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  1. Article ; Online: Comparison of diagnostic methods for assessment of Ostertagia ostertagi exposure in Norwegian dairy herds

    Tonje Opsal / Ingrid Toftaker / Lucy Robertson / Ian Woolsey / Lisbeth Hektoen

    Acta Veterinaria Scandinavica, Vol 65, Iss 1, Pp 1-

    2023  Volume 10

    Abstract: Abstract Background The gastrointestinal nematode (GIN) Ostertagia ostertagi can cause severe disease in first season grazers (FSG) and impaired performance due to subclinical infections in adult cows. Diagnostic methods to assess exposure include faecal ...

    Abstract Abstract Background The gastrointestinal nematode (GIN) Ostertagia ostertagi can cause severe disease in first season grazers (FSG) and impaired performance due to subclinical infections in adult cows. Diagnostic methods to assess exposure include faecal egg count and detection of specific antibodies using antibody-ELISAs resulting in an optical density ratio (ODR). Using the ELISA test on bulk tank milk (BTM) allows for a herd level diagnosis. Appropriate use of diagnostic methods for evaluation of O. ostertagi exposure is required to optimize herd parasite surveillance and aid in a sustainable control regime. The aim of this study was to describe the relationship between different diagnostic tests used to assess GIN exposure in Norwegian production systems. A cross-sectional field study was carried out in twenty herds in Norway in the fall of 2020. Serum and faecal samples were taken from 380 individuals, of which 181 were FSG and 199 were cows. In addition, milk was collected from every cow and one BTM sample was taken from each herd. Faecal egg counts were performed. The distribution of ODR values in individual samples within and between herds and the associations between BTM ODR and individual ODR values were described. The data were analysed using visual assessment of scatter plots, Pearson correlation coefficients and linear regression. Results A high variability of the within-herd individual ODR values in serum and milk in every herd was detected. The ODR in BTM explained a low degree of the variation in the individual serum and milk samples. When plotting the ODR results in milk or serum according to four BTM categories, the distribution of ODR values were notably different in the highest and lowest BTM categories. The correlation between individual milk and serum samples was moderate (r = 0.68), while the highest correlation (r = 0.81) was between the BTM ODR and the group average individual milk samples. Conclusions A poor predictive ability for BTM ODR to assess individual ODR values in both FSG and ...
    Keywords Antibody level ; Bulk tank milk ; ELISA ; Gastrointestinal nematodes ; Optical density rate ; Pasture parasites ; Veterinary medicine ; SF600-1100
    Subject code 630
    Language English
    Publishing date 2023-11-01T00:00:00Z
    Publisher BMC
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Gastrointestinal nematodes and Fasciola hepatica in Norwegian cattle herds

    Tonje Opsal / Ingrid Toftaker / Ane Nødtvedt / Lucy Jane Robertson / Kristoffer Relling Tysnes / Ian Woolsey / Lisbeth Hektoen

    Acta Veterinaria Scandinavica, Vol 63, Iss 1, Pp 1-

    a questionnaire to investigate farmers’ perceptions and control strategies

    2021  Volume 13

    Abstract: Abstract Background Pasture management influences the prevalence and impact of the pasture parasites (PP) in cattle herds, which cause production-limiting disease worldwide. Evaluating farmer management strategies is vital when considering sustainable PP ...

    Abstract Abstract Background Pasture management influences the prevalence and impact of the pasture parasites (PP) in cattle herds, which cause production-limiting disease worldwide. Evaluating farmer management strategies is vital when considering sustainable PP control practices. The aim of this questionnaire-based study was to describe the pasture management and control strategies regarding PP in Norwegian beef cattle (BC) and dairy cattle (DC) production systems with a focus on gastrointestinal nematodes (GIN) and Fasciola hepatica. Results A total of 745 responses from BC (return rate 20.5%) and 1347 responses from DC farmers (30.7%) were included. The mean total pasture time for DC was 4.2 months for first-season grazers and 4.3 months for second-season grazers and cows, while the corresponding finding in BC was 5.4 months. Home pasture was used for most of the pasture period, particularly for first-season grazer dairy heifers (81%), which were also commonly grazed on the same pasture every year (79%). For most farmers it was necessary for grazing areas to be used for cattle for more than one season (77% of BC farmers and 89% of DC farmers). However, changing the pasture during the season was common in both DC (67%) and BC (70%) herds. The majority of DC farmers (60%) stated that they did not consider that they had a problem with PP. Of the remaining 40%, few respondents could specify whether their herds had a problem due to infection by GIN (11%) or liver flukes (12%). Treatment for GIN was performed by 52% of DC and 34% of BC farmers. Diagnostic faecal samples were collected upon suspicion of parasitic disease by 5% of DC and 16% of BC farmers. Veterinarians were stated as a central source of information about parasite management and treatment. Conclusions Potential risks for exposure to PP were identified, such as use of the same pasture every year for first-season grazers and frequent use of home pasture. The perception of problems related to PP appeared low. Regular anthelmintic treatment without concurrent ...
    Keywords Anthelmintic treatment ; Grazing ; Ostertagia ostertagi ; Pasture parasites ; Veterinary medicine ; SF600-1100
    Subject code 630
    Language English
    Publishing date 2021-12-01T00:00:00Z
    Publisher BMC
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article: Experimental infection of cattle with ovine Dichelobacter nodosus isolates

    Knappe-Poindecker, Maren / Bereket Tesfamichael / Hannah Joan Jørgensen / Lisbeth Hektoen / Martha Jakobsen Ulvund / Terje Fjeldaas / Tim Kåre Jensen

    Acta veterinaria scandinavica. 2015 Dec., v. 57, no. 1

    2015  

    Abstract: BACKGROUND: Dichelobacter nodosus is the main causative agent of ovine footrot, and there are strong indications that the bacterium can be transferred to cattle grazing on the same pasture as sheep. The aim of this study was to investigate if benign and ... ...

    Abstract BACKGROUND: Dichelobacter nodosus is the main causative agent of ovine footrot, and there are strong indications that the bacterium can be transferred to cattle grazing on the same pasture as sheep. The aim of this study was to investigate if benign and virulent D. nodosus strains isolated from sheep can be transferred to the interdigital skin of cattle under experimental conditions. Further, we wanted to observe the impact of such infection on bovine foot health, and test the effect of topical chlortetracycline (Cyclo spray®: Eurovet) on the infection. FINDINGS: Six heifers were included in the study. After an initial 18-day maceration period, three heifers were inoculated on one single foot with a benign strain and three with a virulent strain by adding bacterial suspension in a bandage. The bandages were left on for 17 days, and when removed, D. nodosus was isolated from all six heifers. All six heifers developed interdigital dermatitis. In five of the heifers D. nodosus organisms were demonstrated within the epidermis. Twenty-four days after treatment with chlortetracycline all heifers were negative by cultivation, but tested positive for D. nodosus by polymerase chain reaction (PCR). Two of the six heifers still tested positive for D. nodosus by PCR 49 days after treatment. After 70 days, all heifers tested negative for D. nodosus. CONCLUSIONS: This study shows that both virulent and benign D. nodosus strains originating from sheep can be transferred to naïve heifers under experimental conditions. Further, the study supports the hypothesis that infections with virulent D. nodosus in cattle are associated with interdigital dermatitis. No conclusion regarding the treatment of D. nodosus infection with chlortetracycline was possible.
    Keywords bacteria ; bandages ; chlortetracycline ; Dichelobacter nodosus ; footrot ; grazing ; heifers ; maceration ; pastures ; polymerase chain reaction ; sheep ; virulence ; virulent strains
    Language English
    Dates of publication 2015-12
    Size p. 55.
    Publishing place BioMed Central
    Document type Article
    ZDB-ID 40137-7
    ISSN 1751-0147 ; 0044-605X
    ISSN (online) 1751-0147
    ISSN 0044-605X
    DOI 10.1186/s13028-015-0148-5
    Database NAL-Catalogue (AGRICOLA)

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