Farmers' attitude toward the introduction of selective dry cow therapy.

The attitude of Dutch dairy farmers toward selective dry cow treatment (SDCT) is unknown, although a favorable mindset toward application of SDCT seems crucial for successful implementation. Given the fact that blanket dry cow treatment has been strongly promoted until recently, the implementation of SDCT was expected to be quite a challenge. This study aimed to provide insight into the level of implementation of SDCT in 2013 in the Netherlands, the methods used by farmers for selection of cows for dry cow treatment (DCT), the relation between SDCT and udder health and antimicrobial usage (AMU) in 2013, and the mindset of farmers toward SDCT. In 2014, a questionnaire was conducted in a group of 177 herds included in a large-scale udder health study in 2013 and for which all clinical mastitis cases during this year were recorded. In addition, data on somatic cell count (SCC) parameters and AMU was available for these herds. The questionnaire included questions with regard to DCT with a special emphasis on farmers' attitude and mindset with regard to applying DCT in 2013. The data that were obtained from the questionnaire were combined with the data on clinical mastitis, SCC, and AMU. Descriptive statistics were used to evaluate the data and to study the association between DCT, udder health, and AMU. Univariable and multivariable logistic regression models with a logit link function were applied to evaluate potential associations between DCT and farmers' mindset. Selective DCT was taken up progressively by the farmers in our study, with 75% of them implementing SDCT in 2013. The main criterion used to select cows for DCT was the SCC history during the complete previous lactation. The herds were divided into 3 groups based on the percentage of cows dried off with antibiotics in 2013 as indicated by the farmers during interviews. The first group applied BDCT, and the herds for which SDCT was applied were split in 2 equally sized groups based on the median percentage of cows dried off with antibiotics (67%). The incidence rate of subclinical and clinical mastitis were comparable between the groups. Results of the multivariable model showed that 4 factors related to farmers' mindset were associated with the probability to apply SDCT: "financial consequences of SDCT," "uncertainty whether a cow will recover without antimicrobials," the statement "I do not have a problem with the (potential) negative consequences of SDCT," and the usage of internal teat sealants. Application of SDCT appeared to be associated with farmers' attitude. The mindset of farmers with respect to reduction of AMU and the implementation of SDCT was generally positive.

Effect of different scenarios for selective dry-cow therapy on udder health, antimicrobial usage, and economics.

The goal of dry-cow therapy (DCT) is to reduce the prevalence of intramammary infections (IMI) by eliminating existing IMI at drying off and preventing new IMI from occurring during the dry period. Due to public health concerns, however, preventive use of antimicrobials has become questionable. In this study, we evaluated the effects of 8 scenarios for selecting animals for DCT, taking into account variation in parity and cow-level somatic cell count (SCC) at drying off. The aim of this study was to evaluate udder health, antimicrobial usage, and economics at the herd level when using different scenarios for selecting cows for DCT. To enable calculation and comparison of the effects of different scenarios to select cows for DCT in an "average" herd, we created an example herd, with a virtual herd size of 100 dairy cows to be calving during a year. Udder health, antimicrobial usage, and economics were evaluated during the dry period and the first 100 d in lactation, the period during which the greatest effect of DCT is expected. This leads to an estimated 13,551 cow-days at risk during a year in a 100-cow dairy herd. In addition to a blanket DCT (BDCT) scenario, we developed 7 scenarios to select cows for DCT based on SCC. The scenarios covered a range of possible approaches to select low-SCC cows for DCT, all based on cow-level SCC thresholds on the last milk recording before drying off. The incidence rate of clinical mastitis in the example herd varied from 11.6 to 14.5 cases of clinical mastitis per 10,000 cow-days at risk in the different scenarios, and the prevalence of subclinical mastitis varied from 38.8% in scenario 1 (BDCT) to 48.3% in scenario 8. Total antimicrobial usage for DCT and clinical mastitis treatment varied over the scenarios from 1.27 (scenario 8) to 3.15 animal daily dosages (BDCT), leading to a maximum reduction in antimicrobial usage of 60% for scenario 8 compared with BDCT. The total costs for each of the scenarios showed little variation, varying from €4,893 for scenario 5 to €5,383 for scenario 8. The effect of selective DCT compared with BDCT on udder health, antimicrobial usage, and economics is influenced by the SCC criteria used to select cows for DCT. Scenario 2 resulted in the lowest increases in clinical and subclinical mastitis compared with BDCT. The greatest reduction in antimicrobial usage was achieved under scenario 8. From an economic perspective, lowest costs were achieved with scenario 5. Drying off dairy cows with antimicrobials has an effect on udder health, antimicrobial usage, and economics.

Evaluation of the use of dry cow antibiotics in low somatic cell count cows.

The goal of dry cow therapy (DCT) is to reduce the prevalence of intramammary infections (IMI) by eliminating existing IMI at drying off and preventing new IMI from occurring during the dry period. Due to public health concerns, however, preventive use of antibiotics has become questionable. This study evaluated selective DCT in 1,657 cows with low somatic cell count (SCC) at the last milk recording before drying off in 97 Dutch dairy herds. Low SCC was defined as <150,000 cells/mL for primiparous and <250,000 cells/mL for multiparous cows. A split-udder design was used in which 2 quarters of each cow were treated with dry cow antibiotics and the other 2 quarters remained as untreated controls. The effect of DCT on clinical mastitis (CM), bacteriological status, SCC, and antibiotic use were determined at the quarter level using logistic regression and chi-squared tests. The incidence rate of CM was found to be 1.7 times (95% confidence interval = 1.4-2.1) higher in quarters dried off without antibiotics as compared with quarters dried off with antibiotics. Streptococcus uberis was the predominant organism causing CM in both groups. Somatic cell count at calving and 14 d in milk was significantly higher in quarters dried off without antibiotics (772,000 and 46,000 cells/mL, respectively) as compared with the quarters dried off with antibiotics (578,000 and 30,000 cells/mL, respectively). Quarters with an elevated SCC at drying off and quarters with a positive culture for major pathogens at drying off had a higher risk for an SCC above 200,000 cells/mL at 14 d in milk as compared with quarters with a low SCC at drying off and quarters with a negative culture for major pathogens at drying off. For quarters that were culture-positive for major pathogens at drying off, a trend for a higher risk on CM was also found. Selective DCT, not using DCT in cows that had a low SCC at the last milk recording before drying off, significantly increased the incidence rate of CM and SCC. The decrease in antibiotic use by drying off quarters without DCT was not compensated by an increase in antibiotic use for treating CM. Total antibiotic use related to mastitis was reduced by 85% in these quarters.

Protected by nature? Effects of strenuous physical exercise on FVIII activity in moderate and mild haemophilia A patients: a pilot study.

Increase of factor VIII activity (FVIII) after physical exercise has been reported in healthy subjects and small-scale studies in patients with coagulopathies. The aim was to study whether moderate and mild haemophilia A patients are able to increase their endogenous FVIII activity levels by physical activity. We studied changes in FVIII activity levels after high-intensity exercise in 15 haemophilia A patients, 20-39 years, eight with moderate, seven with mild haemophilia. Patients cycled until volitional exhaustion, blood samples were drawn before and 10 min after the exercise test. FVIII activity increased 2.5 times (range 1.8-7.0 times), for both severities. Absolute increases were markedly different: median 7 IU dL(-1) (range 3-9 IU dL(-1) ) in patients with moderate, compared to 15 IU dL(-1) (range 6-62 IU dL(-1) ) in mild haemophilia patients. VWF and VWFpp increased independently of severity; median 50% (range 8-123%) and median 165% (range 48-350%), respectively, reflecting acute release of VWF. These observations may be used to promote high-intensity activities before participating in sports for moderate and mild haemophilia A patients, to reduce bleeding risk. Further studies are warranted to fully appreciate the clinical significance of exercise on different levels of intensity in patients with mild and moderate haemophilia A.

Risk of inhibitor development in mild haemophilia A increases with age.

Mild haemophilia A is a rare disease with a relatively mild phenotype. Treatment with factor VIII (FVIII) is indicated after trauma or for surgery only. FVIII infusion may result in the development of inhibiting antibodies against FVIII. This study describes the relation between age and other risk factors for inhibitor development in mild haemophilia. A retrospective cohort study was conducted among all patients with mild haemophilia (FVIII 0.05-0.40 IU mL(-1)) registered at the van Creveldkliniek, University Medical Centre Utrecht, The Netherlands. Data on peak treatment with FVIII, gene mutation and history of inhibitor development were obtained from patient files from the period between 1st January 1970 and 31st December 2009. A total of 231 out of 297 (78%) patients had at least one exposure to FVIII, of whom 14 (6.1%) developed an inhibitor to FVIII at a median age of 66 years after a median of 50 exposure days (ED). Age at first exposure, age at peak treatment, number of peak treatments and Arg593Cys mutation were significantly associated with the development of an inhibitor, while continuous infusion with FVIII was not. Although the incidence of inhibitors in mild haemophilia is low, it increases with age and peak treatments. With increasing age patients with mild haemophilia will suffer from co-morbidity more frequently, requiring surgical interventions and exposing them to an increased risk of inhibitor development. Especially patients with a change of arginine in cysteine at 593 are at risk for inhibitor development.

Clinical severity of haemophilia A: does the classification of the 1950s still stand?

The classification of haemophilia originates from 1950s and has been adopted unchallengedly by the ISTH in 2001. The aim of this study was: does the current classification compare onset of bleeding and age at first treatment, as well as annual joint bleeding frequency according to baseline FVIII activity? Data on age and reason of diagnosis, onset of treatment, onset of bleeding and bleeding frequency from 411 patients with haemophilia A born after 1970 were collected. Data were analysed according to base-line FVIII activity levels. Age at diagnosis, onset of bleeding and start of treatment according to FVIII activity were compared with the current classification. Overall, the distinction between severe and non-severe haemophilia was clear. The distinction between mild and moderate haemophilia was more difficult, mostly due to the wide variability in the group of patients with moderate haemophilia. Patients with severe haemophilia experienced their milestones like diagnosis, first treatment and joint bleed earliest, mostly as infants aged 0-3 years, whereas patients with moderate haemophilia reached these milestones around toddler age, 2-7 years, and patients with mild haemophilia reached them when they were in elementary school, around the ages of 5-14 years. This study confirms the clinical distinction between severe and non-severe haemophilia A. However, the group of moderate haemophilia patients showed a wide variability, warranting close follow-up and individualized treatment.

Magnetic resonance imaging in teenagers and young adults with limited haemophilic arthropathy: baseline results from a prospective study.

The clinical relevance of subtle changes on magnetic resonance imaging (MRI) for evaluating haemophilia treatment is unknown. To determine the relationship of findings on MRI with joint function and bleeding in joints with apparently very mild arthropathy, a prospective study was performed. Knees and ankles of 26 patients, 13-26 years, were scanned. Two blinded radiologists scored the MRI (IPSG consensus score) and the radiography [Pettersson score (PS)]. Clinical function (HJHS) was scored by one physiotherapist. Life-time number of bleeds was collected from patient files. Of 104 joints scanned, three were excluded because of previous arthrodesis or trauma. Remaining 101 MRI scores correlated weakly with clinical function (r = 0.27, P = 0.01) and less with lifetime number of bleeds (r = 0.16, P = 0.14). MRI scores were 0 in 58 joints, including 27 with major bleeds. In three joints of patients playing intensive sports MRI showed minor changes (MRI score = 1) in the absence of bleeds. Agreement was reasonable between PS and MRI score (r = 0.41, P < 0.01). In 30% of joints, MRI detected abnormalities in soft-tissue and cartilage, while PS was 0 points. No evidence of occult haemorrhages was found. Instead, we found no abnormalities on MRI in 43 joints with a history of repeated joint bleeding. Haemosiderin seemed associated with the time between assessment and last bleed; joints that had suffered a bleed long before MRI had hardly haemosiderin, while those with a recent bleed showed haemosiderin, suggesting joint damage may be reversible. Abnormalities detected by MRI, but not by PS were minor and their clinical implications are not yet clear.

Analysis of low frequency bleeding data: the association of joint bleeds according to baseline FVIII activity levels.

Many studies in the field of haemophilia and other coagulation deficiencies require analyses of bleeding frequencies. In haemophilia, the association of bleeding frequency with factor VIII (FVIII) activity levels is known from experience, but significant results are lacking. Bleeding frequencies in haemophilia are highly skewed count data, with large proportions of zeros. Both the skewness and the high amount of zeros pose a problem for standard (linear) modelling techniques. This study investigated the optimal analysing strategy for bleeding data by using the association of residual clotting factor level and number of joint bleeds in moderate and mild patients treated on demand as example. In total, 433 patients with moderate (27%) and mild (73%) haemophilia A treated on demand were included in this study. One year of self-reported data on joint bleed frequency and baseline clotting factor activity were analysed using Poisson, negative binomial, zero-inflated Poisson, and zero-inflated negative binomial distributions. Multivariate regression analysis using negative binomial distribution provided the optimum data analytical strategy. This model showed 18% reduction [Rate ratio (RR) 0.82; 95%confidence interval (CI) 0.77-0.86] of bleeding frequency with every IU dL(-1) increase in residual FVIII activity. The actual association is expected to be higher because of exclusion (30 out of 463 patients) of patients on prophylaxis (baseline FVIII levels 0.01-0.06 IU mL(-1)). The best way to analyse low frequency bleeding data is using a negative binomial distribution.

Clinical outcome of moderate haemophilia compared with severe and mild haemophilia.

UNLABELLED: Information on outcome and treatment of patients with moderate haemophilia is scarce. In this study, we compared self-reported burden of disease in moderate haemophilia to severe and mild haemophilia. A nationwide questionnaire on bleeding pattern, treatment, impairment and quality of life was sent to 1567 Dutch patients with haemophilia. Out of 1066 respondents (response rate: 68%), 16% had moderate, 44% severe and 39% mild haemophilia. Median age was 36 years. Although overall outcome in moderate haemophilia was in between severe and mild haemophilia, moderate haemophilia patients did report a substantial burden of disease. The majority of patients with moderate haemophilia (73%) reported bleeds in the previous year; and a considerable proportion of moderate patients reported joint impairment (43%), chronic pain (15%), needed orthopaedic aids (24%) or were unemployed because of disability (27%). Within the group of moderate haemophilia patients, a large variation in bleeding pattern and outcome was observed. A quarter of patients with moderate haemophilia reported a more severe phenotype and intermittent use of prophylaxis. These patients reported frequent bleeding, with a median of eight bleeds per year, including two joint bleeds, and 68% reported joint impairment. IN CONCLUSION: Although outcome in moderate haemophilia is generally in between severe and mild haemophilia, moderate haemophilia patients reported a substantial burden of disease, and for more than 25% of patients with moderate haemophilia long term prophylaxis was implemented because of frequent bleeds.