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Deventer, Netherlands

Akineden O.,Justus Liebig University | Hassan A.A.,GD Animal Health Service | Schneider E.,Justus Liebig University | Usleber E.,Justus Liebig University
Journal of Dairy Research

Bacteriological analysis of milk samples from quarters of a dairy cow suffering from subclinical mastitis yielded two isolates of Staphylococcus aureus which gave a negative reaction in the standard coagulase test. Both isolates were also clumping factor and thermonuclease negative, and gave a negative reaction in the Staphaurex® test. The isolates were identified by using commercial biochemical systems, and by PCR analysis of different staphylococcal cell surface protein and exoprotein genes. Further molecular identification of the isolates, which included sequencing of the 16S rRNA gene and RT-PCR of coagulase (coa), clumping-factor (clfA) and thermonuclease (nuc) genes, was consistent with the diagnosis phenotypically coagulase-negative variant of Staph. aureus. The fact that coagulase-negative Staph. aureus variants can occur in the context of intramammary infections in cattle may result in the incorrect diagnosis coagulase-negative staphylococci (CNS) in routine mastitis diagnostic, at least in rare cases. To fully ensure correct species diagnosis, sequencing of the 16S rRNA gene and amplification of specific genes such as coa is necessary in these cases. © 2010 Proprietors of Journal of Dairy Research. Source

Andersen S.,University of Prince Edward Island | Dohoo I.R.,University of Prince Edward Island | Olde Riekerink R.,GD Animal Health Service | Stryhn H.,University of Prince Edward Island
Journal of Dairy Science

The primary purpose of this study was to develop a set of criteria to serve as a pseudo-gold standard for what constitutes an intramammary infection using data from 3 consecutive quarter milk samples taken 1 wk apart. Data from lactating cows in 90 dairy herds in 4 Canadian provinces were used to generate the data sets (profiles) used in the conjoint analysis to elicit expert opinions on the topic. The experts were selected from the participants (n = 23) in the 2007 Mastitis Research Workers' Conference in Minneapolis and from a series of mastitis laboratory courses for bovine practitioners (n = 25) in the Netherlands. Three-week udder quarter profiles with specific combinations of somatic cell count, bacterial species isolated, and plate colony count were selected and included in the conjoint analysis based on the desire to achieve even distributions in the categories of 6 constructed variables. The participants were presented with 3 sets of cards with 20 cards in each set. On each card, they were asked to assign a probability of infection on the middle day (test day) in the 3-wk profile. Depending on the set of cards, they were asked only to be concerned with the probability of infection with coagulase-negative staphylococci, Escherichia coli, or Staphylococcus aureus. These 3 organisms were chosen to represent a minor pathogen, a major environmental pathogen, and a major contagious pathogen, respectively. The assigned probabilities for each organism were cross-tabulated according to the number of times the organism of interest was isolated in the 3-wk period, how many colonies of the organism of interest were isolated on the test day, and the somatic cell count (≤ or >200,000 cells/mL). There was considerable variation in the assigned probabilities within each of the combinations of factors. The median, minimum, and maximum values of the assigned probabilities for each combination were computed. The combinations with a median probability >50% were considered intramammary infection-positive and included as a criterion in the consensus standard. This yielded 4 possible criteria, which were condensed to the following 2 by consensus at the 2008 Mastitis Research Workers' Conference in Toronto: 1) the organism of interest was isolated on the test day with at least 10 colonies (1,000 cfu/mL), and 2) the organism of interest was isolated at least twice in the 3-wk period. © 2010 American Dairy Science Association. Source

Elbers A.R.W.,Central Veterinary Institute | Loeffen W.L.A.,Central Veterinary Institute | Quak S.,Central Veterinary Institute | de Boer-Luijtze E.,Central Veterinary Institute | And 7 more authors.
Emerging Infectious Diseases

Infections with Schmallenberg virus (SBV) are associated with congenital malformations in ruminants. Because reporting of suspected cases only could underestimate the true rate of infection, we conducted a seroprevalence study in the Netherlands to detect past exposure to SBV among dairy cattle. A total of 1,123 serum samples collected from cattle during November 2011-January 2012 were tested for antibodies against SBV by using a virus neutralization test; seroprevalence was 72.5%. Seroprevalence was significantly higher in the central-eastern part of the Netherlands than in the northern and southern regions (p<0.001). In addition, high (70%-100%) within-herd seroprevalence was observed in 2 SBV-infected dairy herds and 2 SBV-infected sheep herds. No significant differences were found in age-specific prevalence of antibodies against SBV, which is an indication that SBV is newly arrived in the country. Source

Kester E.,Qdossier eCTDconsultancy | Holzhauer M.,GD Animal Health Service | Frankena K.,Wageningen University
Veterinary Journal

This article reviews the literature on hock lesions in dairy cattle, focusing in particular on their prevalence and associated clinical signs, as well as the scoring systems used to assess them and the data on risk factors. This analysis was limited to hock lesions where there was inflammation and damage of the skin and the subcutaneous tissue only without involvement of the joint. The presence of hock lesions, or tarsal peri-arthritis, is strongly related to time spent lying on abrasive surfaces, prolonged high local pressure or friction of the hock on hard surfaces, and collisions of the hock with cubicle fittings. Since hocks have almost no fatty tissue or muscles between the bones and skin, there is no protection against these types of trauma and skin damage occurs (resulting in hock lesions). The risk of these lesions becoming infected is strongly dependent on the hygiene of the lying area. The prevalence of hock lesions in dairy cows is generally reported as high (>50%). As hock lesions are often correlated with lameness, they are associated with economic losses and impaired welfare, as well as negative societal perception of the dairy sector. Alterations in cubicle characteristics, bedding material, pasture access and lameness prevention may all lower the prevalence of hock lesions; nevertheless, the actual relationship between housing design and other cow- and management-related risk factors on the occurrence of hock lesions appears to be complex and interrelated. © 2014 Elsevier Ltd. Source

Holzhauer M.,GD Animal Health Service | Brummelman B.,Oppers 112 | Frankena K.,Wageningen University | Lam T.J.G.M.,GD Animal Health Service
Veterinary Journal

To estimate the prevalence of claw disorders in youngstock and first parity heifers and to evaluate the effect of grazing on claw disorders, 10 Dutch dairy herds participated in a 2-year longitudinal study. Five herds were zero-grazed, while in the other five herds cows and youngstock had access to pasture during the summer. Twenty female calves <1. year of age and 20 females between 1 and 2. years of age were randomly selected on each farm, and were individually monitored at 3 monthly intervals for 2. years. Data from 366 animals with at least five observations were analysed using linear mixed models with a binomial error distribution. Independent variables were grazing, age, month of observation and previous occurrence of the disorder, while herd and animal were included as random effects. Of these 366 animals, 287 had calved once and 76 twice at the end of the study. Analytic results were obtained for digital dermatitis (DD), interdigital dermatitis/heel horn erosion (IDHE) and sole haemorrhages (SH), all of which had a prevalence of >15%. The prevalence of DD increased considerably around first calving on both the grazing and the zero-grazing farms. The prevalence of IDHE increased with age while SH prevalence showed a more fluctuating pattern. Digital dermatitis was less frequently observed in pastured animals than in permanently housed animals (OR = 0.12-0.64 depending on month of observation; P< 0.05), with the strongest effect being seen during the period when the herds which grazed cattle actually had animals at pasture (May to August). Grazing was also associated with lower levels of IDHE and SH, again particularly during the grazing season. © 2012 Elsevier Ltd. Source

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