animals may occur. Contact with visitors and nonbovine animals should therefore be minimized. Because of globalization and heightened consumer awareness, the importance of biosecurity now supersedes individual farms, and increased pressure to control transmission of contagious diseases can be expected at industry or government levels in western countries and elsewhere.

Use of data mining techniques to investigate disease risk classification as a proxy for compromised biosecurity of cattle herds in Wales

Background

Biosecurity is at the forefront of the fight against infectious diseases in animal populations. Few research studies have attempted to identify and quantify the effectiveness of biosecurity against disease introduction or presence in cattle farms and, when done, they have relied on the collection of on-farm data. Data on environmental, animal movement, demographic/husbandry systems and density disease determinants can be collated without requiring additional specific on-farm data collection activities, since they have already been collected for some other purposes. The aim of this study was to classify cattle herds according to their risk of disease presence as a proxy for compromised biosecurity in the cattle population of Wales in 2004 for risk-based surveillance purposes.

Results

Three data mining methods have been applied: logistic regression, classification trees and factor analysis. Using the cattle holding population in Wales, a holding was considered positive if at least bovine TB or one of the ten most frequently diagnosed infectious or transmissible non-notifiable diseases in England and Wales, according to the Veterinary Investigation Surveillance Report (VIDA) had been diagnosed in 2004. High-risk holdings can be described as open large cattle herds located in high-density cattle areas with frequent movements off to many locations within Wales. Additional risks are associated with the holding being a dairy enterprise and with a large farming area.

Conclusion

This work has demonstrated the potential of mining various livestock-relevant databases to obtain generic criteria for individual cattle herd biosecurity risk classification. Despite the data and analytical constraints the described risk profiles are highly specific and present variable sensitivity depending on the model specifications. Risk profiling of farms provides a tool for designing targeted surveillance activities for endemic or emerging diseases, regardless of the prior amount of information available on biosecurity at farm level. As the delivery of practical evidence-based information and advice is one of the priorities of Defra's new Animal Health and Welfare Strategy (AHWS), data-driven models, derived from existing databases, need to be developed that can then be used to inform activities during outbreaks of endemic diseases and to help design surveillance activities.

Biosecurity and risk management for dairy replacements

Biosecurity, biocontainment, and disease risk management on dairy replacement operations are time- and labor-intensive, planned programs. Oftentimes the value of these programs is realized only after disease is introduced to a facility or a disease outbreak occurs. There is no “one-plan-fits-all;” each plan must be tailored to meet the needs of management's goals and expectations and problems specific to a production enterprise or geographic region. A standard framework applicable to biosecurity programs includes: (1) hazard identification, (2) exposure assessment, (3) risk characterization, and (4) risk management. The discussion presented here helps lay the framework for development and implementation of biosecurity and risk-management programs within dairy replacement facilities.

A scoring system for risk assessment of the introduction and spread of bovine viral diarrhoea virus in dairy herds in Northern Italy

To support a voluntary disease control program, this study aimed to develop an integrated scoring system for the risk assessment of bovine viral diarrhoea virus (BVDV) infection in dairy herds in Northern Italy. Sixty-two dairy herds were classified according to their BVDV serological status. Farmers were interviewed using a questionnaire on potential BVDV risk factors. Scores were used to define risk levels for factors related to (1) BVDV introduction (through livestock trade, attendance of animals at shows/exhibitions and grazing common pasture), (2) within-herd spread of BVDV and (3) the results of initial serological testing. The calculated odds ratios were significant for all categories, except for livestock trade. The application of the screening test, the questionnaire and the related risk assessment showed this to be a practical approach to predicting BVDV herd status.

Dissemination of Salmonella enterica subsp. enterica Serovar Typhimurium var. Copenhagen clonal types through a contract heifer-raising operation

Salmonella enterica subsp. enterica serovar Typhimurium var. Copenhagen isolates from a heifer-raising operation and from 11 dairy herds that had their calves contracted to the heifer-raising operation were examined for their phenotypic and genotypic characteristics. Results of the study showed that the heifer-raising operation could serve as a clearinghouse for Salmonella serovar Typhimurium var. Copenhagen and perhaps other Salmonella serotypes.

A practitioner's primer on foot-and-mouth disease

Foot-and-mouth disease (FMD) is caused by an RNA virus of the genus Aphthovirus; 7 immunologically distinct serotypes of the virus have been identified. Susceptible species are mainly domestic and wild even-toed ungulates, such as cattle, sheep, goats, pigs, bison, and deer. All body fluids of infected animals can contain the virus and are considered infective. The primary mode of transmission is animal-to-animal transmission through inhalation or ingestion of aerosols containing the virus. The virus can also be spread mechanically by contaminated organic debris and fomites and can survive for 48 hours on human oral and nasal mucosa and be spread to uninfected animals in this manner. There is a rapid progression of clinical signs after an animal becomes infected, and the virus spreads rapidly throughout a herd. Clinical signs include excessive salivation; fever; vesicles and erosions of the oral and nasal mucosa, coronary band, interdigital area, and teats; lameness; sloughing of claws; reluctance to move; anorexia; mastitis; decreased milk production; and abortion or weak newborns. In mature animals, FMD has high morbidity and low mortality rates. Infected animals can become inapparent carriers of the virus.

Multiresistant clones of Salmonella enterica: The importance of dissemination

Increasing anitmicrobial resistance among foodborne pathogens has prompted calls for the reduction of anitmicrobial use in livestock to prevent future emergence or resistance. In the case of Salmonella enterica, clonal dissemination may play a more critical role in regional changes in antimicrobial resistance in Salmonellae than antimicrobial selection pressure. Multi-resistant Salmonella Typhimurium definitive type 104 (mr-DT104) emerged from an unknown location and was disseminated globally during the 1980s and 1990s. Other clones of Salmonella Typhimurium and non-Typhimurium Salmonellae have demonstrated an ability to disseminate widely. The clonal epidemiology of mr-DT104 is in contrast with that of Campylobacter jejuni, in which antimicrobial resistance is polyclonal and seems to develop in response to local antimicrobial pressures. The epidemiology of mr-DT104 is more similar to that of methicillin resistant Staphylococcus aureus, which is also characterized by international transmission of a few clonal subtypes. Control measures for multiresistant disseminated clones of Salmonellae must focus on the interruption of dissemination in order to be effective.

Epidemiologic tools for biosecurity and biocontainment

Quantitative models simplify reality, and therefore may misrepresent it. With that caution, models can be useful for predicting the outcomes of a variety of what-if scenarios related to biosecurity and biocontainment. Graphic representations of the models help to visualize relationships between factors that influence biosecurity that might not be obvious otherwise. The examples in this article illustrate only a few of many epidemiologic relationships relevant to biosecurity and biocontainment. Many other relationships remain to be explored.

Biosecurity for gastrointestinal diseases of adult dairy cattle

As biosecurity management strategies are developed and implemented to prevent introduction and spread of infectious diseases in cattle populations, it is informative to review principles of biosecurity from another livestock species in which these issues have been considered (e.g., swine) and compare these perspectives to the current situation for cattle. The authors follow a biosecurity risk-assessment model to identify important health hazards, evaluate risks, and present principles for implementing a cattle biosecurity program for important gastrointestinal health hazards of adult dairy cattle, after consideration of a swine biosecurity model.

Biosecurity for arthropod-borne diseases

Arthropod-borne diseases (ABD) of cattle include those pathogens transmitted mechanically and biologically from one bovine to another or from other species to cattle. This article provides examples of the more common ABD of North America and reviews strategies to prevent entry of ABD onto cattle operations and control transmission of ABD once established on cattle operations using an integrated approach.