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ABSTRACT: The Nordic countries Denmark (DK), Finland (FIN), Norway (NO) and Sweden (SE) all have unique national databases holding the disease records of dairy cows. The objective of this study was to estimate and compare completeness for locomotor disorders in the four Nordic national databases. Completeness figures for farmer-recorded disease events were calculated on two different levels: the first refers to disease events that were observed on the farm regardless of whether a veterinarian had been involved (FARMER); the second refers to farmer records of cases attended by a veterinarian, i.e. to veterinarian-treated disease events (VET). A sample of herds with 15 or more cows was obtained from a simple random sample of dairy farms in FIN, NO and SE, and from a systematic random sample in DK. There were 105, 167, 179 and 129 participating farmers in DK, FIN, NO and SE, respectively, and during two 2-month periods in 2008 these farmers recorded the disease events they observed on the farm. Data from the four national databases were extracted in May 2009. The two data sources, farmer recordings and national databases, were managed in a comparable way in all four countries, and common diagnostic codes were created and added to match recordings appearing in both datasets. In all 555 farmers completed data records in the first data-recording period, and 515 farmers did so in the second period. In DK, FIN, NO and SE, 55%, 77%, 82% and 75%, participating farmers completed the recordings during the first recording period, respectively; the corresponding figures for the second recording period were 71%, 82%, 83% and 91%. To calculate completeness, disease cases recorded in the national databases were compared with the farmer recordings using an exact match for the locomotor complex defined as same country, herd identification number (id), cow id, and event date at the levels of FARMER and VET. Completeness at FARMER level were 0.22, 0.21, 0.23 and 0.12 in DK, FIN, NO and SE, respectively. At VET level they were 0.37, 0.27, 0.34 and 0.17. To compare differences in completeness between countries exact 95% confidence intervals were calculated. There were significant differences in completeness between DK and SE at both FARMER and VET level. The completeness indicate that the ability to estimate true disease occurrences in the four national databases varies and is in general poor. Completeness should be taken into account when disease occurrences in different countries are compared.
Preventive Veterinary Medicine 07/2012; · 2.05 Impact Factor
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ABSTRACT: Overuse of antimicrobials in food-animal production is thought to be a major risk factor for the development of resistant bacterial populations. Data on non-human antimicrobial usage is essential for planning of intervention strategies to lower resistance levels at the country, region or herd levels. In this study we evaluated Danish national antimicrobial usage data for five antimicrobial classes used in slaughter pigs in different herd sizes and data on the number of slaughter pigs produced per herd, between 2002 and 2008, in Denmark. The objective was to ascertain if there is an association between herd size and amount of antimicrobials consumed. During this period, the overall number of herds with slaughter pigs decreased by 43%, with larger herds becoming more prevalent. The tetracycline treatment incidence (TI) rate increased from 0·28 to 0·70 animal-defined daily dose (ADD)/100 slaughter pig-days at risk while macrolide TI presented a more moderate increase, from 0·40 to 0·44 ADD/100 slaughter pig-days at risk during the study period. Linear regression analyses revealed a significant association between herd size and TI rates for tetracyclines, macrolides, sulfonamides/trimethoprim and cephalosporins, with small herds presenting significantly higher TI than moderate, large and the largest herds. This study highlights the importance of establishing an antimicrobial consumption monitoring programme, integrated with comprehensive food-animal production surveillance. Further research should be performed to address the potential causes of the detected associations between herd sizes and antimicrobial consumption in pigs.
Epidemiology and Infection 12/2010; 139(10):1601-9. · 2.84 Impact Factor
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ABSTRACT: According to the current literature BVDV-infected neighbours probably impose a high risk of infection of susceptible cattle herds. In the present study, the objective was to evaluate the risk of a dairy herd changing infection status (from not having persistently infected (PI) animals to having PI-animals) in relation to location and infection status of neighbouring cattle herds in Denmark. In total, 7921 dairy herds were included in the analysis of spatial and non-spatial risk factors. The spatial risk factors were derived based on the cattle herds in the neighbourhood (N=36,639 cattle herds). The neighbourhood was defined as the first order neighbouring cattle herds using a Delauney triangularization. In total, 13.3% of the dairy herds changed herd status to PI-herds during the study period that lasted from January 1, 1995, to June 30, 1996. The risk of becoming a PI-herd was negatively associated with the mean distance to the neighbouring herds (OR=0.7 for an increase of 1 km). Presence of PI-herds in the neighbourhood increased the risk of becoming a PI-herd (OR=1.37, 1.40, 1.70 for 1, 2, ≥3 PI-herds in the neighbourhood). Increasing herd size increased the risk of becoming a PI-herd (OR=3.9 for an increase of 10 cows). Regional differences were seen.
Preventive Veterinary Medicine 11/2010; 97(2):83-9. · 2.05 Impact Factor
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ABSTRACT: Endemic gastrointestinal (GI) diseases have a substantial negative impact on pig production, because, when present, they reduce animal welfare, productivity and generate high antimicrobial (AM) demand. In Danish legislation, AM can be prescribed only for therapeutic purposes. The objective of the study was to estimate the association between herd-level risk factors and the amount of AM use (AMU) in connection with GI diseases in finisher herds. We conducted a register-based cross-sectional study with repeated measurements from 2004 to 2007. Data were extracted from databases in the Danish Register of Veterinary Medicine, the Central Husbandry Register and the Danish Agriculture and Food Council. In total, 3192 pig herds with 26,973 records (quarters with prescriptions) were included. The outcome was presented as average AM use (measured as Animal Daily Dosage) for GI diseases per finishing pig per quarter per herd. Three potential herd-level risk factors were evaluated: herd size (number of finishers delivered for slaughter); herd health status (herds in the Specific Pathogen Free (SPF) System, conventional herds); and herd type (herds including only finishers, integrated herds). Data were analyzed using general linear mixed models with repeated measurements. Smaller herds had a larger AMU per finisher than larger herds. Integrated herds had lower AMU as compared with herds with only finishers. Herds within the SPF System had a larger decrease in AMU with increasing herd size compared to conventional herds. Significant regional differences in AMU were seen. Additionally, the results showed that other herd factors and veterinarians were more influential than the investigated herd risk factors. This illustrates the difficulties of characterising AM-demanding GI diseases in herds by the use of register data only.
Preventive Veterinary Medicine 11/2010; 98(2-3):190-7. · 2.05 Impact Factor
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ABSTRACT: Salmonella enterica ssp. enterica Dublin is the most common Salmonella serotype found in the dairy sector in Denmark. Salmonella antibody level in bulk-tank milk (BTM), indicative of Salmonella Dublin infection in the herd, has been recorded regularly in all Danish dairy herds through a surveillance program since 2002. The objective of this study was to investigate whether high BTM Salmonella antibody level was associated with high calf mortality at herd level. Other risk factors for high calf mortality were also investigated: breed, production type (organic vs. conventional), number of animals purchased, herd size, and number of neighbor herds within a 4.9-km radius. Data from the Danish Cattle Database including the Salmonella surveillance program from September 2007 through August 2008 were used. Dairy herds with more than 20 cows were included (n=4,337). Because of a highly right-skewed distribution of calf mortality with many zero values, calf mortality had to be dichotomized for the analysis. Therefore, in this study, high calf mortality was defined as calf mortality of more than 6.5% for calves aged 1 to 180 d. A logistic analysis was performed to identify risk factors associated with the probability of a herd having high calf mortality. The following factors were significantly associated with high calf mortality: high BTM Salmonella antibody level, odds ratio (OR)=2.0 (95% confidence interval=1.6-2.4), organic production OR=1.4 (95% confidence interval=1.1-1.7) for organic versus conventional production, and breed. Purchase of 8 or more animals increased the OR of high calf mortality more than purchase of 1 to 7 animals, which again had a higher OR compared with purchase of 0 animals. Because only 14.3% of the population consisted of herds with high BTM Salmonella status, the estimated proportion of herds with high calf mortality could only be reduced from 38.7 to 36.5% by eradicating Salmonella from the Danish cattle population (i.e., a population attributable risk of 2.2%). This showed that although there is a strong association between BTM Salmonella status and calf mortality, the problem with high calf mortality will not be solved by eradicating Salmonella. All other things equal, a population with more Salmonella-infected herds would gain a larger reduction in calf mortality from a Salmonella control campaign. Nevertheless, individual herds with a high within-herd prevalence of Salmonella are likely to benefit, both economically and regarding animal welfare, from controlling pathogenic Salmonella types in cattle.
Journal of Dairy Science 01/2010; 93(1):304-10. · 2.56 Impact Factor
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ABSTRACT: The collection and analysis of data on antimicrobial resistance in human and animal populations are important for establishing a baseline of the occurrence of resistance and for determining trends over time. In animals, targeted monitoring with a stratified sampling plan is normally used. However, to our knowledge it has not previously been analyzed whether animals have a random chance of being sampled by these programs, regardless of their spatial distribution. In this study, we used spatial scan statistics, based on a Poisson model, as a tool to evaluate the geographical distribution of animals sampled by the Danish Integrated Antimicrobial Resistance Monitoring and Research Programme (DANMAP), by identifying spatial clusters of samples and detecting areas with significantly high or low sampling rates. These analyses were performed for each year and for the total 5-year study period for all collected and susceptibility tested pig samples in Denmark between 2002 and 2006. For the yearly analysis, both high and low sampling rates areas were significant, with two clusters in 2002 (relative risk [RR]: 2.91, p < 0.01 and RR: 0.06, p < 0.01) and one in 2005 (RR: < 0.01, p < 0.01). For the 5-year analysis, one high sampling rate cluster was detected (RR: 2.56, p = 0.01). These findings allowed subsequent investigation to clarify the source of the sampling clusters. Overall, the detected clusters presented different spatial locations over the years and we can conclude that they were more associated to temporary sampling problems than to a failure in the sampling strategy adopted by the monitoring program. Spatial scan statistics proved to be a useful tool for assessment of the randomness of the sampling distribution, which is important when evaluating the validity of the results obtained by an antimicrobial monitoring program.
Foodborne Pathogens and Disease 12/2008; 6(1):15-21. · 2.26 Impact Factor
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ABSTRACT: In most existing antimicrobial resistance monitoring programmes, one single bacterial colony from each collected sample is susceptibility tested against a panel of antimicrobials. Detecting the proportion of colonies resistant to different antimicrobials in each sample can provide quantitative data on antimicrobial resistance (resistance prevalence per sample).
In this study, a total of 98 faecal samples from slaughter pigs were tested for tetracycline and sulphonamide resistance in Escherichia coli using the single colony method, and these results were compared with the results obtained using the resistance prevalence per sample method.
The results obtained by the resistance prevalence per sample method showed a lower occurrence of resistance. Tetracycline resistance in E. coli was found in 36.7% of the samples using the single colony method, while the mean tetracycline resistance prevalence was 22.5% using the resistance prevalence per sample method. Similarly, sulphonamide resistance was 32.7% using the single colony method and 19.6% when using the resistance prevalence per sample method. Although different estimates were obtained by each method, the correlation test and the regression model demonstrated that there is a significant association between the results obtained using both methods (P value <0.01) for both antimicrobials tested.
To support risk assessment and analysis of the association between consumption of antimicrobials and occurrence of resistance, there is a need to move towards a more quantitative approach when dealing with antimicrobial resistance in a population, and the resistance prevalence per sample method can provide some of this additional information.
Journal of Antimicrobial Chemotherapy 05/2008; 62(3):535-8. · 5.07 Impact Factor
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ABSTRACT: Previous studies have proved the possibility of preventing parturient hypocalcaemia by zeolite A supplementation during the dry period, and a recent in vitro study has indicated a marked calcium (Ca) as well as phosphorus (P) binding effect of zeolite A in rumen fluid solutions. Because of the connection between the Ca and P homeostatic systems, the preventive effect against parturient hypocalcaemia may arise from zeolite induced decreased availability of dietary Ca as well as P. In the present study, the expected Ca and P binding capacity was challenged by feeding high and low levels of dietary Ca and/or P to zeolite A treated dry cows. Twenty-one pregnant dry cows were assigned to four experimental groups receiving a dry cow ration unsupplemented or supplemented with extra Ca and/or P. During the last 2 weeks of the dry period all cows additionally received 600 g of zeolite A per day. A high level of dietary P prepartum significantly decreased the plasma Ca concentration before as well as immediately after calving (day 0-3). Conversely, the plasma inorganic phosphate concentration was higher among these cows than among cows receiving no supplemental P. The prepartum dietary Ca level significantly affected the serum 1,25-dihydroxyvitamin D concentration during zeolite supplementation, whereas the periparturient plasma Ca concentration was apparently not affected by the dietary Ca level. During zeolite A supplementation plasma parathyroid hormone was significantly higher among cows receiving additional P. The urinary deoxypyridinoline/creatinine ratio was not affected by the prepartal dietary Ca or P level. Serum aluminium (Al) was significantly higher during zeolite A supplementation than during the preceding period, indicating partial destruction of the zeolite in the intestinal tract with subsequent release and absorption of Al. It is suggested that the effect of prepartum zeolite supplementation on the periparturient Ca homeostasis depends on the level of Ca as well as P in the dry cow ration.
Journal of Veterinary Medicine Series A 04/2007; 54(2):82-91. · 0.93 Impact Factor
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ABSTRACT: This paper summarises the views of a European group of scientists involved in the control of bovine viral diarrhoea virus (BVDV), as part of a European Union Thematic Network. The group concludes that the technical tools and the knowledge needed to eradicate BVDV are at hand, as proven by successful national control schemes in several European countries. A generic model for BVDV control is presented, which includes biosecurity, elimination of persistently infected animals and surveillance as central elements. These elements are termed 'systematic', in contrast to control efforts without clear goals and surveillance to evaluate progress. The network concludes that a systematic approach is needed to reach a sustainable reduction in the incidence and prevalence of BVDV in Europe. The role of vaccines in systematic control programmes is considered as an additional biosecurity measure, the effect of which should be evaluated against cost, safety and efficacy. It is also concluded that active participation by farmers' organisations is a strong facilitator in the process that leads up to the initiation of control, and that public funding to support the initiation of organised BVD control programmes can be justified on the basis of expected wider societal benefits, such as animal welfare and reduction in the use of antibiotics. If applied successfully, the focus on biosecurity in systematic BVD control programmes would also reduce the risk of the introduction and spread of other epizootic and zoonotic agents, thereby improving both cattle health and welfare in general, as well as increasing the competitiveness of the cattle industry.
Revue scientifique et technique (International Office of Epizootics) 01/2007; 25(3):961-79. · 1.10 Impact Factor
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ABSTRACT: We reviewed the literature to give an overview over the mortality among dairy cows in countries with a relatively intensive dairy production. A total of 19 studies focussing on dairy cow mortality were identified. Information about objectives, measures of mortality, sample sizes, study designs, causes of death and risk factors from these studies is presented and discussed. Additionally, recommendations for future recordings of mortality that will enable better possibilities for comparison of study results, generalization of results from a study population to a larger population and meta-analysis are given.
The Veterinary quarterly 01/2007; 28(4):122-9. · 1.47 Impact Factor
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ABSTRACT: Several European countries have initiated national and regional control-and-eradication campaigns for bovine viral diarrhea virus (BVDV). Most of these campaigns do not involve the use of vaccines; in Germany, vaccination is used only in states in which it is considered necessary because of high BVDV prevalence. In European countries without organized BVDV control programs, vaccination is commonly used to control BVDV. Diagnostic test strategies are fundamental to all control-and-eradication campaigns; therefore, the purpose of this review is to describe how the available diagnostic tests are combined into test strategies in the various phases of control-and-eradication campaigns in Europe. Laboratory techniques are available for BVDV diagnosis at the individual animal level and at the herd level. These are strategically used to achieve 3 main objectives: 1) initial tests to classify herd status, 2) follow-up tests to identify individual BVDV-infected animals in infected herds, and 3) continued monitoring to confirm BVDV-free status. For each objective or phase, the validity of the diagnostic tests depends on the mode of BVDV introduction and duration of infection in test-positive herds, and on how long noninfected herds have been clear of BVDV. Therefore, the various herd-level diagnostic tools--such as antibody detection in bulk milk or in blood samples from young stock animals, or BVDV detection in bulk milk--need to be combined appropriately to obtain effective strategies at low cost. If the individual diagnostic tests are used with due consideration of the objectives of a specific phase of a BVDV control program, they are effective tools for controlling and eradicating BVDV in regions not using vaccination and where vaccination is a part of the control or eradication program.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 10/2006; 18(5):427-36. · 1.21 Impact Factor
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The Veterinary record 07/2006; 158(23):798-9. · 1.25 Impact Factor
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ABSTRACT: The factors affecting the mortality of cows in Danish dairy herds were investigated by analysing data from 6839 herds. The mean risk of mortality during the first 100 days of lactation was 2.5 per cent. The risk of mortality increased with increasing herd size (odds ratio [OR] 1.05 for an increase in herd size of 50 cows), with the proportion of purchased cows (OR 1.05 for an increase in the proportion of purchased cows of 0.1), and with increases in the somatic cell count (OR 1.16 for an increase in average weighted mean somatic cell count of 100,000 cells/ml). The risk decreased with increasing average milk yield per cow (OR 0.93 for an increase in mean yield per cow-year of 1000 kg). The risk was lower in free-stall barns with deep litter (OR 0.79) than in barns with cubicles (OR 1) or tie-stalls (OR 1.04). Herds with Danish Holstein (OR 1) or Danish Jersey (OR 0.93) cows as the predominant breed had a higher risk of mortality than herds of the Danish red dairy breed (OR 0.67). The risk of mortality was lower in organic herds (OR 1) than in conventional herds (OR 1.17), and lower in herds that grazed pasture during the summer (OR 0.78).
The Veterinary record 06/2006; 158(18):622-6. · 1.25 Impact Factor
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ABSTRACT: A cross-sectional observational study with repeated observations was conducted on 16 Danish dairy farms to quantify the influence of observer, parity, time (stage in lactation) and farm on variables routinely selected for inclusion in clinical protocols, thereby to enable a more valid comparison of udder health between different herds. During 12 months, participating herds were visited 5 times by project technicians, who examined 20 cows and scored the selected clinical variables. The estimates of effect on variables were derived from a random regression model procedure. Statistical analyses revealed that, although estimates for occurrence of several the variables, e.g. degree of oedema, varied significantly between observers, the effects on many of these estimates were similar in size. Almost all estimates for occurrences of variables were significantly affected either parity and lactation stage, or by both e.g. udder tissue consistency. Some variables, e.g. mange, had high estimates for the farm component, and others e.g. teat skin quality had a high individual component. Several of the variables, e.g. wounds on warts, had a high residual component indicating that a there still was a major part of the variation in data, which was unexplained. It was concluded that most of the variables were relevant for implementation in herd health management, but that adjustments need to be made to improve reliability.
Acta Veterinaria Scandinavica 02/2006; 48:15. · 1.00 Impact Factor
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ABSTRACT: An understanding of the driving forces of BVDV transmission can be gained by considering the reproductive rate, between individuals and between herds. The former determines the prospects for eliminating the infection from herds, and the latter is the key to persistence at the population level. In this paper, the relation between these two characteristics, their underlying parameters and measures and priorities for BVDV control are discussed. A general model for BVDV control is outlined, with bio-security, virus elimination and monitoring as three necessary consecutive elements, and with immunization as an optional step. A distinction is made between systematic and non-systematic approaches to BVDV control (where the former refers to a monitored and goal-oriented reduction in the incidence and prevalence of BVDV infection and the latter to where measures are implemented on a herd-to-herd decision basis and without systematic monitoring in place). Predictors of progress for systematic control approaches in general are discussed in terms of the abilities: to prevent new infections, to rapidly detect new cases of infection, to take action in infected herds and to gain acceptance by stakeholders. We conclude that an understanding not only of the biology, but also of the social factors - human behavior, the motives that makes stakeholders follow advice and the cultural differences in this respect - are important factors in forming recommendations on alternative strategies for BVDV control.
Preventive Veterinary Medicine 12/2005; 72(1-2):55-73; discussion 215-9. · 2.05 Impact Factor
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ABSTRACT: Sandy soil is often mentioned as a risk factor in the development of sand-related gastrointestinal disease (SGID) in the horse. There are other variables, but few studies confirm any of these.
To investigate soil type, pasture quality, feeding practice in the paddock, age, sex and body condition score as risk factors for sand intake in the horse.
Faeces were collected from 211 Icelandic horses on 19 different studs in Denmark together with soil samples and other potential risk factors. Sand content in faeces determined by a sand sedimentation test was interpreted as evidence of sand intake. Soil types were identified by soil analysis and significance of the data was tested using logistic analysis.
Of horses included in the study, 56.4% showed sand in the faeces and 5.7% had more than 5 mm sand as quantified by the rectal sleeve sedimentation test. Soil type had no significant effect when tested as main effect, but there was interaction between soil type and pasture quality. Significant interactions were also found between paddock feeding practice and pasture quality.
To evaluate the risk of sand intake it is important to consider 3 variables: soil type, pasture quality and feeding practice. Pasture quality was identified as a risk factor of both short and long grass in combination with sandy soil, while clay soil had the lowest risk in these combinations. Feeding practice in the paddock revealed feeding directly on the ground to be a risk factor when there was short (1-5 cm) or no grass. Also, no feeding outdoors increased the risk on pastures with short grass, while this had no effect in paddocks with no grass. More than 50% of all horses investigated in this study had sand in the faeces.
The identification of risk factors is an important step towards prevention of SGID. Further research is necessary to determine why some horses exhibit more than 5 mm sand in the sedimentation test and whether this is correlated with geophagic behaviour.
Equine Veterinary Journal 08/2005; 37(4):351-5. · 1.46 Impact Factor
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ABSTRACT: Biosecurity measures are important for the herd's protection against diseases and also to provide nationwide protection against the introduction of exotic diseases. In this paper, we describe the farmers' choices and routines regarding biosecurity in Danish fattening herds. Overall, 116 Danish swine fattening herds in three areas of different pig density were interviewed. Of these herds, 78% purchased weaners from one sow herd only, whereas 10% purchased from >5 sow herds during 1 year. Large herds (>500 finishers) purchased weaners more often than smaller herds (< or =500 finishers). Only two swine producers purchased weaners from a market. Almost all herds (95%) received weaners from one sow herd at one time, and only one herd received from >5 sow herds in one batch. Twenty-one percent did not use an effective barrier between the loading area and the stables when delivering pigs for slaughter. Entry rooms (in which clothing and boots are changed) were common at the farm, and the numbers of visitors were generally low (<10 visitors a year). Factor analysis was performed to find underlying structures of the biosecurity measures in the herd; four factors were chosen (eigenvalue > 3.10). A site scoring high on factor 1 was a large SPF herd, which received weaners from a single source, had biosecurity requirements for the transport vehicles, and had a high level of biosecurity for visitors. A site scoring high on factor 2 was a multi-site farm, which had personnel working on more than one of the sites, only received weaners from one sow herd, had delivering herds placed close to the participating site, and transported animals themselves. A site scoring high on factor 3 was a site which hired commercial transport for slaughter, was situated far from the abattoir and had a high level of biosecurity when loading pigs. A production site scoring high on factor 4 was a large site, which used all-in/all-out management, washed and disinfected between each group, and purchased many weaners.
Preventive Veterinary Medicine 01/2005; 66(1-4):49-62. · 2.05 Impact Factor
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ABSTRACT: A cross-sectional study was conducted to explore the applicability of systematic clinical examinations of udders as an additional tool for the evaluation of udder health status on dairy farms. During 2000, each of the 16 dairy farms was visited 5 times; 20 cows per farm were chosen at random at each visit for clinical udder examination immediately after milking. The clinical examination included both pathological and morphological variables. One examination per cow was included in the analysis (n = 707 cows). Principal component analysis (PCA) was performed in 3 steps. First, 19 variables characterizing udder and teats were analyzed (PCA 1). Second, the variables parity and stage of lactation were included (PCA 2). Finally, somatic cell count (SCC) and milk yield (PCA 3) were included. The PCA resulted in 4 components that explained 30% of the variation of the data: 1) small udder, 2) distressed udder, 3) mastitis udder, and 4) soiled udder. Variables with high positive correlation to the "small udder" were small udder shape, short teats, and first parity. Impaired teat surface, hard udder texture, and a long udder shape were related to the "distressed udder." The "mastitis udder" was characterized by the clinical variables asymmetry between front quarters, asymmetry between hind quarters, knotty tissue, and acute clinical mastitis. Reduced milk yield and high SCC were related to the "mastitis udder," whereas low SCC was related to the "small udder." The "soiled udder" was related to early lactation. Including this information in the assessment of udder health may be of substantial value for data analysis in farms with suspected under-reporting of clinical mastitis.
Journal of Dairy Science 06/2004; 87(5):1217-28. · 2.56 Impact Factor
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ABSTRACT: A simulation model was developed to evaluate the long-term effect of control strategies against milk fever (MF); here, we present the base model and sensitivity analyses. The representation of the within-herd dynamics was based on the existing SimHerd II model. Because of the relationships between MF and other diseases, the new model (called "SimHerd III") includes diseases common in a dairy herd. The cow level risk factors modelled were: base risk in the herd, parity, milk-yield potential, lactational disease recurrence, disease interrelationships, body condition and season. The diseases include clinical cases of MF, dystocia, downer-cow syndrome, retained placenta, metritis, displaced abomasum, ketosis and mastitis. The effects of diseases were represented by daily milk yield, daily body weight, daily feed intake, risk of stillbirth, conception probability, decision on culling, death and immediate removal. Simulated technical results showed that the herd effects of reduced risk of MF differed according to the reproductive efficiency in the herd. These interactions between reproduction efficiency and the effect of reduced base risk of MF were related to differences in how the simulated herds reacted to the reduction in replacements caused by MF. In the sensitivity analysis, eight potential key parameters were changed to their lowest and highest expected values retrieved from the literature. When measuring the sensitivity on milk production in the herd (as the economically most important technical effect), the model seemed most sensitive to the uncertainty of effect of MF on death risk and MF-recurrence risk.
Preventive Veterinary Medicine 06/2003; 58(3-4):125-43. · 2.05 Impact Factor
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ABSTRACT: A qualitative research study was conducted to describe and analyze farmers' perspectives on their own choices regarding decisions to have cows treated for mastitis. Through qualitative research interviews of 16 Danish dairy farmers, four levels of the decision-making process used by farmers to decide whether or not to treat a cow with antibiotics were identified. Those levels were: 1) symptom level (seriousness of the mastitis case), 2) cow level (to the extent a cow fulfilled goals of the farmer and the herd), 3) herd level (the situation of the herd, e.g., in relation to milk quota), and 4) level of alternatives (whether the farmer regards such practices as blinding of teats or homoeopathy as serious alternatives to antibiotic treatment). All four levels could be recognized in all herds, but with differing weights and relative importance across herds. Directions of different possibilities within each level also varied among farmers. By identifying those four levels, a model for understanding the farmers' choices is provided. This provides background for dialogue with each farmer about choices in the context of each specific herd. It also provides insight into implications of mastitis treatments for effective treatment versus issues of antibiotic resistance when discussing choices on a more general level. Communication and understanding between farmers and their veterinarians and cattle-oriented advisors is essential. Farmers were shown to be coherent in their choices of treatment, but their decisions often seemed to differ from normal veterinary recommendations. Such differences have to be understood and implemented into effective decisions for the whole farm.
Journal of Dairy Science 05/2002; 85(4):992-1001. · 2.56 Impact Factor
