Dairy Herds

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Ulf Emanuelson - One of the best experts on this subject based on the ideXlab platform.

  • Bovine respiratory syncytial virus and bovine coronavirus in Swedish organic and conventional Dairy Herds
    Acta Veterinaria Scandinavica, 2015
    Co-Authors: Cecilia Wolff, Stefan Alenius, Anna Ohlson, Ulf Emanuelson, Nils Fall
    Abstract:

    Background Infections with bovine respiratory syncytial virus (BRSV) and bovine coronavirus (BoCV) are endemic to the cattle populations in most countries, causing respiratory and/or enteric disease. It has been demonstrated that Herds can remain free from these infections for several years also in high prevalence areas. Organically managed (OM) Dairy Herds have been shown to have lower seroprevalence of both viruses compared to conventionally managed (CM) Herds. The objective of this study was to challenge the hypothesis of a lower occurrence of BRSV and BoCV in OM compared to CM Dairy Herds. In November 2011, May 2012 and May 2013 milk samples from four homebred primiparous cows were collected in 75 to 65 OM and 69 to 62 CM Herds. The antibody status regarding BRSV and BoCV was analysed with commercial indirect ELISAs. Herds were classified as positive if at least one individual sample was positive. Results The prevalence of positive Herds ranged from 73.4% to 82.3% for BRSV and from 76.8% to 85.3% for BoCV among OM and CM Herds, over the three sampling occasions. There was no statistically significant difference between OM and CM Herds at any sampling occasion. The incidence risk of newly infected Herds did not differ statistically between OM and CM Herds at any sampling occasion, neither for BRSV nor for BoCV. The incidence of Herds turning sero-negative between samplings corresponded to the incidence of newly infected. Bulk tank milk (BTM) samples were also sampled in the Herds and analysed. Several Herds were negative on individual samples but positive in BTM. Herd-level data on production, health and reproduction were retrieved from VÄXA Sweden and the study Herds were representative of the source population. Conclusion There was no difference in prevalence of or incidence risk for BRSV or BoCV between Swedish OM and CM Herds. Because the incidence of Herds becoming seropositive was balanced by Herds becoming seronegative it should be possible to lower the prevalence of these two infections among Swedish Dairy cattle Herds if biosecurity is improved.

  • A longitudinal study of the dynamics of bovine corona virus and respiratory syncytial virus infections in Dairy Herds
    Veterinary Journal, 2013
    Co-Authors: Anna Ohlson, Madeleine Tråvén, Stefan Alenius, Ulf Emanuelson
    Abstract:

    Abstract The objective of this study was to examine the dynamics of bovine corona virus (BCV) and bovine respiratory syncytial virus (BRSV) infections in Dairy Herds over a 3-year period. The status of 79 Dairy Herds located in two Northern and two Southern Regions of Sweden were surveyed by measuring antibody concentrations to BCV and BRSV in pooled milk samples from primiparous cows, and in bulk-tank milk twice annually. In the Southern Regions the percentage of antibody-positive Herds remained persistently high (75–100%), whereas in Herds based in the Northern Region, the percentage of positive Herds for BCV and BRSV was 38–80% and 0–80%, respectively, with antibody levels to BRSV decreasing over time. Pooled milk samples of ‘home-bred’ primiparous animals were found to be most useful in terms of monitoring herd status but could gradually be replaced by bulk-tank sampling once freedom from infection was established.

  • herd level risk factors associated with cow mortality in swedish Dairy Herds
    Journal of Dairy Science, 2012
    Co-Authors: Karin Alvasen, Peter T Thomsen, Jansson M Mork, Hallen C Sandgren, Ulf Emanuelson
    Abstract:

    Abstract An increase in on-farm mortality (euthanasia and death) in Dairy Herds has been reported in several countries in the last decade. This does not only imply possible problems with animal welfare, but it also causes economic losses to the farmer. The objective of this study was to evaluate time trends in on-farm Dairy cow mortality in Sweden and identify potential herd-level risk factors. Data were retrieved on all Swedish Dairy Herds enrolled in the milk recording scheme between 2002 and 2010. Herds with a herd size of 40 dead or euthanized cows per 100 cow-years were excluded. Two different models were used: 1 multiple-year analysis, which included 6,898 Herds during the period 2002 to 2010 and 1 single-year analysis including 4,252 Herds for the year 2010, where other variables that were not present during the entire multiple year study were analyzed. The outcome variable was the number of euthanized and dead cows per year and season. A negative binomial regression model, adjusted for clustering within herd, was applied to both models. Fixed effects in the multiple-year analysis were breed, calving interval, herd size, milk yield, region, season, pasture period, and year. The fixed effects in the single-year analysis were breed, calving interval, conventional versus organic farming, herd size, housing system, milk yield, region, and season. The results demonstrated that MR gradually increased from 5.1 to 6.6 events per 100 cow-years during the study period. Swedish MR are consequently on par with, or even greater than, MR among Dairy Herds in other comparable countries. Higher mortality was associated with larger herd size, longer calving intervals, and Herds that had Swedish Holstein as the predominant breed. Lower mortality was observed in Herds with a higher herd average milk yield, during the fall and winter, and in organically managed Herds. There were regional differences in mortality. An interaction between herd size and season was found in both models. Also, an interaction between housing system and milk yield was found in the single-year analysis. This first assessment of on-farm mortality in Swedish Dairy Herds confirmed that the MR has increased over the last few years. The study also identified some herd-level risk factors.

  • mastitis and related management factors in certified organic Dairy Herds in sweden
    Acta Veterinaria Scandinavica, 2006
    Co-Authors: Cecilia Hamilton, Ulf Emanuelson, Kristina Forslund, Ingrid Hansson, Torkel Ekman
    Abstract:

    Background Mastitis is one of the major threats to animal health, in organic farming as well as conventional. Preliminary studies of organic Dairy Herds have indicated better udder health in such Herds, as compared to conventional Herds. The aim of this paper was to further study mastitis and management related factors in certified organic Dairy Herds.

Y H Schukken - One of the best experts on this subject based on the ideXlab platform.

  • effect of lactation therapy on staphylococcus aureus transmission dynamics in two commercial Dairy Herds
    BMC Veterinary Research, 2013
    Co-Authors: John W Barlow, Ruth N Zadoks, Y H Schukken
    Abstract:

    Treatment of subclinical mastitis during lactation can have both direct (individual animal level) and indirect (population level) effects. With a few exceptions, prior research has focused on evaluating the direct effects of mastitis treatment, and to date no controlled field trials have been conducted to test whether beneficial indirect effects of lactation treatment strategies targeting subclinical mastitis can be demonstrated on commercial Dairy farms. Furthermore, there is limited knowledge on the impact of such interventions on the population dynamics of specific bacterial strains. The purpose of this study was to test the hypothesis that lactation therapy targeting S. aureus subclinical intramammary infection reduces transmission of S. aureus strains within Dairy Herds. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to determine strain specific infection dynamics in treated and control groups in a split herd trial conducted on 2 commercial Dairy farms. The direct effect of 8 days intramammary lactation therapy with pirlimycin hydrochloride was demonstrated by an increased proportion of cure and a reduction in duration of infection in quarters receiving treatment compared to untreated controls. The indirect effect of lactation therapy was demonstrated by reduction of new S. aureus intramammary infections (IMI) caused by the dominant strain type in both Herds. Strain typing of representative isolates taken over the duration of all IMI, including pre- and post-treatment isolates, provided more precise estimates of new infection, cure, and re-infection rates. New S. aureus infections in recovered susceptible quarters and the emergence of a new strain type in one herd influenced incidence measures. In addition to demonstrating positive direct effects of lactation therapy, this study provides evidence that treatment of subclinical S. aureus mastitis during lactation can have indirect effects including preventing new IMI and reducing incidence of clinical mastitis within Dairy Herds. Strain specific transmission parameter estimates for S. aureus MLST clonal complexes 5, 97 and 705 in 2 commercial Dairy Herds are also reported.

  • clinical epidemiological and molecular characteristics of streptococcus uberis infections in Dairy Herds
    Epidemiology and Infection, 2003
    Co-Authors: Ruth N Zadoks, O C Sampimon, H W Barkema, B E Gillespie, S P Oliver, Y H Schukken
    Abstract:

    SUMMARY A longitudinal observational study (18 months) was carried out in two Dutch Dairy Herds to explore clinical, epidemiological and molecular characteristics of Streptococcus uberis mastitis. Infections (n=84) were detected in 70 quarters of 46 cows. Bacterial isolates were characterized at strain level by random amplified polymorphic DNA (RAPD) fingerprinting. Persistent infections were usually attributable to one strain, while recurrent infections could be caused by different strains. When multiple quarters of a cow were infected, infections were mostly caused by one strain. In each herd, multiple strains were identified yet one strain predominated. The majority of all infections were subclinical, and infections attributed to predominant strains were more chronic than infections attributed to other strains. Epidemiological and molecular data suggest infection from environmental sources with a variety of S. uberis strains as well as within-cow and between-cow transmission of a limited number of S. uberis strains, with possible transfer of bacteria via the milking machine.

  • prevalence and regional distribution of paratuberculosis in Dairy Herds in the netherlands
    Veterinary Microbiology, 2000
    Co-Authors: J Muskens, Herman W. Barkema, E W Russchen, K Van Maanen, Y H Schukken, Douwe Bakker
    Abstract:

    In the Netherlands a survey was conducted to estimate the prevalence of paratuberculosis in Dairy Herds. In total 15822 cows of at least 3 years of age, belonging to 378 Herds were tested using an absorbed ELISA. Of these Herds, 55% (n=207) had one or more serologically positive cows. Of the positive non-vaccinated Herds, most had one (n=98) or two (n=49) positive cows. The percentage positive cows per herd was 2.5±3.2%. The true prevalences on cow and herd levels, based on a test sensitivity that ranged from 0.3 to 0.4 and a specificity that ranged from 0.985 and 0.995, were estimated at 2.7–6.9% and 31–71%. Seven Herds had been vaccinated against paratuberculosis and these Herds had a significantly higher percentage of serologically positive cows (23%) than the non-vaccinated Herds (2.5%). In conclusion, a small percentage of the Dairy cows and a high percentage of the Dairy Herds in the Netherlands is serologically positive. The percentages true infected cows and Herds are difficult to estimate precisely due to uncertainties in test sensitivity and specificity.

G Van Schaik - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of udder health parameters and risk factors for clinical mastitis in dutch Dairy Herds in the context of a restricted antimicrobial usage policy
    Journal of Dairy Science, 2016
    Co-Authors: I M G A Santmanberends, J M Swinkels, J Keurentjes, G Van Schaik
    Abstract:

    Recently, many changes have been implemented in Dutch Dairy Herds. Herd sizes have increased and antimicrobial use has been reduced. Certain types of antimicrobials can only be used in specific circumstances, and the preventive use of antimicrobials in dry cows is prohibited. The aim of this study was to quantify clinical mastitis (CM), subclinical mastitis (SCM), and risk factors associated with CM in Dutch Dairy Herds in 2013, in the context of these changes. For this study, 240 Dairy Herds were randomly selected from farms that participated in test-day milk recording, used a conventional milking system, and agreed to participate in the study. Eventually, 233 Dutch Dairy farmers had complete records of CM in their Herds in 2013 and 224 of these farmers completed a questionnaire on management factors potentially associated with CM. All participating farmers gave consent to use their routinely collected herd data such as test-day records and cow identification and registration data. Clinical and subclinical mastitis incidence rate (CMI and SCMI, respectively) per 100 cows per year, subclinical mastitis prevalence, and average bulk tank milk somatic cell count were obtained for 2013. The risk factor analysis was conducted using a generalized linear model with a log link function and a negative binomial distribution on herd level in Stata 13.1. A median CMI of 28.6 per 100 cows at risk per year, SCMI of 70.1 per 100 cows at risk per year, SCM prevalence of 15.8%, and bulk tank milk somatic cell count of 171 × 10(3) cells/mL were observed in 2013. Factors that were significantly associated with a higher CMI were cleaning slatted floors only once per day compared with more than 4 times a day (i.e., mechanical), a higher percentage of Holstein Friesian cows present in the herd, treating less than 50% of the cows with CM with antimicrobials, postmilking teat disinfection, and treatment of cows with elevated somatic cell count with antimicrobials. The results of this study indicated that udder health had not deteriorated compared with udder health in previous Dutch studies where herd sizes were somewhat smaller and before the restrictions in antimicrobial use. Several of the risk factors that were found can be influenced by the farmer and can prevent the occurrence of CMI. Still, when cases of CM occur, treatment with antimicrobials might be necessary to cure the CM case and is beneficial for the overall udder health in the herd.

Ruth N Zadoks - One of the best experts on this subject based on the ideXlab platform.

  • effect of lactation therapy on staphylococcus aureus transmission dynamics in two commercial Dairy Herds
    BMC Veterinary Research, 2013
    Co-Authors: John W Barlow, Ruth N Zadoks, Y H Schukken
    Abstract:

    Treatment of subclinical mastitis during lactation can have both direct (individual animal level) and indirect (population level) effects. With a few exceptions, prior research has focused on evaluating the direct effects of mastitis treatment, and to date no controlled field trials have been conducted to test whether beneficial indirect effects of lactation treatment strategies targeting subclinical mastitis can be demonstrated on commercial Dairy farms. Furthermore, there is limited knowledge on the impact of such interventions on the population dynamics of specific bacterial strains. The purpose of this study was to test the hypothesis that lactation therapy targeting S. aureus subclinical intramammary infection reduces transmission of S. aureus strains within Dairy Herds. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to determine strain specific infection dynamics in treated and control groups in a split herd trial conducted on 2 commercial Dairy farms. The direct effect of 8 days intramammary lactation therapy with pirlimycin hydrochloride was demonstrated by an increased proportion of cure and a reduction in duration of infection in quarters receiving treatment compared to untreated controls. The indirect effect of lactation therapy was demonstrated by reduction of new S. aureus intramammary infections (IMI) caused by the dominant strain type in both Herds. Strain typing of representative isolates taken over the duration of all IMI, including pre- and post-treatment isolates, provided more precise estimates of new infection, cure, and re-infection rates. New S. aureus infections in recovered susceptible quarters and the emergence of a new strain type in one herd influenced incidence measures. In addition to demonstrating positive direct effects of lactation therapy, this study provides evidence that treatment of subclinical S. aureus mastitis during lactation can have indirect effects including preventing new IMI and reducing incidence of clinical mastitis within Dairy Herds. Strain specific transmission parameter estimates for S. aureus MLST clonal complexes 5, 97 and 705 in 2 commercial Dairy Herds are also reported.

  • clinical epidemiological and molecular characteristics of streptococcus uberis infections in Dairy Herds
    Epidemiology and Infection, 2003
    Co-Authors: Ruth N Zadoks, O C Sampimon, H W Barkema, B E Gillespie, S P Oliver, Y H Schukken
    Abstract:

    SUMMARY A longitudinal observational study (18 months) was carried out in two Dutch Dairy Herds to explore clinical, epidemiological and molecular characteristics of Streptococcus uberis mastitis. Infections (n=84) were detected in 70 quarters of 46 cows. Bacterial isolates were characterized at strain level by random amplified polymorphic DNA (RAPD) fingerprinting. Persistent infections were usually attributable to one strain, while recurrent infections could be caused by different strains. When multiple quarters of a cow were infected, infections were mostly caused by one strain. In each herd, multiple strains were identified yet one strain predominated. The majority of all infections were subclinical, and infections attributed to predominant strains were more chronic than infections attributed to other strains. Epidemiological and molecular data suggest infection from environmental sources with a variety of S. uberis strains as well as within-cow and between-cow transmission of a limited number of S. uberis strains, with possible transfer of bacteria via the milking machine.

R Boss - One of the best experts on this subject based on the ideXlab platform.

  • a multiarm randomized field trial evaluating strategies for udder health improvement in swiss Dairy Herds
    Journal of Dairy Science, 2015
    Co-Authors: A Tschopp, T. Kaufmann, Michèle Bodmer, Martin Reist, L Kretzschmar, D Heiniger, Beat Berchtold, F Wohlfender, M Harisberger, R Boss
    Abstract:

    The aims of this study were to quantify the effectiveness of specialist advice about udder health in Swiss Dairy Herds and to compare 3 different udder health improvement strategies against a negative control group. In 2010, 100 Swiss Dairy Herds with a high (between 200,000 and 300,000 cells/mL) yield-corrected bulk milk somatic cell count (YCBMSCC) were recruited for a 1-yr multiarm randomized field trial. The Herds were visited between September and December 2011 to evaluate udder health-management practices and then randomly allocated into 1 of 4 study arms containing 25 Herds each. The negative control study arm received neither recommendations for improving udder health nor any active support. The remaining 75 farmers received a herd-specific report with recommendations to improve udder health management. The positive control study arm received no further active support during 2012. The veterinarian study arm received additional support in the form of monthly visits by their herd veterinarian. Finally, the study group study arm received support in the form of bimonthly study group meetings where different topics concerning udder health were discussed. One year later, implementation of recommendations and changes in udder health were assessed. Of the recommendations given, 44.3% were completely implemented, 23.1% partially, and 32.6% were not implemented. No differences in implementation of recommendations were noted between the 3 study arms. At study enrollment, farmers were asked for the study arm of their preference but were subsequently randomly assigned to 1 of the 4 study arms. Farmers that were assigned to the study arm of their preference implemented more recommendations than farmers assigned to a study arm not of their preference. No decrease in the within-herd prevalence of cows that had a high (≥200,000 cells/mL) composite somatic cell count was observed in Herds that had a YCBMSCC ≥200,000 cells/mL at the start of intervention. However, the 3 study arms with intervention (positive control, the veterinarian, and the study groups) prevented an increase in the within-herd prevalence of cows that had a high somatic cell count in Herds with a low YCBMSCC at the start of the intervention compared with the negative control study arm. In the year after sending the report, Herds assigned to the study group study arm had a reduced incidence rate of treated mastitis cases in comparison with the year before sending the report.