An update on environmental mastitis: challenging perceptions

Environmental mastitis is the most common and costly form of mastitis in modern dairy herds where contagious transmission of intramammary pathogens is controlled through implementation of standard mastitis prevention programmes. Environmental mastitis can be caused by a wide range of bacterial species, and binary classification of species as contagious or environmental is misleading, particularly for Staphylococcus aureus, Streptococcus uberis and other streptococcal species, including Streptococcus agalactiae. Bovine faeces, the indoor environment and used pasture are major sources of mastitis pathogens, including Escherichia coli and S. uberis. A faeco-oral transmission cycle may perpetuate and amplify the presence of such pathogens, including Klebsiella pneumoniae and S. agalactiae. Because of societal pressure to reduce reliance on antimicrobials as tools for mastitis control, management of environmental mastitis will increasingly need to be based on prevention. This requires a reduction in environmental exposure through bedding, pasture and pre-milking management and enhancement of the host response to bacterial challenge. Efficacious vaccines are available to reduce the impact of coliform mastitis, but vaccine development for gram-positive mastitis has not progressed beyond the “promising” stage for decades. Improved diagnostic tools to identify causative agents and transmission patterns may contribute to targeted use of antimicrobials and intervention measures. The most important tool for improved uptake of known mastitis prevention measures is communication. Development of better technical or biological tools for management of environmental mastitis must be accompanied by development of appropriate incentives and communication strategies for farmers and veterinarians, who may be confronted with government-mandated antimicrobial use targets if voluntary reduction is not implemented

Danish Stable Schools for Experiential Common Learning in Groups of Organic Dairy Farmers

The farmer field school (FFS) is a concept for farmers’ learning, knowledge exchange, and empowerment that has been developed and used in developing countries. In Denmark, a research project focusing on explicit nonantibiotic strategies involves farmers who have actively expressed an interest in phasing out antibiotics from their herds through promotion of animal health. One way of reaching this goal was to form participatory focused farmer groups in an FFS approach, which was adapted to Danish conditions and named “stable schools.” Four stable schools were established and went through a 1-yr cycle with 2 visits at each of the 5 or 6 farms connected to each group. A facilitator was connected to each group whose role was to write the meeting agenda together with the host farmer, direct the meeting, and write the minutes to send to the group members ater the meeting. Through group focus interviews and individual semistructured qualitative interviews of all participants, the approach of the farmers’ goal-directed work toward a common goal was judged to be very valuable and fruitful and based on a common learning process. Complex farming situations were the focus of all groups and in this context, problems were identified and solutions proposed based on each farmer’s individual goals. In this article, we describe the experiences of 4 stable school groups (each comprising farmers and a facilitator), and the common process of building a concept that is suitable for Danish organic dairy farming

Development and Daily Management of an Explicit Strategy of Nonuse of Antimicrobial Drugs in Twelve Danish Organic Dairy Herds

Promotion of animal health and well-being at the individual animal and herd level is an important goal in organic farming. At the same time, chemical products affecting the natural balance among living organisms are prohibited in all areas of the organic farm. From an animal welfare point of view, however, no animal must suffer. Therefore, veterinary drugs are allowed under the European Union’s regulations for organic farming, despite the fact that they are powerful cell toxins affecting both pathogenic and necessary bacteria, and as such in organic terminology, are regarded as “chemical” or “artificial” products. In this article, we present and discuss interviews with 12 Danish organic dairy producers who claim that minimized use or nonuse of antimicrobial drugs is an explicit goal. The dairy producers were at different levels with regard to reduced antimicrobial treatment. An explicit strategy of no antimicrobial treatments is based primarily on a long-term effort to improve herd health, and secondarily, on finding alternative treatments for diseased animals. Improved hygiene, outdoor access, use of nursing cows, and blinding of chronic mastitis quarters were the main techniques in developing a strategy of not using antimicrobial treatments in the herd by dairy producers. Producers’ perception of disease changed from something unavoidable to a disturbing break in the daily rhythm that often could have been avoided. Change toward a nonantimicrobial strategy was gradual and stepwise. All dairy producers in this study desired to preserve the possibility of using antimicrobial drugs in emergencies

Bayesian estimation of qPCR and bacterial culture accuracy for detection of bovine coagulase‐negative staphylococci from milk and teat apex at different test cut‐off points

Aim:To primarily estimate the sensitivity (Se) and specificity (Sp) of thecommercially available Mastit4 quantitative PCR (qPCR) assay and bacterialculture (BC) for diagnosis of intramammary infections (IMI) and teat apexcolonization (TAC) with coagulase-negative staphylococci (CNS) at differentcut-offs for qPCR cycle threshold values using Bayesian latent class analysis. Asecondary objective was to evaluate two cut-offs of BC for diagnosis of IMIand TAC with CNS.Methods and Results:We randomly selected 13–20 cows with subclinicalmastitis from eight dairy herds. Teat skin samples and aseptically collectedforemilk samples were collected from the right hindquarters (n=149) for BCand qPCR analysis. The Se of qPCR was always higher than BCSein diagnosis ofIMI, however; the Sp of BC was higher than qPCRSp.BCSeand BCSpshowed nosubstantial difference between the tested BC cut-offs. In contrast to IMI,estimates of BC and qPCR in diagnosing TAC were different. BCSewas higherthan qPCRSeat all tested cut-offs, however; qPCRSpwas higher than BCSp.Conclusion:The overall performance of qPCR is higher than BC in thediagnosis of IMI; however, the performance of BC is better than qPCR indiagnosis of TAC. The qPCR and BC are valid diagnostics for bovine IMI withCNS. However, for TAC, both techniques require further investigation toreduce the uncertainty of the true status of the quarter and teat skin.Significance and Impact of the Study:We reported, for the first time, thediagnostic performance of new mastitis technology (Mastit4 PCR) and culturefor detection of CNS in milk and nonmilk samples in dairy herds withautomatic milking systems. Our findings will improve the interpretation of thetest results of culture and qPCR assay and subsequently, will strengthen thecontrol of IMI with CNS in dairy cows.info:eu-repo/semantics/acceptedVersio

Homogeneity density scores of quarter milk in automatic milking systems

Milk quality and clinical mastitis in dairy cows are monitored by detecting visually abnormal milk. A standardized method to evaluate clots in milk and studies of the incidence and dynamics of clots in milk at the quarter level are lacking. We validated a method to score clot density in quarter milk samples and describe the prevalence and dynamics of the density scores between consecutive samplings and periods in 4 farms with automatic milking systems. Using in-line filters, we collected quarter milk samples at each milking during 3 periods of 30 h each in each farm. Clot density was scored based on coverage of the filter area as 0 (negative), 1 (trace), 2 (mild), 3 (moderate), 4 (heavy), and 5 (very heavy). The score for a specific quarter and milking is referred to as the quarter milking score (QMS). Three assessors independently scored 902 images of filter samples with a Fleiss kappa value of 0.72. In total, 21,202 quarter milk samples from 5,398 milkings of 621 cows were collected. Of the quarter filter samples, 2.4% had visible clots, distributed as mild (1.4%), moderate (0.6%), heavy (0.3%), and very heavy (= 4, corresponding to 9.4% of all periods, harbored 86% and 94% of all QMS of 2 to 5 and 3 to 5, respectively. Of these cases, cows sampled in all 3 periods and clots in only 1 period had a quarter period sum score >= 1 in 1.8 different quarters in average. Corresponding numbers for the cows with clots or traces in 2 or 3 periods were 2.2 and 2.5 different quarters, respectively. A QMS of 2 to 5 in the preceding milking increased the chance of a QMS >1 in the following milking, with an average chance of 38%. The probability of a QMS > 1 increased with increasing previous QMS, a higher sum of QMS during the milking period, longer milking interval, and higher lactation number, but decreased with increasing days in milk. Our study showed that the method of clot-density scoring is feasible to perform and reproducible for investigating the occurrence and dynamics of clots in milk. Elevated clot-density scores clustered within certain cows and cow periods and appeared in new quarters of the cows over time. The low recurrence of QMS of 1 and 2 within quarters indicated that QMS 3 could be a reasonable threshold for detecting quarters with abnormal milk that require further attention

Reducing use of antimicrobials — Experiences from an intervention study in organic dairy herds in Denmark

With the aim of phasing out the use of antimicrobials 23 Danish organic dairy producers from the same organic dairy company participated in Stable School farmer groups from February 2004 to March 2005 in order to go through a common learning and development process towards their common goal. Data on production and herd health were evaluated from two years before to three years after the start of the Stable Schools. For comparison, data was collected from the remaining 35 herds delivering to the same dairy company, 118 organic dairy herds delivering to other dairies and 115 conventional herds. On average, the project herds were smaller with lower production and had half the incidence rate of mastitis treatment than the organic herds from other dairies before the start of the project. The incidence rate of mastitis treatments was reduced considerably from 20 treatments per 100 cow years to 10 treatments per 100 cow years after the project period. Somatic cell count (SCC) and scores for acute and chronic intramammary infections did not change significantly during the study period, and milk production increased at the same rate as in the other herd groups. The incidence rate of mastitis treatments or the reduction of the incidence rate could be related to the herd SCC or the prevalence of blind quarters. The incidence rates of locomotive disorders and reproductive disorders were lower in the project herds compared with herds from other dairies before the project start, and the differences increased during the project period though the reduction of the incidence rates in the project herds was not statistically significant. It is concluded that the farmers participating in the Stable Schools managed to reduce the use of antimicrobials in their herds also after the project period without apparent negative effects on production and udder and herd health

Experienced and inexperienced observers achieved relatively high within-observer agreement on video mobility scoring of dairy cows

AbstractAssessment of lameness prevalence and severity requires visual evaluation of thelocomotion of a cow. Welfare schemes including locomotion assessments are increasingly being adopted, and more farmers and their veterinarians might implement a locomotion-scoring routine together. However, high within-observer agreement is a prerequisite for obtaining valid mobility scorings, and within-observer agreement cannot be estimated in a barn, because the gait of cows is dynamic and may change between 2 occasions. The objective of this study was to estimate the within-observer agreement according to the observers’ educational background and experience with cattle, based on video recordings with very diverse types of gait. Groups of farmers, bovine veterinarians, first- and fourth-year veterinary students, researchers, and cattle-inexperienced sensory assessors evaluated mobility using a 5-point mobility score system developed specifically for walking cows (n=102 observers). The evaluation sessions were similar for all groups, lasted 75 min, and were organized as follows: introduction, test A, short training session, break, and test B. In total, video recordings of 22 cows were displayed twice in a random order (11 cows in each test × 2 replicates). Data were analyzed applying kappa coefficient, logistic regression, and testing for random effects of observers. The crude estimates of 95% confidence interval for weighted kappa in test A and B ranged, respectively, from 0.76 to 0.80 and 0.70 to 0.75. When adjusting for the fixed effects of video sample and gait scoring preferences, the probability of assigning the same mobility score twice to the same cow varied from 55% (sensory assessors) to 72% (fourth-year veterinary students). The random effect of the individual observers was negligible. That is, in general observers could categorize the mobility characteristics of cows quite well. Observers who preferred to assess the attributes back arch or the overall mobility score (based on uneven gait) had the highest agreement, respectively, 69 or 68%. The training session seemed insufficient to improve agreement. Nonetheless, even novice observers were able to achieve perfect agreement up to 60% of the 22 scorings with merely the experience obtained during the study (introduction and training session). The relatively small differences between groups, together with a high agreement, demonstrate that the new system is easy to follow compared with previously described scoring systems. The mobility score achieves sufficiently high within-observer repeatability to allow between-observer agreement estimates, which are reliable compared with other more-complex scoring systems. Consequently, the new scoring scale seems feasible for on-farm applications as a tool to monitor mobility within and between cows, for communication between farmers and veterinarians with diverse educational background, and for lamenessbenchmarking of herds

TDMA-Medienzugriffsverfahren im Rueckkanal passiver optischer ATM-Zugangsnetze

Our modern information society is built on the availability and exchange of information as an integral part of both economic and private life. For example, the amount of traffic carried per year by the world-wide Internet is growing both due to the increasing popularity of private and business usage of the Internet and also due to the increasing number and size of documents available in the World Wide Web (WWW). The information and services offered via the WWW -from scientific research reports to culture and travel information, telephone directory services, dictionaries, train time tables and even online shopping -make this medium very attractive also for private use. The availability of powerful computers, the integration of 'classic' data services for file and document exchange (ftp and e-mail) into easy-to-use WWW browsers also facilitate the growth of world-wide date networks. Today, residential broadband network access is mostly realized via copper pairs (telephone network with analog or digital subscriber lines), coaxial cables (TV cable networks), radio technology (terrestrial or satellite) or even the power supply infrastructure (powerline communication, PLC). Several studies [20 41, 47, 50, 69, 70, 87, 136, 154] claim that in the future, passive optical networks (PON) will gain importance in broadband access. One example for a project building an ATM PON demonstrator wars the BAF (Broadband Access Facilities) project funded by the European Union [26]. In such ATM PON networks special attention needs to be paid to the upstream media access control if the network is required to offer certain quality of service guarantees such as low delay variation on the one hand and statistical multiplexing of the traffic from different subscribers on the other hand. In this thesis, the mechanisms for upstream media access control to be used in passive ATM access networks are classified, studied and compared with respect to their performance, particularly concentrating on delay variation issues. (orig.)Available from TIB Hannover: RA 2233(74) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman