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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Research Project #432018

Research Project: Non-antibiotic Approaches to Control Mastitis

Location: Ruminant Diseases and Immunology Research

Project Number: 5030-32000-115-00-D
Project Type: In-House Appropriated

Start Date: Oct 1, 2016
End Date: Sep 30, 2021

Objective:
Objective 1. Develop non-antibiotic interventions to prevent and control mastitis, including developing and testing non-antibiotic immune modulators to prevent periparturient dairy cows from developing mastitis, and developing and testing dry cow therapy(s) that use natural, non-antibiotic strategies that accelerate the development of the cow’s natural antimicrobial dry secretions to prevent mastitis infections in subsequent lactations. Sub-objective 1.1: Develop and test non-antibiotic immune modulators to prevent periparturient dairy cows from developing mastitis. Sub-objective 1.2: Develop and test a dry cow therapy that uses natural, non-antibiotic strategies that accelerates the development of the cow’s natural antimicrobial dry secretions to prevent mastitis infections in the subsequent lactation. Objective 2: Determine the interactions between mastitis-causing pathogens and the host innate immune mechanisms in the mammary gland, starting with determining the host-pathogen interaction associated with Escherichia coli strains linked to persistent mammary gland infections, and determining the host pathogen interaction associated with Staphylococcus aureus persistent infections. Sub-objective 2.1: Determine the host-pathogen interaction associated with Escherichia coli strains linked to persistent mammary gland infections. Sub-objective 2.2: Determine the host pathogen interaction associated with Staphylococcus aureus persistent infections.

Approach:
Mastitis is the most prevalent infectious disease in dairy herds and the most costly disease for dairy producers. Older cost estimates for mastitis are in the neighborhood of $2 billion per year for producers. Newer estimates of the economic impact of mastitis on the dairy industry calculate the cost of a single case of clinical mastitis to be approximately $586 due to mammary gland damage, loss of milk production, discarded milk, and the costs of treatment and labor. Antibiotics are the mainstay for mastitis treatment and control and dairy cattle with mastitis receive more antibiotic therapy for its prevention and treatment than for all other dairy cattle diseases combined. Valid concerns by consumers regarding antibiotic usage need to be addressed by research on non-antibiotic alternatives. To achieve the goal of reducing the use of antibiotics we need a better understanding of how the immune system is failing to completely eliminate mastitis infections. Progress towards this goal can be achieved in two ways. First, is to manipulate the host in a way that optimizes the immune response to pathogens. Second, to gain a better understanding of the various mechanisms that allow bacteria to evade the host’s immune system. To achieve the goal of manipulating the immune system to optimize its response to pathogens we plan to develop non-antibiotic interventions to prevent and control mastitis. This approach would include developing and testing non-antibiotic immune modulators to prevent periparturient dairy cows from developing mastitis, and developing and testing dry cow therapy(s) that use natural, non-antibiotic strategies that accelerate the development of the cow’s natural antimicrobial dry secretions to prevent mastitis infections in subsequent lactations. To achieve the second goal of understanding the mechanisms of how bacteria can evade the immune system by studying the mechanisms that allow for persistent mammary gland infections. Knowledge of how bacteria escape the immune system and establish persistent infections is a necessary precursor to any therapeutic for these persistent infections. Successful manipulation of the host immune system that targets the pathogen at the site of the infection holds the potential of clearing an infection without the use of antibiotics.