Each research project is conducted by a team of researchers, often working in several institutions. Depending on the size of the project, one or more graduate students – masters, doctorate or post-doctorate – are associated with each project.

 

Briefly, the CBMRN research projects are as follows:

 

Principal investigator: Ian Dohoo, University of Prince Edward Island

 

Summary: The importance of mastitis on a dairy farm is directly related to number of new udder infections that occur in the herd. What are the factors and/or management practices that influence the development of these new infections? What are their characteristics? Can they be rapidly identified with the currently available tools in order to prevent them?

 

Principal investigator: François Malouin, Université de Sherbrooke

 

Summary: All strains of S. aureus are not identical and their potential for infection also varies. The identification and characterization of virulence factors in each strain could lead to the development of new vaccines, treatments and diagnostic tools.

 

Principal investigator: Bonnie Mallard, University of Guelph

 

Summary: Thanks to a stronger immune system, some cows have better resistance to mastitis than others. What are the genes and proteins involved in this higher resistance? Their identification could facilitate genetic selection of cows with better health and requiring fewer therapeutic treatments.

 

Principal investigator: Xin Zhao, McGill University

 

Summary: When mastitis caused by coliform occurs, toxins are released by the bacteria. In reaction, the mammary gland’s white blood cells produce a protein called CD14, which attaches to these toxins and neutralizes their toxic effect. If cows could naturally secrete a higher concentration of CD14 in their milk, would they be more resistant to severe clinical mastitis caused by E. coli?

 

Principal investigator: Brian Talbot, Université de Sherbrooke

 

Summary: Numerous vaccines have been developed to protect cows from S. aureus mastitis, but none of them have shown great success. By improving the composition of the vaccine through the addition of certain proteins or bacterial DNA fragments, could a more effective vaccine be produced?

 

Principal investigator: Xin Zhao, McGill University

 

Summary: There are vaccines to protect cows against coliform mastitis but they require several injections. The technique of microencapsulation of the vaccine antigen could greatly improve the situation.

 

Principal investigator: Andrew Potter, Vaccine and Infectious Disease Organization, University of Saskatchewan

 

Summary: The effectiveness of a vaccine is not only determined by the use of the right antigen but also the proper adjuvant and its administration method. Improved products and techniques, as well as a better understanding of the mammary gland’s immune system, could aid in the development of an effective vaccine against S. aureus mastitis.

 

Principal investigator: Greg Keefe, University of Prince Edward Island

 

Summary: Could the development of a rapid identification system for mastitis bacteria at the farm level help to reduce the use of antibiotics on dairy farms? Could it also help reduce the various costs and losses due to mastitis?

 

Principal investigator: Herman Barkema, University of Calgary

 

Summary: Do antibiotics given to treat mastitis cause the development of resistance in the bacteria responsible for mastitis? An audit of the veterinary products used by farms of the National Cohort of Dairy Farms combined with the association between the treatments given and the infections observed should answer this question.

 

Principal investigator: Daniel Scholl, Université de Montréal

 

Summary: Polymerase chain reaction-based amplification, better known by the acronym PCR, is a rapid laboratory technique that offers a promising method to diagnose mastitis. However, little is known about its effectiveness in the field and this must be validated.

 

Principal investigator: Trevor DeVries, University of Guelph

 

Summary: Automatic milking systems are new on dairy farms. Can changes in feeding management associated with the use of this equipment have an influence on cow behaviour in the barn and at the feed bunk, as well as on udder health?

 

Principal investigator: François Malouin, Université de Sherbrooke

 

Summary: The discovery of a gene particular to the bacteria S. aureus has led to the development of a new antibiotic. Preliminary tests have shown promising results, even on staphylococci other than S. aureus!

 

Principal investigator: Ken Leslie, University of Guelph

 

Summary: Monitoring of behaviour is a tool that is used more and more to identify health and well-being problems in dairy cows. When mastitis occurs, does a cow change its behaviour? What signs does it show?

 

Principal investigator: Ian Dohoo, University of Prince Edward Island

 

Summary: Since the creation of CBMRN, many projects have generated a significant amount of data that are stored in various computer databases. The objective of this project is to optimise the access, query and use of the data generated by CBMRN research, both now and in the future.

 

Principal investigator: Marie-Ève Paradis and Serge Messier, Université de Montréal

 

Summary: Species identification of CNS is not done routinely since it involves exhaustive and costly laboratory procedures. In one CBMRN project, DNA analysis was employed to speciate several CNS isolates. These results will now be used to determine if gas chromatography, a cheaper and simpler technique, could be just as effective as DNA analysis in correctly identifying these bacteria.

 

 

The following projects use data generated by the Network’s research activities, but are not financed by the CBMRN.

 

Principal investigator: Ian Dohoo, University of Prince Edward Island

 

Summary: Ostertagia ostertagi is a gastro-intestinal parasite that can have a severe impact on the performance of dairy cows. That being the case, there is a test called ELISA which can be used to estimate the degree of parasitism in cows. Data from the National Cohort of Dairy Farms could help in determining guidelines for the use of this test.

 

Principal investigator: John Middleton, University of Missouri

 

Summary: Recent research suggests that various species of coagulase-negative staphylococci (CNS) induce different levels of udder inflammation and that such infections might persist over long periods. What are the facts? Which strains are the most virulent?

 

Principal investigator: J McClure, University of Prince Edward Island

 

Summary: These two bacteria can cause serious infections in humans since certain strains can be resistant to antibiotics. As there is little information on the presence of these bacteria in Canadian dairy cattle, this project aims to characterize and determine the levels of MRSA and ESBL E. coli in cases of mastitis identified in cows from the National Cohort of Dairy Farms.

 

Principal investigator: Trevor DeVries, University of Guelph

 

Summary: The distribution of fresh feed encourages cows to remain standing following milking. This practice could be beneficial to udder health. But is it really?

 

Principal investigator: Julie-Hélène Fairbrother and Serge Messier, Université de Montréal

 

Summary: Usually, mastitis caused by E. coli is of short duration. However, it seems that some infections can become persistent. What are the factors that differentiate strains that cause short-lived infections from those that cause persistent infections?

The nine research projects funded by the Dairy Research Cluster of the Dairy Farmers of Canada revolve around three major themes:

4. Protective Effect of Vaccination Using Staphylococcus aureus Antigens that are only Expressed during Bovine Intramammary Infections: Challenge in Dairy Cows
Principal investogator: François Malouin, Univeristé de Sherbrooke

In brief: The team of François Malouin used two proteins they discovered to develop a new vaccine. A clinical study on 20 cows will be conducted to verify protection afforded by the vaccine against experimental infection with Staph. aureus.
To find out more…

 

Principal investigator: Pierre Lacasse, Agriculture and Agri-Food Canada

 

In brief: High-yielding cows are dried off when still producing significant quantities of milk. Milk accumulation and leakage allows micro-organisms to gain entry into the mammary gland and, accordingly, the chance of acquiring a new infection during the dry period increase rapidly with level of milk production at dry-off. It is of critical importance, therefore, to develop strategies that reduce milk production before drying-off.
To find out more…

 

 

Principal investigator: Trevor DeVries, University of Guelph

 

In brief: In free stalls, the longer cows remain standing, the more they walk and risk getting dirty, especially if the floors are dirty. In this project, researchers will try to determine if there are connections between time spent standing after milking and stable and cow cleanliness, cow lameness, and rank in hierarchy.
To find out more…

 

Principal investigator: Greg Keefe, University of Prince Edward Island

 

In brief: In Canada, recent data shows that farm milk tanks and store-shelf milk contain moderately high iodine levels. High levels of iodine in milk are a concern, especially in milk intended for young children and infant formulas. The aim of this project is to identify sources of and reasons for the variability of the iodine content in tanks and to target the best dissemination methods to convince farmers to adopt new practices.
To find out more…

8. The Effect of Different Dry-Off Management Procedures on Cow Behaviour and Indicators of Intramammary Infections
Principal investigator: Ken Leslie, University of Guelph

In brief: Currently, there is limited information about drying-off management. Practices include the reduction in feed intake, reduction of milking frequency, the abrupt cessation of milking, and even restriction of water intake. In order to better understand the health and welfare impacts of various dry-off methods, cows will be assigned to specific dry-off methods, and then monitored for behaviour and health changes over time.
To find out more…