| 1. |
- Alvåsen, Karin, et al.
(författare)
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Risk factors associated with on-farm mortality in Swedish dairy cows
- 2014
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 117, s. 110-120
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Tidskriftsartikel (refereegranskat)abstract
- Dairy cow mortality (unassisted death and euthanasia) has increased, worldwide and in Sweden. On-farm mortality indicates suboptimal herd health or welfare and causes financial loss for the dairy producer. The objective of this study was to identify cow-level risk factors associated with on-farm cow mortality. Cows with at least one calving between 1 July 2008 and 30 June 2009 from herds enrolled in the Swedish official milk recording scheme with >40 cow-years were included. Each cow was followed from the day of calving until she calved again or left the herd (died, slaughtered or sold). The effects of potential risk factors on on-farm cow mortality were analysed using a Weibull proportional hazard model with a gamma distributed frailty effect common to cows within herd. The event of interest (failure) was euthanasia or unassisted death. An observation was right censored if the cow was slaughtered, sold, calved again or had an on-going lactation at 500 days after calving. The lactations were split into seasons (January to April, May to August and September to December) and at 30 and 100 days in milk in order to evaluate seasonal effects and the effect of disease in different lactation stages. Primiparous and multiparous cows were analysed separately. The highest hazards for both primiparous and multiparous cows were found for traumatic events and diseases, both in the lactation stage in which the cow died and in the preceding stage. The hazard was higher in early lactation and lower in 2nd parity compared to higher parities. Increased age at first calving (for primiparous cows), calving between January and April, dystocia and stillbirth also increased the mortality hazard. Differences were also found between breeds, between milk production parameters at first test milking and between management types. The results from this study show the importance of good management and preventive health actions, especially around calving, to avoid mortality in dairy cows. (C) 2014 Elsevier B.V. All rights reserved.
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| 2. |
- Egenvall, Agneta, et al.
(författare)
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Days-lost to training and competition in relation to workload in 263 elite show-jumping horses in four European countries
- 2013
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 112, s. 387-400
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Tidskriftsartikel (refereegranskat)abstract
- Orthopaedic, or other, injuries in sports medicine can be quantified using the ‘days-lost to training’ concept. Both the training regimen and the surface used in training and racing can affect the health of racehorses. Our aim was to associate ‘days-lost to training’ in elite-level show-jumpers to horse characteristics, training and management strategies, and the time spent working on various training and competition surfaces. We designed a longitudinal study of professional riders in four European countries. Data were recorded using training diaries. Reasons for days-lost were classified into non-acute and acute orthopaedic, medical, hoof-related, and undefined. We produced descriptive statistics of training durations, relative to type of training, surfaces used, and days-lost. We created zero-inflated negative-binomial random-effects models using the overall days-lost as outcome. In the whole dataset, duration variables related to training surfaces were analysed as independent. The Swedish data only were also used to test whether duration variables were related to competition surfaces. Thirty-one riders with 263 horses provided data on 39,028 days at risk. Of these, 2357 (6.0%) were days-lost (55% and 22% of these were due to non-acute and acute orthopaedic injuries, respectively) in 126 horses. In the all-country model, controlling for season, a significant variable was country. Switzerland and the UK had lower incidence-rate ratios (IR) compared to Sweden (IRs 0.2 and 0.03, respectively). Horses with previous orthopaedic problems had almost a doubled IR (1.8) of days-lost due to orthopaedic injury, compared to baseline. If the horse had jumping training more than 1 minute per day at risk the IRs were 6.9-7 (compared to less than this amount of time); this was, however, likely an effect of a small baseline. Variation in training was a protective factor with a dose-response relationship; the category with the highest variation had an IR of 0.1. In the Swedish model, controlling for season, there was an association of year (IR 2.8 year 2010). Further, if the horse rested >17-25% of the days at risk, or >33% of the DAR2, had IRs 3.5 and 3,0, compared to less time. Horses ≥6 years had IRs of 1.8-2.0, compared to younger horses. Limited training use of sand surface was a risk-factor (IR 2.2; >4≤12 min/day at risk), compared to not training on sand. Training/competing on sand-wood was a protective factor (IRs 0.4-0.5) compared to not using this surface.
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| 3. |
- Egenvall, Agneta
(författare)
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Validation of the diagnosis canine epilepsy in a Swedish animal insurance database against practice records
- 2014
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 114, s. 145-150
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Tidskriftsartikel (refereegranskat)abstract
- Canine epilepsy is one of the most common neurological conditions in dogs but the actual incidence of the disease remains unknown. A Swedish animal insurance database has previously been shown useful for the study of disease occurrence in companion animals. The dogs insured by this company represent a unique population for epidemiological studies, because they are representative of the general dog population in Sweden and are followed throughout their life allowing studies of disease incidence to be performed. The database covers 50% of all insured dogs (in the year 2012) which represents 40% of the national dog population. Most commonly, dogs are covered by both veterinary care insurance and life insurance. Previous studies have shown that the general data quality is good, but the validity of a specific diagnosis should be examined carefully before using the database for incidence calculations. The aim of the current study was therefore to validate the information contained in the insurance database regarding canine epilepsy. The validation focused on the positive predictive value and the data-transfer from the veterinary practice records to the insurance database. The positive predictive value was defined as the proportion of recorded cases that actually had the disease in question. The quality of the data-transfer was assessed by comparing the diagnostic codes in practice records to the codes in the insurance database. The positive predictive value of the diagnostic codes for canine epilepsy (combining "epileptic convulsions" and "idiopathic epilepsy") in the insurance database was validated in a cross-sectional study where insurance claims for canine epilepsy were compared to diagnostic information in practice records. A random sample of dogs with a reimbursed insurance claim during 2006 was included in the study sample (n = 235). Practice records were requested by mail from attending veterinarians. Two independent examiners scrutinized all the records. All 235 dogs were coded correctly in the database as they really had suffered seizures with or without convulsions, and the quality of the datatransfer was therefore excellent. In total, 167 dogs (71%) were classified as cases of canine epilepsy according to pre-defined criteria, and the positive predictive value was therefore considered relatively high. Based on these results, it was concluded that the data regarding canine epilepsy in the insurance database can be used for further population studies. (c) 2014 Elsevier B.V. All rights reserved.
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| 4. |
- Emanuelson, Ulf, et al.
(författare)
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The data - Sources and validation
- 2014
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 113, s. 298-303
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Tidskriftsartikel (refereegranskat)abstract
- The basis for all observational studies is the availability of appropriate data of high quality. Data may be collected specifically for the research purpose in question (so-called "primary data"), but data collected for other purposes (so-called "secondary data") are also sometimes used and useful in research. High accuracy and precision are required (irrespective of the source of the data) to arrive at correct and unbiased results efficiently. Both careful planning prior to the start of the data acquisition and thorough procedures for data entry are obvious prerequisites to achieve high-quality data. However, data should also be subjected to a thorough validation after the collection. Primary data are mainly validated through proper screening, by using various descriptive statistical methods. Validation of secondary data is associated with specific conditions - the first of which is to be aware of the limitations in its usefulness imposed by procedures during collection. Approaches for validation of secondary data will be briefly discussed in the paper, and include patient chart review, combining with data from other sources, two-stage sampling, and aggregated methods. (C) 2013 Elsevier B.V. All rights reserved.
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| 5. |
- Engvall Olsson, Eva, et al.
(författare)
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Risk factors associated with the presence of Campylobacter-positive broiler flocks in Sweden
- 2010
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 96, s. 114-121
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Tidskriftsartikel (refereegranskat)abstract
- Approximately 40% of Swedish broiler producers deliver Campylobacter-negative broilers in 90-100% of their flocks, showing that it is possible to produce Campylobacter-free broilers in Sweden. This study investigated risk factors associated with the presence of Campylobacter-positive flocks at Swedish broiler producers. A total of 37 producers, with 90 broiler houses including 144 compartments, participated in the study. An on-farm interview was performed to collect information on potential risk factors for Campylobacter infection in broilers, with questions about farmcharacteristics such as the environment around the farm and broiler houses, design of the broiler houses and on-farm management practices. Negative binomial regression models were used to assess the statistical significance of risk factors associated with the within-farm number of Campylobacter-positive flocks (the outcome).Campylobacter is transmitted in broiler flocks due to multiple factors and several potential sources, illustrating the complexity of Campylobacter epidemiology in broilers. Factors significantly associated with increased proportion of Campylobacter-positive flocks were the presence of other livestock on the farm, or the presence of cattle, swine, poultry or fur animals within 1 km of the farm. Poor or average general tidiness were associated with increased proportion of Campylobacter-positive flocks, but decreased if split slaughter was seldom or never applied or if farm workers changed footwear twice or three times instead of once before entering the broiler house. (C) 2010 Elsevier B.V. All rights reserved.
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| 6. |
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| 7. |
- Frössling, Jenny, et al.
(författare)
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A novel method to identify herds with an increased probability of disease introduction due to animal trade
- 2014
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 117, s. 367-374
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Tidskriftsartikel (refereegranskat)abstract
- In the design of surveillance, there is often a desire to target high risk herds. Such risk-based approaches result in better allocation of resources and improve the performance of surveillance activities. For many contagious animal diseases, movement of live animals is a main route of transmission, and because of this, herds that purchase many live animals or have a large contact network due to trade can be seen as a high risk stratum of the population. This paper presents a new method to assess herd disease risk in animal movement networks. It is an improvement to current network measures that takes direction, temporal order, and also movement size and probability of disease into account. In the study, the method was used to calculate a probability of disease ratio (PDR) of herds in simulated datasets, and of real herds based on animal movement data from dairy herds included in a bulk milk survey for Coxiella burnetii. Known differences in probability of disease are easily incorporated in the calculations and the PDR was calculated while accounting for regional differences in probability of disease, and also by applying equal probability of disease throughout the population. Each herd's increased probability of disease due to purchase of animals was compared to both the average herd and herds within the same risk stratum. The results show that the PDR is able to capture the different circumstances related to disease prevalence and animal trade contact patterns. Comparison of results based on inclusion or exclusion of differences in risk also highlights how ignoring such differences can influence the ability to correctly identify high risk herds. The method shows a potential to be useful for risk-based surveillance, in the classification of herds in control programmes or to represent influential contacts in risk factor studies. (C) 2014 Elsevier B.V. All rights reserved.
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| 8. |
- Frössling, Jenny, et al.
(författare)
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Application of network analysis parameters in risk-based surveillance - Examples based on cattle trade data and bovine infections in Sweden
- 2012
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Ingår i: Preventive Veterinary Medicine. - : Elsevier. - 0167-5877 .- 1873-1716. ; 105:3, s. 202-208
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Tidskriftsartikel (refereegranskat)abstract
- Financial resources may limit the number of samples that can be collected and analysed in disease surveillance programmes. When the aim of surveillance is disease detection and identification of case herds, a risk-based approach can increase the sensitivity of the surveillance system. In this paper, the association between two network analysis measures, i.e. ‘in-degree’ and ‘ingoing infection chain’, and signs of infection is investigated. It is shown that based on regression analysis of combined data from a recent cross-sectional study for endemic viral infections and network analysis of animal movements, a positive serological result for bovine coronavirus (BCV) and bovine respiratory syncytial virus (BRSV) is significantly associated with the purchase of animals. For BCV, this association was significant also when accounting for herd size and regional cattle density, but not for BRSV. Examples are given for different approaches to include cattle movement data in risk-based surveillance by selecting herds based on network analysis measures. Results show that compared to completely random sampling these approaches increase the number of detected positives, both for BCV and BRSV in our study population. It is concluded that network measures for the relevant time period based on updated databases of animal movements can provide a simple and straight forward tool for risk-based sampling.
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| 9. |
- Gidekull, Maria, et al.
(författare)
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Risk factors for calf mortality in large Swedish dairy herds
- 2011
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 99, s. 136-147
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to identify possible risk factors for 1-90 day calf mortality in large Swedish dairy herds. Sixty herds with a herd size of >= 160 cows were visited once between December 2005 and March 2006. Thirty herds were known to have low mortality (LM) and 30 were known high mortality herds (HM). Upon the visit, data about housing and management was collected from interviews with personnel responsible for the calves. The herd status regarding the calves' passive transfer (total protein), levels of alpha-tocopherol, beta-carotene and retinol, and excretion of faecal pathogens (Cryptosporidium spp., Escherichia coli F5, rota and corona virus) was evaluated based on targeted sampling of high risk calf groups; in each herd, blood and faecal samples were collected from calves 1-7 and 1-14 days old, respectively. Similarly, the herd status regarding clinical respiratory disease in calves and history of respiratory virus exposure was evaluated based on lung auscultations and blood samplings of calves 60-90 days old. The median calf mortality risk (in calves 1-90 days of age) among HM herds was 9% (Range: 6-24%) and among LM herds 1% (Range: 0-2%). LM and HM herds were compared using five logistic regression models, covering potential risk factors within different areas: "Disease susceptibility", "Factors affecting the gastrointestinal tract", "Factors related to transmission of infectious disease", "Hygiene" and "Labour management". The percentage of calves, 1-7 days old, with inadequate serum concentrations of alpha-tocopherol and beta-carotene were significantly higher in HM herds compared to LM herds and also associated with higher odds of being a HM herd (OR = 1.02; p = 0.023 and OR = 1.05; p = 0.0028, respectively). The variable "Average number of faecal pathogens in the sampled target group" was significantly associated with higher odds of being a HM herd (OR = 4.65: p = 0.015), with a higher average in HM herds. The percentage of calves with diarrhoea treated with antibiotics was significantly higher in HM herds and was associated with higher odds of being a HM herd (OR = 1.08; p = 0.021). The median age at death of calves in the age interval 1-90 days that died during a one-year period was significantly lower among HM herds (13 days) than in LM herds (24 days) (p = 0.0013) The results indicate that gastrointestinal disorders may be an important cause of calf mortality in large Swedish dairy herds. Furthermore, our study provides additional indications that fat soluble vitamins might play an important role for calf health. (C) 2010 Elsevier B.V. All rights reserved.
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