Veterinary Science - Theses

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Start date: 2010 × End date: 2019 × Type: Masters Research thesis × Author: Appleyard, Kay ×

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    Formulation and delivery of a novel naturally derived mastitis treatment
    Appleyard, Kay ( 2012)
    Mastitis in dairy cows is an inflammation of the mammary gland which is prevalent at between 0.9% and 21.4% of early lactation cows in New Zealand pasture based herds (McDougall, 1999). Clinical forms of the disease are commonly treated with intramammary antibiotics even though in vivo many antibiotics have poor efficacy. There will always be a need for new and effective treatments as this disease is widely quoted as being the most costly diseases in the dairy industry. Quantec is developing a natural mastitis treatment (NMT) which is based on the natural defence mechanisms of the cow. During a typical mammary gland infection the concentrations of bioactive peptides and proteins in the milk increase. One of the most abundant is lactoperoxidase (Lp) whose concentration is up regulated during bacterial infection even though the levels of its substrates remain low. It was proposed that increasing the concentration or activity of this endogenous antibacterial system may be the key to a natural mastitis treatment. This project aimed to assess the optimal formulation for NMT using various in vitro assay methods. It was found that endogenous Lp could be utilised in a natural treatment with simply the addition of Lp substrates as a mastitis treatment. Both iodide and a hydrogen peroxide/oxygen generating system, allowed NMT antibacterial activity against common mastitis pathogens in vitro. The NMT formulation was then tested in two trials for safety in vivo. All observations of cow health and comfort were within the normal range. There was some evidence of a transient adverse treatment effect of clots in the NMT treated quarters, but these clots were predominately in the foremilk and disappeared after treatment stopped. Milk samples were submitted for product safety analysis which indicated that NMT treated quarters were free of excess iodine and inhibitory substances. The final stage of the project examined the potential for a suitable delivery system which would ensure the stability of NMT and the easy intramammary administration in a future commercial product.