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UBC Theses and Dissertations

Feasibility and preliminary safety of nitric oxide releasing solution as a treatment for bovine mastitis Martins, James Anthony Vieira


The risk of antibiotic resistance in bovine mastitis, one of the most widespread and significant diseases affecting dairy farming, both in terms of animal welfare and economic cost has become a concern, leading to a push for alternative treatments. Nitric oxide releasing solution (NORS) is a liquid formulation that releases nitric oxide, a broad-spectrum antimicrobial, single electron nitroxide radical. This solution was investigated as a potential antimicrobial treatment for bovine mastitis. Three main experiments were performed: 1) the development of NORS so that it is compatible in milk; 2) the antimicrobial effect of NORS in milk with in-vitro and ex-vivo samples; and 3) the consequences of administering NORS to healthy milking cattle using a dose-escalating in-vivo study. NORS was successfully created to be compatible in milk without causing curdling while continuing to release nitric oxide. Additionally, the formula lowered bacterial concentration in all infected samples, in a time and milk-diluted dependant fashion. In the preliminary safety study, metabolite concentrations were measured in their blood for methaemoglobin and nitrite; also, milk nitrite concentration was analyzed to determine a potential clearance time for the drug. Separately, somatic cell count was determined in order to ascertain possible mammary gland inflammation following NORS treatment. Blood methemoglobin concentrations following treatment were all within the normal range for cattle. However, blood and milk nitrite concentrations increased initially but, during the next 24 hours, returned to normal range, as did the somatic cell count after one week, without any clinical signs of mammary gland inflammation. NORS, if shown to be effective, could be an alternative treatment for mastitis with a shorter clearance time.

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