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Canadian Bovine Mastitis Research Network

Our Research  I  Our Results 

High and Low Resistance to Mastitis-Causing Bacteria

The immune system provides protection against infectious diseases, and it is greatly influenced by genetics. Cows with stronger immune systems have greater mastitis resistance and require less treatment. Armed with this knowledge, Dr. Bonnie Mallard, an immunogenetics researcher at the University of Guelph (U of G), extracted DNA from nearly 700 cows from 58 herds belonging to the CBMRN’s national cohort of dairy farms, as well as from 130 cows from U of G’s herd. After the genes were examined, the animals were categorized as having high, medium or low disease resistance. Dr. Mallard also discovered a number of genes and proteins associated with disease resistance and certain production parameters such as somatic cell count, persistence in milk, and milk and protein yield. At the same time, the genotypes of 500 Holstein bulls, 84 Jersey bulls and 50 Guernsey bulls were determined in order to verify their association with various health and production parameters. Once completed, the data analysis will help:
  • Identify disease- and mastitis-resistant cows in commercial herds;
  • Develop an estimated breeding value (EBV) for better herd health, and thereby make it possible to select resistant cows;
  • Discover the genes and proteins associated with production parameters;
  • Support the development of effective vaccines; and
  • Detect mastitis through the presence of certain proteins found in milk.

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