Dairy Research Cluster 2 (DRC2)

Results

• Chitosan is a molecule derived from the shell structure of crustaceans and shellfish and significantly increased the number of immune cells in the udder and levels of compounds associated with involution, while stimulating local immune response during dry-off period.
• The chitosan hydrogel function is not affected by the teat sealant when used together. In addition, the use of a chitosan-based hydrogel in combination with teat sealant may combine the benefits of stimulating the immune response while generating a physical barrier between the teat and outside environment.
• A hydrogel made up of chitosan can be used in combination with existing mastitis-preventing tools during dry off. This method could potentially decrease prophylactic antibiotics while decreasing the risk of developing new mastitis infections during the dry-off period.

Results

• With selectve dry cow therapy, infected cows may be treated with an antimicrobial only or with a combina-
  tion of antimicrobial and a teat sealant at the end of lactation, while uninfected cows receive only a teat
  sealant.
•  Introducing such a treatment strategy will, of course, generate new costs, mainly costs for diagnostic tests
  and extra labor for sampling and conducting the test (for on-farm tests). On the other hand, less antimicrobials are used and costs for drugs and labor for administering drugs are saved.
• Selective dry cow therapy is one potential strategy for achieving a more judicious use of antimicrobials.

Results

• Important risk factors for CM recurrence were identified, these included: parity (i.e. higher risk in older cows), a higher milk production, pathogen species involved in the preceding case, and whether a bacteriological cure was observed following the preceding case.
• The most important effects of recurrent CM were identified: the milk yield reduction following a recurrent CM case, which was reported to be similar to that of the first CM case, and the increased risk of culling and mortality, which were reported to surpass those of first CM cases.

Results 

S. aureus phenotypic and genotypic characteristics were evaluated to predict the duration of IMI. We found that some characteristics of the pathogen including determination of the spa type genes helps to predict duration of infection and the clinical or subclinical outcome of S. aureus IMIs. However, the bovine host genetic and immune status, and the influence of the environment and of management practices are also factors that could help predicting duration of infection. 

Results

• Research-validated spectroscopy-based diagnostic methods improved the species-specificity and accuracy of pathogen diagnosis.
• Sixteen custom reference spectra which covered 10 different species of CNS were developed to enhance the performance of MALDI-ToF MS for CNS species identification. These custom reference spectra are being made available for use by both diagnostic laboratories and researchers that are adopting MALDI-ToF MS for bovine mastitis microbial identification and are improving the accuracy of mastitis diagnosis around the world.
• According to the results of analysis on 5,827 isolates, Staphylococcus chromogenesrepresented 48.2% of the CNS, followed by S. simulans(16.7%), S. xylosus(11.2%), S. haemolyticus(7.8%), and S. epidermidis(4.0%).

Results

To this day, several intriguing molecules have been isolated and shown to hinder biofilm formation. Their exact nature and mechanism of action remains to be identified.

Results

• New knowledge on efficacy of various molecules of a new drug target for S. aureus were acquired.
• The last antimicrobial molecule with a new mode of action was commercialized in the eighties. This is, therefore, a very important discovery that could have a tremendous impact in veterinary and, perhaps, human medicine. The initial discovery of this molecule was voted one of the 10 discoveries of the year in 2010 by the ‘’Quebec Science’’ magazine. We were able to further refine the molecule to obtain a more stable molecule that could be commercially marketed.

Results

• Bedding management can have a profound impact on cow hygiene and bacterial concentrations in the bedding substrates, which in turn may affect mastitis risk. The most important factors affecting this relationship include the addition of new bedding, how often the stalls are scraped, housing type, milking system, and herd size. We observed that, on commercial farms, cows prefer to lie down in cleaner and more comfortable environments.
• Finally, cows with low Body Condition, which were at greater risk of having high SCC, were also the highest producing, had poorest lower leg hygiene, and spent the most time standing.

Results

• Selective dry-cow treatment has been shown to reduce the amount of antimicrobials used, without being the method most correlated with antimicrobial resistance.
• Systemic use of antimicrobials is associated with a higher prevalence of resistance, compared to local antimicrobial administration.
• Limiting the use of antimicrobials, as well as their judicious use will contribute to slowing down the emergence of antimicrobial resistance.

Results

The cost of mastitis in a herd represent $660 per cow

Half of these costs are associated with subclinical mastitis